METHODOLOGICAL DEVELOPMENT ON DISCIPLINE

"TECHNOLOGY OF MECHANICAL ENGINEERING"

Compiled by teacher: Fazlova Z.M.

Introduction

Intensification of production, successful implementation of the latest equipment and technology require improvement of the organization of labor, production and management, which is only possible on the basis of technical regulation.

Labor rationing is the establishment of a measure of labor costs, i.e. the total socially necessary expenditure of working time for the production of products of a certain consumer value for a given period of production and technical conditions. The most important tasks of labor standardization are the consistent improvement of the organization of labor and production, reducing the labor intensity of products, and maintaining economically sound relationships between the growth of labor productivity and wages. Labor standardization should contribute to the active implementation of advanced experience, achievements of science and technology.

The methodological development “Rationing of work performed on machines with a state of emergency” allows you to acquire the necessary skills in establishing a reasonable standard of time for performing a technological operation. It outlines the theoretical basis for establishing time standards for a CNC technological operation. The appendix contains basic mechanical engineering labor standards.

RATING OF WORKS, PERFORMED ON CNC MACHINES

The main way to automate the processes of mechanical processing of parts for small-scale and individual production is the use of computer numerical control (CNC) machines. CNC machines are semi-automatic or automatic, all moving parts of which perform both working and auxiliary movements automatically according to a pre-established program. It includes technological commands and numerical values ​​of the movements of the working parts of the machine.

Resetting a CNC machine, including changing the program, requires little time, so these machines are most suitable for automating small-scale production.

Standard time for performing operations on CNC machines N BP consists of the norm of preparatory and final time T pz and the norm of piece time T pcs:

(1)

T pcs = (T c.a + T in K TV)
(2)

Where n - number of parts in the manufactured batch;

T c.a - cycle time of automatic operation of the machine according to the program, min;

T in - auxiliary time, min;

K TV - correction factor for the time of performing manual auxiliary work, depending on the batch of parts being processed;

a those, a org, and exc - time for technological and organizational maintenance of the workplace, for rest and personal needs during single-machine service, % of operational time.

The cycle time of automatic operation of the machine according to the program is calculated using the formula

T c.a = T o + T mv (3)

where T o is the main (technological) time for processing one part, min:

T o = (4)

L i is the length of the path traversed by a tool or part in the feed direction when processing a technological section (taking into account plunge-in and overtravel);

s m - minute feed in a given technological section, mm/min;

T mv - machine-auxiliary time according to the program (for the supply and removal of a part or tool from the starting points to the processing zones, setting the tool to size, changing the tool, changing the value and direction of feed, time of technological pauses (stops), etc.) , min.

Auxiliary time is determined as follows:

T in = T in.u + T in.op + T in.meas (5)

where Tv.u is the time for installing and removing the part, min;

T v.op - auxiliary time associated with the operation (not included in the control program), min;

T in. change - auxiliary non-overlapping time for measurement, min.

Time standards for installing and removing parts are determined by types of devices depending on the types of machines and provide the most common methods of installation, alignment and fastening of parts in universal and special clamps and devices.

Additional time associated with surgery subdivided:

a) for auxiliary time associated with the operation that was not included during the cycle of automatic operation of the machine according to the program;

b) machine-auxiliary time associated with the transition, included in the program, relating to the automatic auxiliary operation of the machine.

The required dimensions of parts processed on CNC machines are ensured by the design of the machine or cutting tool and the accuracy of their adjustment. Due to this time for control measurements should be included in the piece time standard only if it is provided for by the technological process, and it cannot be covered by the cycle time of the automatic operation of the machine according to the program.

Time for workplace maintenance determined by standards and standard sizes of equipment, taking into account single-machine and multi-machine maintenance as a percentage of operational time.

Time for rest and personal needs when servicing one machine by one worker, it is not allocated separately and is taken into account in the time for servicing the workplace.

Standards for preparatory and final time are designed for setting up CNC machines for processing parts using embedded control programs and do not include additional programming actions directly at the workplace (except for machines equipped with operational program control systems).

Norms of piece time for dimensional adjustment of cutting tools outside the machine are intended to standardize work on setting up cutting tools for CNC machines, which is carried out by toolmakers outside the machine in a specially equipped room using special instruments.

TYPICAL PROBLEM WITH SOLUTION

Initial data: part - shaft (Fig. 1); material - steel 30G; precision surface treatment 1,2,3 - IT10; surface roughness 1, 2 Ra5; 3 - Ra10.

Blank: production method - stamping (usual accuracy IT 16); surface condition - with crust; weight 4.5 kg; allowance for surface treatment: 1 - 6 mm; 2 - 4 mm; 3 - 5 mm.

Machine: model 16K20FZ. Passport details:

spindle speed P(rpm): 10; 18; 25; 35.5; 50; 71; 100; 140; 180; 200; 250; 280; 355; 500; 560; 630; 710; 800; 1000; 1400; 2000;

feed range s m (mm/min)

along the coordinate axis X- 0,05...2800;

along the coordinate axis z - 0,1...5600;

the maximum force allowed by the longitudinal feed mechanism is 8000 N, by the transverse feed mechanism - 3600 N;

main movement drive power - 11 kW;

the range of regulation of the rotation speed of a constant power electric motor is 1500...4500 rpm.

Operation: basing in the centers, with the leash installed on the surface.

1. Selection of processing stages.

The necessary processing stages are determined. To obtain the dimensions of a part corresponding to quality 10, from a workpiece of quality 16, it is necessary to carry out processing in three stages: rough, semi-finish and finishing.

2. Selecting cutting depth.

The minimum required cutting depth for the semi-finishing and finishing stages of processing is determined (Appendix 5).

During the finishing stage of surface treatment 1, the diameter of which corresponds to the size range 8...30 mm, the recommended cutting depth t = 0.6 mm; for surface 2, the diameter of which corresponds to the size range 30...50 mm, t= 0.7 mm; for surface 3, the diameter of which corresponds to the size range 50...80 mm, t = 0.8 mm.

Similarly, at the semi-finish stage of surface treatment / recommended t = 1.0 mm; for surface 2 - t - 1.3 mm; for surface 3 - t = 1.5 mm.

Figure 1 - Sketch of the shaft and tool path

The depth of cut for the roughing stage of processing is determined based on the total allowance for processing and the sum of the cutting depths of the finishing and semi-finishing stages of processing: for surface 1 - t = 4.4 mm; for surface 2 - t = 2.0 mm; for surface 3 - t = 2.7 mm. The selected values ​​are entered into table 1.

Table 1 - Determination of cutting mode

3. Selecting a tool.

The 16K20FZ machine uses cutters with a holder section of 25 x 25 mm, plate thickness 6.4 mm.

Based on the processing conditions, a triangular plate shape with an apex angle is adopted
° from hard alloy T15K6 for roughing and semi-finishing stages of processing and T30K4 - for finishing stage (Appendix 3).

Standard durability period: T = 30 min.

4. Feed selection.

4.1. For the roughing stage of processing, the feed is selected according to adj. 3.

For surface 1 when turning parts with a diameter of up to 50 mm and depth of cut t = 4.4 mm recommended feed s from =0.35 mm/rev. For surfaces 2 and 3, respectively, feed s from =0.45 mm/rev is recommended. and s from =0.73 mm/rev.

According to adj. 3 correction factors for feed are determined depending on the tool material TO s and = 1.1 and method of plate fastening K sp = 1,0.

4.2. For the semi-finishing stage of processing, feed values ​​are determined according to adj. 3 in the same way: for surfaces 1 And 2 s from =0.27 mm/rev., surfaces 3 s from =0.49 mm/rev.

Correction factors for feed depending on tool material K s and = 1.1, method of platinum fastening K sp = 1.0.

According to adj. 3 we determine the correction factors for the feed of the roughing and semi-finishing stages of processing for changed processing conditions: depending on the cross-section of the cutter holder TO s d = 1.0; cutting part strength K s l = 1.05; mechanical properties of the processed material TO s and = 1.0; workpiece installation diagrams TO at =0.90; workpiece surface condition K s p =0.85; geometric parameters of the cutter K sp =0.95; machine rigidity K sj = 1,0.

The final feed rate of the roughing stage of processing is determined by:

For surface 1

s pr1 =0.35·1.1·1.0·1.0·1.05·1.0·0.9·0.85·0.95·1.0 = 0.29 mm/rev. ;

For surface 2

s pr2 =0.45·1.1·1.0·1.0·1.05·1.0·0.9·0.85·0.95·1.0 = 0.38 mm/rev. ;

For surface 3

s pr3 = 0.73 1.1 1.0 1.0 1.05 1.0 0.9 0.85 0.95 1.0 = 0.61 mm/rev.

The feed rate of the semi-finishing stage of processing is calculated similarly:

for surfaces 1 And 2 s pr1.2 = 0.23 mm/rev.;

for surface 3 s pr3 = 0.41 mm/rev.

for surface 1 s from1 =0.14 mm/rev.,

for surface 2 s from2 =0.12 mm/rev.,

for surface 3 s from3 =0.22 mm/rev.

According to adj. 3, correction factors are determined for the feed of the finishing stage of processing for changed conditions: depending on the mechanical properties of the material being processed TO s = 1.0; workpiece installation diagrams TO at=0.9; cutter tip radius K st = 1.0; quality of precision of the workpiece l 4 = 1.0. The final feed rate of the finishing stage of processing is determined by:

for surface 1 s pr = 0.14 1.0 0.9 1.0 1.0 = 0.13 mm/rev.,

for surface 2 s p p = 0.12 1.0 0.9 1.0 1.0 = 0.11 mm/rev.,

For surface 3 s p = 0.22 1.0 0.9 1.0 1.0 = 0.20 mm/rev

The calculated feed values ​​for the finishing stage of surface treatment are entered in the table. 1.

5. Choice of cutting speed.

At the roughing stage of machining alloy steel with skin with depth of cut t = 4.4 mm and feed spr = 0.29 mm/rev. cutting speed for surface 1 V t = 149 m/min; with cutting depth t = 2.0 mm and feed s p p = 0.38 mm/rev. cutting speed for surface 2 V t = 159 m/min; with cutting depth t = 2.7 mm and feed spr = 0.61 mm/rev. cutting speed for surface 3 V t = 136 m/min.

According to adj. 8, 9, correction factors are selected for the roughing stage of processing depending on the tool material: for the surface 1 TO in = 1.0, for surfaces 2 and 3 TO in =0,95.

The final cutting speed for the roughing stage of processing will be:

for surface 1 V 1 = 149·0.85= 127 m/min;

for surface 2 V 2 = 159·0.81 = 129 m/min;

for surface 3 V 3 = 136·0.98 = 133 m/min.

5.2. At the semi-finishing stage of machining alloy steel without skin with depth of cut t up to 3.0 mm and feed s p p = 0.23 mm/rev. cutting speed for surfaces 1 And 2 - V T = 228m/min; with cutting depth t = 1.5 mm and feed s pr =0.41mm/rev. cutting speed for surface 3 - V t = 185 m/min.

Correction factor for the semi-finishing stage of processing depending on the tool material K v = 0,95.

According to adj. 8, 9, the remaining correction factors for cutting speed are selected during the roughing and semi-finishing stages of processing for the changed conditions:

depending on the machinability group of the material TO v With = 0,9;

type of processing K vo = 1,0;

machine rigidity K vo = 1,0;

mechanical properties of the processed material TO v m = 1.0; geometric parameters of the cutter:

for surfaces 1 And 2 K v f =0.95, for surface 3 K v f = 1.15; durability period of the cutting part TO v T = 1,0;

availability of cooling TO v and = 1,0.

The final cutting speed during the roughing stage of processing is determined by:

for surface 1 And 2 V 1,2 = 228 · 0.81 = 185 m/min;

for surface 3 V 3 = 185 · 0.98 = 181 m/min.

5.3. The cutting speed for the finishing stage of processing is determined by adj. 8, 9:

at t = 0.6 mm and s p p = 0.13 mm/rev. for surface 1 V T =380 m/min;

at t = 0.7 mm and s p p = 0.11 mm/rev. for surface 2 V T =327 m/min;

at t = 0.8 mm and s p p = 0.2 mm/rev. V T =300 m/min.

According to adj. 8, 9 the correction factor for the cutting speed is determined for the finishing stage of processing depending on the tool material; K V n =0.8. Correction factors for the finishing stage are numerically the same as those for the roughing and semi-finishing stages.

General correction factor for cutting speed during the finishing stage of processing: K v = 0.68 - for surfaces 1 And 2; K v = 0.80 - for surface 3.

The final cutting speed at the finishing stage:

for surface 1 V 1 = 380·0.68 = 258 m/min;

for surface 2 V 2 = 327·0.68 = 222 m/min;

for surface 3 V 3 = 300·0.80 = 240 m/min.

The tabulated and corrected cutting speed values ​​are entered into the table. 1.

5.4. Spindle speed according to the formula

During the roughing stage of surface treatment 1

n = =1263 rpm

The rotation speed available on the machine is accepted, n f = = 1000 rpm. Then the actual cutting speed is determined by the formula:

V f = = 97.4 m/min.

Calculation of the spindle rotation speed, its adjustment according to the machine passport and calculation of the actual cutting speed for other surfaces and processing stages are carried out similarly. The calculation results are summarized in table. 1.

Since the 16K20FZ machine is equipped with an automatic gearbox, the accepted spindle speed values ​​are set directly in the control program. If the machine used has manual switching of the spindle rotation speed, the control program must provide technological stops for switching or set the lowest calculated rotation speed for all surfaces and processing stages.

5.5. After calculating the actual cutting speed for the finishing stage of machining, the feed is adjusted depending on the roughness of the machined surface.

According to adj. 8, 9 to obtain roughness no more Ra5 When processing structural steel with a cutting speed Vf = 100 m/min with a cutter with a tip radius r in = 1.0 mm, a feed s of = 0.47 mm/rev is recommended.

According to adj. 8, 9, correction factors for feed and machined surface roughness are determined for changed conditions: depending on:

mechanical properties of the processed material K s =1.0;

instrumental material K s u = 1.0;

type of processing K s o =1.0;

presence of cooling K s w =1.0.

Finally, the maximum permissible roughness feed for the finishing stage of processing surfaces 1 and 2 is determined by the formula

s o =0.47·1.0·1.0·1.0·1.0=0.47 mm/rev.

The feeds for the finishing stage of processing surfaces 1 and 2, calculated above, do not exceed this value.

None of the calculated values ​​exceeds the drive power of the main movement of the machine. Consequently, the established cutting power mode is feasible (calculation is not given).

6. Determination of minute feed.

Minute feed according to the formula

s m = n f s o

During the roughing stage of processing for surface 1

s m = 1000 · 0.28 = 280 mm/min.

The minute feed values ​​for other surfaces and processing stages are calculated similarly and are plotted in the table. 1.

7. Determining the automatic operation time of the machine program.

Time of automatic operation of the machine according to the general program.

For the I6VT2OFZ machine tool, the turret head fixation time Tif = 2 s and the turret head rotation time by one position T ip = 1.

The calculation results are given in table. 2.

8. Determination of the norm of piece time.

8.1. The rate of piece time is determined by formula (2)

8.2. Auxiliary time consists of components, the choice of which is carried out according to the 1st part of the standards (formula (5)). Auxiliary time for installation and removal of the part Тв.у = 0.37 min (Appendix 12).

Auxiliary time associated with the operation, Tv.op, contains the time for turning on and off the machine, for checking the return of the tool to a given point after processing, for installing and removing the shield that protects against splashing with emulsion (Appendix 12, 13):

T v.op = 0.15+0.03=0.15 min.

Auxiliary time and control measurements contain time for two measurements with a one-sided limit bracket, four measurements with a caliper and one measurement with a simple shaped template (Appendix 18):

T in.from =(0.045+0.05)+(0.11+0.13+0.18+0.21)+0.13=0.855 min.

8.3. The time for automatic operation of the machine according to the program is calculated for each section of the tool trajectory and is summarized in table. 2.

Table 2 – Time of automatic operation of the machine according to the program

Continuation of table 2

8.4. The final cycle time of the automatic operation of the machine according to the program

T c.a = 2.743 + 0.645 = 3.39 min.

8.5. Total auxiliary time

B =0.37+0.18+0.855 = 1.405 min.

8.6. Time for organizational and technical maintenance of the workplace, rest and personal needs is 8% of operational time (Appendix 16).

8.7. The final rate of piece time:

T PC = (3.39+ 1.405) (1+0.08) = 5.18 min.

9. Preparatory and final time.

The preparatory and final time is determined by the formula

T pz = T pz1 + T pz2 + T pz3 + T p.obra.

Time for organizational preparation: T pz1 = 13 min,

time to set up a machine, device, numerical control device

T pz2 = 4.0 + 1.2 +0.4+0.8+0.8 + 1.0 + 1.2 + 1.2 + 2.5+0.3 =13.4 min;

time for trial processing of the part

T arr = 2.2 + 0.945 = 3.145 min.

General preparatory and final time

T pz = 13 + 13.4 + 3.145 = 29.545 min.

10. Parts Lot Size

n= N/S,

where S is the number of launches per year.

For medium series production S = 12 therefore

n = 5000/12=417.

11. Piece-calculation time

T pcs.k = T PC + T pz / n= 5.18+29.545/417 = 5.25 min.

When developing a technological process for processing parts and control programs for CNC machines, one of the main criteria for assessing the perfection of the selected process or its optimization is the standard of time spent on processing a part or a batch of parts. It is also the basis for determining the salary of a machine operator, calculating the equipment load factor and determining its productivity.

The estimated time limit (min) for processing one part (labor intensity) is determined from well-known formulas:

piece time T piece = T o + T m.v + T v.u + T obs,

piece-calculation time

The total value of the operation time with all movements can be conventionally called the tape time T l = T o + T m.v,

where T o is the total technological time for the entire transition operation, min; T m.v - element-by-element sum of machine auxiliary time for processing a given surface (approaches, outlets, switching, turns, tool changes, etc.), taken from the machine passport depending on its technical data and dimensions, min.

The values ​​of these two components of the processing time norm are determined by the technologist-programmer when developing a control program recorded on punched tape.

The value of T l is almost easily checked when the machine is running using a stopwatch as the time from the start of processing in the automatic mode of starting the belt until the end of processing the part according to the program.

Thus, we obtain: operational time T op = T l + T v.u;

piece time T piece = T l + T v.u + T obs,

where Tv.u is the time for installing the part on the machine and removing it from the machine, taken depending on the mass of the workpiece, min;

T obs = T op *a%/100 - time for workplace maintenance, personal needs and operator rest (taken as a percentage of operational time), min. For single-column turning-boring machines, a = 13% is taken, i.e. T obs = 0.13 T op, and for two-column T obs = 0.15 T op; then T pcs = T op X (1 + a%/100) min.

Scope of works for servicing the workplace.

1. Organizational maintenance - inspection, warming up and running-in of the CNC device and the hydraulic system of the machine, testing of equipment; receiving a tool from a master or service technician; lubricating and cleaning the machine during the shift, as well as cleaning the machine and workplace at the end of work; Submission of a trial part to the Quality Control Department.

2. Maintenance - changing dull tools; input of tool length compensation; regulation and adjustment of the machine during the shift; removal of chips from the cutting zone during operation.

If the number of parts obtained from one processed workpiece on a rotary lathe exceeds one and is equal to q, then when determining T pcs it is necessary to divide T op by the number of parts obtained q.

T p.z - preparatory and final time (determined for the entire batch of parts Pz launched into processing). It consists of two parts.

1. Costs for a set of organizational works that are carried out constantly: the machine operator receives a work order (work order, drawing, software) at the beginning of the work and submits them at the end of the work; instructing a foreman or service technician; installation of the working parts of the machine and the clamping device in the initial (zero) position; installation of the program carrier - punched paper tape into the reading device.

For all this work, the standards for rotary lathes allow 12 minutes. If the design features of a machine tool or CNC system require, in addition to those listed, additional work, then their duration is determined experimentally and statistically and an appropriate correction is introduced.

2. Time spent on adjustment work, depending on the design features of the CNC machine. For example, for single-column CNC lathes the following time standards are accepted: for installing four cams on the machine faceplate or removing them - 6 minutes; to install the device on the machine faceplate manually - 7 minutes, using a lift - 10 minutes; installation of one cutting tool in the tool holder takes 1.5 minutes, removal of it - 0.5 minutes; it takes 4 minutes to install one tool holder in the turret head, and 1.5 minutes to remove it; to install the cross member and calipers to the zero position at the beginning of work - 9 minutes.

If the adjustment of the position of the tools is carried out when processing a trial part, then the time for processing the trial part is also included in the preparatory and final time.

Lecture 6. Standardization of work performed on machines with numerical control

Standardization of work performed on numerically controlled machines

The use of computer numerical control (CNC) machines is one of the main directions in the automation of metal cutting, which makes it possible to free up a large number of universal equipment, as well as improve the quality of products and the working conditions of machine operators. The fundamental difference between these machines and conventional ones is that the processing program is specified in mathematical form on a special program medium.

The standard time for operations performed on CNC machines when working on one machine consists of the standard preparatory and final time and the standard piece time:

Preparatory and final time is determined by the formula:

where T pz - time for setting up and setting up the machine, min.;

T pz1 - time for organizational preparation, min.;

T pz2 - time for setting up a machine, device, tool, software devices, min.;

T pr.obr - time for trial processing.

The rate of piece time is calculated using the formula:

T c.a - cycle time of automatic operation of the machine according to the program, min.;

K t in correction factor for the time of performing manual auxiliary work, depending on the batch of processed parts.

where T o is the main (technological) time for processing one part, min.;

T mv - machine-auxiliary time according to the program (for supplying a part or tool from the starting points to the processing zones and removal; setting the part to size, changing tools, changing the magnitude and direction of feed, time of technological pauses, etc.), min.

L i is the length of the path traversed by the tool or part in the feed direction when processing the i-ro technological section (taking into account the time of cutting in and overtravel), mm;

S mi - minute feed in a given technological section, mm/min.;

i=1,2…n - number of technological processing sections.

The main (technological) time is calculated based on cutting modes, which are determined according to General Machine-Building Standards for time and cutting modes for standardizing work performed on universal and multi-purpose machines with numerical control. According to these standards, the design and material of the cutting part of the tool is selected depending on the configuration of the workpiece, the stage of processing, the nature of the allowance being removed, the material being processed, etc. It is preferable to use a tool equipped with hard alloy plates (if there are no technological or other restrictions on their use). Such limitations include, for example, intermittent processing of heat-resistant steels, processing of small-diameter holes, insufficient rotation speed of the part, etc.

The cutting depth for each processing stage is selected in such a way as to ensure the elimination of processing errors and surface defects that appeared at previous processing stages, as well as to compensate for errors arising at the current processing stage.

The feed rate for each processing stage is assigned taking into account the dimensions of the surface being processed, the specified accuracy and roughness of the material being processed, and the cutting depth selected at the previous stage. The feed rate selected for the roughing and semi-finishing stages of processing is checked based on the strength of the machine mechanism. If it does not satisfy these conditions, it is reduced to a value acceptable by the strength of the machine mechanism. The feed selected for the finishing and finishing stages of processing is checked to ensure that the required roughness is obtained. The smaller of the innings is finally selected.

Cutting speed and power are selected in accordance with previously determined tool parameters, cutting depth and feed.

The cutting mode at the roughing and semi-finishing stages is checked by the power and torque of the machine, taking into account its design features. The selected cutting mode must satisfy the following conditions:

where N is the power required for cutting, kW;

N e - effective power of the machine, kW;

2M - double cutting torque, Nm;

2M st - double torque on the machine spindle, permissible by the machine according to the strength of the mechanism or the power of the electric motor, Nm.

Double cutting torque is determined by the formula:

P z is the main component of the cutting force, N;

D - diameter of the treated surface, mm.

If the selected mode does not meet the specified conditions, it is necessary to reduce the set cutting speed according to the value, permissible power or torque of the machine.

Auxiliary time associated with performing an operation on CNC machines involves performing a set of works:

a) related to the installation and removal of a part: “take and install the part”, “align and secure”; “turn on and off the machine”; “unfasten, remove the part and put it in a container”; “clean the device from shavings”, “wipe the base surfaces with a napkin”;

b) related to the performance of operations that were not included during the automatic operation cycle of the machine according to the program: “turn on and off the tape drive mechanism”; “establish the specified relative position of the part and the tool along the coordinates X, Y, Z, if necessary, make adjustments”; “check the arrival of the tool or part at the specified point after processing”; “move the punched tape to its original position.”

In general, auxiliary time is determined by the formula:

where Tv.u is the time for installing and removing the part manually or with a lift, min.;

T v.op - auxiliary time associated with the operation (not included in the control program), min.;

T v.meas - auxiliary non-overlapping time for measurements, min.

Auxiliary time for control measurements is included in the standard piece time only if it is provided for by the technological process, and only when it cannot be covered by the cycle time of the automatic operation of the machine.

Correction factor (K t in) for the duration of manual auxiliary work, depending on the batch of parts being processed, is determined from the table. 4.7.

Table 4.7

Correction factors for auxiliary time depending on the size of the batch of processed parts in mass production

Correction factors for auxiliary time depending on Map No. 1

on the batch size and processed parts in mass production

Maintenance of the workplace involves performing the following work:

· changing a tool (or a block with a tool) due to its dullness;

Let's consider what the process of standardizing adjustment work on CNC machines is and why it is needed.

When developing complex processes for processing workpieces for CNC machines and the programs that control them, the main criterion is the standard time for manufacturing parts. Without it, it is impossible to calculate the salary for machine operators, to calculate such indicators as labor productivity and equipment load factor.

Start of the process

Typically, workers need to spend additional time on the procedure for approaching and retracting, changing modes, and changing tools. Therefore, the duration of the setup period is also taken into account as part of the time costs for processing parts. Labor standardization begins with timing in the operating conditions of the machine. Using a stopwatch, the time required to install one part on the machine and then remove it is recorded.

Minutes are spent on maintenance of the place of work, the immediate needs of the operator. When working on a rotary lathe (single-column), it takes 14 minutes, and on a two-column machine - 16 minutes.

What is included in workplace maintenance?

The machine maintenance process includes:

• organizational measures - inspection of the machine, warming it up, testing of equipment: running in the hydraulic system and CNC. It takes some time to complete the task (work order, drawing, software) and receive instructions and tools from the master; present the first sample of the part received to the quality control department, lubricate and clean the machine during the shift, clean the work area after its completion. The constant time costs for performing a set of organizational works on rotary turning equipment, in accordance with the standards, are 12 minutes. When additional maintenance efforts are required, an appropriate amendment is introduced;
• technical measures - replacing a tool that has become dull; adjustment of machines throughout the shift and setup. There are other mandatory tasks: during the working process, chips must be constantly removed from the cutting or turning zones.

Time spent setting up the machine

The documents reflecting labor standards define the time for setting up equipment, depending on its design. If processing is performed on, the standards for installing and removing cutting tools are taken as the basis for the calculation.

When it is necessary to correct the positions of tools processing test parts, the period of processing the part is included in the duration of the preparatory stage.

Standards for setting up and maintaining automatic lathes are an important standard standard. They are included in the total time for the production of one part and, accordingly, they form the economic indicators of the employee and production as a whole.

Collections of normative documents

Standardizers of plants and factories where numerically and program controlled machines are used use the standards laid down in the documents when calculating working time:

• Unified Tariff and Qualification Directory of Works;
• All-Russian classifier of workers' professions;
• Unified qualification directory of positions of managers and specialists;
• Collections of labor standards for work performed to set up programmable equipment.

IMPORTANT! All this normative literature is basic for managers of all levels and personnel structures.

Without it, it is impossible to determine the time to complete certain amounts of work, the number of specialists that need to be involved, and the time standards used in the development of maps for technological processes.

Setup cards

For a machine of a certain type, a strictly standardized duration of production adjustment operations is developed and an adjustment map is assigned to it. When developing, many factors are taken into account in order to obtain the final picture.

The time limit allocated to the machine operator provides for:

• specifics of the procedure for diagnosing the machine fleet;
• availability of several setup mode options;
• compliance with service requirements.

In order to determine the labor intensity rate (unit of measurement - man-hours or man-minutes) of any work, the time during which one part is processed on a given machine is taken into account. The standardizer also operates with the concept of a piece time standard, which determines the total time in accordance with the types of work.

Accordingly, the total time is divided into main and auxiliary segments, office maintenance activities; transitions between machines during multi-machine maintenance; monitoring the work process; pauses caused by equipment operation.

The Institute of Labor has the results of standardization for equipment of milling and drilling-boring groups; lathes and automatic lines are provided with standards.

IMPORTANT! Knowing the standards, managers determine the worker’s degree of employment (his work intensity is calculated), distribute work zones and set the optimal work pace.

Multi-machine maintenance - approaches to timing

In factories with a high degree of automation, multi-machine maintenance of CNC machines is practiced (forms of labor organization - in teams, units and individually). Accordingly, service areas are assigned.

Multi-machine maintenance includes time spent on:

• preheating of equipment at idle speed, if this is provided for in the operating instructions for turning equipment;
• work according to the machine control program with workplace maintenance;
• installation of workpieces, removal of parts and quality control;
• meeting the personal needs of the operator;
• loss of the planned plan;
• performing the preparatory and final stage of work;

Multi-machine labor is classified according to work; zones, types and systems; functions performed by a multi-machine operator.

Machine maintenance systems and methods

Enterprises practice a cyclic maintenance system - at workplaces and production lines for machines that have an equal or similar length of time during which the part is processed. She is characterized by a constant flow of demands. Non-cyclical is that the operator immediately goes to service the machine where the automatic operation mode has ended. It is characterized by occasional service requirements.

Other methods are also possible:

• sentry - a worker monitors the entire machine park assigned to him, simultaneously determining the need for maintenance. With priority, the priority in service is determined by the operator, based on the cost of the parts being processed.
• route, it involves walking around a group of machines along a predetermined route.

Servicing several machines with the same or different duration of workpiece processing operations has its own nuances. However, all of them are subject to standardization during the careful development of the production process.

Conclusion

On CNC machines, to standardize adjustment work, you need to take into account many nuances when calculating the duration of various operations.

When determining the final processing time of a part on one machine (we are talking about a turning machine), the standards are calculated for the entire machine park.

page 1

page 2

page 3

page 4

page 5

page 6

page 7

page 8

page 9

page 10

page 11

page 12

page 13

page 14

page 15

page 16

page 17

page 18

page 19

page 20

page 21

page 22

page 23

page 24

page 25

page 26

page 27

page 28

page 29

page 30

CENTRAL BUREAU OF LABOR STANDARDS OF THE USSR STATE COMMITTEE FOR LABOR AND SOCIAL ISSUES

GENERAL ENGINEERING STANDARDS FOR TIME AND CUTTING MODES for standardizing work performed on universal and multi-purpose machines with numerical control

TIME STANDARDS

MOSCOW ECONOMY 1990

Standards for cutting times and modes were approved by Decree of the USSR State Committee on Labor and Social Issues and the Secretariat of the All-Union Central Council of Trade Unions dated February 3, 1988 N9 54/3-72 and recommended for use at machine-building enterprises.

Validity of the standards until 1994.

With the introduction of this collection, the General Machine-Building Standards for time and cutting modes for work performed on metal-cutting machines with program control (MGNII Labor, 1980) are cancelled.

Standards for time and cutting modes (4.1 and L) were developed by the Central Bureau of Labor Standards, Chelyabinsk Polytechnic Institute named after. Lenin Komsomol, Ryazan and Minsk branches of the Orgstakkinprom Institute with the participation of regulatory research organizations and mechanical engineering enterprises.

The first part contains standards for auxiliary time for installation and removal of parts associated with the operation; for control measurements; for workplace maintenance; breaks for rest and personal needs; time standards for setting up equipment; to set up a tool outside the machine; methodology for calculating service standards, time and production standards for multi-machine maintenance.

The second part contains standards for cutting modes and all data on calculating the main time and machine-auxiliary time, i.e. to calculate the cycle time of automatic operation of the machine according to the program.

Time standards and cutting modes have been developed to calculate time standards for work performed on the most common types of universal and multi-purpose computer numerical control (CNC) equipment used in mechanical engineering in medium-scale and small-scale production.

Standards for time and cutting modes cover the work of machine tool setters and manipulators with program control, operators of machine tools with program control, and toolmakers.

The publication is intended for standardization specialists and technologists, as well as other engineering and technical workers involved in the development of control programs and the calculation of technically sound standards for maintenance, time and output for CNC machines.

At the end of the collection there is a review form, which is filled out by the organization and sent to CENT. 109028, Moscow, st. Solyanka, 3, building 3.

The provision of intersectoral normative and methodological materials on labor is carried out at the request of enterprises and organizations through the local bookselling network. Information about these publications is published in the Annotated thematic plans for the publication of literature of the Economics publishing house and Book Trade Bulletins.

011(01) -90 ISBN 5 - 282 - 00697 - 9

KB - 32 - 76 - 89

© Central Bureau of Labor Standards of the USSR State Committee for Labor and Social Issues (CBNT), 1990

The piece time for assembly, adjustment and disassembly of the kit ipprumepm n.i d>* teleoperation is determined by the formula

^"Un* = S^shlr1 G ^"|i pr 2 * ^N1I|zh)* (1*1 M

where T shlzh - piece time for assembly, adjustment and disassembly of a set of tools for a detail operation, min; n - number of customizable ingtrumsn mu per distal operation, pcs.; T t ... T sh>fa - piece time for assembly, adjustment and handling of different types of tools included in the kit, min.

1.8. Tariffication of work should be carried out according to the Unified Tariff and Qualification Directory of Work and Professions of Workers (issue 2, approved by the Decree of the USSR State Committee on Labor and Social Issues and the All-Russian Central Council of Trade Unions of January 16, 1985 No. 17/2-541, taking into account subsequent additions and changes to it The discrepancy between the worker’s qualifications and the established level of work cannot serve as a basis for any changes in the time standards calculated according to the collection.

1.9. With the improvement of CNC machines and control systems, as well as in those cases, the cost in enterprises has already been achieved higher)! labor productivity with high-quality performance of work, reducing correction factors can be established to time standards.

In cases where the local time standards in force at enterprises are less than those calculated according to the standards, the current standards must be left unchanged.

1.10. Time standards are put into effect in the manner prescribed by the “Regulations on the organization of labor standardization in the national economy”, approved by Resolution of the USSR State Committee for Labor and Social Issues and the Presidium of the All-Union Central Council of Trade Unions dated June 19, 1986 No. 226/II-6.

L11. To explain the procedure for using time standards, examples of calculating preparatory-final time and piece time for setting up a tool are given below.

Examples of calculating time standards, cutting modes and the time of automatic operation of the machine according to the program are given in Part II of the collection in the relevant sections.

1.12. Examples of calculating standards for preparatory and final time and piece time for setting up a tool

1.12.1. Examples of calculating the norms of preparatory and final time

Initial data

1. The name of the operation is turning-turret.

2. Machine - CNC turret lathe.

3. Machine model - 1P426DFZ (diameter of the processed rod - 65 mm).

4. Model of the CNC device - "Electronics NTs-ZG, program carrier - memory.

5. Part name - amplifier piston.

6. Processed material - steel 45, weight - 0.5 kg.

7. The method of installing the part is in a collet chuck.

8. Labor organization conditions: centralized delivery of workpieces, tools, devices, documentation to the workplace and their delivery after processing a batch of parts; receiving instructions before starting to process the part. Group processing of parts is carried out (the collet chuck is not installed on the machine spindle).

The part processing program is compiled by a software engineer and entered into the memory of the CNC system by the lathe operator; the program contains 17 processed sizes.

9. Number of tools in setup - 5:

1. Cutter 2120-4007 T15K6 (groove).

2. Cutter 2102-0009 (through persistent).

3. Special cutter (groove).

4. Cutter 2130-0153 T15K6 (cutting).

5. Drill 2301-0028 (hole 010).

Map 29, 8.8+t

note 1

Total preparatory and final time for a batch of parts

1. The name of the operation is turning and rotary.

4. Device model CNC-N55-2, program carrier - punched tape.

5. Part name - flange. "l.

6. Processed material - ~ SCh20 cast iron, weight -1500 kg.

7. The method of installing the part is in four cams with boxes, each is secured with six bolts on the faceplate of the machine.

8. Labor organization conditions: delivery of tools, devices, documentation, workpieces to the workplace and their delivery after finishing processing of a batch of parts is carried out by the operator (adjuster).

The tool on the device for setting outside the machine is not pre-set.

9. Number of tools in the setup - 4 (including one groove cutter, tools 1 and 2 - from the previous setup):

1. Cutter 2102-0031VK8 (through).

2. Cutter 2141-0059 VK8 (boring).

3. Cutter 2140-0048 VK8 (boring).

4. Cutter NZh212-5043 (groove).

I t o g o T

Total preparatory time for a batch of parts

T„-T i1 + T„ a + T yarv ^ 91.9

Initial data

1. Name of the operation - turning.

Z Machine - chuck lathe with CNC.

3. Machine model - 1P756DFZ (the largest diameter of the product installed above the bed is 630 mm).

4. CNC device model - 2S85, program carrier - punched tape, memory.

5. Part name - flange.

6. The material being processed is SCh25 cast iron, weight - 90 kg.

7. The method of installing the part is in a three-jaw chuck.

8. Labor organization conditions: delivery*/to the workplace of tools, fixtures, documentation, workpieces and their delivery after processing a batch of parts is carried out by the operator (adjuster). Group processing of parts is carried out (a jaw chuck is not installed on the machine spindle).

The part processing program is compiled by a software engineer and entered into the memory of the CNC system by the lathe operator. The program contains 20 processed sizes.

adjustments):

1. Cutter 2102-0005 (through persistent).

2. Cutter 2141-0604 (boring).

3. Cutter 2141-0611 (boring).

4. Cutter NZh 2126-5043 (groove).

5 Number of tools in setup - 4 (tools 1 and 2 - from previous

Map, police, index

Time, mii

*1.0

1 Organizational preparation

Map 21. to 1). 2,3,4, inl. P

tions and their delivery after processing a batch of parts; receiving instructions before starting to process parts; Tool assembly is carried out in a special tool setting area for CNC machines.

9. Number of tools in setup - 25 (four tools: 1.12, 24.25 - from the previous setup):

1. End mill 6221-106.005 (plane 800x800).

2. Semi-finish cutter (hole 0 259.0).

3. Finishing cutter (hole 0259DN9).

4. Semi-finish cutter (hole 0169.0).

5. Finishing cutter (hole 0169.5Н9).

6. Rough cutter (hole 0 89).

7. Semi-finish cutter (hole 0 89.5).

8. Finishing cutter (hole 0 90js6).

9. Rough cutter (hole 0 79).

10. Semi-finish cutter (hole 0 79.5).

1L Finishing cutter (hole 0 80js6).

12. Disc cutter 2215-0001VK8 (lowering 0 205).

13. Rough cutter (hole 0 99).

14. Semi-finish cutter (hole 0 99.5).

15. Finishing cutter (hole 0100js6).

16. Semi-finish cutter (undercut 0130).

17. Drill 23004)200 (hole 0 8.6).

18. Tap 26804Yu03 (thread K1/8").

19. Drill 2301-0046 (hole 014).

20. Drill 2301-0050 (hole 015).

21. Countersink 2320-2373 No. 1VK8 (hole 015.5).

22. Reamer 2363-0050Н9 (hole 015.95Н9).

23. Reamer 2363-00550Н7 (hole 016Н7).

24. Drill 2317-0006 (centering).

25. Drill 2301-0061 (chamfer).

Total preparation time^extreme time for a batch of parts

T "1 + T "2 + T arr.

Example 5 Initial data

1. Name of the operation - vertical milling.

2. Machine - vertical milling with CNC.

3. Machine model - 6Р13РФЗ (with table length -1600 mm).

4. CNC device model - NZZ-1M; program carrier - punched tape.

5. Part name - strip.

6. Processed material - steel 45, weight -10 kg.

7. The method of installing the part is in a reconfigurable universal assembly device (USF).

8. Labor organization conditions: centralized delivery of workpieces, tools, devices, documentation to the workplace and their delivery after processing a batch of parts; receiving instructions before starting to process parts.

9. Number of tools in setup - 6 (tools 1 and 5 - from the previous setup):

1. Drill 2317-003 (centering).

2. Drill 22-2 (hole 0

3. Special end mill (for groove b = 20).

4. Milling cutter 2234-0007 (for groove b = 8Н9).

5. Drill 6-1 (hole 0 6).

6. Countersink 2350-0106 VK6 (lowering 016).

Total T about 60 _

Total preparation and closing time for a batch of parts

Toz 1 + T and # 2 + Tprobr

1.12.2. An example of calculating the unit time for setting up a tool

Initial data

1. Name of the operation - assembly, adjustment and disassembly of a set of tools necessary for processing parts on a drilling-milling-boring machine.

2. Name of the device - BV-2027, with digital display.

3. Characteristics of the machine - cone 7:24 No. 50.

4. Labor organization conditions: delivery of tools and technical documentation to the toolmaker’s workplace is carried out by service production workers, dismantling of used tools is carried out by a toolmaker.

2. MULTI-SITE SERVICE

2.1. To develop and improve the efficiency of multi-machine maintenance of machine tools with numerical control (CNC), the enterprise must create certain organizational and technical conditions that can significantly increase the productivity of operators and adjusters. Work on servicing CNC machines involves combining the functions of an operator and an adjuster.

2.2. The most economically feasible form of labor organization in areas of CNC machine tools is link (group). In the link (group) form, a certain service area is assigned to a link or group of workers included in the team.

The experience of enterprises testifies to the advantage of the link form of labor organization when servicing CNC machines, which ensures better use of working time and equipment.

The best division of labor when servicing workplaces of CNC machines is considered to be one in which the multi-machine operator and the setup operator have, in addition to the separated ones, some common functions. General functions include carrying out operational work, adjusting machines; The functions of setting up equipment are carried out by an adjuster. This division of labor has economic and social advantages. The ability to perform the same functions by two workers allows you to reduce equipment downtime due to the coincidence of the need to service several machines and improve the use of working time. At the same time, the mastery of adjustment functions by multi-machine operators increases the content of their work and creates opportunities for growth in qualifications.

2.3. To introduce multi-machine maintenance and rational use of working time, it is necessary to create a sufficient scope of work for each worker. Equipment and organizational supplies must be conveniently located and meet the requirements of the brigade form of labor organization. For this purpose, the design of the organization of workplaces for multi-machine operators is carried out in accordance with the diagrams presented in Section 3.5. Preference should be given to schemes that ensure full worker load with active work, the shortest length of transitions within the workplace and good visibility of all machines.

There are cyclic and non-cyclic maintenance of machines at a multi-machine workplace. During cyclic maintenance, the worker consistently performs auxiliary work techniques, moving from machine to machine. During non-cyclic maintenance, the worker approaches the machine on which automatic operation has ended, regardless of the location of the machines on the site.

2.4. Calculation of service standards

2.4.1. Service standards are set taking into account the normal level of employment - K yes. When working on CNC machines, taking into account heterogeneous technological operations with a changing range of manufactured parts, K l l - 0.75...0.85. When working on backup machines K A5 = 0.85. D95.

Z42. Calculation of the number of machines served by one worker, required to service the CNC equipment available on the site, and the number of units is carried out using the formulas:

a) when working on backup machines

П с = (-bs- + 1) К Л1; (21)

b) when working on machines that produce heterogeneous products,

"c = + 1) k, (2-2)

where is the cycle time of the automatic operation of the machine (machine-programmed time for processing a part, the operation of a manipulator or robot, not covered by the processing time of the part), min (according to formula 13); 2j - sum of processing time

rolls of parts (according to the program and operation of the manipulator or robot) at the workplace for the period of one cycle, min; T, is the time a worker is busy performing manual, machine-manual work, active monitoring of the progress of the technological process, etc., min; Jj T a - the sum of the worker’s employment time on all serviced machines for the period of one cycle, min; - normal level of employment.

The number of units is calculated using the formula

S - -b»-, (23)

where S is the number of units required to service the equipment available on site, people; Pu Ch - the number of CNC machines installed on the site; p s - the number of machines serviced by one worker.

T, - T, y + TYo, + T MM(+ T. + T n + T^, (2.4)

where T lu is the time for installing and removing the part manually or with a lift, min; Тіо„ - auxiliary time associated with the operation (not included in the control program), min; T i - time of active monitoring of the technological process, min; T p - time of transition of a multi-machine operator from one machine to another (during one cycle), min (given in Table 2.4); T m - auxiliary time for control measurements, min; - time for servicing the workplace, min.

2.43. The number of machines at multi-machine workplaces is determined on the basis of a comparative calculation of labor productivity and processing costs, especially when installing expensive equipment such as multi-purpose CNC machines.

The cost-effective number of machines serviced by a multi-machine operator can be determined by comparing the costs associated with the operation of a multi-machine operator and equipment when operating the machines and various options for the equipment being serviced.

When calculating the number of serviced machines corresponding to the lowest total costs of performing operations, take into account the costs of performing operations, the costs of materialized labor required to produce the same volume of products, which include depreciation costs, expenses for routine repairs and maintenance, electricity, through 0

ratio and employment coefficient K/. 3

1. GENERAL PART

1.1. Standards for time and cutting modes are intended for technical regulation of work performed on universal and multi-purpose machines. numerical program control in conditions of small-scale and medium-scale production types. One of the main characteristics of the type of production is the coefficient of consolidation of operations (K^), calculated by the formula

where O is the number of different operations; P is the number of jobs performing various operations.

The coefficient of consolidation of operations in accordance with GOST 3.1121-84 is taken equal to:

10 < К м £ 20 - для среднесерийного типа производства;

20 < 3 40 - для мелкосерийного типа производства.

The value of the operation consolidation coefficient is taken for a planning period equal to one month.

The collection is based on the medium-batch type of production. For small-scale production enterprises or for individual sections in a medium-scale production type operating in small-scale production conditions, correction factors for auxiliary time are applied.

1.2. When introducing a brigade (team, group) form of labor organization, standards can be used to calculate service standards, complex time standards, production and number standards.

13. The use of machine tools with numerical control is one of the main directions of automation of metal cutting, provides a significant economic effect and makes it possible to free up a large number of universal equipment, as well as improve the quality of products and working conditions of machine operators. The greatest economic effect from the introduction of numerical control machines is achieved when processing parts with a complex profile, which is associated with constantly changing cutting parameters (speed, feed direction, etc.).

The use of numerically controlled machines instead of universal equipment allows:

use multi-machine service and brigade (team, group) form of labor organization;

increase labor productivity by reducing auxiliary and machine processing time on the machine;

eliminate marking operations and interoperational control; thanks to abundant cooling and favorable conditions for chip formation, increase processing speed and eliminate the need for visual monitoring of markings;

automate auxiliary work techniques (approach and removal of a tool or part, setting a tool to size, changing a tool), use optimal tool trajectories;

Expenses* associated with one minute of work of the main worker-multi-machine operator based on the average percentage of compliance with standards, taking into account the accrual of wages, the cost of maintaining auxiliary and maintenance personnel -

Job category

w

2.4.4. Calculation of occupancy rate

t+t

still - operational time, min.

reduce the labor intensity of metalwork finishing due to obtaining high accuracy and lower roughness of curved sections of contours and surfaces of parts;

reduce the labor intensity of product assembly, which is due to the stability of the dimensions of parts (increased accuracy) and the elimination of fitting operations; reduce costs for design and manufacturing of equipment.

L4. The collection is developed in two parts. Part I contains standards for preparatory and final time, time for installing and removing parts, auxiliary time associated with the operation, for servicing the workplace, breaks for rest and personal needs, for control measurements, for setting up tools outside the machine; Part P contains standards for cutting conditions, allowing you to select the standard size of the tool, its geometric parameters, the brand of the cutting part of the tool, the required allowance, the number of feed strokes, cutting speeds, and the power required for cutting.

Standards for time and cutting conditions are given both in tabular and analytical form, thereby allowing the use of a computer when drawing up a program and calculating time standards that correspond to the lowest cost of the operation and the highest productivity of the machine while ensuring increased reliability of the tool. Operation of tools in the modes recommended by the standards is possible only if technological production discipline is observed (equipment, tools, workpieces, accessories must meet the required standards).

The time standards given in the collection are designed to standardize work when servicing one machine by a worker. When rationing multi-machine work, to calculate the time standard, it is necessary to use the guidelines and time standards for multi-machine work given in maps 17,18,19.

15. When developing standards for time and cutting modes, the following materials were used as initial data:

primary materials of production observations on labor organization, technology, time spent and cutting modes of mechanical engineering enterprises;

industry standards for time and cutting modes developed by GSPKTB "Orgariminstrument" (Moscow), Ryazan, Minsk and Novosibirsk branches of the Orgstankinprom Institute, the Center for the Scientific Organization of Labor of the Ministry of Heavy Machinery (Kramatorsk), etc.;

Determination of time standards for rest and personal needs. Intersectoral methodological recommendations (Moscow: Research Institute of Labor, 1982);

Development of multi-machine service and expansion of service areas in industry. Intersectoral methodological recommendations and scientifically based regulatory materials (Moscow: Research Institute of Labor, 1983);

General machine-building standards for auxiliary time, for servicing the workplace and preparatory and final time on metal-cutting machines. Small-scale and individual production (Moscow: Research Institute of Labor, 1982);

General machine-building standards for auxiliary time, for servicing the workplace and preparatory and final time for work performed on metal-cutting machines. Medium-scale and large-scale production (M.: Research Institute of Labor, 1984);

passport data of metal-cutting CNC and multi-purpose machines; technical literature.

1.6. Standard time and its components

1.6.1. The standard time for performing operations on CNC machines when working on one machine (H^ consists of the standard preparatory and final time (G in J and the standard piece time (T^)

a tta ^ a org a exc \

T D1 = Cr u . + T.-Kj(i +

where T n is the cycle time of automatic operation of the machine according to the program” min;

T.-T. + T., (13)

where T s is the main (technological) time for processing one part, min;

Т„ = £ (1.4)

where C is the length of the path traversed by a tool or part in the feed direction when processing a technological section (taking into account plunge-in and overtravel), mm; S* - minute feed in a given technological section, mm/min; T m - machine-auxiliary time according to the program (for supplying a part or tool from the starting points to the processing zones and removal; setting the tool to size, changing the tool, changing the value and direction of feed, time of technological pauses (stops), etc.), min. ;

t. = Т„ + + Т„„, (1.5)

ede T m - time to install and remove the part manually or with a lift, min; T w - auxiliary time associated with the operation (not included in the control program), min; T may - auxiliary non-overlapping time for measurements, min; K TV - correction factor for the time of performing manual auxiliary work, depending on the batch of parts being processed; a^, a^, a ex - time for technical and organizational maintenance of the workplace, for rest and personal needs during single-machine maintenance, % of operational time.

1.6.1.1. With a collective form of labor organization, complex standards of labor costs are calculated (N vrl, man-hour), which can be obtained by applying correction factors to the sum of operating standards calculated for the conditions of the individual form of labor organization. It is possible to use correction factors to the sum of individual components of the complex norm, reflecting the total value of time spent by categories of these costs.

Complex norm Determined by the formula

n,p,= £n.„-k*, (1.6)

where N (is the time standard for manufacturing the i-th part of the brigade kit, man-hours; i = 1,2,3,..., l - the number of parts included in the brigade kit;

N.R, = S n* (1.7)

more H Bpj - standard time for performing the jth operation, person-hour; j = 1, 2,3,..., w - the number of operations required to manufacture the j-th part; - coefficient

effect of team work (K^< 1).

The coefficient of the effect of team work (K^) takes into account the average increase in labor productivity expected during the transition from an individual to a team form of labor organization, which should be included in complex standards.

As a result of the redistribution of functions between team members, mutual assistance or interchangeability, the required time to complete the amount of work assigned to the team is reduced, therefore, the corresponding time standard should be reduced. This occurs due to a decrease

For more complete and detailed data, see Methodological recommendations for standardizing the work of workers in conditions of collective forms of its organization and stimulation. M.: Economics, 1987.

the values ​​of individual components of the time standard: auxiliary time, time for servicing the workplace, regulated breaks, preparatory and final time, and also due to the overlap of individual components of the time standard with computer time (in the latter case, the value of each component of the time standard may remain unchanged).

In end-to-end teams, the labor intensity of manufacturing a team set can be reduced by eliminating individual elements of preparatory and final time and time for servicing the workplace when handing over a shift “on the fly.”

Team work effect coefficients (K^) are established: at the industry level;

at the enterprise level, if there are no industry coefficients or they do not fully reflect the specifics of the team organization of labor at a particular enterprise.

are introduced as a Standard for the entire industry for a certain period (at least 1 year).

In order to expand the possibility of using the teamwork effect coefficient, in addition to the general value of the coefficient, the values ​​of each of its components are calculated.

The effect of team work can be achieved through the following components:

expansion of the combination of professions (K^; expansion of multi-station service (IQ; mutual assistance and interchangeability of team members (K); transfer of shifts "on the fly" in cross-cutting teams (K 4); redistribution of functions between team members (K 3), etc.

The total value is determined as the product of its components (for a given type of brigade), i.e.

K*-K, -K, -K, ...K, (1.8)

At the enterprise level, as a rule, general values ​​of K^ are established, accepted during the period for which they are designed, but not less than a year, if production conditions do not change.

If the team, in addition to deal workers, includes time workers and engineering and technical workers, then the complex time standard (person-hours) cl "is the sum of the time standards of piece workers, time workers and engineering technical workers for the production of one brigade set, adjusted for the teamwork effect coefficient.

L6.2 Standards for auxiliary time for installation and removal of parts. The time standards for installing and removing parts are given by type of fixture, depending on the type of machine tool, and provide for the most common methods of installing, aligning and fastening parts in universal and special clamps and fixtures. The main factors influencing the installation and removal time of a part are the weight of the part, the method of installing and fastening the part, the nature and accuracy of the alignment. In addition to these factors, the size of the installation surface, the number of simultaneously installed parts, the number of clamps, etc. are taken into account.

The standard time for installing and removing a part involves performing the following work:

when installing and removing manually

take and install the part, align and secure; turn the machine on and off; unfasten, remove the part and place it in a container; clean the device from shavings, wipe the base surfaces with a napkin;

when installing and removing a part with an overhead crane

call the tap; rig the part; transport the part to the machine; install the part, rig the part, align and secure; turn the machine on and off; unpin part; call the tap; rig the part; remove from the machine and transport it to a storage location; strap the part, clean the fixture or table surface from shavings, wipe the base surfaces with a napkin.

When installing and removing a part with a lift at a machine (or group of machines), they perform the same work as when installing and removing a part with an overhead crane, with the exception of calling the crane.

When installed in special devices, auxiliary time is defined as the sum of time: for installation and removal of one part; for installation and removal of each subsequent part more than one in multi-place devices; to secure the part, taking into account the number of clamps; to clean the device from chips, to wipe the base surfaces with a napkin.

In addition to universal and special devices on CNC machines, enterprises also use robots, manipulators and satellite tables to install and remove parts.

Due to the wide variety of types and technical characteristics of robots and manipulators, it is not possible to develop time standards for installing and removing parts with their help; Each enterprise needs to draw up maps for the use of robots. Appendix 15 is given as an example. For cases of working on multi-purpose machines using satellite tables, it is necessary to use map 20, which shows the satellite loading scheme and the time for changing satellites.

In some cases, when the program provides for a special technological pause for refastening a part, the standard time should be reduced by an amount covered by the automatic operation of the machine. The standards provide for the installation and removal of parts weighing up to 20 kg manually and over 20 kg using lifting mechanisms.

The time for manual installation of parts weighing over 20 kg is given in the standards for use in certain cases when processing in areas where there are no lifting vehicles. Manual installation of parts weighing over 15 kg is not allowed for men under 18 years of age or women.

It is taken into account that parts installed manually are located at a distance of 2 m from the machine, and parts installed by crane are up to 5 m.

1.6.3. Standards of auxiliary epeuienu associated with the operation. Auxiliary time associated with the operation is divided into:

auxiliary time associated with an operation that is not included during the cycle of automatic operation of the machine according to the program and provides for the following work:

turn the tape drive mechanism on and off; set the specified relative position of the part and the tool along the coordinates X, Y, 2 and, if necessary, make adjustments; open and close the cover of the tape drive mechanism, rewind, insert the tape into the reading device; check the arrival of a part or tool at a given point after processing; advance the punched paper tape to its original position; install the shield against splashing with emulsion and remove;

machine-auxiliary time associated with the transition, included in the program and related to the automatic auxiliary operation of the machine, providing for: supply of a part or tool from the starting point to the processing zone and removal; setting the tool to the processing size; automatic tool change; turning the feed on and off; idling when switching from processing one surface to another; technological breaks provided

when suddenly changing the feed direction, checking dimensions, inspecting the tool and reinstalling or re-fastening the part.

Machine-auxiliary time associated with the transition, included in the program for the listed techniques, is determined from the passport data of the machines or other regulatory documents, is included as constituent elements during the automatic operation of the machine and is not taken into account separately (see appendices 27-30, part II ).

1.6.4. Standards for auxiliary time for control measurements. The required dimensions of parts processed on numerically controlled machines are ensured by the design of the machine or cutting tool and the accuracy of their adjustment.

In this regard, the time for control measurements (after completion of work according to the program) should be included in the standard piece time only if it is provided for by the technological process and taking into account the necessary frequency of such measurements during the work process, and only in cases where it cannot be covered by the cycle time of the automatic operation of the machine according to the program.

1.6.5. Time standards for servicing a workplace. The time for servicing a workplace is given by type and size of equipment, taking into account single-machine and multi-machine maintenance as a percentage of operational time. Maintenance of the workplace involves performing the following work:

changing a tool (or a block with a tool) due to its dullness; adjustment and adjustment of the machine during operation (changing the tool correction value);

sweeping and periodic removal of chips during work (except for sweeping chips from the base surfaces of installation devices, the time for which is taken into account in the auxiliary time for installing and removing the part).

Organizational maintenance of the workplace includes work to care for the workplace (main and auxiliary equipment, technological and organizational equipment, containers) related to the work shift as a whole: inspection and testing of equipment during work;

laying out tools at the beginning and cleaning them up at the end of the shift (except for multi-purpose machines);

lubrication and cleaning of the machine during the shift;

receiving instructions from the foreman and foreman during the shift;

cleaning the machine and workplace at the end of the shift.

1.66. Time standards for rest and personal needs. Time for rest and personal needs for the conditions of servicing one machine by one worker is not separately allocated and is taken into account in the time for servicing the workplace.

For cases of multi-machine service, a map of the time of rest breaks and personal needs is provided, depending on the characteristics of the work and with recommendations for the content of rest.

1.6.7. Standards for preparatory and final time. The standards are designed for setting up CNC machines for processing parts using implemented control programs and do not include actions for additional programming directly at the workplace (except for machines equipped with operational program control systems).

The standard time for setting up a machine is presented as the time for preparatory and final work to process a batch of identical parts, regardless of the batch, and is determined by the formula

T p, = T pz1 + T pz2 + T prlbr, (1.9.

where T pz is the standard time for setting up and setting up the machine, min; T pz (- standard time for organizational preparation, min; T pe 2 - standard time for setting up sgaikg

devices, tools, software devices, min; - time limit for trial processing.

The time for preparatory and final work is set depending on the type and size of the equipment, as well as taking into account the features of the program control system and is divided into time for organizational preparation; for setting up the machine, devices, tools, software devices; for a test run according to the program or trial processing of a part.

The scope of work for organizational training is common to all CNC machines, regardless of their group and model. Time for organizational preparation includes:

receiving work orders, drawings, technological documentation, software, cutting, auxiliary and control tools, fixtures, workpieces before the start and handing them over after finishing the processing of a batch of parts at the workplace or in the tool storeroom;

familiarization with the work, drawing, technological documentation, inspection of the workpiece;

master's instructions.

In a brigade form of labor organization, when workpieces are transferred between shifts, organizational preparation takes into account only the time for familiarization with the work, drawing, technological documentation, inspection of workpieces and instructing the foreman.

The work for setting up a machine, tools and devices includes adjustment work techniques, depending on the purpose of the machine and its design features:

installation and removal of fastening devices;

installation and removal of a block or individual cutting tools;

setting the initial operating modes of the machine;

installing the software into the reading device and removing it; zero position adjustment, etc.

The time for trial processing of parts on lathe machines (up to 630 mm) and turret groups includes the time spent processing the part according to the program (cycle time) plus auxiliary time for performing additional techniques related to measuring the part, calculating corrections, and entering correction values ​​into the CNC system , and auxiliary time for techniques for controlling the machine and the CNC system.

The time for trial processing of parts on turning (over 630 mm) rotary, milling, boring groups, and other machines includes time spent on processing parts using the test chip method with cutting tools, end mills, plus auxiliary time for performing additional techniques related to measuring the part, calculation of correction values, introduction of correction values ​​into the CNC system, and auxiliary time for techniques for controlling the machine and the CNC system.

1.7. Norms of piece time for dimensional adjustment of cutting tools outside the machine

1.7.1. Piece time standards are intended to standardize work on setting up cutting tools for CNC machines, which is carried out by toolmakers (to set up tools) outside the machine in a specially equipped room using special instruments.

Piece time standards are set depending on:

type of devices used;

type and size of the tool being adjusted;

number of customizable coordinates;

the nature of the setting (by actual size or at a given coordinate).

To set up tools at enterprises in the mechanical engineering and metalworking industries, the following devices are used:

for machines of the drilling-milling-boring group - optical with digital indication type BV-2027, without digital indication type BV-2015 and contact type devices;

for turning machines - optical with digital display type BV-2026, without digital display type BV-2010, BV-2012M and contact type devices.

Taking into account the peculiarities of the tool setting processes, time standards have been developed separately for machines of the drilling-milling-boring group and machines of the turning group.

The most advanced devices with digital display are taken as the basis, but taking into account the correction factors given in the maps for changed operating conditions, these standards are used when rationing work on devices without digital display (type BV-2015, BV-2010, BV-2012M, etc.) and contact type devices.

When setting up a tool without instruments (using universal measuring instruments), the time standards must be calculated according to the standards for contact-type devices.

Piece time standards for assembling and setting up cutting tools on imported devices with digital display must be calculated according to the time standards for domestically produced devices such as BV-2027 and BB-2026 with a coefficient of 0.85; for devices without digital display - but for devices gopa BV-2015 and BV-2010 with a coefficient of 0.9.

The regulatory materials in this section cover the most typical connections for the mechanical engineering and metalworking industries, standard/cutting and auxiliary tools and are presented in the form of enlarged piece-time standards.

When calculating the time standards for assembling and adjusting the snow profile cutting tool, take a multiplying factor of 1.2.

In addition to the time for the main work, assembling and setting up the tool, the piece time schedule includes additional time spent on organizational and technical maintenance of the workplace, preparatory and final time and time for rest and personal needs in the amount of 14% of operational time.

The advisability of including additional costs in the general time standard is due to the difficulty of separating them from the total time associated with preparing the workplace for setup, and the time of assembling and setting up the tool itself.

To determine the norms of piece time for disassembling a used tool, the cards for assembling and setting up tools contain correction factors calculated differentially for each type of work.

Piece time standards for individual methods of assembling and setting up tools that are not included in the complexes are reflected in cards 50 and 51.

1.7.2. The standard piece time for assembling, setting and disassembling one tool is determined by the formula

T ShLR = T shk + t^, 0.10)

food T - piece time for assembling, setting up and disassembling one instrument, min; T shi - piece time for assembling and setting up one tool, min; T shr - piece time for tool disassembly, min.

V * «b* T «p = T - K ’ 0-11)

where K is the correction factor for piece time depending on the device used.

T ShLR = T sh. + = t shn + t shn K = T shi (3 + K).

The most common operations are cheese-liquor-frostrao-restoration.