Miniaturized Diaphragm Vacuum Pump by Multi-Material Additive Manufacturing

This paper reports the first demonstration of a multi-material, fully additively manufactured, miniature diaphragm pump for creation and maintenance of low vacuum from atmospheric conditions. Using polyjet 3-D printing technology with 42 μm XY pixelation and 16 μm or 25 μm tall voxels, a single-stage vacuum pump design with active valves that has a total pumping volume of 1 cm 3 with 5% dead volume was implemented. Optimization of the devices resulted in manufacturing different constitutive parts of the pump in flexible materials of different stiffness. Finite element simulations of the pump design estimate at 0.20 MPa the maximum stress on the piston diaphragm root at full actuation, and at 106 Hz the natural frequency of the compression chamber. While operating at 1.82 Hz, the devices consistently pumped down from atmospheric pressure to 110 Torr in under 4 s, which is the smallest and fastest base pressure reported in the literature for a microfabricated diaphragm vacuum pump. In addition, the pumps can deliver mass flow rates as high as 200 sccm at 535 Torr, which is much higher than any of the reported flow rates from a diaphragm vacuum pump manufactured with standard microfabrication. The outgassing rate of the TangoBlack Plus® photopolymer used to print the pumps was measured and is on par with vacuum compatible elastomers. Compression chamber diaphragms exhibited lifetimes approaching 1 millioncycles, while the valves membranes have not leaked after over 2 million cycles.