Group Assignment: Test the design rules for your 3D printer(s)

1 What is 3D Printing?

3D printing is a rapid prototyping system that creates objects by layering powder or liquid adhesive materials. It belongs to the category of additive manufacturing.3D printing uses a "bottom-up" approach based on the principle of "discrete accumulation." Unlike traditional subtractive manufacturing, it incrementally adds material in layers to form solid parts.

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2 Equipment and Materials Overview

2.1 3D Printer Description

The 3D printer used in this time is personal, Creality CR-200B, which is small in size and cost-effective, suitable for family, school and other occasions. FDM is the full name of melt deposition molding, which was developed in 1988 by Scott Crump of the United States.

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2.2 Material Description

CR-PLA is a high-performance polylactic acid material with high strength, high toughness, excellent surface gloss and low warpage rate, suitable for education, creative design and functional prototyping, easy to use and environmental protection, and beautiful printing effect.

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3 Parameter Settings and Testing Procedures

3.1 General Printing Process

  1. Check the filament: Ensure the filament is dry, free of tangles, and compatible with the printer.
  2. Insert SD Card: Verify the printing temperature settings match the material specifications.
  3. Prepare the Bed: Clean the print bed and apply glue stick for better adhesion.
  4. Heat Up: Select the correct file, confirm the nozzle extrudes material at the set temperature, and start the print.
  5. Monitor the Print: Stay nearby during the initial stages to ensure there are no issues with filament feeding or nozzle temperature.

3.2 Software installation and printer addition

Install Creality Slicer & 123 Design

Add printer in Creality CR-200B

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3.3 Incoming and returned materials

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4 Key Parameter Tests

4.1 Layer Height Test

Layer Height 0.1mm 0.2mm 0.3mm
Material Usage (g) 4g 4g 4g
Print Time 48min 26min 18min
Surface Finish Very smooth, almost no stair-step effect Fairly smooth, slight stair-step effect Rough, noticeable stair-step effect
Detail Representation Clear details, suitable for complex models Good details, suitable for most applications Lost details, not suitable for fine models
Use Case High-precision parts, detailed models, products with high appearance requirements Everyday printing, balancing speed and quality Quick prototyping, efficiency-focused projects
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4.2 Shell Thickness Test

Shell Thickness (mm) Printing Performance Structural Strength Use Case
0.4 mm Incomplete or uneven shell Weak, prone to deformation or breakage Ultra-lightweight models
0.8 mm Good shell uniformity Moderate strength, suitable for most daily applications Daily use applications
1.2 mm Stronger shell, smoother appearance High strength, good compression and tensile resistance Daily use applications
1.6 mm Very strong shell, almost no deformation Very high strength, suitable for high-strength requirements Functional parts or high-strength requirements
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4.3 Infill Density Test

Infill Density (%) Printing Performance Structural Strength Use Case
5%-10% Very lightweight, sparse filling, may be incomplete Lowest strength, prone to deformation or breakage Ultra-lightweight models
20% Balance of weight and strength, common default value Moderate strength, suitable for most daily applications General-purpose parts
50%-80% Dense filling, strong structure, nearly solid High strength, suitable for functional components Functional parts
100% Fully solid, strongest Maximum strength, suitable for extreme load-bearing Structural components, special purposes

4.4 Print Speed Test

Print Speed (mm/s) Printing Performance Surface Quality Structural Strength Use Case
20-40 mm/s Long print time, material extrusion is sufficient Smooth surface Strong High-detail models
60 mm/s Moderate print time, stable performance Slightly rough but acceptable Moderate Rapid prototyping, general-purpose parts
80 mm/s Significantly reduced print time, minor quality issues may occur Possible stringing or slight roughness Weaker Fast prints
100 mm/s Shortest print time, significant quality issues may occur Rough surface, noticeable defects possible Very weak Extreme speed testing

5 Comprehensive 3D Printer Testing

A comprehensive all-in-one test model was downloaded from Thingiverse.

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3D printed test model

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5.1 Test Model Analysis

Test Type Purpose Test Content Evaluation Results Test picture
Overhang Test To test the printer's ability to print overhang structures at different angles Angles include (10°/20°/30°/40°/50°/60°/70°/80°) and (15°/30°/45°/60°/75°) At 70°-80° overhangs, there is sagging in the inner layers; this can be improved by increasing the cooling fan speed. 3
Bridging Test To evaluate the printer's ability to print suspended structures across horizontal spans Lengths vary (2mm/5mm/10mm/15mm/20mm/25mm) The bridges did not collapse and showed no significant sagging; all conditions were good. 3
Diameter Test To test the accuracy of cylindrical or columnar object diameters during printing Design: 4mm / 6mm / 8mm / 10mm
Actual: 3.89mm / 5.95mm / 7.89mm / 9.94mm
Average diameter error: 0.0825mm 3
Hole Test To assess the dimensional accuracy and shape precision of circular holes Design: 4mm / 6mm / 8mm
Actual: 3.85mm / 5.8mm / 7.88mm
Average hole error: 0.1567mm 3
Support Test To evaluate the effectiveness of support structures and the surface quality after removal L-shaped supports The slight gap in the support is nice, but seems too tight to remove easily. 3
Precision Test To test dimensional accuracy in two dimensions (horizontal and vertical) Design: 30mm / 20mm / 10mm
Horizontal: 30.33mm / 20.45mm / 10.37mm
Vertical: 30.36mm / 20.69mm / 10.52mm
Horizontal average error: 0.3833mm
Vertical average error: 0.5233mm
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6 3D Scanning

A 3D scanner captures the three-dimensional geometry of an object through digital technology. The principle includes:

4.1 Know POP3 scanner and install the device

POP3The POP3 3D scanner is an efficient and accurate 3D scanning device that quickly captures the 3D geometry of objects and generates high-quality point cloud data.

windowsRevoScan5

4.2 Procedure

Scanning, point cloud editing, grid editing, mapping

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4.2.1 Model black and white mode, no subsequent texture mapping.

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4.2.2 Model color mode, then direct texture mapping

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4.2.3 Self modeling

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4.3 Goertek VR model full-body scanner

With the help of Goertek colleagues, we completed the model calibration, full-range photography of the human body, camera parameter calculation, model training, mesh reconstruction optimization, texture generation, and finally obtained the full-body scan model

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