(I) Process analysis of rough crankshaft machining

(1) If the blank quality is good, the machining allowance is small, and the machining allowance is evenly distributed, and the center of the crankshaft machining is basically coincident with the geometric center, it is not necessary to spend a high cost to purchase the centering device, and the geometric center hole is selected. , saving expensive quality centering equipment investment. At present, Western European countries recommend geometric center holes for good quality blanks after many years of practice.
 
(2) If the blank quality is poor, the margin for rough machining is large, and the margin is unevenly distributed, the center hole of the drill is preferred. Because the initial unbalance is large, if the geometric center hole is drilled and the mass distribution is uneven, the moment of inertia is large, which is easy to damage the precision of the processing equipment. Furthermore, in the case of fine balance, the dynamic balancing machine has certain requirements for the initial unbalance amount allowed to be balanced on the upper machine, and cannot be balanced beyond the specified requirements. In order to meet the balance accuracy requirements, it is also necessary to use mass centering to perform the first dynamic balance and control the initial unbalance. In the case of fine balance, the balance can be checked by the dynamic balance.