Integral Logistics Management — Operations Management and Supply Chain Management Within and Across Companies

8.1.1b Manufacture of By-Products in Mechanical Production: Sheet Metal Working

Intended learning outcomes: Describe the manufacture of by-products in sheet metal working.

Continuation from previous subsection (8.1.1).

The second example is taken from sheet-metal working. Here, washers are stamped from a strip of metal. In this case, beyond the technical process itself, by-product production makes economic sense: it allows the fullest possible utilization of the raw material. Figure shows a section of the metal strip after a typical stamping operation.

Fig.        Washers stamped from a strip of sheet metal by a stamping press.

To utilize more of the strip when producing washer X, a small washer Y is stamped inside each large washer. In addition, the press stamps other washers, of a size determined by the honeycomb principle, between the larger washers. As a result, 5 parts are obtained from each pass of the stamping machine: 2 each of part X and part Y and 1 of part Z. This can be expressed as the goods flow shown in Figure The waste product obtained is the stamped sheet metal strip B′. There is an interesting parallel here to our first example: This stamping procedure makes sense only if the washers are separated out according to size. In the first example, it was necessary to separate the primary products (A, B, and C) from by-product (N).

Fig.        The manufacture of by-products in the sheet-metal working industry.

Continuation in next subsection (8.1.1c).

Exercise: Manufacture of by-products in mechanical industry
Try to produce a washer stamping pattern in such a way that the least amount of waste is produced. Be aware, however, that the need for the individual washers varies and over-production should be avoided.
The Flash animation shows a part of a continuous metal sheet from which the washers, etc. are cut.

Course section 8.1: Subsections and their intended learning outcomes