Why DFM matters more for sheet metal
Sheet metal starts as a flat blank and is plastically deformed on a press brake, so geometry, material behavior and tooling all interact. A hole placed too close to a bend line will distort when the part is bent, and the flat pattern and laser cutting can look clean right up until that point.
Bend radius drives tooling cost
The inside bend radius should be at least equal to material thickness; going tighter risks cracking on harder alloys. Standardizing one radius across a part avoids extra punch setups, so a part with six different bend radii costs more to tool than the same part with one consistent radius.
Hole-to-edge and hole-to-bend distance
Keep holes at least 1.5-2x material thickness from any sheet edge, and at least 3-4x thickness (or 2.5x thickness plus bend radius) from any bend line. A hole placed too close to a bend elongates or loses roundness during forming, so a hole that must sit near a flange for functional reasons should be flagged in the RFQ notes.
Tolerances should match fit, not habit
Standard formed-edge-to-hole tolerance runs around ±0.010 in (±0.25 mm) unless the application demands tighter control. Tighten tolerances only where they affect fit or function, separate flat-pattern tolerances from post-form tolerances, and mark critical dimensions on the drawing rather than in a cover email.
Laser cutting vs. punching changes clearance needs
Laser cutting suits tight, complex profiles and low-volume runs since there is no per-feature tooling cost. Punching is more economical at higher volumes with repeated hole sizes but needs more generous hole-to-edge clearance to avoid edge tearing.
| Input | Why it matters |
|---|---|
| Bend radius | Consistent across the part and at or above 1x material thickness to avoid cracking and extra tooling. |
| Hole-to-edge distance | At least 1.5-2x material thickness from any sheet edge; wider for punched holes. |
| Hole-to-bend distance | At least 3-4x material thickness (or 2.5x thickness plus bend radius) from any bend line to prevent distortion. |
| Minimum hole diameter | At or above material thickness for punched features. |
| Tolerances | Called out only where fit or function requires them, clearly marked on the drawing. |
| Material and grade | Alloy, temper and gauge specified precisely, not just “steel” or “aluminum”. |
| Finish and cosmetic notes | Visible faces, surface finish and masking needs for plating, powder coat or anodizing. |
| File formats | Native CAD or STEP for geometry, DXF/DWG for flat patterns, plus a PDF print with dimensions. |
Next step
Use the guide to prepare a cleaner inquiry, then attach the best available files through the RFQ form. If an item is unknown, say so directly so the first reply can separate quote assumptions from confirmed requirements.