Design
Maximising Value
In this context value can be thought of as the ratio of cost to benefits provided. It mostly depends upon getting the previously discussed details right and where necessary trading one against the others to provide the optimum solution for the particular application. Formal approaches such as Failure Mode and Effects Analyses can be useful in identifying the optimum solution.
When converting a component to a zinc alloy diecasting from some other manufacturing process, the potential for consolidation with mating components should be considered. It may be an obvious point but is sometimes forgotten and the opportunity to gain extra value is missed.
Occasionally a case can be made for splitting a component into two parts even though it may be possible to diecast it in one piece. For example when doing so enables net shape casting and hence substitutes an assembly operation for a machining operation, or where it permits the avoidance of a heavy section and hence cuts material cost and increases production rates.
In general the designer should be alert to the fact that a multiplicity of detail features can be added to castings to provide the product with extra attraction or to assist in secondary operations and assembly. The extra cost will be minimal if die members that are required by the basic geometry of the part can readily form them.
Value Analysis Check List
Check the design against this list before it is finalised.
If in doubt consult an experienced die caster.
Function:
Can more functions be accommodated by redesign of the part?
Material Specification:
Are you using the zinc alloy that will produce the most economical component?
Material Content:
Can wall thickness be reduced?
Is the component over engineered judged by calculation or physical test or compared with associated parts or competitors products?
Material Waste:
Can revised manufacturing methods reduce material waste?
Tolerances:
Are all the tolerances called for strictly necessary? Wider tolerances could make the part more economical.
Process of Manufacture:
Can a larger batch size reduce the cost?
Can minor design changes reduce machining operations?
Surface Finish:
Are finish requirements essential?
Can alternative methods of applying finish be used?
Is the design optimized for the proposed finishing operation?
Direct Labour Costs:
Can manual operations be eliminated or reduced by design or method change or improved plant?
Can assembly operations be reduced or simplified or automated?