Manufacturing Process
Sheet Cutting
板材切割
Separating sheet metal into blanks with laser, CNC punch or shearing before further processing.
Process Steps
- Nesting
- Cut profile
- Deburr
- Blanks sorted
What is sheet metal cutting?
Direct answer: it is the family of processes that turn a coil or sheet into flat shapes — and the right one is decided by three numbers: thickness, tolerance, and how many pieces you need.
The methods compared
| Method | Tolerance | Edge | Best volume |
|---|---|---|---|
| Shearing (guillotine) | ±0.1–0.3 mm | Straight cut, burr on one side | Any; single straight cuts |
| Blanking in a die | ±0.05–0.25 mm | Sheared profile with burr | High volume, any outline |
| Laser cutting | ±0.05–0.1 mm | Clean, small heat-affected zone | Prototypes to a few thousand |
| Plasma cutting | ±0.2–0.5 mm | Rougher, dross on the underside | Thick plate |
| Waterjet | ±0.1–0.25 mm | Smooth, no heat | Thick or heat-sensitive material |
| Nibbling | ±0.2 mm | Series of small cuts | One-off shapes without a laser |
| Wire EDM | ±0.003–0.01 mm | Very fine | Tooling, thick or hardened material |
How to choose
- Is the cut straight and the part a rectangle? Shear it. Nothing else is cheaper.
- Is the outline complex and the volume low? Laser or waterjet, depending on whether heat is a problem.
- Is the material thick? Plasma for structural steel, waterjet where the edge must not be heat-affected.
- Is the volume high and the shape repeating? A blanking die. Laser is a prototyping tool once you are making hundreds of thousands of parts.
- Does the thickness make shear impractical and the tolerance impossible for a die? Wire EDM.
Where cutting sits in a production route
Almost every stamped part starts as a cut shape. A blank is cut first, then formed, drawn, pierced, deburred and finished. The cutting decision therefore affects everything downstream: a blank that is 0.2 mm oversize on a profile can take a forming die outside its tolerance, and an edge with a heavy burr has to be deburred before plating.
In coil-fed stamping the cut happens inside the die and there is no separate cutting step at all — which is exactly why volume changes the answer so sharply.
Cut edge quality, in plain terms
- Sheared or blanked: rollover, burnish band, fracture zone, burr. Normal, and usually adequate.
- Laser: narrow kerf, small dross, a thin heat-affected zone. The edge is not the parent material.
- Waterjet: a matte, slightly tapered edge with no thermal effect.
- EDM: near-polished with a thin recast layer, removed by finishing passes.
Frequently asked
What is the most accurate way to cut sheet metal?
Wire EDM, at ±0.003–0.01 mm, but only for conductive material and at high cost. Laser is the practical answer for sheet profiles at ±0.05–0.1 mm; blanking in a die is the answer at volume.
When does a die become cheaper than laser cutting?
When the tooling cost divided by the annual volume is less than the difference in piece price — in practice a few thousand pieces a year for a simple flat part, less if the part is small and the outline simple.
Does cutting leave a burr?
Shearing, blanking and laser cutting all leave a small burr or dross. Where the edge matters, plan a deburring step and specify a maximum burr height on the drawing.
Can cut parts be formed afterwards?
Yes, and this is the normal route: cut flat, then bend or draw. What matters is that the blank is correct for the forming operation, which is why the flat pattern is calculated rather than guessed.
Related: laser cutting · blanking · trimming · deburring · deep drawing