We see it all the time: A drawing for a simple bracket with +/- 0.01mm tolerances on every dimension.
Can we do it? Yes. Do you want to pay for it? Probably not.
Understanding the difference between "Standard," "Precision," and "Ultra-Precision" tolerances is the easiest way to lower your part cost without sacrificing functionality.
The Cost of Precision
Tooling cost rises exponentially as tolerances get tighter.
Standard
+/- 0.1mm
Cost Index: 1.0x
Standard dies, normal wear.
Precision
+/- 0.05mm
Cost Index: 1.5x
Requires precision grinding & frequent maintenance.
Ultra-Precision
+/- 0.01mm
Cost Index: 3.0x+
Carbide tooling, temperature control required.
Realistic Tolerances by Feature
Not all features are created equal. A hole diameter is easier to hold than a bend angle.
| Feature | Standard Tolerance | Notes |
|---|---|---|
| Hole Diameter | +/- 0.05mm | Determined by the punch, very consistent. |
| Hole-to-Hole | +/- 0.05mm | Fixed in the die, very stable. |
| Bend Angle | +/- 1 degree | Affected by material springback (especially in aluminum). Hard to hold tighter without coining. |
| Bend Length | +/- 0.15mm | Varies with material thickness. |
| Flatness | 0.5mm / 100mm | Stamping releases stress, causing warp. Requires leveling. (See our defect guide). |
How to Optimize Your Design
- Identify Critical Features: Only apply tight tolerances to mating surfaces. Leave the rest open.
- Use Slots for Adjustment: If a hole location is critical for assembly, use a slot instead of a round hole to allow for adjustment.
- Talk to Us Early: Let us review your GD&T before you freeze the design. We can suggest small changes that save big money.
Free DFM Review
Upload your drawing. We'll highlight any tolerances that are driving up costs and suggest practical alternatives.
Upload Drawing for Review