In short: Choose laser bevel cutting for thin and medium plate where bevel accuracy, small parts and holes in the same program matter.
Choose plasma bevel for heavy plate where speed and lower investment count more than precision. Both commonly bevel up to about 45°. A bevel makes the cut path longer than the plate thickness — at 45° about 1.41 times — so check capacity at the effective thickness, not the nominal one.
Why bevel on the cutting machine
A full-penetration butt weld in thicker plate needs a prepared edge — a V, Y, X or K groove — so the weld can reach the root. Traditionally the part is cut square and the bevel is ground, milled or flame-cut afterwards. A bevel head on the cutting machine tilts the torch or laser head and cuts the bevel in the same program, removing that second operation. A plasma system maker states plainly that a bevel head lets you eliminate secondary operations (source 2).
The joint types themselves are defined in ISO 9692-1:2013, which specifies types of joint preparation for arc, gas, TIG and beam welding of steels, for full-penetration butt welds and fillet welds (source 1). Its dimension ranges — groove angle, root face, root gap — are design ranges for the joint, not manufacturing tolerances. Your welding procedure specification and drawing decide the values; the cutting process has to hit them.
Bevel types the machines cut
- V (single bevel, top): one angled cut through the full thickness.
- A (bevel on the underside): the same, inverted — the "negative" bevel.
- Y: a straight land (root face) plus an angled cut — two passes.
- X and K: bevels from both sides, with or without a land — usually three passes.
A machine maker lists A, V, X, K and Y bevels at up to 45° on its fiber laser bevel system, demonstrated on 25 mm steel with a 15 kW source (source 3). On plasma, a system maker's bevel tables cover V and A cuts from 15° to 45° and Y top cuts from 22.5° to 45°, with lands from 20 % to 50 % of the plate thickness (source 2).
The thickness you really cut
A bevel lengthens the cut. The path through the plate is the plate thickness divided by the cosine of the bevel angle: at 30° it is about 1.15 times the thickness, at 45° about 1.41 times. A 25 mm plate bevelled at 45° is therefore a cut of roughly 35 mm through steel. Plasma makers make the same point — bevelling increases the effective thickness (source 5). When you compare machines, ask for bevel cutting capacity and speed at your angle, not the square-cut maximum.
ISO 9013:2017 grades laser cuts from 0.5 to 32 mm and plasma cuts from 0.5 to 150 mm (source 4). That is the scope of the quality standard, not the limit of a machine, but it shows where each process has traditionally been used: laser in sheet and medium plate, plasma up into heavy plate.
Plasma bevel: strengths and limits
Plasma bevel heads are a mature, widely used route for weld preparation on structural and heavy plate (source 5). A system maker's bevel process tables cover mild steel from 6 to 50 mm (source 2). The same white paper explains the main difficulty: the plasma arc behaves differently when the torch is tilted, so hitting the target size and angle needs compensation for both angle and kerf — a process it describes as time-consuming and iterative without ready-made tables (source 2).
It also notes practical limits: on thinner material an A cut may not reach 45°, because compensation can call for up to 10.3° extra tilt, beyond the roughly 48° the torch is designed for; and A cuts tend to give better edges from about 38 mm upwards (source 2).
Laser bevel: strengths and limits
A fiber laser bevel head cuts the contour, holes, slots and bevels in one program, with the narrow kerf and square geometry of laser cutting. That suits parts where many features and accurate fit-up matter — brackets, connection plates and machine frames that go straight to welding. Typical bevel ranges are up to about 45° (source 3).
The limit is effective thickness and power. A 45° bevel on 25 mm plate needs the laser to cut about 35 mm of steel. High-power sources of 20 kW and more make this practical, but cutting speed falls with the longer path, and very heavy plate remains plasma territory. On our machines, bevel cutting is available as an option on the HL-F and, for formed and tubular parts, the HL-3D five-axis; ask for bevel test cuts at your thickness and angle.
What to check on a bevel test cut
A bevel that looks right can still fail fit-up. When you evaluate test cuts from either process, measure the same things your welders depend on:
- Bevel angle at several points along the edge, including near corners and lead-ins, where the head changes direction.
- Land (root face) height on Y and K bevels — consistency matters more than the nominal value, because it controls root penetration.
- Part size at top and bottom. On a V bevel the bottom edge defines the part; on an A bevel the top does. Confirm which dimension your drawing controls and that the program compensates for it.
- Edge condition: dross on the underside, rounding of the top edge and any oxide layer that must be removed before welding.
- Repeatability: cut the same part at the start and end of a sheet, and on two different days.
Ask each supplier how bevel parameters are created for a new material or angle — from built-in tables, or by trial cuts on your plate — and how long that takes. On plasma, a system maker describes building compensation values without tables as time-consuming and iterative, and notes that some users leave bevel heads idle for that reason (source 2). The same question applies to laser: a bevel head is only productive if your programmers can set up new angles quickly.
Finally, include the downstream cost. If a laser-cut bevel goes straight to welding while a plasma bevel needs light grinding, the extra machine cost can be recovered in the welding bay rather than at the cutting table.
Side-by-side comparison
| Laser bevel | Plasma bevel | Source / note | |
|---|---|---|---|
| Bevel types | A, V, X, K, Y | V, A, Y (and multi-pass X, K) | Sources 2, 3 |
| Typical maximum angle | Up to about 45° | Up to about 45° | Sources 2, 3 |
| Published bevel tables or demos | 25 mm steel at 15 kW (demo) | 6–50 mm mild steel (process tables) | Sources 2, 3 — vendor data |
| Thickness range of ISO 9013 quality grading | 0.5–32 mm | 0.5–150 mm | Source 4 |
| Holes and small features in the same part | Strong | Weaker; small holes often drilled | Source 5 |
| Angle and kerf compensation | Needed; set per material and angle | Needed; arc changes when tilted | Source 2 |
| Heavy plate (above about 40 mm) | Limited by power and speed | Traditional strength | Effective-thickness rule above |
| Investment | Higher | Lower | Compare cost per finished part |
How to decide
- List your bevelled parts by thickness, bevel type and angle — and how many holes and features each part has.
- Work out the effective thickness for each (thickness ÷ cos angle).
- If most bevelled work is below about 25 mm and parts carry many features: laser bevel.
- If most is heavy plate above about 40 mm with simple contours: plasma bevel remains the practical choice.
- In between, request bevel test cuts on both, measure angle, land and root against your welding procedure, and compare cost per finished part including grinding. Send drawings through our test cut request.
Frequently asked questions
Can a fiber laser cut weld bevels?
Yes. A laser with a bevel head cuts A, V, X, K and Y bevels, typically up to about 45°, in the same program as the contour and holes. Capacity depends on power and the effective thickness at your bevel angle.
What bevel angles can plasma cut?
One plasma system maker's bevel tables cover 15° to 45° for V and A cuts and 22.5° to 45° for Y top cuts on mild steel from 6 to 50 mm. Thin material may not reach 45° on A cuts.
Why is bevel cutting slower than straight cutting?
Because the cut path is longer than the plate thickness: thickness divided by the cosine of the angle. At 45° that is about 1.41 times the thickness, so a 25 mm plate becomes a 35 mm cut.
Which standard defines weld joint preparations?
ISO 9692-1:2013 specifies types of joint preparation for arc, gas, TIG and beam welding of steels. Its dimension ranges are design limits, not manufacturing tolerances.
Is laser or plasma better for bevelling thick plate?
For heavy plate with simple contours, plasma bevel is usually the practical and lower-cost choice. For thinner plate with many holes and tight fit-up, laser bevel saves secondary operations.
Sources
- ISO 9692-1:2013, Welding and allied processes — Types of joint preparation — Part 1: Manual metal arc welding, gas-shielded metal arc welding, gas welding, TIG welding and beam welding of steels (catalogue entry: scope) — online.standard.no (accessed 2026-10-28)
- Hypertherm, “True Bevel technology — Bevel compensation cut charts” (plasma system maker’s white paper): thickness and angle coverage, compensation, limits — www.hypertherm.com (accessed 2026-10-28)
- Voortman, “V353 bevel laser cutting” (machine maker): 15 kW fiber laser, 25 mm demo parts, A/V/X/K/Y bevels up to 45° — www.voortman.net (accessed 2026-10-28)
- ISO 9013:2017, Thermal cutting — Classification of thermal cuts (catalogue entry: scope and thickness ranges) — www.iso.org (accessed 2026-10-28)
- Hypertherm, “Is plasma a viable alternative to laser?” (plasma manufacturer’s view): bevels increase effective thickness; small holes — hypertherm.com (accessed 2026-10-28)