Introduction

3D Printing is one of the prototyping technologies in the OEDK that I have actually had some experience with before, and I was excited to broaden my experiences by using much nicer software and hardware than I had ever been able to before! In the past, I had been responsible for converting my STL files to GCODE using open source software such as Slic3r, with myriad confusing settings that always resulted in imperfect prints. However, using Simplify3D actually did simplify the process, combining slicing and printing control into one intuitive interface. Through the course of this project, I was also able to use 3D printers other than the free PLA extruding ones, and tried my hand using the Dimension SST 768 (with less than astounding results.) Altogether, however, I had a good time learning more about the subject and was able to produce the requisite two functioning 3D prints.

Object 1 (Fail)

Through thingiverse, I was able to find my first desired print: a Voronoi Skull. As you can see below, this skull consists of a series of meshed nodes with some minor thickness, that together form a webbed version of the solid. Clearly, this is something that is truly lends itself to 3D printing, as not many other prototyping techniques would be able to produce this object.

Because of my previous experience with the 3D printers available for free use in the OEDK, I had a suspicion that they would be unable to produce this object without physically non-removable support material. For this reason, I elected to use the Dimension SST in the wet lab, which I knew had removable supports.

In order to print, I found a lab tech and got them to assist me in getting the file loaded, scaled, and printed, which was accomplished with little issue.

At this point, I had a support filled skull that actually looked pretty promising!

Sadly, upon closer inspection, I realized that this printer was not actually terribly high definition. In fact, comparing its specs to those posted by the free to use printers, I found out that it actually has a resolution that is no better than the free ones! Because of the fine composition of this object, and the fact that I had had to scale it down, many of the web links were barely one extrusion width of plastic, and frankly did not look very good.

At this point, I still had to post process the piece, and so I (with the assistance of a lab tech) set up the Sodium Hydroxide bath, setting it to heat the object in solution for 12 hours.

Sadly, this post processing revealed a sad sight upon its completion: a dead print.

Apparently the fibers were indeed slightly too fine, and the heat of the bath caused the print to disintegrate. Given the difficulties inherent in this print, and the fact that I would be unable to print it any better on other printers (same issues, or no dissolvable support) I decided to find a different object.

Object 2 (Success)

For my final pieces, I decided to print another object that would be otherwise impossible to create: an epicyclic gear train made out of herringboned helical gears. What makes this print an ‘impossible’ object is this herringbone: there is no way the gears can be assembled or disassembled without one or more of the pieces breaking. Below is an image of a piece of one of the bearings I broke, showing this internal herringbone structure.

This print was relatively straightforward, so I decided to attempt it using the free-for-use printers. I ensured that no support material was used (in order to prevent any internal gunk from being deposited), scaled the file, then printed it.

Once I had produced a few pieces, I ran into an issue: do to the relative imprecision of these printers, many of my objects had fused points, and were therefore impossible to turn or operate. After I removed any rafts (if I had chosen to use them for that particular print) I then set about post processing them, attempting to make them spin freely. I did this by first using an Allen wrench to ‘break’ the initial connection, a measure that often resulted in me simply stripping the plastic hex slot in the center of the object. In two cases, it actually resulted in the entire print shattering, as whatever overlap there was between parts clearly did not want to give up. Other attempts actually did begin spinning, albeit roughly.

In order to smooth them out, in my final post processing step I found the appropriate bit for a cordless drill, then spun the bearings at the highest RPM possible for several minutes each. This made them relatively easy to move, but some parts also failed at this point, either having gears deform substantially or breaking catastrophically.

By the end, however, I was able to produce two functioning object, which are on the table.

One point of interest: one of the above prints (white) is in plain PLA, while the other is in wood fill PLA, a very interesting material that happened to be loaded in the printer while I was printing. I read a little bit about it, and it ends up it is PLA filled with fine wood flour.

Conclusion

In conclusion, I was definitely able to expand my 3D printing capabilities through numerous failed attempts (seen below).

Luckily, through trial, error, and repeated attempts, I was able to learn several new things (how to use a 3D printer with soluble supports, that wood pla is a thing that exists, etc). In addition, I was able to produce two bearings that hopefully will pique the interest of some future Rice student that may receive my item from the coin machine in the OEDK!

Below, I will leave you with a video of my object operating.