Cutting fluids are important in machining zinc alloy castings. Such fluids lubricate and cool the tool and workpiece, minimize galling and burr formation, and promote good chip formation and surface finish.
Emulsifiable oils mixed with water are recommended over non-water-based fluids because of their superior cooling properties. About 20 parts water to 1 part oil by volume is adequate for most operations. Direct stream application to the cutting area is generally preferred to mist and spray application.