6. 3D Scanning and printing¶

group assignment: - test the design rules for your 3D printer(s) individual assignment: - design and 3D print an object (small, few cm3, limited by printer time) that could not be made subtractively - 3D scan an object (and optionally print it)

Research¶

group assignment:

So for the group assignment we need to test the limitations of the 3D printers we will be using in a similar manner to how we characterised the laser cutter in our previous weeks assignment. However 3D printers are additive manufacturing and the design rules will differ greatly and will require completely different characterization. 3D printers in a nutshell heat up plastic filament and pile thin layers of this molten plastic on to of each other in a process known as extrusion to create complex designs. The more blatant limitng factors on the output of these prints are bed size, axis height of your printer, nozzle diameter and properties of the type of filament used. But the art of 3D printing is just that, an art. There is alot of trial and error and fine tuning that takes place with knowlege gained from time spent using your machine, fiddling with the settings and sinding whats best for you. So lets begin with the machines we will be using.

what machines I will be using

BOLD Lab has a colletion of 3D printers that seem to extend from the early history of 3D printing to current day industry standards. For this weeks assignments both group and individual I will be using the renowned Prusa Mk3 and its step sister the Ender 3 printing using PLA filament.

Both really good printers wich have a great online ocmmunity and support software. The software I will be using is the Prusa slicer program along with my usual Fusion 360 and occasional Mesh mixer for final touches.

most important factors to test

Factors I will be testing for in this assignment are things that could limit my individual assignment where I will be designing an interlinking joint that can be printed as one component. So things to look for here need to be expressed in the FDM test model.

I chose this model because it was the most comprehensive test model I could find as it tested Overhangs, bridging, negative feature resolution, fine feature flow control and dimentional accuracy as these would all have a big impact on the additive manufacturing design I have in mind.

failures

The print started off well and I was extremely impress at the speed of the Prusa Mk3

Unfortunately the bed adhesion soon failed as the structure started to lift off of the bed at the edges and this caused the nozzle to catch the print.

what I did to fix it

I added a 5 layer raft and tried the print again but the same issue caused the print to fail again.

changing model

I decied on a smaller model to hopefully fix this issue with the bed adhesion. This model was great at testing the overhang, stepping, incline and negative feature resolution.

My instructor Mirriam showed me a neat trick with the trusty old glue stick that would hopefully further prevent bed adhesion from becoming an issue.

It worked beautifully and the test printed without issue.

The finished product passed all tests except shoed some deformation on the 85 degree angle.

Ender 3

Having the original model failing on the Prusa I decided to test it on the Ender. This would give me some hands on experience with yet anothe awesome printer I havent had a chance to use yet which was pretty cool.

First I had to change the filament which stook some getting used to as I hadnt had experience with this feeding mechanism before.

The Ender 3 has a manual bed leveling system which is old school and i love it. There are no sensors telling you what to do so you need a keen eye and fast fingers to adjust the bed while the bed lebvel test print runs.

The print finishe dand it looked really awesome although took alot longer than the projected print time of the Prusa Mk3.

individual assignment:

inspiration

When I used to teach 3D printing to kids at my previous school I used to print these little flexible dinos and give them as gifts to the kids who participated in my classes. I thought the person who designed these must have been some sort of a genius but i think with my newly acquired knowlege on 3D design I could design something similar.

skectch