Push and pull production logistics systems. Comparative analysis of push and pull manufacturing logistics systems

Methods of organizing procurement.

Advantages and disadvantages of the main procurement methods

Advantages of the method	Disadvantages of the method
For bulk purchases
1. Simplicity of paperwork 2. Guaranteed delivery of the entire batch 3. Increased trade discounts	1. Greater need for warehouse space 2. Slow capital turnover 3. Increased storage costs
For regular purchases in small quantities
1. Accelerates capital turnover 2. Saving warehouse space 3. Reducing costs for documenting delivery, because an order is placed for the entire supply	1. The probability of ordering an excess quantity of goods 2. The need to pay for the entire quantity of goods in the order
When receiving the goods as needed
Features of this method: the quantity of goods is determined approximately, only the quantity of goods delivered is paid, and suppliers contact the buyer before completing each order. 1. Lack of firm commitments to purchase a certain number of goods 2. Minimum work on paperwork
When purchasing for immediate delivery
With this method, infrequently used goods are purchased - the goods are ordered when they are needed and removed from suppliers' warehouses	1. Increased costs associated with the need for detailed documentation for each order 2. Small sizes orders 3. Many suppliers
For daily purchases according to quotation sheets
When using this procurement method, cheap and quickly consumed goods are purchased. Quotation sheets are compiled daily (monthly) and include information about full list goods, required and available quantity of goods
Quoted - characterizing a certain ratio
1. Acceleration of capital turnover 2. Reduction of warehousing and storage costs 3. Timely delivery

Production logistics– management of material and accompanying information flows within the technological cycle of product production, ensuring timely release of products and provision of services with minimal costs.

Target: Optimization of the flow of material resources and work in progress within the framework of the production and technological cycle, covering the movement from the supply warehouse to the warehouse for the sale of finished products through a qualitative change in characteristics.

Tasks:

1. Maintain levels of all inventories of material resources, work in progress and finished goods

2. Support of performance indicators of the in-production transport and warehouse complex

3. Determination and optimization of production cycle time

4. Determination of operational logistics costs in the production of finished products

5. Selection of an internal production information and management system for internal flows

6. Waste disposal and efficient use of secondary material resources, reducing losses from defects in production

7. Ensuring flexibility of production logistics systems

Quality flexibility Productive capacity Quantitative flexibility

Universal service personnel Equipment reserve

Flexible equipment automation Labor reserve

14. Push manufacturing logistics systems: MRP I, MRP II.

Push system

MRP(material requirements planning) – automated system planning production needs for the necessary material resources.

Goals:

1. Satisfy the need for materials, components and products to plan production and delivery to customers

2. Maintain low inventory levels

3. Planning of production operations

Basic Operations:

1. Gross demand (for materials, taking into account the specifications and production program)

2. Net demand (for materials taking into account current stock and open orders) = gross demand - available stock - ordered stock

3. Time to place orders

4. Additional facts: discounts, minimum inventory levels, deviations in order lead time

Advantages:

¾ MRP operates on data about future needs, not about past ones

¾ Reducing the volume of inventories, that is, saving money, space, personnel, etc.

¾ Increased inventory turnover rate

¾ No delays caused by material shortages

¾ Reducing the number of urgent orders

¾ Using MRP data to plan other operations

Flaws:

¾ Large amount of information and necessary calculations

¾ Low flexibility does not allow you to quickly respond to external changes

¾ Availability of complex control systems

¾ Order size may not be effective

MRP II(modification of MRP) – a production resource planning system that allows you to plan requirements not only for materials, but also for other resources: employees, equipment, facilities, finances, etc.

15. Pull production logistics systems: “Just-in-time” and KANBAN.

Pulling system

Just-in-time- The main idea of ​​this concept is as follows: if the production schedule is predetermined, then the movement of material flows can be organized in such a way that all materials, components and semi-finished products will arrive in the required quantity, to the right place and exactly on time for production, assembly or sale finished products. In this case, insurance reserves that freeze the company’s funds are not needed.

The just-in-time concept includes the following Components :

1. Leveling up production.

2. Order in the workplace.

3. Production in small batches.

4. Reduced changeover time.

5. End-to-end preventative maintenance.

6. End-to-end quality control.

7. Purchasing using the just-in-time system.

8. Balanced production lines.

9. Flexible production.

10. Activities in small groups.

11. Staff training in the just-in-time system is carried out in short sessions (several hours a week) to avoid information overload.

The necessary conditions implementation of the J I T concept:

1. the presence of reliable suppliers in the economic system;

2. use of systems for exchanging information about the required MR, for example, kanban for JIT;

3. high speed of physical delivery of MR, including by reducing the time of intermediate storage and waiting for cargo processing;

4. accurate information about the current state of production, accurate forecasts for the near future. To achieve this, reliable telecommunication systems and information and computer support must be used in the organization and operational management of production processes.

The main advantages of just-in-time technologies are: explaining their widespread use in logistics practice are:

1. Low level stocks of material resources and finished products.

2. Reduction of production space.

3. Improving the quality of products, reducing defects and rework.

4. Reduced production time.

5. Increased flexibility when changing the product range.

6. Smooth flow of production with rare failures caused by quality problems; more short time preparation of the production process; multi-skilled workers who can help or replace each other.

7. High productivity and efficient use of equipment.

8. Participation of workers in solving production problems.

9. A good relationship with suppliers.

10. Less non-production work, such as warehousing and moving materials.

KANBAN– flow control system in pull-type production. Developed in 1972 At the Toyota Motors plant. " Kanban"(Japanese) – card, label.

Principle Kanban systems:

All production departments are supplied with material resources only in the quantity and within the time period necessary to fulfill the order placed by the consumer department.

Types of Kanban cards:

1. White (travel card) – addressed to the transport driver

2. Black (production card) – addressed to the worker and contains a production order.

Work cycle Kanban systems:

Let there be 2 workshops. Shop 1 uses parts A and produces parts B. Shop 2 uses parts B and produces parts C.

A workshop 1 B workshop 2 C

At the entrances to workshop 1 and workshop 2 there are containers with products A and B with white Kanban cards attached. At the exits there are containers with items B and C with black Kanban cards attached.

1. Shop 2 receives an empty container with a black card C. This means the receipt of a production order for the manufacture of parts C.

2. To fulfill the order, shop 2 uses the entire container of parts B and releases the white card.

3. A worker on a forklift picks up an empty container with a white card B.

4. A worker on a forklift with an empty container and a white card arrives at workshop 1, where he removes the black card from the container filled with parts B and attaches a white card from the empty container to it.

5. Free container with black card B is a production order for shop 1.

Advantages of the Kanban system:

¾ Reduction of inventories at all stages of the production cycle

¾ High flexibility

¾ Reduced paperwork

¾ Reduced production cycle

¾ Increased employee responsibility

¾ Improved quality

Flaws:

¾ Inability to cope with unforeseen circumstances

¾ Dependence on suppliers

¾ Costs for staff development

¾ Failure at one stage of the material flow leads to a failure of this system

Comparative analysis push and pull production logistics systems.

Pulling system– such an organization of the movement of material flows in which material resources are supplied to the next technological operation from the previous one as needed, and therefore there is no strict schedule for the movement of material flows.

Push system– such an organization of the movement of material flows in which material resources are supplied from the previous operation to the next one at the command of the central control system in accordance with a pre-formed rigid schedule.

Comparison of push and pull systems

Characteristics	Pulling	Pushing
1. Purchasing strategy (supply)	Focused on a small number of suppliers, deliveries are frequent, in small batches, strictly on schedule	Focus on a significant number of suppliers, deliveries are mainly irregular, in large quantities
2. Production strategy	Orientation of production to changes in demand and orders	Focus on maximum utilization of production capacity. Implementation of the concept of continuous production
3. Production planning	Begins with the assembly or distribution stage	Planning for production capacity
4. Operational production management	Decentralized. Production schedules are prepared for the assembly stage only. The execution of schedules of other stages is monitored by the management of the workshops	Centralized. Schedules are drawn up for all workshops. Control is carried out by special departments (planning, dispatching bureaus)

17. Combined production logistics systems: Lean Production.

Lean Production– a lean production system that involves eliminating the duplication of certain operations.

Lean manufacturing is a philosophy based on the idea of ​​continuous improvement by eliminating those activities that do not add value - first in a company's own manufacturing plants, and over time in the plants of key suppliers. In particular, lean manufacturing involves more effective time control at all functional levels by removing obstacles to the normal flow of resources and information. Of these obstacles, the most common are the so-called “seven disastrous losses”, which the Japanese call Muda:

• Overproduction;
• Unnecessary transportation;
• Downtime;
• Excess inventory;
• Marriage;
• Extra processing steps, excessive movement of people during work.

The goals of lean manufacturing are:

1. reduction of labor costs,
2. reduction of development time for new products,
3. reduction of product creation time,
4. reduction of production and warehouse space,
5. guarantee of delivery of products to the customer,
6. maximum quality at minimum cost.

The LIN approach allows you to better meet customer needs, while using fewer resources, in smaller areas, with less equipment, using less human effort, in less time.

Related information.

In logistics, there are two types of systems for promoting material flows: push and pull.

Push system 1 , is a system for supplying materials, parts or assemblies into a production process or from a previous technological operation to a subsequent one, regardless of whether they are needed at a given time and in a given quantity at a subsequent technological operation. The push system is characteristic of the traditional production organization; it is less capable of flexible restructuring and response to fluctuations in demand. In a push-type system, each technical unit, each technological limit has information and control connections with the central control body (Fig. 1).

Fig. 1. Diagram of material flow control in a push-type system

The first system, which remained essentially a push system, but already used the principles of logistics, was the MRP (material requirement planning) system. In the pushing system, a list is formulated necessary materials to produce a certain amount of finished products in accordance with the forecast of market conditions, then orders are generated for suppliers. MRP has a wide range of computer programs that provide coordination and operational regulation of supply, production and sales functions across the company in real time.

The MRP consists of a set of logically interrelated procedures, decision-making rules and records aimed at transforming the main production plan (GPP) into “net requirements” divided into time phases, and the planned “coverage” of these requirements for each item of material inventory that must be obtained in accordance with the GPP. The MRP system recalculates the actual requirements for materials, which occur either as a result of changes in the main production plan and available inventories, or as a result of changes in the composition of the components included in the final product. The MRP system achieves its goal by calculating the actual needs for each item of materials, placing these needs over time and determining the way to properly satisfy them.

The planning process in the MRP system begins with determining how much of the final product needs to be received on a certain date. The MRP breaks down time and requirements into component components based on the planned need for the final product.

Customer order Forecasted demand

List necessary Program Report on stored

materials MRP materials

Rice. 2. MCI system

The MRP system is used to ensure a smooth production process. It is designed to ensure effective planning of production resources so that there is no overstocking of materials and at the same time maintaining the necessary supply of materials to ensure the maintenance of the production process for a certain time.

Using the MRP system is especially convenient for planning and monitoring orders and receiving large quantities of various components and technological materials that interact with each other during the production process. Computerization is a necessary condition for using MRP.

The current MRP-2 system is considered as the second generation of the MRP system. The difference between the systems lies in the level of control flexibility and the breadth of functions performed. MRP-2 includes the functions of the MRP system in terms of determining the need for materials, as well as the functions of managing technological processes (see Fig. 3).

Rice. 3. Functional diagram of the MRP-2 system

To determine the need for materials, it is necessary to solve a number of problems, including forecasting, inventory management, purchasing, etc. Solution forecasting problems involves the development of a forecast of the need for raw materials and supplies separately for priority and non-priority orders, analysis of possible deadlines for fulfilling orders and levels of safety stocks, taking into account the costs of their maintenance and quality of customer service, retrospective analysis of business situations to select a forecasting strategy for each type of raw materials.

When deciding inventory management tasks are produced:

processing and adjustment of all information about the arrival, movement and consumption of raw materials, materials, and components;

inventory accounting at the place of their storage;

selection of individual strategies for replenishment and control of inventory levels for each item in the range of raw materials;

control of inventory turnover rate;

reserve analysis using the ABC method;

issuing messages about stocks approaching a critical point (order point), about excess stocks, etc.

For solutions procurement management tasks an orders file is used, into which information about orders and their execution is entered. Information can be provided at different intervals. It can be issued by supplier, customer, type of raw materials and materials, indicating additional data.

The principles of logistics are most fully embodied in pull-type production systems, which, unlike push systems, are based on the logic of the goal.

Pulling system 2 submissions parts and components from the previous technological operation to the subsequent one are carried out as necessary. When working using a pulling system, a strictly defined stock of finished parts and assemblies is created at each production site. The subsequent section orders and pulls products from the previous section strictly in accordance with the norm and time of production consumption. The pull system allows you to prevent the spread of fluctuations in demand or production volume from the subsequent production process to the previous one, minimize fluctuations in inventories at production sites, and decentralize the management of production inventories.

In a pull-type system, the control actions of the central body are applied only to the last unit of the logistics system at the output of the finished product, and information connections signaling the state of the subsystems are directed from the output to the input of the technological chain. The activity of the previous blocks of the logistics system appears only when, at the next stage, the level of the stock of materials reaches a minimum value. These connections ensure the implementation of the pulling principle of the functioning of the logistics system. Material flow management in such a system is presented in Fig. 4.

Rice. 4. Scheme for managing material flows in

pull type system

Of the pull-type systems, the most famous is the Kanban system (translated from Japanese as a card), which makes it possible to implement the principle of a Just in Time (JIT) supply system. This system was developed and implemented by Toyota (Japan).

The Kanban system does not require total computerization of production, however, it presupposes high supply discipline, as well as high personnel responsibility, since centralized regulation of the intra-production logistics process is limited. The Kanban system allows you to significantly reduce production inventories.

It is based on the management of material flows depending on the actual load of production subsystems. The very phrase “just in time” implies that materials should be available only when the enterprise needs them - not earlier, not later. An integral element of the JIT system are:

lack of material reserves;

fast delivery;

small, frequently replenished quantities of material;

high quality and absence of defects.

The experience of many leading foreign companies (such as IBM, General Motors, Toyota, etc.) testifies not only to the effect achieved through the practical application of the JIT system, but also to the complexity of the required reorganization of not only production, but also sales.

Other process control systems in logistics:

OPT system(optimized manufacturing technology) has been widely used in the US and other countries since the 1980s. The main principle of OPT is to identify “bottlenecks” or, in the terminology of the system’s creators, critical resources, which can be stocks of raw materials and supplies, machinery and equipment, technological processes, and enterprise personnel.

The rate of development of the production system depends on the efficiency of use of critical resources, while increasing the efficiency of use of other resources, called non-critical, has virtually no effect on the development of the system.

In the OPT system, a number of tasks of operational and short-term production management are solved in an automated mode, including the formation of a production schedule for the day, week, etc. When forming a production schedule close to the optimal one, the criteria of supply of orders with raw materials and materials, efficiency of resource use, minimum working capital in reserves, flexibility.

Product distribution management and planning system (PDP) allows you not only to take into account the situation, but also to actively influence it. This system ensures stable connections between supply, production and sales using elements of the MRP. Initially, the DRP carries out aggregate planning using forecasts and data on actual orders received. Next, a production schedule is formed, the production plan is disaggregated, and a specified plan is drawn up indicating specific dates, the number of components and finished products. And finally, using the MRP system, the need for material resources and production capacity is calculated for the production schedule.

The DRP system allows you to predict market conditions with a certain degree of reliability, optimize logistics costs by reducing transport costs and costs of goods distribution. Using DRP, you can plan supplies and inventories at various levels of the distribution chain and provide information support different levels distribution chains based on market conditions.

The final function of the DRP system is transportation planning. The system processes requests for transport services, compiles and adjusts transportation schedules in real time. Long-term warehouse operating plans serve as the basis for calculating vehicle requirements; adjustments to needs are made taking into account the operational situation. The basis of the DRP system database is information about transported and stored products received from the manufacturer, and information from warehouses.

Among domestic logistics systems, it should be noted integrated system of optimal transport services (ICSTS) . A necessary condition for its creation was the presence of stable transport links, and a sufficient condition was the organizational unity of the management structure of transport services. In the process of mathematical support for QSOTO, the following problems were solved:

Creation of an optimal system of permanent routes and construction of a mathematical model of in-plant transportation;

Optimization of the number of vehicles, construction of a mathematical model of the problem of optimizing the number of vehicles required to service technological transportation;

Modeling the technological process of inter-shop transportation;

Studying the dynamics of existing cargo flows at the enterprise, which allows you to create a mathematical model of inter-shop transportation and develop an algorithm for simulating the transportation of finished products for a given quantity, taking into account the minimization of transport costs;

Optimizing the structure of the company's vehicle fleet; on the basis of route schemes, volumes and technological processes of cargo transportation, a mathematical model is created and the problem of optimizing the transport fleet is solved; CSOTO also allows you to select a rational mode of transport to serve a local system or a separate route;

Creation of an optimal transportation system based on constantly operating routes, while optimizing the volume of the transport lot for goods transported in standardized containers;

Development of a methodology for determining unit costs for loading and unloading, transport and warehouse work during inter-shop transportation; at the same time, general and specific costs for these works are developed both for individual workshops and for the enterprise as a whole.

1. The order in which orders are processed by each link in the logistics chain is determined by a priority rule.

Priority rule - this is some expression that allows everyone application(order) to match a quantitative value called priority. The following priority rules are used.

elementary(simple) - to assign the priority of an application, use one of its characteristic:

FIFO (first in first out): “first in - first out”, i.e. applications are serviced in the order they are received into the system;

LIFO (last in first out): "last in first out", The application that entered the system last is processed first. This rule is often used in warehousing systems. This is explained by the fact that sometimes materials can only be obtained from above, i.e., the materials that were the last to arrive at the warehouse are available;

DDATE: rule of planned dates, The first order selected is the one with the shortest planned production time, i.e., which should be ready before everyone else;

SPT: shortest operation rule, The first to be serviced is the application that has the minimum duration of servicing the application;

MST: minimum slack time, The request with the minimum reserve time is served first. Reserve time is difference between deadline order and execution time this order does not take into account the waiting time for service;

RANDOM: the order of service may be random, the random variable is selected according to a uniform law, i.e. applications are selected with equal probability;

combined(complex) - to assign priority to an application, several of its characteristics are used with some coefficients:

additive - when forming a formula for calculating priority, addition operations are used;

multiplicative - When forming a formula for calculating priority, a multiplication operation or m.b. is used. exponentiation;

alternative.

2. "Pull" material flow management system - this is what it is production organization, with which details and semi-finished products are fed to the next technological operation from the previous one as needed, and therefore there is no strict schedule. Placement of orders to replenish inventories of material resources or finished products occurs when their quantity reaches a critical level (Fig. 1).

Material flow

Information flow

Rice. 1. "Pulling" system

An example of the functioning mechanism of a pulling material flow management system. The enterprise received an order from the consumer for the production of n units. products. The control system transmits this order to the assembly shop. To fulfill an order, the assembly shop requests n parts from shop No. 1. Having transferred n parts from its stock, shop No. 1, in order to replenish the stock, orders n blanks from shop No. 2. In turn, shop No. 2, having transferred n blanks, orders materials from the raw material warehouse for the production of the same number of blanks, also in order to restore the stock. Thus, the material flow is “stretched” with each subsequent link.

The system involves reducing the difference between the time of receipt of materials at the next stage of production, bypassing the stage of intermediate storage, and the time of their consumption. Goals of the "pull" system :

preventing the spread of increasing demand fluctuations or the volume of production from the subsequent process to the previous one;

Minimizing fluctuations in parts inventory between operations to simplify inventory management;

increasing the level of shop management through decentralization of management.

The “pull” system involves maintaining a certain level of inventory at each stage of production. For the practical implementation of the system, it is necessary to establish the moment of order renewal and the standard batch size of the ordered parts. The "pull" system assumes:

orientation of production to changes in demand, those. "flexible" production;

use of universal equipment, which is placed according to a linear or ring principle;

the use of highly qualified multi-machine workers;

decentralized operational control production;

starting planning from the assembly stage;

minimum operational backlog;

Virtually no stocks of finished products.

The "pull" system has some advantages over the push system because the individual shop staff is able to take into account many more specific factors that determine the size of the order than a central control system could.

3. "Push" material flow management system is a system of production organization in which objects of labor are transferred from the previous technological operation to the next one in accordance with a pre-formed rigid production schedule.

Material resources are “pushed” from one link of the production logistics system to another upon a command coming from the central production management system (Fig. 2).

"Push" systems are characteristic of traditional production methods.

Material flow

Information flow

Rice. 2. "Push" system

At the same time, when demand changes or disruptions in the production process, it is almost impossible to reschedule production for each stage. This leads to the creation of excess internal inventories between different process stages, called buffer stocks, which serve to increase managerial flexibility in those areas of production where supply disruptions may occur or working in small batches is uneconomical.

Standard production planning– this is the main one moment of organizational design, in which information about the dynamics of demand for products “joins” production schedules with decisions on supply services for production. Production flexibility in this case is increased due to the fact that production planning combines sales forecasts for a given period and the production schedule for each stage. However, the emergence of buffer stocks leads to the freezing of material and Money, installing excess production equipment and attracting additional labor when order size increases. This prevents the push system from becoming more efficient.

"Pushing " the system is characterized by:

focusing on a significant number of suppliers, irregular deliveries, mainly in large quantities;

orientation of production towards maximum load production capacity and implementation of the concept of “continuous” production;

planning, which begins with procurement production;

centralized operational production management; drawing up production schedules for all stages of production;

reserves in the form of excess material resources; lack of buffer stocks, which can lead to production failure; not always a minimum operational backlog; existence of stocks of finished products;

using specialized equipment, located in sections, and universal - according to the linear principle;

the use of highly specialized multi-machine workers;

solid(selective) control at all stages of production, which lengthens its duration.

Disadvantages of the "push" system:

Insufficient demand tracking;

Mandatory creation of safety stocks that prevent production disruptions as a result of changes in demand;

Slowdown in turnover of working capital as a result of storing inventories;

Increase in the cost of finished products.

Advantages of the push system: stability systems with sharp fluctuations in demand and low reliability of suppliers.

7.5.1. Pull and push logistics systems

Push system– this is an organization of MP movement in which MPs are supplied from the previous operation to the next one in accordance with a pre-formed rigid schedule. MRs are “pushed out” from one link of the LS to another (Fig. 7.9).

Rice. 7.9. Schematic diagram of the pushing system

The push system is traditionally used in manufacturing processes. For each operation, the general schedule sets the time by which it must be completed. The resulting product " pushed through» further and becomes a work-in-process inventory at the input of the next operation. Those. This way of organizing the movement of the MP ignores what the next operation is currently doing: busy performing a completely different task or waiting for product to arrive for processing. The result is delays in work and an increase in work-in-process inventories.

Pulling system – This is an organization of MP movement in which MPs are fed (“pulled”) to the next technological operation from the previous one as needed, and therefore there is no strict schedule for MP movement. Placement of orders to replenish MR or GP stocks occurs when their quantity reaches a critical level (Fig. 7.10).

Rice. 7.10. Schematic diagram of the pulling system

The pulling system is based on " pulling» product by a subsequent operation from a previous operation at the point in time when the subsequent operation is ready for this work. That is, when one operation completes processing a unit of production, a request signal is sent to the previous operation. And the previous operation sends the processed unit further only when it receives a request for it.

7.5.2. Material Requirements Planning (MRP)

When choosing a method for organizing MP management, it is necessary to find out what type of demand the organization is dealing with: dependent or independent. If the general demand is formed big amount individual buyers, each of whom, independently of the others, needs some product, then there is independent demand. In this case, a forecast is made and planning resource requirements(see clause 7.2). If, for example, a manufacturer uses a number of components to make a product, then the demand for each of these components is related to each other and depends on the production plan for the final product. In this case there is dependent demand. With dependent demand it becomes possible material requirements planning(material requirements planning) or MRP. The essence of this approach is to calculate the requirements for all types of materials, raw materials, components, parts necessary to produce each product from the main schedule in the required volume, and submit the corresponding purchase orders. The general sequence of actions is as follows:
1) the main schedule is “divided” into individual products, and the volume of their output is determined;
2) according to the specification sheets of materials, all types of materials, raw materials, components, parts necessary for the production of each product are determined, their quantity required to fulfill the main schedule (gross demand) is determined;
3) availability is checked for this moment all components (materials, parts, etc.) in the warehouses of the enterprise and the net requirement is determined, i.e. taking into account existing reserves;
4) the order submission time is determined based on the duration of deliveries and the time by which they must arrive, and other factors (minimum inventory level, minimum order size, reliability of suppliers, etc.).

Thus, with independent demand or in the absence of an MRP approach, inventories are not directly linked to production plans and therefore must be high enough to allow any possible demand to be met. When using MRP, inventory levels are low and are only raised just before order fulfillment.

MRP use case

One of the oldest airlines in the world, British Airways flies to 150 destinations and has over 1,200 routes. Its passengers consume 50 million servings of food per year. The airline prepares some of the food products in-house, and deals with such issues as dishes, drinks, dry food, cutlery, etc. On a typical flight, a Boeing 747 carries around 45,000 different items. In 1997, the company began implementing an MRP system for several million units of product from 300 suppliers. Ticket orders by passengers were taken as the main schedule. Comparing supply with known demand made it possible to eliminate many wastes, reduce inventories, warehouse space, inventory lead times, and shortages began to occur less frequently. Thanks to the new way of managing aircraft, British Airways saves about £4 million. Art. in year.

Benefits of MRP

· MRP operates with data not about past consumption, but about future needs.
· Reducing the volume of inventories, i.e. saving money, space, personnel, etc.
· Increasing the speed of inventory turnover.
· No delays caused by material shortages.
· Reducing the number of urgent orders.
· Ability to use MRP data for planning other logistics types of activities, both within the enterprise and in the supply chain.

MRP problems

· Requires a large amount of detailed and accurate information and necessary calculations.
· Low flexibility does not allow you to quickly respond to external changes.
· The presence of very complex control systems of large size and load, which can lead to a significant number of failures in the system.
· Order sizes suggested by MRP may not be effective.
· MRP may not take into account power and other limitations.
· Expensive and time-consuming implementation.

7.5.3. Manufacturing Resource Planning (MRP II) and Enterprise Requirements Planning (ERP)

MRP can be improved different ways, for example, taking into account when placing orders the possibility of combining several large orders into a larger one; combining demand for the same materials required by different types products; linking MRP with planning the use of suppliers' capacities, etc.

One of the major extensions of MRP is production resource planning(manufacturing resource planning) or MRPII. Materials are only one resource, but an organization needs to schedule other production resources: employees, equipment, facilities, finances, transportation, etc., which is what MRPII does. Let an organization use MRP to schedule the purchase of materials and the production of a number of materials within the organization. If you know when the materials produced internally should be ready, then you know when they should begin production. Thus, MRPII can set production schedules for components. In the same way, an organization can use component production schedules to develop schedules for the use of equipment, employees working with this equipment, traffic flows, product quality checks, etc. With this approach, schedules are drawn up for all operations. In the future, this approach can be applied to finance, marketing, sales, etc. Ultimately, a fully integrated system can be achieved in which the master schedule forms the basis for planning all of the organization's resources. Those. MRPII creates an integrated system for synchronizing all functions performed in an organization.

With all the advantages of MRPII, similar to MRP, the main disadvantages remain the lack of flexibility required in some situations and the complexity of implementing an integrated control system.

The extension of the MRPII approach to LC enterprises in accordance with the trend of external integration is called enterprise needs planning(enterprise requirements planning)or ERP. Let the manufacturer's MRP system determine the required supply volume of some material. Electronic Data Interchange can link the MRP system to the supplier's system. Then the supplier, knowing when and how much it must deliver materials, can begin scheduling its operations to meet the deadline. If second-tier suppliers are linked to the first-tier supplier's MRP system, they can also begin their preparations. In this way, the original message moves backwards through the supply chain, enabling integrated planning throughout the entire LC.

Technically, the implementation of an ERP system is helped by electronic data interchange, an electronic payment system, the Internet, etc. The problems are to achieve complete trust between organizations, to ensure the presence of consistent systems at different enterprises, etc. ERP software has been available since the 1990s. Currently, the market for it is developing very quickly, with companies such as SAPAG, BAAN, JD Edwards, SSA, PeopleSoft, Frontstep Inc. present on it. Some companies, for example, Frontstep Inc. operate in Russia and the CIS, and software adapted to Russian legislation and working conditions in Russian markets.

Let us summarize the basic information about the concept of “requirements/resource planning” that underlies the MRP, MRPII, and ERP systems.

Concept idea “needs/resource planning” – first, it is determined how much and in what timeframe it is necessary to produce GP, then the time and required quantities of MR are determined to fulfill the production schedule. The concepts of “requirements/resource planning” implement pushing systems.

primary goal concepts – ensuring the flow of planned quantities of MR and product inventories over the planning horizon.

The necessary conditions implementation of the “needs/resources planning” concept:
· use of effective mathematical methods of forecasting, planning, organization of production processes;
Availability of computer technology that allows automate solving optimization problems, planning and production management, operational management technological processes;
· the presence of organizations in the LC with a desire for long-term cooperation (for ERP).

7.5.4. Just in time (JIT) concept

A number of companies, Toyota among the first, spent years developing the concept in the 1970s "right on time"(just in time) or JIT another name for just-in-time. These methods have proven so effective that all major organizations now use elements of this approach to one degree or another. The traditional approach to organizing work assumes that inventory is an important element of the entire system, ensuring that operations do not fail. MRP reduces inventory by using the master schedule in a manner that provides a closer match between supplies of materials and demand for them, while still maintaining some safety stock in case of unforeseen problems. Obviously, the higher the degree of correspondence between supply and demand is ensured, the less inventory we will need. If we can completely eliminate the mismatch between supply and demand, we won't need inventory at all. Just-in-time work is based on this.

Interesting example, illustrating the essence of just-in-time work, consists in operating a gas stove using bottled gas and gas supplied through a pipeline. In the first case, sometimes there is a discrepancy between the availability of fuel in the cylinder and the need for it. To eliminate interruptions, you need to purchase gas cylinders in advance, i.e. create a stock. In the second case, gas supply exactly matches demand, and the consumer does not have any fuel reserves.

This concept is based on the belief that inventories arise due to poor management, poor coordination of work, and therefore problems are hidden in inventories. From this follows the conclusion that it is necessary to find the reasons causing the difference between supply and demand, improve the execution of operations, after which the stocks will disappear. In a broader sense, JIT views the enterprise as a set of problems that prevent effective performing operations, such as long lead times, instability in order delivery, unbalanced operations, limited capacity, equipment breakdowns, defective materials, work interruptions, unreliable suppliers, poor quality of GPs, too much paperwork and many more. Managers try to solve these problems by creating reserves, purchasing additional capacity, installing backup equipment, inviting firefighting specialists, etc. However, in reality, these actions only hide the causes of the problems. The constructive approach is to identify the real problems and solve them. The JIT concept leads to changes in views in the following areas:
· Reserves. Organizations must identify and resolve problems leading to inventory, aiming for minimum (zero inventory) MR, WIP, WIP.
· Quality. It is necessary to achieve not acceptable level defects, but its complete absence on the basis of integrated quality management.
· Suppliers. Customers must rely entirely on their suppliers, so they need to establish long-term partnerships with a small number of reliable suppliers and carriers.
· Volume of batches. It is necessary to look for ways to reduce the volume of production batches, to achieve short production cycles so that excess production does not accumulate in SOE stocks.
· Lead time. It is necessary to reduce lead times to reduce uncertainties that can change the situation during long delivery times.
· Reliability. All operations must be performed continuously without failures, i.e. there should be no equipment breakdowns, defects, absenteeism, etc.
· Workers. A spirit of cooperation is necessary, both between workers and between managers and workers, because... the well-being of everyone depends on overall success at work; all employees should be treated equally and fairly. Any creative initiative expressed by any employee regarding possible improvements in work is encouraged.
· Information support should allow for the rapid exchange of information and synchronization of all processes of MR delivery, production and assembly, and GP supply.

Thus, JIT is not only a way to minimize inventories, but also to eliminate waste for any type of resource, improve coordination and increase operational efficiency.

JIT example

The famous American motorcycle manufacturer Harley-Davidson faced increased competition from Japanese companies in the 1970s: Honda, Yamaha, Suzuki and Kawasaki. Most previously stable companies in this industry have gone bankrupt. The four Japanese companies could supply their motorcycles almost anywhere in the world with higher quality and lower prices than their competitors. In 1978, Harley-Davidson tried to prove in court that Japanese companies were selling motorcycles at dumping prices, i.e. below their cost. But during court hearings it turned out that the operating costs of Japanese companies are 30% lower than those of Harley-Davidson. One of the main reasons for this state of affairs was their use of the JIT operating mode. Therefore, in 1982, Harley-Davidson began developing and implementing a materials-as-needed program, similar to JIT. The company struggled at first, but over the course of 5 years, it had reduced setup time by 75%, reduced warranty and waste costs by 60%, and reduced work-in-process inventories by $22 million. During the same period, the company's productivity increased by 30% and the company is now doing well in the market.

Benefits of JIT

Some organizations that have implemented JIT have seen inventory reductions of up to 90%; areas where work is performed – up to 40%; supply costs – up to 15%, etc. The benefits of JIT include:
· reduction of inventories of materials and work in progress;
· reduction of inventory lead time;
· reduction of production time;
· productivity increase;
· use of equipment with higher load;
· improving the quality of materials and GP;
· reduction of waste volume;
· more responsible attitude of employees to work;
· improving relations with suppliers;
· developing the habit of constructively solving problems that arise during work.

JIT Implementation Challenges

· High initial investments and costs for implementing JIT (purchase of high-quality expensive modern equipment, costs for training specialists and high wages, increased production costs due to small production batches, etc.).
· Inability to cope with unforeseen circumstances (breakdowns, strikes of supply workers, etc.);
· Dependence on the high quality of supplied materials.
· The need to operate in a stable production environment, although demand often fluctuates.
· Reduced flexibility in meeting changing consumer demands.
· Difficulty in reducing changeover time and associated costs.
· Inability of individual suppliers to operate in a JIT manner.
· Problems of linking JIT to other information systems of partners.
· The need to change the general layout of structures.
· Work of employees in an environment of increased stress.
· Lack of spirit of cooperation and trust among employees.
· Failure of individual employees to take on greater responsibility.

7.5.5. Effective Customer Response (ECR) Concept

JIT forces suppliers to change the way they operate to ensure faster deliveries, higher quality, smaller batch sizes and absolute reliability. An obvious way to meet these demands is for suppliers themselves to adopt JIT practices. This ensures that the entire LC operates in a coordinated manner based on the same goals and principles. Concept effective response to consumer requests(efficient consumer response)or ECR involves expanding the JIT zone to the entire supply chain. Other names used are quick response (QR) and continuous replenishment planning (CPR). In an ECR environment, the required materials are communicated backwards through the supply chain, causing the MRs to move forward, i.e. ECR “extends” MR through organizations included in the LC.

Examples of using MRP

In 1985, one of the world's first ECR partnerships was formed in the United States, involving retailer J.C. Penney, textile manufacturer Burlington and clothing manufacturer Lanier Clothing. As a result, they increased sales by 22% and reduced inventory by 50%.

Much interest in ECR arose in the second half of the 1990s in the grocery industry. Currently, in supermarkets using this approach, when a pack of cookies is sold to a customer, the cash register automatically sends a message to the supplier to replace this pack, after which the supplier's system sends a similar signal to its supplier, i.e. this signal goes back along the entire circuit. It was within the framework of ECR ​​that the technology arose seller managed inventory(see clause 1.3.5).

Necessary conditions for implementing the just-in-time concept

· Availability of reliable suppliers in the economic system. For example, American and European manufacturers were able to introduce this concept 10-15 years later than the Japanese due to low supply reliability.
· Partnership relationships between organizations in the supply chain.
· Use of systems for exchanging information about required MRs, such as Kanban for JIT and Electronic Data Interchange for ECR.
· High speed of physical delivery of MR, including by reducing the time of intermediate storage and waiting for cargo processing.
· Accurate information about the current state of production, accurate forecasts for the near future. To achieve this, reliable telecommunication systems and information and computer support must be used in the organization and operational management of production processes.

ECR Implementation Challenges

· Seasonality of production of some supplied inputs, such as agricultural crops.
· Disagreement of any of the LC organizations (does not want or cannot) to work in ECR mode - this interrupts the flow.
· If the LC crosses a boundary where the MP is slowing down, or encounters other problems that reduce performance, ECR does not work.

Let us summarize the basic information about the just-in-time concept underlying the JIT and ECR systems.

Concept idea "right on time" – synchronization of the delivery processes of MR and GP in the required quantities exactly at the moment when the links in the logistics chain need them to fulfill the order specified by the consumer department. Just-in-time concepts are implemented pulling systems.

Target concepts "right on time" – minimizing costs associated with creating inventories.

Previous

This is a production organization system in which materials, parts, semi-finished products or components are supplied to the subsequent technological operation (to a work center or production unit) from the previous one (previous) as needed (see figure).

The advantages of pull material flow management systems include the following:

1. the system involves calculating and creating on its basis the amount of working reserves at all workplaces;
2. the system is widespread in mass production based on the combination of modules;
3. response to market demands is fast.

The following features are considered to be the disadvantages of these systems:

1. an enterprise that has implemented a pulling system is faced with limited possibilities for planned coordination and adjustment of plans, as well as the actions of all production departments for future periods;
2. Until the order is received from the previous technological link, there is uncertainty in the planning of the actions of production departments.

The pulling system for managing material flows was implemented in practice in the form of the “kanban” system, developed by the Japanese corporation Toyota Motor in 1972 and implemented at the Takahama plant, which is located in Nagoya.
On Toyota the system " kanban" developed as a means of operational management of production within a month and historically was a consequence of the development of the "just in time" system. " Kanban"is an internal production system that allows you to minimize the duration of the production cycle, eliminate warehouses of raw materials, materials, components, finished products from the production units of the logistics system and reduce to a minimum the possible volumes of interoperational inventories.
The principle of operation of the system " kanban» – ensuring production of products at sites only in the required quantity and only at the right time. According to this principle of the system " kanban“Only what is “required” at the “output” goes into production. In other words, the product is produced without unnecessary production losses at the time of demand: production is directly related to real consumption, bypassing the formal stages of “paperwork”.
« Kanban" is a label or accompanying card for each part produced, where there is information about it and recommendations for its use in the production process - "Who? Where? When?". That is, the accompanying cards indicate the type and quantity of products that should come from the previous site, and where and by whom they should be used. In fact, " kanban» organizes work operating system(production) as a single conveyor: if at one of the stages of the production process there is a downtime (temporary delay), the conveyor stops. The reason may be the lack of resources (materials, semi-finished products, products, etc.) necessary to perform subsequent operations, or cards (to perform previous operations). This is the main advantage of the Kanban system - to quickly see a problem (mainly of an organizational nature) and immediately solve it. The complexity of using the system " kanban"is that for normal operation, production must be adapted to rapid and, at the same time, smooth changes in the volume and range of products entering the main conveyor, that is, the entire line must be fully equipped with the necessary parts. In addition, for the effective functioning of the kanban system, it is necessary to align production in technical and organizational aspects. It is thanks to leveling that it is possible to reduce interoperational backlogs to a minimum and increase the rhythm of production. This is also one of the tools for increasing the sensitivity and flexibility of the intra-production logistics system to changes in the market environment. In leveling lies the reserve of capacity of the intra-production logistics system itself, which is a reserve of its stability and survivability.
After the system was implemented at the Toyota car company, components began to be delivered to the assembly site no earlier than two hours in advance - if this is done earlier, then there will simply be nowhere to put them (the parts): the Japanese do not have utility rooms, everything goes into use instantly. This results in a savings of $64 per Toyota. And, accordingly, it is unthinkable to exceed the plan. Just the right amount is needed. This is how we can once again describe the advantages of implementing the system.