As we are supplyier of Siemens Global , so durining daily manufacture , use forging process to get the raw blank is very common .Because for Siemens High voltage switch parts , ask parts with hardness and without hole , crack and others defects . Use forging process , can be less these defects . How do you think forging process ? Make or shape (a metal object) by heating it in a fire or furnace and beating or hammering it. Process is : hammer out , beat into shape , found , cast , take out the mold , then get the model .