When making powder metal parts such as belt tensioner pulley、MIM-Lock parts. Your supplier will place a precise amount of powder into the mold or cavity. A punch then compacts the powder, ensuring that every part of the die is filled. After release, the compressed part enters the furnace for sintering. This fuses the powder particles to form a hard or semi-finished product.
Compared with traditional processes, mesh forming has at least four advantages, but it also has limitations. The axial compression created by the movement of the punch into the die means that certain features cannot be formed. Either the powder doesn't move into the mold, or if it does, subsequent part release becomes difficult or even impossible. Design engineers often specify powder metal parts to take advantage of the material's unique capabilities. While most powder metal parts are made from iron-carbon-copper blends, there are other options that provide enhanced performance.
Typically, these metals add corrosion resistance, strength, and hardness, but there are other benefits. For example, nickel is used in heat-treated PM parts because nickel promotes better mechanical properties when heat-treated. Chromium improves tensile and fatigue properties, and niobium and vanadium refine grain size.
Harder materials are more difficult to machine (i.e. stainless steel vs. aluminum), but powder metals also pose their own challenges. The overall hardness may not seem particularly high, but don't underestimate the wear effect of pores in the part. Low porosity is inherent (and often desirable) in powder metal parts, however, this can result in micro-interrupted cuts that can lead to chatter, reduced cutting, and machine tool life.
To sum up, when machining powder metal parts, cutting forces tend to be higher and tool life is shorter. Also, flutter can be detrimental to surface finish, especially if aesthetics are related to your components.