The cheapest cutting process can produce the most expensive part. The first cut sets stock allowance, rework and microstructure.
As a precision engineering and CNC manufacturer in Werl, Vulcanus cuts blocks, rings and hardened steels for further machining.
Here, the main metal cutting processes are compared: sawing, laser, plasma, flame cutting, waterjet and EDM. It helps you choose the right process for your part.
Key Takeaways
- Laser is the most precise and fastest contour process for thin to medium sheet.
- Plasma and flame cutting are economical for thick steel plate but create a heat-affected zone.
- Waterjet cuts almost any material cold, but is slower and more expensive.
- Sawing is the first choice for solid stock, large cross-sections and hardened steels.
- Thickness, material, contour, tolerance and downstream machining decide the right choice.
What Metal Cutting Processes Are There?
Under DIN 8580, all cutting processes belong to the main group of separating processes. However, they work on fundamentally different principles. Our guide to types of manufacturing processes shows the full classification.
Mechanical Processes
Sawing and milling cut with a defined edge and produce chips. Shearing splits sheet without chips. All three work cold and barely affect the microstructure.
Thermal Processes
Laser cutting, plasma cutting and flame cutting separate by melting or burning. They are fast and flexible for contours. In return, they create a heat-affected zone at the cut edge.
Cold Special Processes
Waterjet cutting uses a high-pressure jet, usually with abrasive. Wire EDM removes material with electrical sparks. Both suit demanding materials and contours.
The Processes in Detail
Laser Cutting
A focused laser beam melts the material while a gas blows the melt out. Modern fibre lasers cut structural steel economically up to around 25 to 30 mm. The kerf is narrow, and tolerances are often around 0.1 mm.
Strengths and Limits
- Strengths: high precision, fine contours, high speed on thin sheet
- Limits: restricted thickness, heat input, high investment
Fibre or CO2 Laser?
Fibre lasers now dominate metal cutting. They are more efficient and cut reflective metals such as aluminium and copper better. CO2 lasers remain mainly for thick plate and non-metals.
Plasma Cutting
A plasma arc melts electrically conductive materials. At medium thicknesses, it is faster than laser. Typical thicknesses reach around 50 to 80 mm.
Strengths and Limits
- Strengths: fast, relatively low-cost, for structural steel, stainless and aluminium
- Limits: wider kerf, slightly bevelled edges, larger heat-affected zone
Flame Cutting
In oxy-fuel flame cutting, steel burns in an oxygen jet. This cuts unalloyed steels several hundred millimetres thick. Stainless steel and aluminium, however, cannot be cut this way.
Strengths and Limits
- Strengths: very large thicknesses, low equipment costs
- Limits: coarse tolerances, high heat input, distortion and edge hardening
Waterjet Cutting
A water jet at several thousand bar cuts almost any material. With abrasive, even thick metals of around 200 mm are possible. There is no heat-affected zone.
Strengths and Limits
- Strengths: cold cut, all materials, good tolerances
- Limits: slow on large thicknesses, high operating costs, slight taper
Pure Water or Abrasive?
Pure waterjet only cuts soft materials such as rubber or foam. For metals, an abrasive such as garnet sand is added to the jet. This abrasive is also a major cost factor.
Sawing
Sawing cuts with a multi-tooth tool and produces chips. Band saws handle large cross-sections, circular saws high volumes. The microstructure stays unchanged right up to the cut edge.
Strengths and Limits
- Strengths: solid stock, very large cross-sections, hardened materials, little waste
- Limits: mainly straight cuts, hardly any internal contours
Achievable sawing accuracy is covered in our article on cut-to-length tolerances.
Shearing
Shearing splits sheet between two blades without chips. The process is very fast and inexpensive. It suits only straight cuts in thin to medium sheet.
Contour Milling
Milling can also cut contours directly from solid. It is slower than laser or plasma, but very accurate. It makes most sense when the part is milled anyway, as in CNC milling and turning.
Wire EDM
A thin wire removes material through spark discharge. The process reaches tolerances in the micron range. It only works on conductive materials and is relatively slow.
Metal Cutting Processes Compared: The Overview
The table summarises typical reference values. Actual values depend on machine, material and thickness.
| Process | Typical thickness (steel) | Tolerance (approx.) | Heat input | Materials |
| Laser | up to approx. 25 to 30 mm | approx. ±0.1 mm | low | steel, stainless, aluminium |
| Plasma | up to approx. 50 to 80 mm | approx. ±0.3 to 0.5 mm | medium | conductive metals only |
| Flame cutting | up to several 100 mm | approx. ±1 mm and more | high | unalloyed and low-alloy steels |
| Waterjet | up to approx. 200 mm | approx. ±0.1 mm | none | almost all materials |
| Sawing | solid stock up to 600 mm and more | approx. ±0.15 to 0.3 mm | none | all metals, including hardened |
| Wire EDM | up to approx. 300 mm | micron range | very low | conductive materials only |
The table makes one thing clear: there is no best cutting process, only the right one for each part.
How to Choose the Right Cutting Process
By Thickness and Shape
- Thin sheet with contours: laser
- Medium to thick steel plate: plasma or flame cutting
- Blocks, bars, rings and solid stock: sawing
- Thick plate without heat input: waterjet
- Finest contours in hard materials: wire EDM
By Material
Flame cutting only works on unalloyed and low-alloy steels. Plasma and EDM require conductive materials. Sawing and waterjet are the most universal, as our guide to CNC material selection also shows.
Special Case: Hardened Materials
Thermal cutting softens the edge of hardened steels. Cracks are also a risk. Cold processes such as hard sawing or waterjet preserve the effect of prior heat treatment.
By Tolerance and Downstream Machining
If the part is milled or turned afterwards, an even allowance matters most. Thermal processes need more machining allowance because the edge zone must be removed. What counts is the required manufacturing tolerance on the finished part.
By Batch Size and Lead Time
For single parts, short setup times and flexible programming matter. In series production, cutting speed and automation become more important. Laser and automatic saws play to their strengths here.
By Cut Edge and Surface
Laser and waterjet deliver clean edges that often need no rework. Plasma and flame cuts show striations and dross. The difference can be expressed through surface roughness.
Cut Edges for Welding
Many blanks are welded later. Plasma and flame cutting can produce weld bevels in the same pass. Our overview of welding processes shows which joining method fits next.
Combined Process Chains
In practice, a single process is rarely used alone. Two steps often complement each other ideally.
- Sawing, then milling: solid blank with little allowance for precision machining
- Flame cutting, then milling: thick contoured plate, edge zone milled away
- Laser, then bending: precise sheet blanks for formed parts
- Waterjet, then grinding: heat-sensitive parts with fine final tolerances
The first step should always suit the second. A blank with an even allowance saves the most time in downstream machining.
Cutting Process Costs Compared
What Drives the Price
- Machine hourly rate and cutting speed
- Material thickness and cut length
- Consumables such as nozzles, electrodes, saw bands or abrasive
- Rework on edges and heat-affected zones
- Material loss through kerf and allowance
Total Cost Is What Counts
A fast plasma cut looks cheap. If a hardened edge zone must then be milled away, the numbers change. Our guide on how CNC quotes are calculated explains how downstream steps drive price.
Looking at the whole process chain helps you reduce per-part cost.
Material and Sustainability
A narrow kerf saves material, especially with expensive alloys. Cold processes also avoid energy for post-treatment. Both support sustainable manufacturing.
Common Mistakes When Choosing a Process
- Flame cutting stainless steel: the process does not work there.
- Thermal cutting of hardened parts: the edge zone softens or cracks.
- Laser on very thick plate: cut quality and cost-efficiency drop sharply.
- Too little allowance after plasma: the heat-affected zone reaches the final dimension.
- Waterjet for simple straight cuts: sawing is usually faster and cheaper.
Cutting at Vulcanus: Specialists in Sawing Large and Hard Components
Vulcanus-Stahl & Maschinenbau in Werl specialises in cold cutting. We saw where thermal processes reach their limits.
- Vertical sawing: cutting lengths up to 3,800 mm and heights up to 600 mm
- Horizontal sawing: lengths up to 20,000 mm and diameters up to 580 mm
- Hard sawing: hardened materials up to 65 HRC, tungsten and special alloys
- Segmenting and contour sawing: rings up to 2,200 mm diameter and complex profiles
For thin sheet contours, we openly recommend laser or plasma. Our strength lies in solid material and the machining that follows. Learn more on our industrial sawing services page and in our article on CNC machining for large parts.
Conclusion: Comparing Metal Cutting Processes Starts With the Finished Part
Laser, plasma, flame cutting, waterjet, sawing and EDM each have clear areas of use. No process wins on every count.
Planning backwards from the finished part leads to the lowest total cost. To find the right partner, read how to choose a CNC machining supplier. To outsource complete parts, see our guide to CNC contract manufacturing.
Need to cut large blocks, rings or hardened material? Contact Vulcanus for a technical assessment and a no-obligation quote.
FAQ: Metal Cutting Processes Compared
Which cutting process is the most accurate?
Wire EDM reaches tolerances in the micron range. Among the fast processes, laser and waterjet are the most accurate.
Laser or plasma: which is better?
Laser is more precise on thin and medium sheet. Plasma is faster and cheaper on thicker steel plate.
Which process suits very thick material?
For solid stock, sawing is the first choice. Thick steel plate can also be flame cut, while waterjet suits heat-sensitive materials.
Which cutting processes work without heat input?
Sawing, shearing and waterjet cutting are cold processes. Wire EDM causes only very slight edge effects.
Can stainless steel be flame cut?
No. Stainless steel is usually cut by laser, plasma, waterjet or saw.
When is sawing cheaper than laser cutting?
For bars, blocks and solid stock with straight cuts. There, sawing is faster, saves material and adds no heat.