Thank you Phaedrux for your response. This is my master's degree project I am doing at school. In my labotary, students have studied the MIM process with very low viscosity feedstock since the past 8-10 years. I am the first student to try and print their custom feedstocks. I designed and fabricated this inverted delta printer to validate that it is possible to print such feedstocks. I think the school will buy the Desktop Metal Studio during summer, but I won't be able to use it before the end of my program.
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The piston type extruder has not been used a lot for 3D printing metal paste, because you need to remove air almost completely from the feedstock prior to printing due to the compressibility of air. Once this is done, controlling the flow rate is much easier with a piston type extruder because the is no slippage possible as with filaments and screw extruder. Filaments are not the best solution because it limit the solid loading (the amount of metal powder compared to the binder). Desktop proposes a 6 mm rod, which is better than filaments, but from what I read, there is still some slippage (some articles say that they increased the flow multiplier up to 127% to reduce the interlayer voids, which means that there is slippage). If I increase my extruder flow rate to 127%, the part will be overfilled by a lot.
I am not saying that the piston type extruder is without problems. I had great success with bigger nozzles (0.8 mm), but I am still working on making better prints with the 0.4 mm nozzle. If you guys are interested, I might be able to show what I am able to acheive with this setup, I just need to confirm with my supervisor that it is okay to do so.
