The size control of powder metallurgy parts is often affected by the uniformity of powder filling. The uneven shrinkage rate after sintering is caused by the uniformity of powder filling and the uneven density of embryo. Is there any way to improve it?

1. Powder with good fluidity should be used as far as possible. Generally speaking, powder with high density has a fast flow rate, which can shorten the filling time and improve the forming speed. The flow rate of the two powders is 28s/50g and 32s/50g respectively. The length distribution of the embryonic body produced by the former is narrow while that of the latter is wider.

2. New cartridges have been available in the market for the past year. The concept of the cartridges is to install ventilation lines in the cartridges to provide air flow so that the powder can flow easily, just like the powder in a fluid bed. The input value of this gas can be matched with the shape of the workpiece to achieve a very good effect. The standard tolerance of the thickness is reduced from 0.0016 "to 0.0004", so the effect is quite good.