The best process depends on the part
Straight strips, nested contours and thick plate demand different processes. Define drawing, material, thickness, quantity, tolerance, edge and downstream work before comparing price.
Include deburring, drilling, bending, welding and coating in total cost. Critical parts require an engineer's process and acceptance criteria.
1. Shearing for fast straight cuts
Mechanical shearing is efficient for rectangular blanks and strips and creates no heat-affected zone.
It cannot make internal or curved contours. Blade clearance and material affect burr, rollover, fracture and distortion; state burr side and tolerance.
2. Laser for detailed geometry
Laser cutting can provide repeatable narrow cuts for complex profiles, slots and nested parts in suitable thicknesses.
Quality depends on material, thickness, laser, gas and parameters. A heat-affected or oxidised edge may need preparation before welding or coating.
3. Plasma for conductive metals
Plasma melts conductive metal with an ionised gas jet and can be practical across medium and heavy thicknesses.
Kerf, taper, dross and heat effect depend on current, height, consumables, speed and gas. Specify machine capability and tolerance.
4. Specify tolerance and edge quality
Replace terms such as 'clean' with dimensions, general tolerance, squareness, burr, radii and hole requirements.
Agree first-part inspection and measuring references. Incoming sheet thickness, flatness and residual stress also affect the part.
5. Connect heat effects to later work
Thermal cutting may alter colour, oxide and local properties. Define edge preparation for fatigue, welding, coating or special service.
Coated sheet loses protection at cut edges; specify compatible repair. Provide extraction, fire controls and PPE.
6. Compare total part cost
Nesting, rolling direction, margins and bridges affect yield. Include bending direction and allowances before cutting.
Compare material, programming, cutting, deburring, sorting, marking, packing and delivery, and lock the drawing revision.
Quotation checklist
Provide:
- Material, grade and thickness
- Dimensioned PDF and DXF/DWG
- Part code, revision and quantity
- Critical dimensions and holes
- Burr side and edge requirement
- Rolling direction and downstream work
- Finishing and protection
- Packing, delivery and certificates