The 3D printer arrived a week ago and I have been using it pretty much every day since. The Prusa I3 DIY printer kit I ordered from Amazon came from a company called Shenzhen Anet Technology. They provided instructional videos of how to assemble it, and it took me about a full day to put it all together. Assembling the printer was quite fun and it’s great to know what every nut and bolt in it does. The printer also came with two spools of PLA filament.
Here’s the completely assembled 3D printer:
So for my first test I decided to print the Gyro’clock case I designed previously. The 3D printer firmware understands G-code. To convert the 3D design made in FreeCAD to G-code it must be given to a slicer software. The 3D printer manual recommended to use Cura for slicing, so I decided to use it. The slicer program literally slices the 3D model into many layers for the 3D printer to print one by one.
After exporting the design in FreeCAD as a .stl (stereo-lithography) file I opened it up in Cura. When you first start up Cura, you have to give it information about your 3D printer such as print size, nozzle and filament type etc. After loading the .stl file, Cura also gives options to scale, rotate and mirror the object, which is handy. After converting the image to G-code I saved it in an SD card, which can be inserted into a slot in the printer.
It took about an hour and a half to print the bottom part of the case, and this is how it turned out:
The top piece took only 30 minutes or so since it was smaller in size, and this is how it turned out:
During this first run of the printer I noted a few problems with my design and a few issues with the printer:
- The walls were too thin. I designed the walls to be 0.8 mm wide. This made the case too flimsy and it was too flexible. My attempt to remove the pieces from the printer bed caused them to bend slightly.
- The holes were too small. The screw holes I made to attach the board to the case and the top piece to the bottom piece were non-existent in the print.
- Printer does not wait for minimum time interval before moving to the next layer. There is a setting in Cura for selecting the minimum time spent on a layer. I set this value to 5 s. But I noticed when the top piece was printing the printer does not wait the minimum interval between the layers. This caused the snap on part of the top piece to deform. Could be a firmware bug.
- I forgot to create a window for the switch and the charger LED. There is no excuse for such carelessness!
- The printer has trouble making small overhanging features at 90°. This is understandable because there is no support underneath to hold the thin strands of melted plastic. So the first few layers of an overhanging section (or a bridge) does not hold well. But if the overhang is thicker and the bridge is not that wide then later layers will build up properly.
- Masking tape on the heated bed lifts causing the print to bend. This printer has a heated bed. Masking tape is put on the metal bed so the print job will not stick to it. On repeated use this masking tape looses its adhesiveness and lifts from the bed causing the printed object to bend. The solution for this is to replace the masking tape for each print.
- Formation of snags causes the printer head to jump. It was good that I noticed this problem before it became an issue. When the printer head moves across a gap following the same route multiple times, excess plastic can cause snags to form. The next time the printer head comes around the same path the snag could block it. This could cause the printer to misalign. Fortunately I saw the printer jolt a few times on a snag and cut off the snag before it got too large. A good reason not to leave a print job unattended for too long.
After cleaning up the two pieces of the case to remove snags and excess plastic I put the two pieces together. There was no need to attach the board to the case with screws since it fitted snugly. I also cut off the deformed snap on piece of the top part.
And here’s the resulting case:
This was a good learning experience about 3D printing. Now I know what to do for the second version of the case. It’s coming soon!