This past week, I 3D printed an articulating shark as part of the impossible object print challenge. I wanted to print something articulated because it is physically impossible to make this object in another way such as CNC or other subtractive processes. This is because the finger joints are built encapsulated into the receiver joints, and therefore the geometry would not allow for them to be inserted after the manufacturing process. I found a design I liked on Thingiverse, a website that has STLs of many different designs.

From this, I decided to use both the SLA and FDM printing techniques. I started with FDM, by importing the file and scaling it to 40% of the original size. I sliced it and hit print, but when the print came out it turned out to be too small for the nozzle, so the joints didn’t work correctly. I decided to print it again. This time I scaled it to 60% and sliced it.

Once it was sliced, I queued it to an open printer and started the print.

I also decided to print on the SLA printer and sliced it on the software.

I then queued it and printed it on the Formlabs SLA printer. Once it finished printing, I removed to supports.

Because it is an articulated design, the SLA curing fused the joints together and it was unable to move in the desired pattern. Thus, for this design, I think an FDM printer is better suited. When the FDM prints came out, they had a thick raft attached to the bottom, which took quite a bit of work to get off. Finally, I was able to remove all the supports and put them. I then printed out the creator slips and the products were finished!

Reflection: The printing itself was easy, but the post-processing was more difficult. The SLA method didn’t work well for my articulated design, even with careful post-processing. In the end, this was a fun project that was a good introduction to 3D printing.

Cost Estimation:

Formlabs Printer – $2400

Prusa i3 – $800

Plastic cost – $2

Time (4 hrs @ $30/hr) – $120

Total: $3,322