Vacuum Performance of Metal Additive Manufacturing Ti-6Al-4V UHV Chamber

The vacuum performance of the Ti-6Al-4V vacuum chamber, which was produced by additive manufacturing (AM), was measured. It was shown that a 10－6 Pa ultra-high vacuum was achieved by exhausting with a turbomolecular pump. The residual gases in the AM chamber were H2, H2O, CO, CO2, etc. as in a general machined stainless steel vacuum chamber. A vacuum with the order of 10－9 Pa was achieved by exhausting with a turbomolecular pump after baking. It was also shown that outgassing can be significantly reduced by vacuum firing, which is a heat treatment at high temperature in a vacuum furnace. We also developed a prototype vacuum transfer case with NEG coating by utilizing the roughness of the AM surface. The NEG-coated AM chamber achieved an order of 10－8 Pa without a vacuum pump. The results of this study show that metal AM can be utilized in the field of UHV.