Binder-free pressing of valve metal component such as tantalum - uses small amount of excess powder, supplemented by constant amount of fresh powder

摘要

Process is for the pressing of e.g. tantalum sinter bodies. The powder is fed from a storage in exactly proportional amounts into a press to fill a die holder. Excess powder is returned to the holder via the storage in a cycle. The ratio between pressed powder and excess powder is maintained relatively small, so that after each cycle, a constant amount of fresh powder is added. The press has a cylindrical upper punch to press the sinter bodies, and a cylindrical lower die with holder, to eject the pressed blanks. The head (7) of the lower die (7) has a small tolerance relative to the bores (2) in the holder (1), whiles its stem (8) has a relatively large tolerance. The shoulder between die head and stem forms an angle of =90 degrees.