Zinc alloys are generally easy to machine and do not cause many problems. However, as with any material, they exhibit specific behaviors that require certain considerations and adjustments by machinists to get the best results. Some core aspects of zinc machinability are discussed below.
Gummy Behavior
Zinc heats up quickly during machining. The thermal softening accompanying the temperature rise can lead to ‘gumminess’ in the material. This means that the zinc alloy tends to stick to the tool’s cutting edge, enhancing tool wear, and deteriorating cutting performance.
Low Melting Point
A similar temperature-related issue is that thermal softening can sometimes prevent machinists from taking an aggressive machining approach. For example, very high feeds may not be possible due to excessive material shearing.
Brittleness
Although inherently ductile, the brittle behavior of some high-aluminum alloy grades can create chipping issues.
Safety Hazards
While zinc machining produces short, manageable chips, fine machining or grinding applications may produce dust that should not be inhaled. Thus, it is recommended to have proper ventilation when performing such operations.
