Friday 14 December 2018

The MRP planning method.

A MRP planning method - Methodology MRP is designed, once known demand independent of the final products of an organization, quickly and accurately can calculate dependent demand caused by such products, and the needs that these productions they will generate.

It has been historically divided into two distinct methods, the "MRP I" and the "MRP II". Actually the "MRP II" is the evolution of the "MRP I". Today I present a really interesting topic. We have discuss many issues related to the quality and even of production systems already in this corner as the Just in Time. Today touches speak a closely related to this subject: MRP planning method.


The acronym "MRP I", come from the English "Material Requirements Planning". Which could be translate as "Materials requirements planning". This planning process, base on the matrix algebra of the Gozinto method, development it for the first time in the year 1954, Andrew Vaszonyi. It was announce through the publication of an article in the American magazine "Management Science". But until 1975, when Joseph Orliky, from IBM, published his book "Material Requirements Planning", it is not put into practice or are popularized under the name of MRP.

The MRP was create in 1954 but I will not apply until 21 years later, in 1975, when Joseph Orliky published his book, due to lack of computational capacity of the computers of the time. The MRP system needs high information, both the production process and the demand for the products. In such a way that it is not cost-effective to try it manually and 1954 computers were unable to treat her. The reliability of the MRP system will only the reliability of such data, so it is necessary that they are the most accurate possible.


Click here to see a short presentation that will help us better understand today's theme:

All the necessary information can be collected through three files or specific documents:

  • MPS (Master Production Schedule): Master Plan of production. Here is Indica demand and delivery of finish products. The demand for end products is independent, this can be known by the company. Or it may be an estimate base on past claims and the State of the market.

  • BOM (Bill of Materials): List of materials. Below the items and the quantity of each require to produce a final product. In a way, that if independent of the final products demand. Known demand dependent items that form the product can be calculate.

  • The State of the stocks. It is necessary to know the quantity of items in stock to be able to calculate. The real needs of each product and thus consume unnecessary stocks.

The Organization of the materials in the manufacturing process. It has been a problem to solve since prehistoric times, during the construction of the pyramids, for example.

Classic Methods

The classical methods of stock management and procurement of material, assume that the demand for all items is independent and practically homogeneous. So vast with calculating the size of lot more efficient for each product individually, without taking into account other products or their demands.

But in most cases these restrictions are not met. Products are formed by the union of various items and sub assemblies. In such a way that the demand for such items is directly dependent on demand for the final product marketed by the company.

Today, it is not acceptable to assume that the demand for all items is homogeneous. In the majority of articles can be checked seasonality, trends in demand... Markets evolve increasingly faster and not a homogeneous demand. It can be assume or you evolve, you back off.

MRP System

The MRP system is base on the basis that it is possible to know or estimate the demand for finished products. Since this is independent to the other products. You can meet directly will be the demand for the items that compose them and at that time will be necessary. Using this information, it is possible to calculate what must supply and/or manufacture. How much and in what time. This information allows to reduce the stock of the companies.

Know the amount of articles and in that time are necessary, reduces the safety stock, or completely eliminate the total stock of an item while it is not necessary. If we know the necessary demands at all times also be can calculate. The resources need in order to achieve such productions. The calculation of non-material resources (labor, necessary machines,) necessary is the section to be introduce more later by the MRPII system.

Classical methods are push systems, i.e. occurs regardless of demand, manufactured stock. Instead the MRP system is consider a traction system. In such a way that only produces what is really going to sell or has been sold at a given time.

The following diagram shows the general scheme of the implantation of an MRP I:

"MRP I" production system is a system for planning production and stocks that, taking into account the expect demand, updated stock, and deadlines for delivery or production; calculates: who, in that amount, and that moment must manufacture and/or supply each article to satisfy the demand. In this way, only manufactures claim by the market, avoiding the overproduction. MRP follows the same essential philosophy of the "Just in Time" (JIT), reduce intermediate stocks and waste in the production process. In many cases, it is possible to combine MRP with Kanban systems or other typical systems of the JIT philosophy of Japanese production is giving excellent results around the world.

The "MRP II".

The "MRP II" we can define it as 'Manufacturing Resource Planning “which could be translated as “Production resources planning". This system is an extension of "MRP I" so that, in addition to defining:

Who, how, and when it must produce; also defines which resources, in that amount, and in that time will be necessary to carry out such calculated production.

Another aspect of improvement of MRP II, is the increase in beforehand to the realization of the Master Plan of production. In order to ensure to a greater degree that the plan will be viable and that it won't be having to modify, lacking of value calculated before.

Using a "MRP II" system it is possible to plan and control capacity, define the master production plan, including financial aspects, take advantage of the historical information through the closed loop feedback for update the information on which the MRP calculations are perform, and the possibility of simulating scenarios for, base on the data obtained, take strategic decisions of the Organization in the long run. Ultimately, using a system "MRP II" is possible to plan the entire organization.

No comments:

Post a Comment