Before any weld is made, the plate has to be cut to size. CNC cutting tables do that work automatically — plasma, oxy-fuel, and laser each have a thickness range and edge-quality profile where they make sense. This guide explains the three processes, what drives consumable cost, and the maintenance routine that keeps a table cutting clean.

PLASMA CUTTING

Plasma uses an electric arc to ionize gas into a plasma jet that melts and blows away metal. It is the workhorse of CNC cutting: fast on plate from 1 mm up to about 80 mm, and the best all-around choice for most fabrication shops. Modern fine-plasma systems deliver near-laser edge quality on thinner plate.

  • Cut speed beats oxy-fuel by a wide margin on thin and medium plate.
  • It cuts any conductive metal — including stainless and aluminum, which oxy-fuel cannot.
  • Air plasma is cheap to run; oxygen and nitrogen plasma give cleaner edges on stainless.

Choosing a machine: the plasma cutters guide covers capacity ratings, torch design, and duty cycles.

OXY-FUEL CUTTING

Oxy-fuel preheats the steel with a flame, then blows a high-pressure oxygen stream through the hot spot to burn it away. It cannot cut aluminum or stainless, but it is unbeatable for thick carbon steel — from 50 mm up to 300 mm and beyond — and its consumables are nearly free. See the dedicated Oxy-Fuel Cutting cutting process for a detailed walkthrough of preheat, cutting oxygen jet, kerf, and cut quality.

  • The slow process: seconds per inch on thick plate, where plasma struggles.
  • Edge quality is very good, and it leaves no heat-affected dross problems on heavy sections.
  • Tips are cheap; gas consumption and operator skill in setting preheat are the real variables.

LASER CUTTING

Laser uses a focused high-power beam — fiber lasers are the modern standard — to melt and vaporize metal. It delivers the tightest tolerances, the cleanest edges, and the narrowest kerf, which matters when parts nest tightly on expensive plate.

  • Best for thin-to-medium steel, stainless, and aluminum — typically up to 25 mm.
  • High purchase price and running cost: assist gas (nitrogen or oxygen), electricity, and optics maintenance.
  • It pays off through nesting density and minimal secondary finishing on high-volume parts.
Pro Tip

Match the process to the plate: laser for tight tolerance thin parts, plasma for everyday fabrication, oxy-fuel for thick plate. Most shops with a table run two processes on it.

CONSUMABLES

Consumables are where cutting tables quietly burn money. The consumables guide breaks down each category in detail.

  • Plasma: electrode, nozzle, swirl ring, shield — the set that must be replaced together. Track hours and change as a set.
  • Oxy-fuel: cutting tips, plus the gas flow settings that protect the torch from flashback.
  • Laser: nozzles, lenses, and protective windows — contamination ruins cut quality before you notice.
  • Buy original consumables for plasma and laser; aftermarket parts fail faster than the savings.

MAINTENANCE

A CNC table is a machine tool, and it needs machine-tool care. A dirty table cuts poorly long before it breaks.

  • Check and clean the torch height control sensor daily — pierce height drift ruins cut quality.
  • Clean the water table or downdraft filter on schedule, not when it smells.
  • Replace the grounding strap contacts and check that the work lead is truly connected.
  • Keep rails and racks clean and lubed; a worn rack shows up as wavy edges on parts.
  • Log consumable hours so replacement happens by the book, not by the smoke.
Watch Out

A sudden drop in cut quality is almost always a worn consumable set or a bad work-ground — not the machine. Diagnose in that order and you will not be replacing expensive drives you did not need.

THE BOTTOM LINE

Plasma cuts everything fast, oxy-fuel owns thick steel, and laser earns its cost on precision and nesting. Keep the table maintained, change consumables as sets, and the difference between a profitable cutting shop and a money pit is mostly routine.