What is precision blanking?
First of all, we should know what is blanking? The stamping blanking process almost same with punching and trimming.
No matter what kind of stamping parts must have a blanking step to remove the material which you do not need. Sometimes blanking designed together with punching with one mold, we called it compound die stamping. The blanking process requires a blanking press, sheet metal stock, blanking punch, and blanking tool. Put the sheet metal on the blanking die, operate the blanking press, the blanking die will cut the sheet metal into required shape.
The blanking dies consists of two part: upper punch and bottom die. When they punch together, the fed sheet metal will be cut into customized shape. Upper punch and bottom die are made of tool steel or carbide steel. The carbide steel for tooling must be heat treated to get good strength and improve the surface abrasion performance. Between the punch and die, there have a small clearance, typically 10-20% of the material thickness. When the punch impacts the sheet, the metal in this clearance quickly bends and then fractured. The scraped material sheared off from the stock sheet metal. This is the whole process of blanking, and it mostly is the first step of manufacture for the stamping part. And it is also the simplest step compare with the whole process. Punching and trimming process is the same as blanking.
Typical blanking part with big burrs and rough edge, if the material thickness between 2.5mm to 4mm, there have 3 obvious zones on the cut-off surface, we call it rounded zone(rollover zone), fine zone(shear zone), torn zone(crack zone).
Blanking deformation process with stamping part