This was the last week of the project. We focused on printing our final designs and testing the functionality and connection of mating parts. All three final prints were designed to be printed with SLS. Unfortunately, we found out Wednesday morning that due to a computer glitch the final design of the Beer Flipper and Pin Wheel did not print. Therefore this blog post will focus on the the final design and testing of the Beer Tap and will talk only about our finalized designs of the Beer Flipper and Pin Wheel.
Beer Tap
The final design of the beer tap was printed with SLS and it was very successful. In the previous FDM print the wall thickness was increased from 1 mm to 2 mm in order to ensure water tightness. This same 2 mm wall thickness was kept for the SLS print. The detail of SLS allowed Josh and Brad to design three different thread connections: the tap handle connection, shank connection, and attachment connection. These threaded surfaces use 3/4-28 threads which can be seen in the picture below. All three sets of threads came out correctly and function well. Next the internal valves were placed inside the tap. The inside of the tap was designed to accommodate these valves and to create an effective seal with the valves. A picture of the valves inside of the beer tap can be seen below. The final print was then threaded onto an actual tap handle and was tested and proven to be both watertight and to provide an effective seal with the internal valves.
Pin Wheel
Unfortunately the pin wheel’s final design was not printed with SLS as was planned due to a computer glitch. However there were some improvements made for the final deign. In the previous FDM print the wheel and the axle were printed as two separate parts. Using SLS the wheel and the axle were going to be printed as one complete part. This would allow for less variation with the pinwheel and would allow for more accurate dimensions. In previous FDM prints there were clearance issues with the pinwheel rotation. The wheel was coming in contact with the spout when it rotated. The SLS print would have fixed this issue by giving ample clearance between the pinwheel and the spout and would have been a fully functioning part.
Beer-Flipper/Dual Filler
The beer-flipper/dual filler was also unfortunately not printed due to the computer glitch. Several design updates were made to it though. The first major update was the the threads. In our first SLS print the inner diameter of the threads was made to be .75 inches. This is the same as the outer diameter of the mating threads on the beer tap. This lead to the threads not matching up and actually acting more like a press fit assembly. In the final design we updated the threads to overlap with the mating threads allowing proper threading function. The other change made to the final design was eliminating the internal surfaces created by the STL file in our original design. These surfaces were created inside of the tube and completely blocked any liquid flow. The final design allowed for smooth uninhibited flow through the tube.
