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Design for Manufacturing

Design smarter.
Ship faster.
Spend less.

Every manufacturing process has rules. Break them, and you pay in cost, lead time, or failed parts. Follow them, and your designs manufacture economically, repeatably, and without drama. This is our free DFM guide.

01 · DFM by process

Each process has its own rules.

General DFM principles apply across all processes, but the specific constraints differ dramatically. Design rules for CNC are completely different from injection molding or sheet metal.

CNC Machining

  • Internal radii ≥ 0.8 mm
  • Depth-to-width ≤ 4:1
  • Wall thickness ≥ 1.0 mm
  • Thread depth 1.5–3× dia

3D Printing

  • Feature size ≥ 0.5 mm
  • Wall thickness 1.0+ mm
  • Hollow if > 100×100 mm
  • Drain holes for SLA/SLS

Injection Molding

  • Uniform wall ±10%
  • Draft angle 0.5–1.5°
  • Fillet ≥ 0.5× wall
  • No sharp corners

Sheet Metal

  • Bend R ≥ thickness
  • Hole-to-edge ≥ 2t
  • Hole-to-bend ≥ 3t
  • K-factor 0.33–0.40
02 · Universal principles

DFM rules that always apply.

These seven principles work across every manufacturing process. Internalize them, and you\'ll be a better hardware designer regardless of production method.

01

Specify tolerance by function, not habit

Default to ISO 2768-m (±0.1 mm) unless the feature mates with another part or affects performance. Every ±0.01 mm callout adds $30–80 per part. Tight tolerances should appear on < 10% of features on most drawings.

02

Keep wall thickness uniform

For injection-molded parts, wall thickness variation > 10% causes warp, sink marks, and ejection problems. For CNC, thin walls (<1 mm) deflect under cutting forces. Aim for constant wall thickness throughout the part.

03

Avoid sharp internal corners

Internal sharp corners concentrate stress, trap chips in CNC, and require EDM or expensive micro-tools to produce. Use fillets with R ≥ 0.5× wall thickness as a default.

04

Minimize setups

Every CNC setup costs time and introduces tolerance stack-up. A part machinable in one or two setups is dramatically cheaper than one requiring five setups. Use 4- or 5-axis machining to consolidate setups when cost-effective.

05

Use standard sizes

Standard fastener sizes, bearing bores, and common stock materials are cheaper and faster. An Ø 10 mm bore is standard; an Ø 10.47 mm bore requires custom tooling or interpolation.

06

Design for inspection

Features hidden from CMM probes require teardown inspection or special tooling. Leave reference surfaces, add datum features, ensure critical dimensions are accessible for measurement.

07

Consider assembly

Parts that assemble themselves (self-piloting features, bolt-through holes with chamfers, captive fasteners) save 30–60% of assembly time over parts requiring alignment and care.

FAQ

DFM questions.

DFM is the practice of designing parts so they can be produced economically and reliably by the chosen manufacturing process. Good DFM considers: tool accessibility, wall thickness uniformity, draft angles (for molding), tolerance stack-up, material properties, and process limitations. Following DFM principles typically reduces part cost 20–50% and lead time 30%.
Yes — free with every formal quote. Our engineers review your CAD within 24–48 hours, flagging issues like: tolerances tighter than functionally needed (cost driver), wall thickness or feature size below process minimums, draft angle problems on molded parts, inaccessible features requiring special tooling, and opportunities to simplify geometry for cost savings. DFM feedback is provided in writing with specific suggestions.
1) Over-tightened tolerances — specifying ±0.01 mm everywhere when 90% of features could be ±0.1 mm. Each tight tolerance adds $30–80 per part. 2) Inconsistent wall thickness on molded parts — causes warp, sink marks, and ejection issues. 3) Missing or insufficient draft angle on injection molded parts — causes damage during ejection and expensive tool modifications to fix.
On typical projects, implementing our DFM feedback reduces part cost 20–50%, often dramatically. Most common savings: opening non-critical tolerances ($50–200 per part), consolidating materials, eliminating unnecessary features, and combining assemblies into fewer parts. We've seen individual DFM suggestions save over $500 per part on aerospace components.
No — DFM is advisory, not mandatory. You can accept or reject any of our suggestions based on your design requirements. We just ensure you understand the cost, schedule, or performance trade-offs. Some suggestions are cosmetic optimizations; others would have significant downstream manufacturing consequences.
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