Week 3

The first print for the phone case began yesterday and was retrieved this morning. The print failed, interrupted while making the phone-bearing portion of the case, with many factors possibly responsible for this outcome. The case may have been set to print too thinly, resulting in the "spider webbing" effect that interrupted the print. This also could have been caused by an excessive overhang on the edge of the case, or the lack of support braces in the print. However, the printing technician indicated that the printer used has a reputation for spider webbing, and a higher quality printer may be able to complete the exact same print. Much of the case was completed before the failure, however, including the entire inside of the case that contains the amplifying horn. The print was cut in half to analyze the inside. Some complications inside the case were expected; because the concept of the horn requires an unobstructed pathway for sound waves, braces were omitted from the design. However, printing a hollow object without braces very often results in sagging; since the plastic is laid at melting temperature, the top portion of a print often caves in if no support is provided. Surprisingly, the hollow inside of the case was found to be perfectly smooth. This reveals that an essential component of the case design, the unimpeded hollow center, will not be as great a manufacturing obstacle as expected. The images below show the first print attempt, and the spider webbing that occurred at failure, as well as the inside of the case after being cut in half.

First print (rear)

First print (face)

Spider web that occurred during face manufacture

Inside view of hollow portion, no sagging evident

The CAD model of the case was redesigned with chamfered edges to increase the chances of a successful print. Only the top "half" of the case, which caused the failure in the first print, was printed in the second trial to save printer plastic. The second model printed successfully, but is too small for the phone. However, the alterations made at the edges of the case proved to result in a successful print, so the model will likely just need to be enlarged to fit the phone. Once the phone-holding portion of the case is perfected, it will be able to be combined with the sound-amplifying portion, and sound amplification tests will be performed. The next case design is expected to be complete and printed by Tuesday. If the case fits, another prototype will be printed with the sound-amplifying portion, and sound enhancement tests will begin immediately. The images below show the second print. Note the difference in the shapes of the edges in the first and second print; the images above show straight edges that likely contributed to printer failure, while the edges in the images below are rounded and easier for the printer to create.

Second print (rear)

Second print (angled face)

Second print (angled face)