Plasma cutting cost per inch: how CNC plasma jobs are priced
CNC plasma tables are behind a lot of custom metal work: wall art, ranch and house-number signs, fire-pit rings, brackets, gussets, trailer parts. If you've asked a few fabricators for a price, you've probably heard it expressed several ways: by the hour, by the inch of cut, per pierce, or just a flat number per piece. They're all versions of the same calculation.
How a plasma table spends its time
A plasma torch cuts by blowing an electrically heated jet of gas through the metal. Two things take time:
- Travel along the cut. The torch follows every outline and every hole at a cut speed that depends on the metal, its thickness and the machine's amperage. Thin sheet cuts fast; thicker plate is much slower.
- Pierces. Every separate shape starts with a pierce: the torch has to blow through the plate before it can move. Each pierce takes time and wears the consumables (electrode and nozzle) more than cutting does. A design with 300 small cut-outs has 300 pierces.
That's why many shops talk about cost per inch of cut plus a charge per pierce. It's a way to put machine time and consumable wear into numbers that come straight from your file. Shops that quote by the hour are doing the same thing, just with time.
You can estimate run time yourself with the CNC cut time calculator: enter the total cut length, a feed rate, one pass (plasma cuts through in a single pass) and the number of pierces.
The full price
Price = setup + (cut length × rate per inch) + (pierces × rate per pierce) + material + finishing.
Setup
Loading the file, cleaning it up in CAM, nesting parts on the plate, setting amperage and cut height, a test cut. Paid once per job.
Cut length and pierces
Get the total length from your CAD or vector program, and count the closed shapes. A simple 24 in ring is one outline and one inner circle: a few feet of cut and two pierces. A 24 in landscape scene with trees, birds and fence posts can be ten times the cut length and a hundred pierces.
Thickness
Thicker steel means slower cutting, more amperage, faster consumable wear and more expensive stock. Common gauges for wall art (around 16 to 14 gauge) cut quickly; 1/4 in plate for fire pits and brackets is slower and much heavier.
Material
Mild steel is the cheapest and most common. Stainless and aluminum can be plasma-cut but cost more per sheet, and not every table is set up for them. Material is priced by sheet or by weight, plus waste.
Finishing
Plasma leaves dross (re-solidified metal) on the bottom edge and a slight bevel on the cut face. Most parts need some grinding. Then there's the finish: raw steel (which will rust), clear coat, paint, a deliberately rusted patina, or powder coating. Powder coat is often subcontracted and is a meaningful share of the cost on a finished sign.
What drives the price up
- Fine detail. Small cut-outs and thin bridges are slow, need many pierces, and can warp thin sheet from heat. A detail smaller than about the material thickness may not survive at all.
- Thick plate. Slower cutting and heavier, costlier stock.
- Large size. A piece bigger than the table needs to be split, or sent to a shop with a bigger table.
- Finish. Powder coating and careful grinding are labor.
- One-offs. Setup on one sign costs the same as setup on a run.
Plasma vs laser vs waterjet
Plasma is the go-to for steel art, signs and brackets in roughly 16 gauge to 1/2 in and up. It's fast and affordable, but leaves a slight bevel and some dross, and the minimum feature size is larger than a laser's.
Fiber laser cuts sheet metal with a cleaner, narrower kerf and finer detail, and is usually better for precise small parts in thin sheet.
Waterjet cuts almost anything, with no heat-affected zone, but it's slower and generally pricier per part.
For a 30 in steel house-number sign, plasma is usually the sensible choice. For a hundred tiny stainless tags, a fiber laser probably is.
How to get a lower plasma quote
- Simplify the design. Merge small cut-outs, thicken thin bridges, remove details nobody will see from six feet away. Fewer pierces, shorter path.
- Pick the thinnest steel that works. Wall art rarely needs plate.
- Send a clean DXF. Closed paths, no duplicate lines, at 1:1 with units stated. Plasma CAM needs closed shapes to know which side to cut on.
- Decide on the finish up front. "Raw, dross ground off" is cheapest; powder coat in a custom color is not.
- Batch. If you need six signs for a family or a set of brackets, put them in one job.
- Collect locally. Steel is heavy, and freight on a large piece adds up.
Keep it legal and safe
Plasma tables can cut almost any steel shape, but The Spool List doesn't allow firearm or weapon parts, and makers can decline any job. Decorative work, signs, brackets, furniture frames and fire-pit parts are all fine.
Get bids on your metal job
The rate per inch and per pierce varies with each fabricator's machine and consumables, so comparing bids on the same DXF is the fastest way to a fair price. Post the job with the material, thickness, finished size, finish and quantity. Posting is free, there's no buyer fee, and the payment is held until the work arrives and you confirm delivery. The price guide covers the rest of the cost drivers.