DFM Guide · Auto Assembly

Pick. Place. Assemble.
By robot.
Design for it.

Automated assembly demands specific design considerations: chamfered insertions, snap features, asymmetric orientation aids, force-controlled engagement. Get this right and robots assemble reliably; wrong and they jam.

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01 · Key principles

Key principles.

Chamfered insertions

Self-aligning

Lead-in chamfers (45° × 1mm typical) on mating features. Compensates for robot positioning tolerance. Critical for press fits.

Asymmetric orientation

Robot can't flip

Parts must orient correctly when picked. Asymmetric features ensure correct orientation, prevent backwards assembly.

Snap features

No fasteners

Snap-fit assembly eliminates fastener handling. Engineered snap angles (typically 30-45°) for engagement force.

Stable picking surface

Vacuum or grip

Flat surface for vacuum picking, or finger-grip features for mechanical grippers. Curved surfaces problematic.

Tolerance allocation

Loose where possible

Robot positioning ±0.1 mm typical. Mating features must accept this tolerance with chamfers and lead-ins.

Captured fasteners

In carrier

Fasteners pre-installed in carrier strip, or snap-in retainers. Loose fasteners difficult for robots.

FAQ

How does this differ from manual assembly?

Manual assembly tolerates orientation errors, complex motions, dexterity. Automated needs unambiguous orientation, simple insertion paths, force-controlled engagement.

Snap-fit design rules?

Cantilever snap: depth/length ratio 0.1-0.2 for repeated use. Permanent snap: higher engagement force. Consider material flexibility (nylon, ABS good; brittle materials avoid).

Vibration feeders compatibility?

Parts must orient consistently when fed. Asymmetric weight distribution helps. Avoid features that catch on each other.

Robot vision systems?

Modern robots use vision for orientation. Reduces orientation features needed. But adds cost — design for vision OR design without vision.

Fastener handling robots?

Specialty robots can handle screws and washers. Mass-producing assemblies often use snap-fits or press fits to avoid this complexity.

Cost tradeoff?

Automation-friendly design adds upfront engineering cost. Pays back at production volumes (10,000+ assemblies). For low volume, manual assembly often cheaper.