Plasma cutting is a cutting technology that uses a high-temperature, high-energy-density plasma arc to heat material at the cutting point and quickly melt it.
This cutting method is considered ideal for medium to thin sheets due to its high cutting efficiency and good quality, so it is very popular among users.
Since the 1990s, plasma technology has continually improved, leading to longer lifespans for its consumables such as electrodes, nozzles and vortex rings. This has greatly reduced the cost of plasma consumables and expanded the potential for plasma cutting applications.
According to an investigation carried out in the steel processing workshop of Dalian Shipyard, a comparison was made between plasma cutting machines and traditional oxyacetylene cutting methods.
1. Cost-cutting comparison
The primary cost of plasma cutting is related to consumables such as electrodes, nozzles and vortex rings, while the primary cost of oxyacetylene cutting is attributed to oxygen and acetylene. The costs for both cutting methods are calculated as follows:
1. NC oxyacetylene cutting, 18mm thick steel plate cutting, consumption cost per meter:
| Gas | M3 /bottle | Yuan/bottle | Yuan/ m3 |
| oxygen | 4 | 19 | 4.75 |
| acetylene | 5 | 70 | 14 |
| Board thickness (mm) |
Cutting speed (mm/min) |
Oxygen flow (m 3 h) |
Acetylene flow ( m2 /h) |
| 18 | 520 | 3.65 | 0.73 |
Oxygen consumption for cutting one meter steel plate:
3.65÷60÷0.52=0.12 ( m3 )
0.12 yuan x 4.75 = 0.57 yuan
Acetylene consumption cost for cutting one meter steel plate:
0.73÷60÷0.52=0.024 ( m3 )
14 yuan x0 024 = 0.34 yuan
Total cost of cutting one meter of steel sheet:
0.57 yuan + 0.34 yuan = 0.91 yuan
2. CNC plasma cutting to cut 18mm thick steel plate. Consumption cost per meter:
See the MAX200 from Hypertherm as an example:
| Project | Continuous cutting life | Unit price | Calculated useful life | Yuan/hour |
| Electrode | 46 hours | 50 yuan | 4 hours | 12.5 |
| Injector | 4-6 hours | 128 yuan | 4 hours | 32 |
| Vortex Ring | 15-25 hours | 181 yuan | 10 hours | 18.1 |
| Electric current | Power | Efficiency | Board thickness | Electricity price |
| 200A | 30 kW | 100% | 18mm | 0.80 yuan/degree |
Hourly electricity rate for steel plate cutting:
30 kW x 100% x 0.8 yuan = 24 yuan
Cost of consumables per hour:
(12.5 yuan + 32 yuan + 18.10 yuan) = 62.6 yuan
Cost per minute for cutting steel sheet:
(12 yuan + 62.6 yuan) ÷ 60 = 1.24 yuan
The total cost of cutting one meter of steel sheet:
1.24 yuan ÷ 1.5 = 0.826 yuan
Theoretical calculation shows that the cost per meter of oxyacetylene cutting is higher than that of plasma cutting. However, research carried out at the shipyard reveals that in practical application the cost of both methods is practically the same, with plasma cutting having a slight advantage.
2. Comparison of production efficiency
When cutting an 18mm steel plate with plasma, the speed is 1500mm/min, while the cutting speed with oxyacetylene is 500mm/min. This means that plasma cutting is three times faster than flame cutting, resulting in much higher production efficiency.
3. Comparison of cutting quality
When comparing cut quality, plasma cutting shows its advantages. The plasma cut part has no burrs or slag and the surface is smooth and free from edge collapse. The cutting accuracy tolerance per meter of length is no more than 0.5mm, and the part has minimal deformation. This means that plasma cutting can often replace or eliminate the need for machining.
Practice has proven that plasma-cut parts do not require machining and fully meet the quality requirements for welding assembly.
4. Comparison of economic benefits
The plasma cutting process eliminates the need for machining, which means that machining equipment can be saved and the machining cost, which can reach hundreds of thousands of yuan per year, can be reduced.
Furthermore, plasma cutting is highly efficient, which means that one plasma cutting machine can replace 2 to 3 oxyacetylene cutting machines. This significantly reduces the production area and improves the effective utilization efficiency of the plant.
The overall benefits of plasma cutting are substantial.
5. Conclusion
The cost of operating a plasma cutting machine is comparable to that of an oxyacetylene cutting machine. However, due to its high efficiency, high quality and substantial economic benefits, investing in a plasma cutting machine is still the best choice despite the large initial investment.
It is recommended that factory managers create the necessary conditions to purchase a CNC plasma cutting machine. The manufacturer may also choose to include a flame and plasma cutting gun in their configuration to prepare for future production increases.
