DESIGNING A COST SYSTEM

Designing a Cost System

Designing a Cost System

The cost attribute 'geometry' consists of the global dimensions and the relations and tolerances between the components and features. The cost attribute 'material' consists of the material requirements for the components. The processes on assembly level are obvious; assembly processes are required to assemble components and/or (sub)assemblies. It is also possible that fabrication processes are applied.

At all levels, the cost attribute 'production planning' is concerned with the in-time availability of the required resources. In general, the in-time delivery is very important, so expensive resources might be applied in order to deliver on time. This is more likely than to produce with cheaper resources and exceeding the delivery date.

It is obvious that the cost attributes 'material' (on component level) and 'process(es)' (on all aggregation levels) determine the production costs. The other two cost attributes 'geometry' and 'production planning' have restrictions to the attributes 'material' and 'process(es)'. These attributes have to be taken into account, because they influence the cost attributes material and processes significantly. By taking into account the geometry and production planning as well, the origin of the product costs can be determined easily.

The product will not be treated entirely; only a number of aspects will be elaborated upon. The power unit assembly consists of a base component, consisting of a lot of holes and slots, a small strip, consisting of two holes and a form feature, and a cap to seal up the electrical components inside. The base and the cap possess a lot of holes, which are necessary for cooling. The number of holes depends upon the amount of heath produced inside the unit.

The global structure of the power unit assembly is given in Fig. 9. As shown, the cost attributes are allocated to assembly, component and feature level. For reasons of readability, the cost attributes are not filled in. The costs of the features are determined by the value of the cost attribute process(es). By adding the values of the cost attributes material and process(es) of component level, the costs of the component are obtained. Finally, by adding the costs of all components and the values of the cost attributes on assembly level, the costs of the complete assembly are obtained.

The structure of the upper face of the cap component is given in Fig. 10. The grey regions around one or more white rectangles represent the features of the upper face. The cost attributes are allocated to these features and to the component itself. The mutual relations between the faces are not represented in this figure. Two bending lines are shown in this figure. In ...