Zinc alloy diecastings have good machinability – providing high finish quality and productivity over a wide range of machining conditions. Long tool life, low cutting forces, good surface finish and small chip formation are easily achieved. Optimum conditions for one aspect of machinability (e.g. chip formation) are often different than those for another feature (e.g. surface finish). Tradeoffs are therefore required in some cases to achieve specific requirements. The rules below apply to all of the alloys featured in this publication and they also apply to the other zinc aluminium alloys (ZL12 and ZL27) that might be used to manufacture prototypes.
The following recommendations were derived from studies using high-speed steel and carbide tools for machining zinc alloys in various cast forms.
The conditions presented are intended to give good overall results. If one aspect of machining requires optimisation, other aspects may deteriorate. For example, optimum conditions for chip formation and cycle times (high speeds and feeds) are not the same as those for optimising surface finish, burr formation and tool life.