The CNC vs laser cutting decision depends on whether the part is really a flat profile or a three-dimensional component. Laser cutting uses a focused beam to cut 2D shapes from sheet and plate quickly and at low cost. CNC machining removes material with rotating tools to create pockets, counterbores, threads, precision bores and controlled surface finishes. Many parts use both: a laser-cut blank followed by machining of the critical features.
CNC vs Laser Cutting: Comparison Table
Figures are typical for a flat plate part with a profile and holes. Cost is a relative per-part index, where one machined part at quantity 1 equals 100.
| Factor | CNC machining | Laser cutting |
|---|---|---|
| Relative cost, qty 1 | 100 | 20 to 30 |
| Relative cost, qty 10 | 45 | 7 to 10 |
| Relative cost, qty 100 | 25 | 3 to 5 |
| Relative cost, qty 1,000 | 18 | 2 to 4 |
| Typical tolerance | ±0.001 to ±0.005 in, including hole position and diameter | About ±0.005 in on profile; hole size and roundness vary with thickness |
| Edge and surface finish | Ra 32 to 125 µin, square edges | Striated edge, some taper and dross in thicker plate |
| Materials | Nearly any metal or plastic, any thickness | Steel, stainless, aluminum, some plastics; thickness limited |
| Thickness | Any, including 3D features | Typically up to about 1 in steel, less for aluminum |
| Lead time | Days to a few weeks | Often a few days |
| Material effects | No heat affected zone | Heat affected zone at the edge; may harden or discolor |
| Typical use case | Precision plates, pockets, threads, bores, 3D parts | Flat profiles, brackets, gussets, blanks |
When Laser Cutting Wins
- Flat profiles. If the part is a 2D shape with holes that do not need tight tolerances, laser cutting is fast and inexpensive.
- Thin sheet at volume. Nesting many parts on one sheet keeps cost per part very low.
- Blanks for later work. Laser blanks remove most of the waste before forming, welding or machining.
When CNC Machining Wins
- Precision holes. Bearing bores, dowel holes and reamed fits need machining. Laser-cut holes are not round or sized closely enough for these fits.
- Threads, counterbores and pockets. Any feature that is not through the full thickness requires a cutting tool.
- Heat-sensitive material or edges. Machining leaves no heat affected zone, which matters for heat-treated parts, edges that will be welded later, and parts that need consistent hardness.
- Flatness and parallelism. Machined faces can hold flatness callouts that raw plate cannot.
Common Mistakes
- Specifying ±0.001 in hole sizes on a laser-cut part. Plan to machine or ream those holes.
- Laser cutting small holes in thick plate. As a rule, holes smaller than the plate thickness are hard to cut cleanly.
- Tapping laser-cut holes without checking the heat affected zone. Hardened edges can break taps.
- Machining an entire profile from plate when only a few features need precision. A laser blank plus targeted machining often costs less.
The Hybrid Route: Laser Blank, Then Machine
For plate parts with a few precise features, the common approach is to laser cut the outline with extra stock on critical edges, then machine the precise holes, pockets and datum faces. Leave about 0.030 to 0.060 in of stock on edges that will be machined so the heat affected zone is removed. Clear datum definitions on the drawing tell both suppliers which features come from which process.
How This Applies at Wexmar
Wexmar does not laser cut. We machine parts from bar and plate, and we can machine customer-supplied laser-cut blanks where the precise features justify it. Our horizontal machining centers with pallet changers and tombstone fixturing handle plate parts efficiently, and our CMMs verify hole position and flatness. See CNC milling, capabilities, and the related guide on CNC vs waterjet.
Getting a Quote
Send the drawing and note which features are critical. You can upload a drawing for an instant estimate, confirmed by a human estimator, or call (315) 400-2654.