As projects grow, parts must fit together reliably. Designing for assembly is where many 3D prints fail.

Snap Fits in 3D Printing

Snap fits rely on controlled flex.

Best practices:

• Use PETG or nylon (not PLA)
• Avoid sharp internal corners
• Design generous lead-in angles
• Test multiple tolerances

Printed snap fits should flex once not repeatedly.

Press Fits and Interference

Press fits require extremely careful tolerancing.

Guidelines:

• Start with 0.1–0.2 mm interference
• Test with small calibration prints
• Account for material shrinkage

Never assume theoretical dimensions will work first time.

Modular Design Benefits

Breaking designs into modules allows:

• Easier printing
• Better orientation
• Reduced support
• Improved repairability

Fastening options include:

• Screws with heat-set inserts
• Pins and dowels
• Adhesives (epoxy, CA glue)

Tolerance Stacking

Multiple small inaccuracies add up.

Avoid:

• Long chains of mating parts
• Tight tolerances across many components
• Single-point failure designs

Instead, design adjustment points.

Professional Assembly Support

BritForge3D regularly prints:

• Multi-part assemblies
• Mechanical enclosures
• Functional prototypes

We can advise on fit, tolerance, and assembly strategy before printing.

Upload your project at BritForge 3D