This week’s blog post will focus on our printed prototypes and the overall beer faucet assembly. Before delving into the results of our printed prototypes, I’d like to recap the three parts that our group is creating. These three parts include a beer tap, an aesthetic attachment that allows two glasses to be filled at once, and an aesthetic attachment with a pinwheel that causes aeration of beer flowing through it. The CAD models of these three parts are displayed below:
From left to right: (A) Beer tap, (B) attachment that can fill two glasses, and (C) attachment with pinwheel.
Printed Prototypes
Over the past two weeks, our group has been able to print our three parts using the FDM printers available for this course. Parts (A) and (C) took approximately 4-5 hours to print, while part (B) took nearly 18 hours to print using the FDM printer. After our first attempt at printing the parts, the following observations were made: part (A) was printed most accurately with no visible failures, part (B) failed due to the FDM ceasing production part-way through the print, and part (C) failed due to the FDM extruder nozzle crashing into the part after reboot. Images of our first attempts for parts (A) and (C) are shown below.
From left to right: First attempts at printing part (A) and part (C)
As we’ve mentioned in our previous blog posts, one of the main goals of our printed prototypes is that they are water tight. Unfortunately, due to being failed prints, our first attempts at parts (B) and (C) have been unable to be tested for water tightness. We were, however, able to test part (A), and it was found to not be water tight.
Assembly of Prototypes
Of course, one of the main goals of this blog post is to discuss the problems encountered during assembly, so our team decided to reprint parts (B) and (C) in order to evaluate how well they could attach to part (A).
Parts (A) and (B) Assembly
The second attempt for part (B) was produced using the SLS printer. For the SLS, part (B) was designed to be smaller than the first attempt on the FDM. Unfortunately, the SLS print for part (B) used a CAD file with threads modeled incorrectly, so part (B) could not attach to part (A).
Parts (A) and (C) Assembly
The second attempt on the FDM printer for part (C) proved successful and the part could be tested with part (A). Before attaching the part, a problem was noticed immediately; part (A) had a threaded male attachment, while part (C) was a female attachment with no threads. Ideally, both parts would be designed to either utilize a press-fit attachment or a threaded attachment; however, part (C) still fit securely into part (A) as a press-fit attachment.
Part (A) Discussion
Although the assemblies of Parts A+B and A+C were not completely successful, it is expected that problems still would have been encountered if parts (B) and (C) had the correct male threads. This is due to the slight warpage of part (A) near its attachment threads. Additionally, the FDM printer is not capable of the level of resolution that an SLS printer can achieve, so the threads may not have worked correctly with either part (B) or (C).
Moving Forward
In the upcoming weeks, we will be printing additional attempts of all three of our parts, optimizing each part in order to improve water tightness and accuracy of mating surfaces and to decrease build time and support structure usage. Specifically, in order to improve water tightness we will experiment with increased wall thicknesses and fill densities. Additionally, to further optimize the parts, we will experiment with build orientation.
Throughout the design process thus far, one goal of the project has been to determine whether an FDM printer or and SLS printer would be best for the creation of parts (A), (B), and (C). From conversations within the group, it has become clear that the SLS printer is the desired process for our parts. This is because the SLS is capable of printing multi-component sub-assemblies as single parts, can produce high-resolution functioning threads, can produce improved surface finishes compared to the FDM printers (this is an excellent feature for the interior of the pipes where beer flows through), and SLS printed parts do not require support structures. As a result, in the future, if possible, parts (A), (B), and (C), will be printed using an SLS printer.