3D Printing and Scanning¶
Group Assignment¶
Test the design rules for your 3D printer(s), document your work on the group work page and reflect on your individual page what you learned about characteristics of your printer(s).
3D Printer¶
This week’s group assignment focused on testing the design rules of our 3D printer by using different 3D models, each made to test a specific feature or limitation of the printer. We looked at aspects such as overhangs, bridges, holes, and overall print accuracy. The 3D printer available in our lab is the Prusa i3 MK3, and all the test prints were done using this machine.
Image source: Prusa Research
About the Prusa i3 MK3S¶
The Prusa i3 MK3S is an open-source Fused Deposition Modeling (FDM) 3D printer developed by Prusa Research. It is widely used in labs and schools because it is reliable, easy to maintain, and produces consistent, high-quality prints.
Technical Specifications¶
This table summarizes the technical specifications of the Prusa i3 MK3S. This information was extracted from this site.
| Specification | Details |
|---|---|
| Technology | Fused Deposition Modeling (FDM) |
| Build Volume | 250 × 210 × 210 mm (9.84 × 8.3 × 8.3 in) |
| Layer Height | 0.05 – 0.35 mm |
| Nozzle Diameter | 0.4 mm (default); other diameters supported |
| Max Nozzle Temperature | 300 °C |
| Max Bed Temperature | 120 °C |
| Max Travel Speed | 200+ mm/s |
| Filament Diameter | 1.75 mm |
| Extruder Type | Direct drive (Bondtech gears, E3D V6 hotend) |
| Mainboard | Einsy RAMBo 8-bit with Trinamic TMC2130 drivers |
| Print Surface | Magnetic heatbed with removable PEI spring steel sheet |
| Bed Leveling | Automatic Mesh Bed Leveling (SuperPINDA probe) |
| Filament Sensor | Yes (IR-based) |
| Power Panic | Yes (hardware-based, single G-code line accuracy) |
| Connectivity | SD card, USB |
| Display | Monochromatic LCD |
| Power Supply | 240 W (custom Delta PSU with Power Panic hardware) |
| Printer Dimensions | 50 × 55 × 40 cm (19.6 × 21.6 × 15.7 in) |
| Weight | 7 kg |
Supported Filament Materials¶
The MK3S is compatible with a wide range of thermoplastic filaments, including:
- PLA (Polylactic Acid): Recommended for beginners, it is biodegradable and easy to print
- PETG (Polyethylene Terephthalate Glycol): Strong, slightly flexible and good chemical resistance
- ABS (Acrylonitrile Butadiene Styrene): High temperature resistance and requires enclosure
- TPU/Flex: Flexible filaments for soft parts
3D Printing Procedure¶
To evaluate the 3D printer’s capabilities and limitations, we printed two different test models. The first was an all-in-one design that included multiple feature tests such as diameter accuracy, hole sizing, bridging performance, vertical pillars, overhangs, and angle tests. The second model was used to test clearance, meaning it helped us see how much space is needed between printed parts so they don’t fuse together.
This is us with the designs:
Printing Procedure¶
We struggled a lot printing the all-in-one design. After several failed attempts, we asked for help from our fellow Fab Academy graduates. And it turns out, the problem was due to humidity and the room being a bit cold, which made the printer work unevenly. To fix this, we covered the printer with a clear plastic sheet during printing to help maintain a stable temperature.
Our Failed Attempts 😅:
Taking out the support for the Clearance model took forever 😩
The All in One Model¶
The Clearance Model¶
Both Test Models¶
Conclusions¶
Design One: All in One¶
1. Bridging Test¶
A bridging test is a calibration print used to check how well a 3D printer can print horizontal spans in mid air, meaning printing over empty space with no support underneath.
During the bridging test, we found that smaller sections, like the 5 mm and 2 mm bridges, were much more unstable compared to the rest, with even parts being broken off. Some parts of the filament deposited in mid-air held up, but overall the print wasn’t very accurate. There were noticeable gaps between the strands and excess filament hanging below. This showed how important the bridge’s height and gap are for successful printing, as a stable bridge is needed to lay filament across empty spaces.
The bridging test shows that the printer struggles to keep the filament stable when printing over open gaps, which can lead to issues such as drooping or breaks in the bridged sections. This instability in filament flow affects the overall quality and strength of the printed bridges. To improve the results, the printer settings need to be adjusted and fine-tuned, particularly focusing on cooling performance and bridging speed, as better cooling allows the filament to solidify faster before it begins to sag. Experimenting with these settings and finding the right balance between speed and cooling can help reduce common defects like gaps and excess filament buildup.
2. Hole and Diameter Test¶
This test evaluates how accurately the 3D printer can produce small features, focusing on tolerance and precision. A printer with good accuracy should create holes and cylindrical shapes that match the intended dimensions closely, with minimal excess material or distortion. During printing, a small amount of extra filament can be deposited along edges or in gaps, either due to over-extrusion, nozzle width, or filament spreading. This can slightly change the dimensions of printed features.
During the hole test, we noticed that most of the smaller gaps and text didn’t come out clearly, making them hard to read, except for the 8 mm spacing, which was somewhat visible. This highlighted the printer’s limitations when handling very fine details. The diameter test produced much better results. The circles were smooth and free of wobble or extra filament, showing that the printer can handle simple round features reliably.
The holes and cylinders appear reasonably round and consistent across the different sizes, suggesting that the printer handles circular geometry and diameter accuracy well. The text labels are also difficult to read as the letters are too close together, causing them to merge at the printer’s small scale resolution.
3. Vertical Pillar Test¶
The Vertical Pillar Test evaluates how well a 3D printer can produce accurate and stable vertical structures. From the results, it was observed that the printer had difficulty maintaining consistency as the pillar grew taller, with the filament becoming increasingly uneven and shaky toward the upper sections. This suggests possible issues with layer adhesion, cooling, or the printer requiring further calibration.
4. Overhang Test¶
The Overhang Test evaluates how well a 3D printer can print angled structures without the need for support material. The results showed that the printer performed well up to 50 degrees on the 10 degree increment overhang, with clean and consistent filament deposition. Beyond that angle, the quality noticeably dropped, with the filament becoming saggy and droopy, particularly at 80 degrees. For the 15 degree increment overhang, the printer maintained good quality up to 45 degrees, after which the filament began to sag with visible excess strands appearing along the surface.
The printer handled overhang angles reasonably well up to around 60 degrees for the 10 degree increment test and 45 degrees for the 15 degree increment test. Beyond these points, the print quality deteriorated with visible sagging, drooping, and excess filament. To achieve better results at steeper angles, further tuning of the printer settings and thoughtful design adjustments would be needed.
Design Two : Clearance Test¶
A clearance test checks how well a 3D printer can print two separate parts or surfaces that are very close to each other without them fusing or sticking together. It prints features with gradually decreasing gaps between them to find the minimum clearance the printer can achieve while still keeping the parts distinct and movable. This helps determine how precisely the printer can produce parts that need to fit together or move relative to one another, such as joints, slots, or interlocking components.
From the images, the clearance test shows that the printer was able to successfully separate parts with a clearance of 0.3 mm and above, with the 0.3 mm gap still allowing slight movement between the parts. However, at 0.2 mm and below, the parts were no longer separable, and at 0.1 mm the part had completely fused to the pillar. This indicates that the printer’s minimum functional clearance is around 0.3 mm, meaning any parts designed to fit together or move relative to each other should have at least 0.3 mm of gap to ensure they remain distinct and functional after printing.
Overall Conclusion¶
The design rule tests collectively revealed key limitations of the printer across several areas, including bridging, overhangs, vertical pillars, and dimensional accuracy. Issues such as filament instability, sagging at steeper angles and parts fusing at clearances below 0.3 mm were observed throughout the tests. These findings highlight the areas that need further adjustment and tuning to achieve better overall print quality.