In this paper, the design of a multi-material micropump will be described. The micropump inhibits a very simple design and therefore is very cost efficient. The pump consists of one plastic part, one metal diaphragm, and three piezo lead-zirconate titanate (PZT) ceramics. The PZT ceramics, glued on a metal diaphragm, form two active valves (inlet and outlet valve) and one actuation diaphragm. The valve seats, the pump chamber, and the inlet/outlet interfacing channels are formed in the plastic body. Due to its function principle, the micropump is able to pump bidirectionally. The design of the micropump covers bubble tolerant and self-priming features. Therefore, design measures have been carried out to realize a large compression ratio and to reduce the capillary pressures of bubbles in the pump chamber. The pump is able to handle gases and liquids. The plastic body is made of poly- ether-ether-ketone, and the metal diaphragm is made of stainless steel. Therefore, a good chemical resistance will be given. First prototypes of the actuation unit have been manufactured and tested successfully. Each actuation unit is able to perform a stroke of more than 40 mu m. Furthermore, the plastic body has been realized by milling, and preliminary measurements were carried out. For future work, the development and optimization of an improved micropump using microinjection moulding instead of milling are envisaged

Selective laser sintering (SLS) is used widely for additive manufacturing because of its many advantages including the ability to produce complex part geometries without trapping material in internal cavities, manufacturing speed, and reliable mechanical properties for the produced parts. 1 SLS utilizes a laser, powder feed system, heated powder bed, and heated build chamber to produce geometrically complex, three-dimensional parts. A slicing program takes an imported CAD model and transforms it into two-dimensional layers that are approximately 100 µm thick. The powder feed system spreads powder onto the preheated powder bed using a counter-rotating roller. After powder deposition, the laser precisely scans the powder bed utilizing a pair of galvanometers according to the two-dimensional model created by the slicer.The combination of preheating and the laser is used to bring the powder slightly above the melting point, allowing it to selectively bond to surrounding particles as well as to the powder layer below it. Following scanning of each layer, the piston supporting the power bed is lowered, another layer is spread, and the process is repeated until the fabrication is complete.Polymers such as nylon 11 and 12 are often used for direct selective laser sintering, due to their relatively large thermal processing windows and relatively low melting temperatures. Design rules have been studied extensively to provide guidelines to successfully resolve features for parts made with this process. Examples of design guidelines for SLS can be found in work by Allison et al 2,3 and Adam and Zimmer. 4 Studies have also been done to validate the strength, 5 surface roughness, 6 and porosity 7 of parts produced in this manner to drive design for end-use parts. Research in this field has focused on simple