ENGINEERING STANDARDS • 25-POINT DFM CHECKLIST

25-Point Sheet Metal Design for Manufacturability (DFM) Checklist

Avoid expensive redesigns and tooling delays. Our manufacturing engineering team has distilled 50 years of shop floor sheet metal expertise into an actionable 25-point checklist for mechanical design engineers submitting 3D CAD models.

Checklist Scope 25 CRITICAL POINTS CAD to Machine Verification

Supported CAD STEP • SLDPRT • DXF Native 3D & 2D Flat

Cost Reduction UP TO 30% SAVINGS DFM Tooling Optimization

Review Time 24 HOURS Fast-Track Engineering Intake

Fast-Track CAD Intake → View Machine Specifications Direct: (860) 410-1801

Pre-Release CAD Verification Checklist

Verify these 25 engineering criteria in your SolidWorks or Inventor model before submitting your RFQ drawing package.

1. Geometry & Bending (Points 1–8)

✓ Uniform Inside Radius: Maintain the same inside bend radius throughout the part to eliminate press brake tool changeovers.
✓ Minimum Inside Radius: Radius $ge 1.0T$ for steel and 5052 aluminum; $ge 2.0T$ for 6061-T6 aluminum.
✓ Minimum Flange Length: Flange height $ge 4 imes T + R$ to seat properly on the V-die shoulders.
✓ Corner Bend Reliefs: Relief cutouts placed at all intersecting flanges with width $ge T$ and depth past the bend tangent.

2. Holes, Slots & Cutouts (Points 9–16)

✓ Hole-to-Bend Distance: Hole edge $ge 2.5T + R$ from the bend line to prevent teardrop distortion.
✓ Minimum Hole Diameter: Hole diameter $ge 1.0 imes T$ to prevent laser piercing blowout.
✓ Hole-to-Edge Spacing: Distance from hole edge to sheet edge $ge 2.0 imes T$ to avoid bulging.
✓ Slot Spacing: Maintain at least $2.0 imes T$ material web between adjacent slots or perforations.

3. Fasteners & PEM Hardware (Points 17–20)

✓ Centerline to Edge: Follow Haeger fastener catalog minimum edge distance ($C$) to prevent outward bulging.
✓ Fastener to Bend Clearance: Place studs and nuts far enough from flanges so the installation anvil clears the part.
✓ Hole Sizing: Laser cut holes to manufacturer-recommended decimal hole sizes (+0.003 / -0.000").

4. Welding & Finishing (Points 21–25)

✓ Weld Joint Fit-Up: Maintain tight laser-cut gaps (≤ 0.030") for robotic and aerospace GTAW welding.
✓ Drainage & Vent Holes: Provide weep holes for closed tubular frames to allow wash pretreatment liquids to drain.
✓ Grounding Masks: Clearly specify masked unpainted ground contact pads for electrical conductivity.
✓ Powder Coat Clearance: Factor 0.003"–0.005" paint buildup per surface on slip-fit assemblies.

TECHNICAL SPECIFICATIONS & COMPLIANCE

Frequently Asked Engineering Questions

Detailed answers regarding our Plainville facility capabilities, material certifications, testing protocols, and defense contract compliance.

Q: Can Fabtron perform a preliminary DFM review before my CAD models are final?

Yes! Our manufacturing engineers regularly collaborate with mechanical designers during concept and prototype phases to optimize bend sequences, reduce hardware costs, and accelerate production lead times.