Non-free machining materials are often hard to cut, but are non-corrosive making them ideal for precision parts for medical and aerospace applications. Below is a list of the non-free machining alloys we most often work with.
Machines well despite long chips. Tool wear is drastically higher than all other plastics. Often used for medical components.
This alloy is often chosen for precision parts that need corrosion resistance. Requires a strong machine as material can be “gummy” in the machine.
304L is known for its toughness and ductile properties. Burrs are a challenge because this material is soft so it’s easier to push this material, rather than cut it. Often better suited to parts that utilize cold forming processes.
When heat treated, 440C has the highest hardness values of any stainless steel (Rc 60). Material is a challenge to machine due to its high carbon content. Primarily used for bearings or other precision part applications needing wear resistance, however, this material does not offer significant corrosion resistance.
This implant quality alloy is difficult to machine due to its soft nature. It produces razor sharp chips, which affect tool quality.
This material is very expensive, but can machine better than some implant quality stainless steels.
More difficult to machine than Grade 5 and requires fire safety measures on the machine.