5. 3D Scanning and Printing¶
Members: Koji Yamada / Hajime Itoh
Group Assignment Overview¶
This is the group assignment of the week.
- Test the design rules for your 3D printer(s)
3D Printers of FabLab Kannai¶
FabLab Kannai has three FDM 3D printers: (i) Creality Ender3 Pro, (ii) Creality Ender3 V2, and (iii) FlashForge Adventure3.
While the last one is box-type and the extruder and the buildplate are placed in the chamber, the other two are open-type. We have two major typs of filament: PLA and ABS. ABS has wider variety of color options, but the printed objects could easily shrink and be peeled off from the buildplate as they are cooled down. It could be easily affected by the cool room temperature in winter. The box-type 3D printer could mitigate the risk of shrinkage. Compared to ABS, PLA filament is less vulnerable to room temperature. Therefore, when we use Creality Ender3, we had better use the PLA filament.
Here is the temperature settings for the two types of filaments (Unit: degree Celsius):
| Nozzle | Buildplate | |
|---|---|---|
| PLA | 200 | 60 |
| ABS | 230 | 100 |
Data For Testing¶
Using the STL files they downloaded from the Fab Academy sites, students of the previous batches had already printed the similar kits for testing unsupported angles, overhangs and bridges. One additional test was the kit for extra bridges.
- Bridge Test: When we saw the image of the bridge test at the Global Session, it was difficult to see at which distance the bottom of the bridge started collapsing. It seemed that until 20mm, all the bridges were okay. Therefore, our seniors designed extra test kit for 30mm to 80mm and 3D-printed it. Then it was learned that the bottom of the bridge started collapsing at around 40-60mm.
- Screw Hole Test: Also, the users of the FabLab Kannai made a test kit for threaded screw holes for M3 screws. The outer diameter of the M3 screw is 3mm. But if we design the screw holes with 3mm inner diameter, the screw may not be fit into the hole. Therefore, in order to get the best diameter of the screw hole, they designed the screw holes with diameter’s increment by 0.1mm. Also, they prepared the screw holes, not only cylinder-shape, but also hexagonal cylinder-shape. In case you 3D-print the objects with horizontal screw hole, the thickness setting for the layer may affect the shape of the arch due to the taper angle issue. If this is the case, we had better design the screw hole which has hexagonal cylinder.
Building on their past experience, we discussed what value-added we could contribute, and decided to do the angle test for two 3D-printers and compare the results. This is the STL file downloaded. STL
- Wall Thickness Test: This was also undertaken by the other users. The photo shows that the printer cannot print the wall if the thickness is less than the diameter of the nozzle. Still the gap could be printed if it is 0.2mm.
Slicer¶
Althoguh Creality releases its own slicer, Creality Slicer, we used Ultimaker Cura. Cura covers more 3D printers manufactured by many different manufacturers. Creality Slicer has its advantage in the wider coverage of the latest versions of the Creality machines.
We started downloading the program from Ultimaker Cura to our laptop. Once we completed the installation and opened the program, the first step was to register our 3D printers on Cura. If we clicked four times as indicated in the following screenshots, the registration was complete. You can also initialize the machine settings for each machine. But for this group assignment, we took the default settings for granted.
Then we clicked the folder icon on the top-left corner of the panel and uploaded the STL file for testing.
Then we applied the following settings:
Filament: Generic PLA, 0.4mm
Resolution: Standard Quality 0.2mm
Infill: 20%, Grid
Support: None
Adhesion: Skirt
Print Speed: 50mm/sec
Once we decided on the print settings, we proceeded to slicing and got the following information:
Printing Time: 1 hour 28 minutes
Filament Usage: 9 g / 2.95 meters
This information will help us to judge how long the filament should be loaded for printing. Once we got this information, we exported the g-code file to microSD card.
3D-Printing¶
Once we switched on the printers, we took the following steps:
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Pre-Heating: In order to load the filament, we selected “Preheat PLA Filament.” We
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Loading Filament: Both machines had wheels that could drive the filament in the tube to the extruder. We had to cut the edge of the filament by 45 degrees so that it could easily be slid into the nozzle. We kept turning it until the filament reached the nozzle and started discharging melt filament.
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Print from SD Card: Now we inserted the microSD card to the slot, and selected “Print from SD Card” for printing. In case you fail in getting the g-code file list on the control panel, you click “Refresh” for Ender3 Pro or switch off and on again for Ender3 V2.
The print process starts with heating the buildplate until target temperature (60 degrees), and then the nozzle (200 degrees). Once the first two layers are successfully printed on the buildplate, then there is nothing to do until they finish printing.
It was learned that there was no significant difference between the two Ender3 machines.
Other Notes¶
Filament Choices¶
In our group assignment of the week, we only had two filament choices: PLA and ABS. In the global session, however, we learned that there were many types of filaments. One of our group members has once made the table to compare the four major types of filaments: ABS, PLA, PETG and TPU. For our reference, we will post the two tables.
