Category: Design Tutorials

Design Tutorials delivers actionable, step-by-step CAD workflows and modeling methodologies, guiding makers and engineers from 2D concept sketches through 3D solid construction, assembly modeling, and additive manufacturing optimization.

Foundational Pillars
Technical Foundations
Topic Directory
Frequently Asked Questions

Foundational Guides & Core Pillars

Foundational Guide

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Design for Additive Manufacturing (DfAM) fundamentals: wall thicknesses, chamfers over fillets on bed contact, and teardrop holes.

Technical Analysis

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Step-by-step introduction to parametric sketch constraints, solid extrusions, shell commands, and exporting watertight mesh formats.

Practical Methodology

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Exporting Building Information Modeling (BIM) architectural models, stripping internal plumbing/ductwork, and scaling structural shells.

Comprehensive Reference

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Generating high-contrast lithophanes, heightmaps, displacement maps, and bas-relief engravings from 2D photographic images.

Practical Design Engineering: Tolerances, Wall Thickness & Features

Designing components specifically for additive manufacturing requires an intimate understanding of machine kinematic constraints, thermal shrinkage, and toolpath geometry. Unlike traditional subtractive CNC milling where internal sharp corners are impossible without corner undercuts, 3D printing can easily generate square interior pockets. Conversely, horizontal overhangs past 45 degrees cannot be deposited onto thin air without sacrificial supports or specialized bridging protocols.

Mechanical joint design necessitates calibrated clearance offsets. When designing interlocking snap-fits, hinges, or sliding assemblies, engineers must incorporate clearance gaps between 0.15mm (for tight friction fits on calibrated machines) and 0.35mm (for free-rotating mechanical bearings). Failing to incorporate proper radial clearance results in adjacent perimeter beads fusing together into an immovable monolithic block.

Hole orientation dictates roundness and dimensional accuracy. Vertical holes (printed along the Z-axis) are constrained by slicer polygon chords, frequently resulting in undersized diameters by 0.1mm to 0.2mm due to plastic shrinkage pulling inward toward the center of the arc. Horizontal holes (printed through the side of a part) can sag at the apex; designing self-supporting ‘teardrop’ or diamond-shaped holes eliminates the need for internal support removal while maintaining exact fastener clearances.

Design Feature	Recommended Minimum	Optimal Practice	Common Engineering Failure
Wall Thickness	1.2 mm (3 perimeter passes @ 0.4mm)	Match integer multiples of nozzle diameter	Single-perimeter fragile walls that delaminate
Horizontal Clearance	0.20 – 0.30 mm	Test print clearance gauge on target machine	Parts fuse together; snap-fits fracture upon insertion
Overhang Angle	45° from vertical (standard)	Use 45° chamfers rather than round fillets on bed	Steep downward overhangs curl up into print head
Bridge Span	Up to 50 mm (with 100% cooling)	Keep bridges straight and anchored at both ends	Sagging filament loops beneath long unsupported spans
Pin / Boss Diameter	3.0 mm minimum	Reinforce base with 1mm fillets to distribute shear	Slender vertical pins snap under shear load

Topic Directory & Specialized Workflows

CAD Modeling Tutorials

Image & Lithophane Conversion

Frequently Asked Questions: Design Tutorials

Why do 3D printed circular bolt holes always print slightly smaller than designed?

When a slicer converts a true circular CAD arc into polygonal G1 vectors, the polygon chords cut across the inner radius of the circle. Furthermore, surface tension pulls molten plastic inward toward the center of the arc. Adding +0.2mm to hole diameters compensates for this shrinkage.

Why are chamfers preferred over round fillets on bottom surfaces touching the build plate?

A round fillet touching the build plate begins at near 0 degrees, creating a severe horizontal overhang that sags and curls. A 45-degree chamfer maintains a consistent, self-supporting 45-degree angle from the first layer, producing a crisp, clean edge.

How do lithophanes work and what slicer settings are required?

Lithophanes translate image grayscale values into varying plastic thicknesses: dark pixels become thick walls that block light, while light pixels become thin translucent sections. Lithophanes must always be printed vertically (on edge) at 100% solid infill along the Y-axis to maximize resolution.