6. 3D Scanning and printing¶
updated (4/2/2021): Added detail about my 3D design and why it cannot be fabricated on a subtractive machine. Also added 3D print test image and detail about lessons learned from group assignment.
3D Printer Design Rules¶
Machine: Prusa Mini Filament: Marble PLA
Extrusion Issues: Cold Pull¶
Upon booting up the machine and attempting to load and print a test file, I noticed the machine was not extruding properly. That is, it was not purging the filament without my assistance. To troubleshoot, I began cold pulling the filament to try and clean out any clogs in the nozzle.
Cold Pulling is when you load the extruder with filament, bring it up to temperature (215) and then cool the extruder down to about 100 degrees Celsius, at which point you pull the filament out manually. This will hopefully remove any clogged filament in the nozzle or extruder.
Extrusion Issues: Idler¶
So, as it turns out, the nozzle seems to be fine. This pointed me towards the extruder gear/idler, which on a MINI is set back on the machine, away from the nozzle. There is a long clear PTFE tube that the idler pushes the filament through towards the hotend nozzle.
I hopped onto Prusa’s LiveChat on their online store. For Prusa owners, this is the primary way to contact Prusa about getting technical support with your machine. I opened a chat up with them to see that their thoughts were about the issue. This helps my troubleshooting process and can signficantly reduce the amount of time spent on a problem.
I disassembled the extruder, which was an educational experience. Checked the grub screw on the gear and make sure everything was clean and tight. I stopped here because I had spent too much time troubleshooting and we have working machine at the lab. I swapped the MINI out for a MK3 and decided to use this machine instead.
Machine: Prusa Mini Filament: Colorfabb PLA/PHA
Test Files¶
dimension.stl I started this with file on our MK3S. I ditched the MINI because it was causing my a lot of issues, I figured I would save troubleshooting that machine for another day.
I used the following settings for my dimension file. If this works, I will set this as a constant for all other test files to keep things as constant and consistent as possible.
| Setting | Value |
|---|---|
| Material | Colorfabb PLA/PHA |
| Layer Height | 0.2mm |
| Supports | None |
| Infill | 15% |
multi-test file I found a nice test file shared on thingiverse that allows you to inspect and evaluate multiple variables with one efficient print.
Takeaways from Testing¶
The above image shows the final output from my testing on the machine. This print does a good job showing some of the capabilities and limitations of the machine. For instance, you get a sense of the tolerance, or how fine of detail, the machine is able to handle. You also can see the amount of bridging the machine can handle, which can be seen towards the back of the print, with all the plastic strings/hairs hanging off of it. Finally, you can see how the printer handles particular shapes and text. I plan on using this print to help explain to people coming in the Fab Lab about the what the machine is capable of doing. Sometimes it can be difficult to manage people’s expectations with the quality of prints off the machine and so this can prepare them ahead of time.
3D Printing¶
For my 3D printing project, I wanted to design something that could be integrated into my final project, “PlayStack” concept. I also wanted the design to take advantage of the 3D printer’s ability to fabricate objects that subtractive machines would not be able to.
Toy Table Saw¶
For this project, I landed on designing an all-in-one table saw, with a moving “blade” that can spin freely after printing. This technique takes advantage of support structures that can break free after fabricating and then be removed for an object of moving parts without having to fabricate and assemble them separately. In other words, this object could not be made on a subtractive machine without making multiple parts and assembling together. The 3D printer allows you to print support structures to suspend parts and then break them free after the fact. Creating single fabricated objects with moving parts is something that additive machines can do that subtractive machines cannot.
I designed the table saw in Fusion 360, using parameters to control for the axle-width, saw blade inner and outer diameter measurements. This allowed me to make quick adjustments after test prints and get the design optimized.
A final look of the table saw design using the XRAY view mode.
To setup the print job, I used PrusaSlicr’s software to add custom supports at the bottom of nested saw blade area, just to keep it floating inside while printing. My plan was to break and clear the support structure by spinning the blade.
Obligatory failed print for my first attempt. I didn’t add any supports on the nested saw blade, so it had some issues
A look at the final successful print of the toy table saw.
User Testing with Lucia¶
Fusion 360 Model¶
3D Scanning¶
I attempted to scan a antique tool (plane) as part of my 3D scanning project, and because it could potentially be apart of the PlayStack play set. After reviewing a couple of articles on 3D Scanning apps for the iPad Pro, I ended up using Trnio as my 3D scanning app. This allows you to both use the photogrammetry method and also the LiDAR camera sensors on the new iPad Pro.
I setup the plane on a white countertop, thinking it would be a good contrast with the plane. I did this scan first thing in the morning, with lots of light coming into the room and turned on all the lights to get as much light as possible.
The scan ended up picking up a lot of extra objects surrounding the plane, but I planning on cropping and editing all of that with a mesh-editing tool.
Below is an interactive model of the scan that I uploaded to Sketchfab. Sketchfab is an online platform for hosting and sharing 3D models, and it is integrated with Trnio so you can directly send scans to Sketchfab. Unfortunately, the free account limits you to only uploading one scan per month.