Logistics of production processes. push system. pull system.

Logistics research can be divided into two areas:
1. The enterprise is considered as an independent unit and the focus is on operations related to the input and output of the material flow.
2. Attention is paid to the details of the passage of the product within the enterprise.

The organization of material flows within the enterprise should depend on the problem of product sales. In conditions of shortage, when there is complete confidence that the products will be sold, much attention should be paid to issues of high equipment utilization (increase in the shift ratio, equipment utilization factors in terms of time, power, volume of work), increase in production series, reduce the range of products, increase stocks . Under these conditions, products are released to the warehouse in accordance with the plan developed at the enterprise.

In conditions when the problem of implementation and unpredictability of demand comes to the fore, production to stock is replaced to a large extent by production to order. It becomes unprofitable to maintain large stocks and at the same time, one should not miss the opportunity to fulfill emerging orders[1]. Therefore, it is important to quickly adapt the system (enterprise) to environmental changes, which is ensured by the ability of its subsystems (purchase, warehouses, stocks, etc.) to quickly change the composition of the output stream.

Management of material flows within the framework of intra-production logistics systems is carried out on the basis of two main approaches.

The first approach is a system with “pushing out” (Push system) of the product (Fig. 1).


Fig.1 System with ejection of a product put into production

It assumes that the manufacture of products begins at one end of the production line, goes through a series of technological steps and ends with processing at the other end of the production chain. The material flow is “pushed out” to the recipient by a command received by the transmitting link from the central production control system. At the same time, upon completion of processing in one section, the product is transferred to the next, regardless of whether this section is ready to accept the product for processing or not. Each section has a production plan. However, it is impossible to create a “rigid” technological process, all the parameters of which would be accurately calculated in advance. Therefore, enterprises should always have a certain production stock, which plays the role of a buffer and increases the flexibility of the system. Push systems are known as “MRP systems”[1]. The above systems are largely characteristic of traditional methods of organizing production. The possibility of their application for the logistics organization of production appeared in connection with the widespread use of computers, which made it possible to increase the flexibility of this system.

The reduction of inventories while increasing the flexibility of production is facilitated by the system of in-line production with the “pulling” of products (Pull system) (Fig. 2).


Fig. 2 System with pulling a product put into production

This system involves the receipt of products from the previous site as needed. The central control system does not interfere in the exchange of material flows between different sections of the enterprise, does not set current production targets for them. At industrial enterprises, the plan has only a final assembly line, and from here information about the need to produce the necessary parts is sent to previous sections through special cards. The site plan is formed every day, which ensures the flexibility of the system[1].

Pull logistics systems include the KAN-BAN system [1].

In this system, two types of cards are distinguished: selection cards;
production order cards.

The selection card indicates the number of parts that must be taken from the previous processing site.

The production order card specifies the number of parts to be produced in the upstream department.

At the place of storage, the parts are loaded into a forklift in the quantity indicated on the selection cards. At the same time, order cards attached to them are removed from the boxes, which inform about the order for the manufacture of new parts in a strictly defined quantity. The site plan is formed every day. This provides system flexibility. Any movement of products without cards is unacceptable. Usually the CAN-BAN system is combined with a quality control system. This system does not require a total computerization of production, but it implies a high discipline of deliveries and a high responsibility of the personnel, which limits its implementation in various countries.

The production process is a total set of all the actions of people and tools necessary in a given production for the manufacture of a particular type of product.

The following production processes are distinguished:

1) basic. Technological processes during which changes in the geometric shapes, sizes and physical and chemical properties of products occur;

2) auxiliary. These are processes that ensure the uninterrupted flow of basic production processes, such as providing heat and electricity, repairing equipment, etc.;

3) serving. Processes that do not create any products related to the maintenance of the main and auxiliary processes (storage, transportation, cleaning, etc.).

The organization of any production processes must comply with the principles:

1) specializations. This is the organization of a specific production process using a certain type of equipment, technology, tools, technological equipment, raw materials, materials, labor of workers of a certain qualification. It can be subject, technological or subject-technological;

2) universalization. In contrast to the principle of specialization, it provides for the manufacture of products and parts of a wide range at each production link or the performance of various production operations;

3) proportionality. This is the presence of a certain ratio between individual elements to match the throughput of a particular workplace;

4) parallelism. This is the principle of rational organization of the production process, which characterizes the degree of combination (simultaneity) of operations in time and space (serial, parallel and parallel-sequential);

5) continuity. This principle involves the minimization or complete elimination of interruptions in the production process;

6) direct flow. Ensuring the shortest path for the movement of products between the individual stages of the production process and within them;

7) rhythm. The need to observe the same time intervals at all stages of the technological chain and the regular repetition of individual operations to ensure uniform output;

8) differentiation. Division of the production process between separate divisions according to technological, subject or other characteristics;

9) concentration. This is the concentration of the performance of certain homogeneous production operations in specific individual areas, workplaces, workshops and production facilities of the logistics system;

10) standardization. This is the application of standards, technical regulations or the development, establishment and application of uniform conditions that ensure the best flow of the production and technological process. The general production process consists of a number of production, technological and production-technological processes. In turn, technological processes are divided into phases, operations. The phase is a certain set of works, after which the object passes from one qualitative state to another and a certain part of the technological process is completed.

The following types of phases are distinguished: procurement, processing, assembly. An operation is a part of the technological process performed at one workplace, consisting of certain actions on a specific object of labor.

There are the following types of operations: manual, machine-manual, machine, automated.

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