Widely versatile 676p milling machine was once in demand in many industries where milling, drilling and other operations were performed. The instruction manual for the 676p milling machine also provided for the possibility of processing at an angle.

High accuracy and versatility in use

The universal milling machine 676p has very high accuracy, which determined its use in the most various fields. According to accepted standards, the model has an accuracy class of P. The versatility of the equipment is characterized by the fact that when using it, it is possible to carry out slotting operations. Spare parts for the milling machine, including the slotting head, can be purchased separately.

Specifications

Considering the 676p milling machine specifications The following points should be noted:

1. The 676p universal milling machine has 16 spindle speeds.
2. The horizontal spindle of the 676p machine can have rotation speeds ranging from 50 to 1630 rpm. The vertical spindle has this indicator in the range from 63 to 2040 rpm.
3. The specifications also indicate that the number of feeds is 16. The operator can select the feed value from 13-395 mm/min.
4. The technical data sheet for the 676p milling machine indicates that the power of the electric motor is 3 kW.
5. Dimensions of corner horizontal steel: 800 x 250 mm; vertical steel surface 630 x 250 mm; Dimensions of the entire machine: 1200 x 1240 x 1780 mm.
6. Looking at the technical data sheet of the 676p machine, it can be noted that the spindle can be rotated at an angle of up to 90 0.

The given parameters determine that milling can take place by applying fixed speed and feed values. The features of the spindle allow the installation of a wide variety of cutters and some other cutting tools.

The design of the 676p universal milling machine is represented by the following main elements:

1. Mains and electric pump switch. The electrical circuit provides for complete de-energization if necessary. In this case, the electrical circuit is made in a classic style, when all power is controlled through the “start” and “stop” buttons.
2. Control is represented by flywheels, which are used to control the table, spindle and headstock.
3. The passport determines the presence of quite large quantity handles, which are responsible for controlling the main elements during processing of parts.
4. The main part of the structure is represented by a vertical frame, on the sides of which controls are located. At the top there is a headstock with a gearbox and spindle feed; at the front there is a table with several controls and a feed mechanism. The structure has a base, which, if necessary, can be rigidly fixed with bolts.

In general, we can say that the design of this model does not differ significantly from the design of many other models of the vertical milling group. Key Feature 676p is the ability to rotate the spindle.

Gearbox

When considering the features of a milling machine, attention should be paid to the spindle speed box:

1. The design of gears, which are made from high strength steel. The passport of the 676p milling machine determines the possibility of carrying out repair and maintenance work by opening the housing and dismantling the gearbox. The housing is attached to the side.
2. At the moment of switching, there is a possibility that the teeth will coincide and the gears will engage when the discs cannot be brought together. The passport contains information on application recommendations, where it is prohibited to change gears while the 676p milling machine is operating under load. This action can cause gear failure.

The description of this 676p milling machine also specifies that the speeds are controlled by switching the position of the corresponding handle.

Gearbox

For faster movement, a feed box was installed. A recommendation for using this function is to set the cross handle to the neutral position. This eliminates the possibility of a fairly large number of problems with gears.

The piston pump significantly extends the service life of the structure. Its intended purpose is to supply a lubricating fluid, which helps reduce friction. The design of the piston performs a reciprocating movement, due to which the lubricating fluid is sucked in and supplied to the friction area. To control the degree of lubrication, the 676p milling machine has a transparent eye, through which the process of oil mist formation in the gear friction zone is monitored.

Headstock

This structural element is also represented by a separate housing in which the gears are located. The structure can move along installed guides, which represents a transverse feed. The decoding of the name of the machine determines that it belongs to the vertical milling group due to vertical arrangement the spindle itself. The tool is clamped using a special cleaning rod. Intermediate stops are installed as a limiter. The design features allow for coordinate boring work. For this purpose, an indicator holder and a tile holder were installed, which are necessary for fixing the measuring tile.

In conclusion, we note that the 676p milling machine is suitable for performing small-scale work on metal processing by milling or performing another operation. The model is designed in such a way that it is possible to install additional equipment. Examples include adapter bushings, rotary cleats, mandrels and much other equipment. The maximum stroke of the cutter is 80 meters, the weight of the installed head is 30 kg. Modern analogues of the model can be called TOS Olomuc machines, the production of which is established in the Czech Republic.

The SF676 machine allows you to perform various operations: milling flat and shaped planes, drilling, threading, centering, counterbore, boring, chiseling, marking and other types of work. The machine can process parts of the most complex configurations from various materials with high accuracy. The machine is used in single and small-scale production in tool and mechanical shops machine-building enterprises.

The presence of two spindles, horizontal and rotary vertical, as well as a large number of accessories for the machine, makes it highly versatile and convenient for working in the manufacture of fixtures, tools, relief stamps and other products;
- The massive cast iron bed absorbs vibrations and allows you to maintain the quality of the parts processed on the machine. The frame guides are protected by a special corrugated casing that protects the frame from premature destruction;
- Convenient, intuitive, classic machine control;
- The small dimensions of the machine allow it to be placed in almost any room;
- A wide range of rotation of horizontal and vertical spindles allows you to select the most suitable cutting modes. Coolant supply to the cutting zone is carried out through a modular hinged tube;
- A wide range of spindle speeds and feeds, the presence of mechanical feeds and fast movements ensure economical processing of various parts in optimal modes;
- The machine uses an original solution to the VFG design, based on the “DOUBLE CYLINDER” principle, which can be rotated at an angle of ±90 degrees. The “DOUBLE CYLINDER” design ensures stability of processing and safety of the body from destruction, allows for power milling;
- The machine uses industrial LED lighting; it is possible to install additional, more powerful, sealed lighting;
- The machine can be equipped with digital display units produced by SKB IS and produced by GIVI-Electonics. The DRO unit is equipped with a direct reference system, which displays the actual position or movement of the working unit in space, and not the rotation of the axis drive screw.

BASIC DELIVERY SET:
- The machine is assembled;
- Tool kit;
- Set of crackers of 7 pcs.;
- 764К001.01-ДЦ Vertical head (removable unit);
- 676.60.001 Shield;
- 7681K001.01 (250/4) Standard corner table (removable unit);
- 766K012 Horizontal trunk (removable unit);
- 766K013 Earring (removable knot);
- Mandrel Ø27 with stacked rings and bushing;
- 676.83.000 Handle;
- cleaning rod of the head;
- Headstock ramrod;
- ICH-10 class 1 Dial indicator;
- Set of clamping devices (50 items);
- Collet chuck with a set of collets ER32 or ER40 (6 pcs.)
- Cooling system;
- SF676.00.000RE Milling machine RE. Blueprints.

ADDITIONAL EQUIPMENT:(supplied at extra cost)
- Vibration support OV-31M (4 pcs.);
- 7681K001-02 (300/5) Additional removable table 800 x 300 mm. 5 grooves;
- 7681K003G Additional globe table (installation in 3 planes);
- LED 24 - 5 CL Additional lighting (sealed);
- 6512-125,6582-2 Machine vice S=125mm, with a reinforced movable jaw and a closed screw with a rotary platform;
- UDG-D-160A Universal dividing head;
- Set of accessories for UDG-D-160A (rest, guitars, gear wheels, mandrel);
- 3-100.02.01 (Ch 7100-0002) Three-jaw lathe chuck Ø 100 mm;
- RKV 7205-4003 Horizontal-vertical rotary table Ø 250 mm;
- 61P-17-000 Round milling table Ø 250 mm;
- 7200-0215-02 Cast iron rotary machine vice (jaw width 160 mm);
- 7200-0215-05 Steel rotary machine vice (jaw width 160 mm);
- GD-1 Slotting head;
- NT40/KM2.3.4 Adapter sleeve for threaded tightening - 3 pcs.;
- NT40/KM2.3.4 Adapter sleeve for drill - 3 pcs.;
- NT40/ER32/40 Collet chuck with a set of collets Ø 32 mm. (18 pcs.);
- NT40-16/22/32315 Mandrel Ø16,22,32 with stacked rings and bushing;
- NT40/PSS16 Self-clamping drill chuck with NT40 mandrel;
- NT40/DCH Boring bar NT40 with a set of cutters;
- CR1 Lever center finder (with indicator).

Since 2012, the wide-universal milling unit model SF676 has been produced by the Vyatka Machine Tool Repair Plant, and the first manufacturer of this unit in the 1960s was the Kirov plant "Selmash".

1 Milling machine SF676 – all the advantages and features

The installation makes it possible to use shaped, disk and cylindrical cutters when operating its horizontal spindle, as well as keyway, end and face cutters when operating a vertical spindle.

The machine provides excellent accuracy for boring and milling operations in production shops that meet generally accepted standards (no strong vibration, no heat sources, humidity at 60–70%, temperature from +18 to +22 °C).
Except specified works the unit allows you to perform a number of other working procedures (chiselling, drilling, boring, counterbore, reaming, reaming, centering, countersinking).

Analogues of the machine are milling equipment from the following plants:

• Chinese manufactory "Shandong Rooy" (X8132);
• Vladimir Machine Tool Plant "Tekhnika" (FSM-250/676M);
• Chita plant (6T80);
• Vitebsk (Republic of Belarus) "VIZAS" (VZ–371);
• Vilnius "Vingriai" (67K25PF1, 676P, 67K25PF2–0, 6725PF1);
• Yerevan milling equipment plant (67E25PF1, 675P);
• Votkinsk Mechanical Engineering Plant (VM130);
• Irkutsk Machine Tool Plant (67K25PF1, 676);
• Dmitrov plant (DF-6725).

The main advantages of the machine we are considering, as well as all its analogues, include:

• convenient traditional control scheme;
• using an electric pump to supply coolant (as well as lubricant);
• the ability to mill fairly large (up to 250 mm wide and 800 mm long) and smaller parts;
• the presence of an additional spindle head that moves vertically (the machine designers placed it on the retractable trunk of the unit);
• minimal vibration level of a massive cast iron frame;
• relatively modest dimensions (height - 1780 mm, width - 1240 mm and length - 1200 mm) and low weight (1050 kg);
• spindle rotation in a wide frequency range (from 63 to 2040 rpm - vertical, from 50 to 1630 rpm - horizontal).

2 Machine SF676 – design and components of the installation

All main components and units of the unit ensure its high operational potential. These include:

• removable round and corner horizontal table;
• caliper;
• gearboxes and feeds;
• removable vice;
• vertical head (it is also a removable element);
• electrical equipment;
• spindle head;
• accessories and milling tools fully equipped.

If you purchase additional tools (various tools, devices for boring and drilling, and so on), the capabilities of the machine expand significantly, and it becomes truly multifunctional.

All key components of the unit are installed on its frame. On its side there are two boxes - feeds and speeds. The spindle head (vertical) is mounted on the front end of the headstock, which moves along horizontal guides (they are located at the top of the frame).

The support moves along vertical guides, and the table moves along horizontal ones. The base plane of the machine is considered vertical. A corner table is connected to it, on which parts are fixed, which the operator processes using a milling unit.

All electrical equipment of the installation is mounted in the frame under protective covers. And at its base there is an electric motor, feed and main movement chains. There is also an electric pump there (it also acts as a container for collecting liquid used to cool the structure during operation).

The vertical spindle, fixed in the head with a trunk, is placed in the sleeve. It is moved manually using a special rack roller. On the faceplate of the trunk, the head can be rotated from a vertical position by ±90°. Two conical pins equipped with handles serve to fix the vertical zero position of the head. It is clamped to the faceplate using bolts (they are very reliable, since their inner surface is hexagonal).

The spindle supports (vertical) are:

• top: thrust radial bearings (they also bear axial loads);
• bottom: double-row roller bearing (the design of the machine provides for the presence of a conical hole in it).

The spindle mass is balanced by a leaf helical spring. It is connected to the vertical head (with its body) at one end, and to the rack roller at the other end. Labyrinth seals on the head protect it from contamination and lubricant leakage. At the same time, daily in accordance with the requirements for conducting Maintenance unit, the vertical head is lubricated.

3 Features of other components and mechanisms of the milling machine

The support moves the main work table horizontally and vertically. Vertical feeding is carried out due to the movement of the caliper along the guides of the bed. They are made in a dovetail format. The caliper body contains a feed control device, which begins to function when the drive shaft receives movement from the feed box. After this, the feed mechanism distributes the rotation to the lead screws (horizontal and vertical).

The feed box provides the spindle head and support with different feeds, and also makes it possible to carry out accelerated movement. Its shafts receive rotation from the gearbox (from its main shaft). Standard feed changes to accelerated feed when the operator presses the corresponding control handle. When he releases it, the machine begins to operate normally again.

The piston pump lubricates the gears of the spindle head and two boxes. This happens according to this scheme:

• the eccentric of the gear sets the piston of the mechanism into reciprocating motion;
• Oil in the required quantity is sucked out of the bed container, which is then sprayed;
• all gears, without exception, are lubricated due to the resulting oil mist.

The worker operating the unit can monitor the described process through a peephole with transparent glass, which is mounted on the feed box (on the flange of this unit) and allows you to control the pulsation of the oil.

Rotation is transmitted to the installation spindle by two gears (one of them is located directly on the spindle). The trunk and vertical head are mounted on guides on top of the spindle head. To support the mandrels, there is a special earring attached to the trunk. In a horizontal spindle, the working device is fastened using a ramrod.

Due to the well-thought-out design of the unit, its operator has the opportunity to carry out very precise coordinate boring operations. The tile and indicator holder is responsible for this process.

The 676th series of milling machines, extremely popular during the Soviet era, has not lost its popularity today. Both equipment manufactured in the 70s and 80s, as well as modern modifications of these models, are widely used.

In this article we will look at the universal milling machine SF-676, study its layout and principle of operation, and also pay attention to the analogue of this model - the 676P milling machine, and find out how they differ from each other.

1 Purpose and scope of use of SF-676

The widely-universal milling cutter SF-676 can be equipped with two types of spindles - a rotary-vertical one, for working with face and key cutters, and a horizontal one, when using which you can install shaped, disk and cylindrical type cutters on the machine.

It is the presence of a second spindle head, adjustable in perpendicular planes, that distinguishes widely universal milling cutters from conventional machines. SF-676 can operate using two spindles simultaneously, while the unit, in addition to milling, performs operations such as drilling, countersinking and boring.

In industrial practice, SF-676 is widely used to perform the following operations:

• processing of external, internal surfaces and bodies of revolution by turning;
• cutting grooves and ledges;
• turning splines on shafts;
• formation of gears.

Units of the 676 series belong to the class of high-precision milling machines (H). The greatest processing accuracy is achieved in the absence of vibration sources near the equipment, at a temperature environment 20 degrees and humidity around 65%.

SF-676 and 676P are in demand both in single and small-scale production; most often they can be found in the workshops of machine-building enterprises and tool factories. The popularity of these machines is due to the presence of following operational benefits:

1. The machine bed is made of cast iron; its heavy weight prevents vibration during processing, which makes it possible to maintain a high milling point in any conditions.
2. The 676 series milling cutters are universal; they can process both small-sized parts and workpieces up to 80 cm long and 25 cm wide.
3. The equipment can be equipped with a slotting head, which will allow it to perform the corresponding operations.
4. The machines are relatively small in size among equipment in their class; if necessary, they can even be placed in a garage.

Also among the advantages, we note the wide range of rotation of the spindle heads, which allows you to select the optimal mode for processing metals of any hardness.

1.1 Milling cutter SF-676 in operation (video)

1.2 Equipment specifications

Let's look at the technical characteristics of the SF-676 machine:

• work table sizes: horizontal - 250*800, vertical - 250*630 mm;
• weight of the workpiece being processed - up to 100 kg;
• distance along the spindle-table axis - from 80 to 450 mm;
• spindle reach - from 125 to 375 mm;
• maximum spindle head travel: along the X axis - 300 mm, along the Y axis - 380 mm;
• highest spindle rotation speed: horizontal - 1630, vertical - 2040 rpm;
• number of rotation speeds - 16;
• cone standard - 40AT5;
• spindle head feed speed - 13-395 m/mm;
• number of innings - 16.

The SF-676 is equipped with a 3 kW electric drive; there is also an auxiliary motor for the coolant supply system, which powers an electric pump with a capacity of 23 l/min. The dimensions of the machine are 120*124*105 cm, weight - 1 ton. The cost of this model in a modern version varies between 700 thousand rubles.

Model 676P, similar in terms of layout and functionality, differs from SF-676 in the following parameters:

• 10 mm shorter distance along the spindle-table axis;
• vertical spindle headstock stroke 250 mm;
• main electric drive power 2.2 kW;
• weight 910 kg, dimensions - 126*121*178 cm.

The widely-universal milling machine 676P has been completely replaced by an analogue SF-676; today new batches of equipment are not being produced. On the secondary market, equipment can be found at a price of 250-300 thousand rubles.

2 Schemes and structural design

The bed of the wide-universal milling cutter SF-676 is made of cast iron; it acts as a load-bearing base on which the main structural components of the machine are fixed. A feed box and a speed unit are mounted on the left side of the frame. The headstock, on which a horizontal spindle is mounted, moves along its upper part. On the same headstock, if necessary, you can attach a vertical spindle (to the front end part).

The router support is mounted on vertical guides, and the table is mounted on horizontal guides. SF-676 is equipped with two work tables, the main one of which is horizontal; workpieces measuring up to 80 cm in length and 25 cm in width are mounted on it.

The electric drive of the machine is located in the lower part of the frame, on the base plate, inside of which there is a reservoir for coolant. All electrical equipment of the unit is located under the top cover of the frame, which provides free access to the equipment as needed.

The main functional elements of the design of the SF-676 router are the support and spindle head:

• the caliper holds and moves the working table of the machine in the longitudinal-transverse plane; it is driven by a running shaft, which transmits the torque coming from the engine to the feed box;
• the spindle head is connected to the feed box via a drum gear, the spindle itself is mounted on ball and radial bearings, the possibility of precise movement of the spindle is provided by the indicator holder.

5 built-in LEDs are responsible for illuminating the workplace. Also, the modern SF-676 has a digital display unit, which displays the parameters of the current operating mode of the machine.

The highly versatile machine SF-676 is a reliable and durable piece of equipment capable of operating in difficult conditions operation subject to maintenance standards. Maintenance must be performed regularly, within a strictly established time interval:

• every 10 hours of operation, the guides and lead screws are lubricated with liquid machine oil;
• every 40 hours, linear bearings are coated with machine lubricant; Litol and its analogues are suitable;
• every 400 hours, the belts in the feed box are inspected and adjusted; if wear or damage is detected, the belts must be replaced;
• screw assemblies are inspected and tightened every 400 hours.

Also, all moving parts of the router should be regularly inspected. Before putting the machine into operation for the first time after maintenance, the following points must be completed:

1. Check the presence and reliability of protective covers and covers.
2. Remove repair tools from the work area and clear the table of lubricants and liquids.
3. Start the machine and make sure it is working at idle speed.

The performance check begins with running the machine at the minimum spindle speed, after which the speed increases up to the maximum. In the main operating speed mode, the unit should operate for 2 hours, after which the spindle supports should not heat up to a temperature of more than 50 degrees.

After running at idle, the machine is checked under load. The unit should operate at maximum cutting force and at 25% overload (short-term). SF-767, in good condition technical condition, even when overloaded within the specified limits, does not produce vibrations that affect the accuracy of milling. The machine must be checked at an ambient temperature of +20 degrees, the recommended air humidity is 65%.