Basics of MRP-MRPII class systems. MRP II - history and modernity Components of the mrp system
One of the most popular logistics concepts in the world, on the basis of which a large number of micrologistics systems have been developed and operate, is concept of “requirements/resource planning”(requirements/resource planning , RP). The RP concept is often contrasted with the just-in-time logistics concept, meaning that push-type logistics systems are based on it (unlike the JIT approach).
Push (pull) system is a production organization system in which parts, components and semi-finished products are supplied from the previous technological operation to the next one in accordance with a pre-formed rigid production schedule.
Material resources and semi-finished products are “pushed” from one link of the production logistics system to another. In a similar way, finished products are “pushed” into the distribution network. A common disadvantage of the push system is insufficient tracking of demand with the mandatory creation of safety stocks. It is the presence of safety stocks that allows us to take into account changes in demand and prevent production disruptions. As a result of storing inventory, turnover slows down working capital enterprises, which increases the cost of production of finished products. Proponents of this concept, comparing it with the Just-in-Time concept, note the greater stability of the “push” system in the face of sharp fluctuations in demand and unreliability of resource suppliers.
Based on the established production schedule, MRP I systems implement a time-phase approach to establishing the value and regulating the level of inventory. Since this, in turn, generates the volume of required material resources for production or assembly of a given volume finished products, then MRP I is a typical “push” type system, an enlarged diagram of which is shown in Fig. 4.
Basic micrologistics systems based on the concept of “requirements/resource planning” in production and supply are systems of “materials/manufacturing requirements/resource planning, MRP I / MRP II”, and in distribution (distribution) - systems, “product/resource distribution planning” (distribution requirements/ resource planning, DRP I / DRP II).
Material flow
Order
Fulfillment of an order
Fig.4. MRP I as a “push” type system;
MR - material resources; WP - work in progress; GP - finished products
The MRP I system was developed in the USA in the mid-1950s, but became widespread in both the USA and Europe only in the 1970s, which was associated, as already noted, with the development of computer technology. Micrologistics systems similar to MRP I were developed around the same time period in the USSR and were initially widely used in the military-industrial complex. The usual practice of using MRP I systems in business is associated with planning and monitoring procedures for ordering and supplying (purchasing) material resources, as a rule, a wide range for industrial enterprises manufacturing engineering products. The problems that arise during the implementation of the MRP I system relate to the development of information, software and mathematical support for calculations and the selection of a set of computer and office equipment, i.e. to those problems that are typical for automated control systems for production and technological processes. The purpose of implementing MRP I is to increase the efficiency and quality of planning resource requirements, reduce the level of inventories of material resources and finished products, improve procedures for controlling inventory levels and reduce costs associated with these logistics functions.
Practical applications typical of MRP I systems are in the organization of production processes along with the procurement of material resources. According to the definition of the American researcher J. Orlisky, one of the main developers of the MRP I system, the “materials requirements planning (MRP system) system in the narrow sense consists of a number of logically related procedures, decisive rules and requirements that translate the production schedule into a “chain of requirements” which are synchronized in time, as well as the planned coverage of these requirements for each unit of inventory of components required to meet the schedule. The MRP system reschedules the sequence of requirements and coverages as a result of changes in either the production schedule, inventory structure, or product characteristics.”
MRP systems deal with materials, components, semi-finished products and their parts, the demand for which depends on the demand for specific finished products. Although she herself logistics concept, which forms the basis of the MRPI system , was formed quite a long time ago (since the mid-1950s), but only with the advent of high-speed computers was it possible to put it into practice. At the same time, a revolution in microprocessor and information technology has stimulated the explosive growth of various MRP system applications in business. The main objectives of MRP systems are:
Improving the efficiency of quality planning of resource requirements;
Planning production process, delivery schedule, procurement;
Reducing the level of inventories of material resources, work in progress and finished products;
Improving control over inventory levels;
Reducing logistics costs;
Satisfying the need for materials, components and products.
MRP I made it possible to coordinate plans and actions of units logistics system in supply, production and distribution throughout the enterprise, taking into account constant changes in real time (“on line”). It is now possible to coordinate medium- and long-term supply, production and sales plans in MRP, as well as carry out ongoing regulation and control of the use of inventories.
In the process of achieving these goals, the MRP system ensures the flow of planned quantities of material resources and product inventories over the planning horizon. System
MRP first determines how much and in what time frame the final product needs to be produced. The system then determines the time and required quantities of material resources to complete the production schedule. In Fig.5. A block diagram of the MRP I system is presented.  |
Rice. 5. Block diagram of MRP I system
It includes the following information:
1. Consumer orders, forecast of demand for finished products, production schedule - MRP input I.
2. Database of material resources - nomenclature and parameters of raw materials, semi-finished products, etc.; norms of consumption of material resources per unit of output; timing of their delivery for production operations.
3. Inventory database - the volume of production, insurance and other stocks of material resources in warehouses; compliance of cash reserves with the required quantity; suppliers; supply parameters.
4.Software package MRP I - the required total volume of initial material resources depending on demand; chain of requirements (needs) for material resources, taking into account inventory levels; orders for volumes of input material resources for production.
5. Output machinegrams - a set of output documents: an order for material resources from suppliers, adjustments to the production schedule, delivery schemes for material resources, the state of the MRP I system, etc.
The input of the MRP I system is consumer orders, supported by forecasts of demand for the company's finished products, which are included in the production schedule (finished product release schedules). Thus, as with just-in-time micrologistics systems, customer demand is the key factor in MRP I.
Information Support MRP I includes the following data:
Production plan for a specified item for a specific date;
Materials data containing specific names of required parts, raw materials, assembly units indicating their quantity per unit of finished product;
Data on stocks of material resources necessary for production, lead times of orders, etc.
The database on material resources contains all the required information about the nomenclature and main parameters (characteristics) of raw materials, materials, components, semi-finished products, etc., necessary for the production (assembly) of finished products or their parts. In addition, it contains standards for the consumption of material resources per unit of output, as well as files of the times of delivery of the corresponding material resources to the production divisions of the company. The database also identifies connections between individual inputs of production units in terms of material resources consumed and in relation to the final product. The inventory database informs the system and management personnel about the presence and size of production, insurance and other required stocks of material resources in the company's warehouse, as well as their proximity to a critical level and the need for their replenishment. In addition, this database contains information about suppliers and parameters for the supply of material resources.
The MRP I software package is based on systematized production schedules (schedules for the release of final products) depending on consumer demand and comprehensive information obtained from databases on material resources and their stocks. The algorithms embedded in the system’s software modules initially translate the demand for finished products into the required total volume of initial material resources. The programs then calculate a chain of requirements for input material resources, semi-finished products, and work-in-process volumes based on information about the appropriate inventory level, and place orders for volumes of input material resources for production (assembly) areas of finished products. Orders depend on the specified nomenclature, volume of requirements for material resources and the time of their delivery to the appropriate workplaces and warehouses.
After completing all the necessary calculations, the output complex of machine diagrams of the MRPI system is generated in the company’s information and computer center , which is transferred in documentary form to production and logistics managers for making decisions on organizing the provision of production sites and warehouse facilities of the company with the necessary material resources. A typical set of output documents from an MRP I system contains:
Requirements for material resources ordered from suppliers specified in terms of nomenclature, volume and time;
Changes that need to be made to the production schedule;
Schemes for the delivery of material resources, volume of supplies, etc.;
Canceled requirements for finished products, material resources;
MRP system status.
However, the preparation of primary data requires significant costs and accuracy. MRP I is typically used in planning ordering and supply procedures for a large range of materials, for example, machine-building enterprises. The following disadvantages of micrologistics systems based on the MRP approach can be identified:
A significant amount of calculations, preparation and pre-processing of a large amount of initial information, which increases the duration of the production period and logistics cycle;
An increase in logistics costs for order processing and transportation as the company strives to reduce inventory levels or switch to producing finished products in small volumes with high frequency;
Insensitivity to short-term changes in demand, since they are based on control and replenishment of inventory levels at fixed order points;
A significant number of failures in the system due to its large size and overload.
These disadvantages are superimposed on the general disadvantage inherent in all “push” type micrologistics systems, which include MRP1 systems , namely: insufficiently strict monitoring of demand with the mandatory presence of safety stocks.
MRP I systems are primarily used when the demand for input materials is highly dependent on customer demand for final products. The MRP I system can work with a wide range of material resources (multi-assortment initial material flows). Although proponents of the just-in-time concept argue, and not without reason, that “pull” micrologistics systems based on the principles of this concept respond faster and more efficiently to changes in consumer demand, there are cases when MRP I systems are more effective. This is true for firms that have fairly long production cycles under conditions of uncertain demand. At the same time, the use of MRP I systems allows firms to achieve the same goals as when using JIT technology, in particular, to achieve a reduction in the duration of the full logistics cycle and the elimination of excess inventories, if the time for making decisions on managing production operations and purchasing material resources is comparable to frequency of demand changes.
course work
Introduction
The MRP-1 system is one of the most popular in the world, based on the logistics concept of “requirements/resource planning”. This system operates with materials, components, semi-finished products and their parts, the demand for which depends on the demand for specific finished products.
The main goals of this system are to meet the need for material resources for planning production and delivery to consumers, maintaining a low level of inventories of material resources, work in progress, finished goods, planning production operations, delivery schedules, and purchasing operations.
The basic idea of MRP systems is that any accounting unit of materials or components required for the production of a product must be available in right time and in the right quantity.
The need to plan the need for MR is due to the fact that the majority of problems in the production process are associated with the delay or advance of the receipt of components, raw materials and materials, as a result of which, as a rule, in parallel with a decrease in production efficiency, an excess (shortage) of materials received earlier occurs in warehouses or later than scheduled. In order to prevent such problems, the MRP I (Material Requirements Planning) methodology was developed. Created computer programs, allowing you to optimally regulate the supply of MR, control stocks in the warehouse and the production technology itself.
the main task MRP I - provide guarantees of the availability of the required quantity of required materials (components) at any time within the planning period, along with a possible reduction in current inventories, and therefore, unloading of warehouses.
One of the most popular logistics concepts in the world, on the basis of which a large number of micrologistics systems have been developed and operate, is the concept of “requirements / resource planning” (RP). The concept is often contrasted with the just-in-time logistics concept, meaning that push-type logistics systems are based on it.
Based on the established production schedule of the MRP I system, they implement a time-based - phase approach to establishing the value and regulating the level of inventory. Since this, in turn, generates the volume of required material resources for the production or assembly of a given volume of finished products, MRP I is a typical “push” type system, an enlarged diagram of which is given.
MR
MRP system as a whole:
Description of planning units and planning levels;
Description of planning specifications;
Formation of the main production plan graphic arts.
MRP subsystem:
Product management (description of materials, components and finished product units);
Inventory Management;
Product configuration management (product composition);
Maintaining a bill of materials;
Calculation of material requirements;
Formation of MRP purchase orders;
Formation of MRP orders for movement.
CRP subsystem:
Work centers (description of the structure of production work centers with determination of capacity);
Machines and mechanisms (description of production equipment with determination of standard capacity);
Production operations performed in connection with work centers and equipment;
Process routes, representing a sequence of operations performed over a period of time on specific equipment in a specific work center;
Calculation of capacity requirements to determine critical load and make decisions.
19. MRPII class systems. Differences from MRP, structure of MRPII system, advantages of using MRPII systems.
However, the MRP concept has a serious drawback. The fact is that when calculating the need for materials within the framework of this concept, neither the available production capacity, nor their load, nor the cost are taken into account work force. This deficiency was corrected in the MRPII (Manufacturing Resource Planning) concept. MRPII made it possible to take into account and plan all production resources of the enterprise - raw materials, materials, equipment, personnel, etc.
As the MRPII concept developed, the ability to account for other enterprise costs was gradually added to it. This is how the concept of ERP (Enterprise Resource Planning) was born, sometimes also called enterprise resource planning
The MRPII system should consist of the following functional modules (Figure 3):
Business development planning module determines the company’s mission: its niche in the market, assessment and determination of profits, financial resources. In fact, he states, in financial terms, what the company intends to produce and sell, and estimates how much money needs to be invested in the development and development of the product in order to reach the planned level of profit. Thus, the output element of this module is a business plan.
Sales planning module estimates (usually in units of finished goods) what the volume and dynamics of sales must be in order for the established business plan to be fulfilled. Changes to the sales plan will undoubtedly lead to changes in the results of other modules.
Production planning module approves the production plan for all types of finished products and their characteristics. Each type of product within the product line has its own production program. Thus, the set of production programs for all types of manufactured products represents the production plan of the enterprise as a whole.
Material Requirements Planning Module(or types of services) based on production program for each type of finished product, determines the required schedule for the purchase and/or internal production of all materials components for this product, and, accordingly, their assembly.
Planning module production capacity converts the production plan into final units of work capacity utilization (machines, workers, laboratories, etc.)
Feedback module allows you to discuss and solve emerging problems with suppliers of component materials, dealers and partners. Thus, this module actually implements the famous “closed loop principle” in the system. Feedback especially necessary when changing individual plans that turned out to be impracticable and are subject to revision
Figure 3. - Interaction of modules in the MRPII system
1. MRP (Material Requirements Planning)
MRP systems, the intensive development of the theory of which has been carried out since the early 60s, are currently present in almost all integrated information systems ah enterprise management.
Currently, the use of modern integrated systems in Russian enterprises has not yet found widespread use, especially the functionality of material resource planning (MRP)
In what cases is the use of MRP systems appropriate?
First of all, it should be noted that MRP systems were developed for use in manufacturing plants. If the enterprise has a discrete type of production (Assemble to order - ATO, Make to order - MTO, Make to warehouse - MTS, Serial - RPT, ...), i.e. when there is a bill of materials and product composition for manufactured products, then the use of an MRP system is logical and appropriate. If the enterprise has process production (Process Industry, Continuous-Batch Processing), then the use of MRP functionality is justified in the case of a long production cycle.
MRP systems are rarely used for planning material needs in service, transport, trade and other non-production organizations, although potentially the ideas of MRP systems can, with some assumptions, be applied to non-manufacturing enterprises whose activities require planning materials over a relatively long period of time.
MRP systems are based on planning materials for the optimal organization of production and include directly MRP functionality, functionality for describing and planning the load of production capacity CRP (Capacity Resources Planning) and are aimed at creating optimal conditions for the implementation of the production plan for production.
The main idea of the MRP system
The basic idea of MRP systems is that any accounting unit of materials or components needed to produce a product must be available at the right time and in the right quantity.
The main advantage of MRP systems is the formation of a sequence of production operations with materials and components, ensuring timely production of components (semi-finished products) for the implementation of the main production plan for the production of finished products.
Basic elements of MRP
The main elements of an MRP system can be divided into elements that provide information, software implementation of the algorithmic basis of MRP, and elements that represent the result of the functioning of the MRP software implementation.
In a simplified form, the initial information for the MRP system is represented by the following elements:
MRP elements
Master Production Schedule (MPS)
The main production plan, as a rule, is formed to replenish the stock of finished products or satisfy customer orders.
In practice, the development of the EPP appears to be a planning loop. Initially, a draft version is formed to assess the possibility of ensuring implementation in terms of material resources and capacities.
The MRP system details the operational planning in terms of material components. If the required item and its quantitative composition is not present in the free or previously ordered stock, or in the event of unsatisfactory planned deliveries of materials and components, the OPP must be adjusted accordingly.
After the necessary iterations, the operational process is approved as valid and production orders are launched on its basis.
Bill of materials and product composition
A bill of materials (BM) is a nomenclature list of materials and their quantities for the production of a certain unit or final product. Together with the composition of the product, the VM ensures the formation of a complete list of finished products, the quantity of materials and components for each product and a description of the structure of the product (assemblies, parts, components, materials and their relationships).
The bill of materials and product composition are database tables, the information of which correctly reflects the relevant data when changing physical composition product or VM, the state of the tables must be adjusted in a timely manner.
Stock status
The current state of inventories is reflected in the corresponding database tables indicating all the necessary characteristics of accounting units. Each accounting unit, regardless of its use in one product or many finished products must have only one identifying record with a unique code. Typically, an accounting unit identification record contains a large number of parameters and characteristics used by the MRP system, which can be classified as follows:
- Total information
- description, type, size, weight, etc.
- stock data
- stock unit, storage unit, free stock, optimal stock planned for order, ordered stock, distributed stock, batch/series attribute, etc.
- purchasing and sales data
- purchasing/selling unit, main supplier, price,
- data on production and production orders, etc.
Accounting unit records are updated whenever inventory transactions are performed, for example, planned for purchase, ordered for delivery, capitalized, scrap, etc.
Based on the MRP input data, the system performs the following basic operations:
- based on the operational planning process, the quantitative composition of final products is determined for each planning time period,
- spare parts not included in the operational documentation are added to the composition of the final products,
- for OPP and spare parts, the total need for material resources is determined in accordance with the VM and the composition of the product with distribution over planning time periods,
- the total material requirement is adjusted taking into account the stock status for each planning time period,
- orders for replenishment of inventories are generated taking into account the necessary lead times.
- The results of the MRP system are:
- schedule for the supply of material resources for production - the quantity of each accounting unit of materials and components for each period of time to ensure operational production.
To implement the supply schedule, the system generates an order schedule based on time periods, which is used to place orders to suppliers of materials and components or to plan independent production.
- changes in the supply schedule plan - making adjustments to the previously formed production supply schedule,
- a number of reports necessary to manage the production supply process.
One of the components of integrated enterprise management information systems of the MRP class is the capacity planning (CRP) system.
The main task of the CRP system is to check the feasibility of MPS in terms of loading equipment along production technological routes, taking into account changeover time, forced downtime, subcontracting work etc. The input information for CRP is the schedule of production orders and orders for the supply of materials and components, which is converted in accordance with technological routes into the loading of equipment and working personnel.
Typical functionality of MRP systems:
- description of planning units and planning levels
- description of planning specifications
- formation of the main production schedule plan
- product management (description of materials, components and finished product units)
- Inventory Management
- product configuration management (product composition)
- maintaining a bill of materials
- calculation of material requirements
- generation of MRP purchase orders
- generation of MRP transfer orders
- work centers (description of the structure of production work centers with determination of capacity)
- machines and mechanisms (description of production equipment with determination of standard capacity)
- production operations performed in connection with work centers and equipment
- technological routes, representing a sequence of operations performed over a period of time on specific equipment in a specific work center
- calculation of capacity requirements to determine critical load and make decisions.
2. MRP II (Manufacturing Resources Planning)
MRP II systems are a further development of MRP systems and are focused on effective planning of all resources manufacturing enterprise. In general, the following directions can be distinguished:
- business planning
- production planning
- formation of the main production schedule
MRP II systems involve the involvement of the financial component (business planning) in information integration. MRP II systems assume special tools for forming financial plan and budgeting, forecasting and traffic management Money, on the basis of which the possibility of implementing the production plan is determined in terms of available and expected funds.
3. ERP systems s
ERP systems (Enterprise Resources Planning), like further development Integrated enterprise management information systems, in addition to the above functionality, usually include planning of distribution resources (DRP - I, DRP - II), and resources for technological maintenance and repairs.
DRP systems provide the optimal solution (planning, accounting and management) transport tasks on the movement of material and technical resources and finished products.
In addition, MRPII and ERP systems are characterized by the presence of a special subsystem for managing the implementation of long-term projects ( Project Management), which involves fully functional planning of material resources, labor resources, equipment, formation of network work schedules, management of progress and invoicing of ongoing projects.