Test the design rules for your 3D printer(s) by creating a comprehensive test print that evaluates various design constraints and capabilities.
These tests evaluate features that should print reliably without additional support structures:
Overhang Testing (Supported)
Test Result: Supported right angle overhang was successful with snug support (default)
We didn't need to try organic support for this test
Support Removal: Successfully removed support with pliers
Clean removal without damaging the part
Printer Used: Prusa Core One with white generic PLA
Standard settings provided good results
Clearance Testing
Minimum Clearance: 0.2mm is the minimum clearance for an object to be separable
Tight fit, hard to rotate at this clearance
Optimal Clearance: Above or equal to 0.3mm is looser and more functional
Better for moving parts and assemblies
Non-functional: Below 0.2mm is not separable
Parts fuse together at this clearance
Helical Support Thickness Testing
Too Fused: 0.48 revolutions/mm — too fused (28 revolutions over 60mm with 6mm diameter, 2mm thickness)
Parts become inseparable at this density
Optimal Range: 0.35 revolutions/mm — works (21 revolutions over 60mm with 6mm diameter, 2mm thickness)
Good balance between support and separability
Sweet Spot: Optimal exists between 0.35-0.48 revolutions/mm
Fine-tuning within this range for specific applications
These tests push the boundaries of what the printer can achieve without additional support structures:
Angle Testing (Unsupported)
Minimum Angle: 20 degrees is minimum overhang angle (defined as degrees above right angle)
Below this angle, the print quality degrades significantly
Good Quality: 30 degrees and above are nicely formed
Reliable print quality at these angles
Poor Quality: 10 degrees and below result in spaghetti
Printer cannot maintain structural integrity at these angles
Overhang Testing (Unsupported)
Maximum Distance: 2-3mm is maximum unsupported overhang distance before spaghetti
Beyond this distance, the print quality fails
Acceptable Range: Below 2-3mm is fine
Good print quality within this range
Failure Point: After 2-3mm becomes awkward
Structural integrity is compromised beyond this point
Bridging Testing
Maximum Bridge: 18mm is maximum bridge size
Reliable bridging performance up to this length
Acceptable Performance: 20mm is actually not too bad
Slight degradation but still functional
Test Method: Horizontal unsupported spans
Evaluates printer's bridging capabilities without support
Wall Thickness Testing
Minimum Thickness: 0.6mm is the minimum wall thickness that is sturdy
Below this thickness, walls are too fragile
Fragile Range: Thinner walls just break off if you touch them
Not suitable for functional parts
Design Implication: Use 0.6mm+ for structural elements
Critical for load-bearing applications
Dimensional Accuracy Testing
Outer Distance: 20.05mm measured (one offset from 20mm design)
0.05mm offset in outer dimensions
Inner Distance: 9.90mm measured (twice offset from 10mm design)
0.10mm total offset in inner dimensions
Height Variation: Dimensions actually slightly differ as a function of height
Z-axis accuracy varies with print height
Anisotropy/Orientation Testing
Quantification Method: Use filament width (w, XY) and layer height (h, Z) for geometric approximation
A ≈ w/h where A > 1 indicates anisotropy
Unsupported Results: w=730, h=545, A=730/545=1.339
Significant anisotropy in unsupported prints
Supported Results: w=20.11, h=20.16, A=20.11/20.16=0.998
Much more isotropic with proper support
Surface Finish Testing
Layer Visibility: With default surface finish settings, layers are clearly visible
Further optimization necessary for smoothing
Nozzle Tracking: Can see the track of the nozzle during step height process
Step height can be adjusted and tuned for curvature needed
Roundedness Limitation: Limited roundedness, flat at the top
Can be adjusted from the step height settings
Infill Testing
Optimal Density: 15% infill is optimal
Good balance between strength and material usage
Interior Quality: There is spaghetti in the interior, but very minimal
Acceptable level of internal defects
Application Guidelines: Higher infill for stiffer structures, lower infill for flexible structures
Further characterization of other infills can be done
Efficient Testing Approach: By grouping all supported tests in one print and all unsupported tests in another, we were able to efficiently evaluate printer capabilities while minimizing material waste and print time. This approach allowed for direct comparison between different test geometries and provided comprehensive data on the printer's performance across various design constraints.
The supported tests focused on features that should print reliably, while the unsupported tests pushed the boundaries of what the printer could achieve without additional support structures.
Comprehensive STL files for testing various 3D printing design rules and constraints:
anisotropy.stl
Evaluates directional strength properties
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clearance.stl
Tests minimum clearance between parts
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