Manufacturing Master Schedule

The United States' manufacturing community moves fast, maybe too fast at times. In our haste to find the latest whiz-bang system to solve our problems, we tend to overlook the obvious—the basics. The master production schedule (MPS) and the bill of material (BOM) are two of the most basic elements of manufac­turing control. (Note: Throughout this paper, references to the BOM will mean the manufacturing bill of material.) They can, and should, be used to gain control of the company. This paper is not an introduction to master production scheduling or bills of material; it is assumed that these disciplines exist in one's environment. This paper cites three case studies where different MPS and BOM techniques were utilized to control companies.

Master Production Scheduling 101 tells us that every company has resources that have to be coordinated in order for the company to operate effectively. The first step, then, is to identify those items that should be mastered scheduled. The items could be raw materials, parts or assemblies. Or, they could be items that are less conventional, such as a bottleneck resource or a process, like the release of drawings from Engineering. In any case, the application of the concept is to master schedule those items that are key to regulating the business.

The MPS and BOM compliment each other. The BOM is the tool that makes the execution of the MPS possible. Once the MPS items have been identified, bills of material must be constructed to support them. This is an area of the concept application that typically causes organizational controversy, because bills of material must represent the way the product is built, not the way it is engineered or costed. Costing structures may have to change along with the bill of material. It is also safe to assume that the "as built" configuration of the products represented in the BOM's will be different than the "as designed" configurations maintained by Design Engineering. This condition is certainly acceptable, but it is at times difficult to accept by the engineers. Engineering, like all other support departments, must remember that a manu­facturing company manufactures for a living. Engineering, Finance, Sales, Materials, and others, are steps within the man­ufacturing continuum. When any of these disciplines isolates themselves from the continuum, problems arise, and the process will be disrupted. The results from these disruptions almost always carry dollar signs with them. If the understanding of these relationships does not exist in one's company, then all affected parties must be educated in the principles, quickly!

The companies referred to in this document are all manufacturing entities, but of significantly different character from each other. A brief profile of each will be helpful.

Company A is an automotive, original equipment manufacturer. This company produces fiberglass-reinforced plastic components for a variety of customers. They have a high-volume, repetitive process. The company produces its own molding compound, from

which it molds many of its own parts. The parts are combined with other purchased parts in an assembly process. The assembled products are then painted in a variety of colors for shipment. The product structure is simple. The total part number population is less than 1000. The company employs about 800 people, and has a sales volume of about $70 million per year.

Company B is an aerospace and defense subcontractor. The company produces large airframe structures for prime contrac­tors. The company (at the time of the study) had eight end items that move at relatively slow rates out the door. One to three shipments of finished products per week was typical. Each of the products had a very complex structure, with 5,000 to 15,000 components. Company B produced a large portion of its own components. Some of the components were machined parts; others, sheet metal; still others, bonded assemblies. The company made its profits in the final assembly portion of its business. The company employed over 7000 people at its peak, with a sales volume of about $700 million per year.

Company C produces pressurized containers for the industrial gas market. The product structures are fairly simple and the part number population moderate (3000 items). The company has shipped five to seven end products per month. There are basically three distinct product lines. Each product line has "models" that are different depending upon the customer. Company C is pri­marily an assembly shop, making very few of their components in-house. The company employed about 170 people and had a sales volume of about $25 million per year.

To be Continued

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