There are many ways of calculating the operating costs of a fiber laser cutting machine, some of which can be very complex.
A calculation is shown here that is not very complex, but is very suitable for helping you during the decision-making phase of purchasing a laser cutting machine. We focus on the most important parameter – the cost per part.
The data required to perform the calculation:
A. Working hours per month
(the number of working hours per month to be taken into consideration in the calculation - freely selectable)
We have chosen 300 working hours per month, which corresponds to the typical situation in practice
B. Production per hour
(Machine productivity, we have selected the data from the sample part cutting test, see video). The sample part was cut at the standard production cutting speed ).
We chose three different machines for this test:
4kW machine; 69 pieces per hour (cutting time 52 sec. per part),
8kW machine; 138 pieces per hour (cutting time 26 sec. per part)
and
15kW machine; 277 pieces per hour (cutting time 13 sec. per part)
C. Monthly leasing cost
We have selected the typical monthly rate for the relevant machine category as the monthly leasing rate, in accordance with the quote from the leasing company:
7.500 € /Mo. (4 kW), 9,500 € (8 kW) and 11,500 € (15 kW)
D. Hourly machine rate and hourly technology costs
(The level of these costs corresponds to the typical hourly machine tariff costs - excluding depreciation). This is the final parameter that we need in order to make our calculation.
These parameters are not consistent for all cases, and can vary based on the laser, the operator, and the company practices. Overall, we have found these parameters to be practical.
Let's start with the definition of the hourly machine rate of the laser machine:
The typical calculation of the hourly machine cost has the following structure:
Fixed costs:
- Depreciation costs
- Space costs
- Calculated interest costs
Variable costs:
- All wear part, spare part and service costs
- Energy costs
- Cutting Gas costs
- Compressed air costs
- Lab our costs
Overhead costs:
We strongly recommend adding the overhead costs to the above-mentioned costs (fixed + variable costs) to make the calculation more realistic. These costs are often neglected, which can change the overall calculation considerably.
To keep the calculation simple and be realistic at the same time, we have chosen the following hourly rates for the machine:
- 4kW Machine 100 EUR/ hour (100% indexing)
- 8kW Machine 120 EUR/hour
- 15 kW Machine 140 EUR/hour
A calculation for production of 300 hours per month using these parameters can be found in the following.
| Same production time | 4kW | 8kW | 15kW | ||
|---|---|---|---|---|---|
| A | Selected parameters | Monthly working hours | 300 | 300 | 300 |
| B | Achieved result | Hourly production | 69 | 138 | 277 |
| C | Achieved result | Monthly leasing cost | 7,500 € | 9,500 € | 11,500 € |
| D | Selected parameters | Machine rate/h | 100.00 € | 120.00 € | 140.00 € |
| E= | C / A | Leasing per hour | 25.00 € | 31.67 € | 38.33 € |
| F= | A x B | Production parts per month | 20,700 | 41,400 | 83,100 |
| G= | D / B | Cost per part | 1.45 € | 0.87 € | 0.51 € |
| Same production output |
4kW | 8kW | 15kW | ||
|---|---|---|---|---|---|
| B | Achieved result | Hourly production | 69 | 138 | 277 |
| C | Achieved result | Monthly leasing cost | 7,500 € | 9,500 € | 11,500 € |
| H= | J / B | Monthly working hours | 300 | 150 | 75 |
| I= | C / H | Hourly leasing cost (new) | 25.00 € | 63.33 € | 153.89 € |
| J= | A x B = Constant | Constant production per month | 20,700 | 20,700 | 20,700 |
| K= | I + ( D-E ) | Machine rate/h (new) | 100.00 € | 151.67 € | 255.56 € |
| H= | K / B | Cost per part | 1.45 € | 1.10 € | 0.92€ |
In the next graphic you will find a calculation of the monthly working hours from 100 -600 hours and the costs per part which correspond to these working hours, depending on the laser power of the cutting machine.
In the last graph you will find the required use of the laser cutting machine in shifts (8 working hours) to achieve the necessary production in accordance with the laser power of the machine.
