Design Guide for 3D Printing

Everything you need to know to design parts optimized for additive manufacturing. Follow these guidelines to ensure the best quality prints.

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Get a comprehensive reference guide with all design specifications and best practices.

Choosing the Right Technology

FDM (Fused Deposition Modeling)

Best for functional prototypes, durable parts, and larger prints. Ideal for mechanical components and testing.

  • Layer height: 0.1mm - 0.3mm
  • Min wall thickness: 0.8mm - 1.2mm
  • Tolerance: ±0.5mm

SLA (Stereolithography)

Perfect for high-detail models, smooth surfaces, and intricate designs. Great for jewelry, dental, and precision parts.

  • Layer height: 0.025mm - 0.1mm
  • Min wall thickness: 0.4mm - 0.6mm
  • Tolerance: ±0.1mm

File Requirements

STL

Most common, widely supported

OBJ

Supports color and texture

STEP

CAD format, fully editable

Watertight Mesh

Ensure your model has no holes or gaps in the mesh. All edges must be connected.

Correct Units

Export in millimeters (mm). Verify dimensions before sending.

Single Object

Merge multiple parts if they should be printed as one piece.

Critical Design Principles

1. Wall Thickness

Recommended

  • FDM: Minimum 0.8mm - 1.2mm
  • SLA: Minimum 0.4mm - 0.6mm
  • Optimal: 2mm+ for strength
  • Uniform thickness throughout

Avoid

  • Walls thinner than minimum spec
  • Sudden thickness changes
  • Paper-thin features
  • Unsupported large flat areas

2. Support Structures & Overhangs

45-Degree Rule

Overhangs greater than 45 degrees from vertical require support structures. Design self-supporting geometries when possible to reduce post-processing and material waste.

  • 0-45°: No supports needed
  • 45-70°: Supports recommended
  • 70-90°: Supports required
  • Horizontal bridges: Max 5mm unsupported span

3. Fine Details & Features

Minimum Feature Size

FDM: 0.8mm | SLA: 0.3mm

Fine text, intricate patterns, small holes

Engraved Text

Min 0.5mm depth, 2mm height

Use sans-serif fonts, avoid serifs

Embossed Text

Min 0.5mm height, 2mm size

Better than engraved for visibility

Holes & Threads

Min 2mm diameter

Consider drilling for precision holes

4. Clearances & Tolerances

For moving parts or assemblies, add clearance between mating surfaces:

0.3-0.5mm

Tight fit / Press fit

0.5-0.8mm

Sliding fit / Assembly

1mm+

Loose fit / Easy assembly

Common Design Mistakes to Avoid

Thin Walls

Problem: Walls thinner than minimum specification

Solution: Use minimum 0.8mm for FDM, 0.4mm for SLA

Extreme Overhangs

Problem: Angles greater than 45° without support

Solution: Add chamfers or design self-supporting geometry

Sharp Internal Corners

Problem: Stress concentrations and print difficulties

Solution: Add fillets (0.5mm minimum radius)

No Tolerance Gaps

Problem: Parts fused together in assemblies

Solution: Add 0.3-0.5mm clearance between parts

Tiny Features

Problem: Details smaller than nozzle diameter

Solution: Keep features above 0.8mm for FDM

Large Solid Sections

Problem: Warping, long print times, material waste

Solution: Add internal hollowing or honeycomb infill

Best Practices & Pro Tips

Orient for Strength

Position parts so layer lines run perpendicular to expected stress for maximum strength.

Design for Printability

Minimize supports by orienting parts with flat bases and avoiding extreme overhangs.

Add Draft Angles

Include 2-5° draft angles on vertical walls to improve surface finish and ease support removal.

Use Chamfers over Fillets

Chamfers are easier to print than fillets on bottom edges, reducing support material.

Test Before Scaling

Print a small test version first to verify fit, function, and design before full-scale production.

Simplify Geometry

Remove unnecessary details that won't be visible or functional to reduce print time and cost.

Material-Specific Guidelines

PLA (FDM)

Easy to print, minimal warping, good for prototypes and non-functional parts.

  • Low heat resistance (~60°C)
  • Biodegradable, eco-friendly
  • Excellent surface finish
  • Not suitable for outdoor use

ABS (FDM)

Strong, durable, good heat resistance, suitable for functional parts.

  • Higher heat resistance (~100°C)
  • Can be acetone smoothed
  • Prone to warping on large prints
  • Use enclosed printer for best results

Standard Resin (SLA)

High detail, smooth finish, perfect for display models and intricate designs.

  • Excellent surface quality
  • Brittle, not for functional parts
  • UV sensitive, may yellow over time
  • Requires post-curing

Need a quick-reference comparison of all materials?

View Material Cheat Sheet

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