There are many ways to calculate the cost of operating a fiber laser cutting machine; some can get quite complex.
Here we present a calculation that is not very complex, but is more than adequate to help in the decision phase of purchasing a laser. We focus on the most important parameter – cost per part.
The data required to perform the calculation:
A. Working hours per month
(the number of working hours per month for which we want to do the calculation - freely selectable)
We choose 300 working hours per month - it corresponds with typical situation in the praxis
B. Production per hour
(Machine productivity, we have selected the data from our cutting test for the sample part, see video). The sample part was cut with standard production cutting speed ).
We choose from this test three different machines:
4kW machine; 69 pieces per hour (cutting time 52 sec per part),
8kW machine; 138 pieces per hour (cutting time 26 sec per part)
15kW machine; 277 pieces per hour (cutting time 26 sec per pieces)
C. Leasing per month
Monthly leasing rate, we have chosen the typical monthly rate for such category of the machine according the budget offer of the leasing company:
7.500 € /Mo. (4kW), 9.500 € (8kW) and 11.500 € (15kW)
D. Machine rate cost and Technology costs per hour
(The amount of these costs corresponds to the typical machine tariff costs per hour - excluding depreciation costs) This is the last parameter we need to be able to make our calculation.
These parameters are not consistent for all cases, and can vary based on the laser, the operator, and shop practices. Overall, we have found these parameters to be practical.
Let's start with the definition of the machine rate cost of the laser machine:
The typical calculation of the machine cost per hour has the following structure:
- depreciation cost
- space cost
- Calculated interest Cost
- all wear spare and service cost
- Energy Cost
- Cutting Gas Cost
- Compressed air costs
- Labour Cost
We strongly recommend to add the overhead costs to the above-mentioned costs (Fix + Variable) to make the calculation more realistic. These costs are often neglected, which can change the overall calculation considerably.
To keep the calculation simple and at the same time be close to reality, we have chosen the following hourly rates for the machine:
- 4kW Machine 100 EUR/ hour (100% Indexing)
- 8kW Machine 120 EUR/hour
- 15kW Machine 140 EUR/ Hour
According to these parameters you can find a calculation when production is 300 hours per month.
|Same Production Time||4kW||8kW||15kW|
|A||selected parameters||Working hours per Mo.||300||300||300|
|B||achieved result||Production per hour||69||138||277|
|C||achieved result||Leasing per Month||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
|B||obtained result||Production per hour||69||138||277|
|C||obtained result||Leasing per Month||7.500 €||9.500 €||11.500 €|
|H=||J / B||Working hours per Month||300||150||75|
|I=||C / H||Leasing per hour (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€|
On the next graph you will find the calculation for working hours per month from 100 -600 hours and the costs per part corresponding to this working time depending on the laser power of the cutting machine
On the last graph you will find the required use of the laser cutting machine in shifts (8 working hours) to achieve the necessary production according to the laser power of the machine.