Technical report
Servo Conversion Report
100% servo controlled machines compared with pneumatic systems: energy consumption, initial investment, payback period and carbon footprint.
Advantages
What does a 100% servo controlled machine gain you?
High weld quality
Force variability disappears; welding is controlled and precise.
No pneumatic equipment cost
Valves, regulators, air tanks, hoses, the compressor and the cost of producing compressed air are all eliminated.
Lower maintenance costs
Downtime caused by breakdowns and maintenance of the multi-component pneumatic system is reduced to a minimum.
Smooth and quiet operation
No pneumatic delay in welding speed; measurement is more precise than an incremental encoder.
Comparison
Pneumatic and servo, by the same criteria
The values come from the Siff engineering servo conversion study.
Pneumatic system
- Cylinder diameter
- 125mm
- Air pressure
- 5.5bar
- Cylinder force
- 6.75kN
- Cylinder speed
- 0.2m/s
- Output power
- 1.35kW
- System efficiency
- 0.22
- Cylinder cost
- 1100euro
Servo electric system
- Cylinder diameter
- 125mm
- Motor torque
- 4.77Nm
- Cylinder force
- 6.5kN
- Cylinder speed
- 0.2m/s
- Output power
- 1.30kW
- System efficiency
- 0.78
- Cylinder cost
- 3250euro
The energy cost in the calculation is taken as 0.09 euro/kWh.
Looking at the charts, you can see how far apart the energy consumption of pneumatic and servo electric cylinders is. Even before counting the maintenance needs of pneumatic equipment (cylinder maintenance, valves, regulators, hose replacement, conditioners), the energy consumption of the servo motor system stays far lower, and the gap widens as usage hours grow.
When the initial investment is added, the servo cylinder starts out more expensive, as expected. After 5,200 hours of operation, however, the two systems break even, and beyond that point they diverge sharply.
In a three-shift working pattern, the servo electric cylinder pays for itself within 1.5 years.
Carbon emissions and carbon footprint
Every method with low efficiency and energy sourced from fossil fuels increases the emission of greenhouse gases, measured in carbon dioxide equivalents and held chiefly responsible for global warming.
Traditional pneumatic systems increase carbon emissions in two main ways: the system's high energy consumption spread over the years, and the CO2 released into the atmosphere by the cumulative energy consumption of the compressor that feeds it.
The leading standards covering the six main greenhouse gases of the Kyoto Protocol (CO2, CH4, N2O, PFC, HFC, SF6) are the Intergovernmental Panel on Climate Change methodologies, together with the GHG Protocol, ISO 14064, CDP and PAS 2050.
In Türkiye, 33% of electrical energy comes from natural gas and around 30% from lignite and imported coal; among renewables, a significant share belongs to waste conversion. Against this background, the effect of electricity supply on greenhouse gas emissions becomes clearer. (Figures from TEİAŞ, EPDK and TSKB.)
While companies try to source even their heating and lighting energy from renewables when calculating their carbon footprint, using servo systems, with far lower energy consumption, no CO2 emission and much higher efficiency, is an important step both in improving the carbon footprint and in bringing energy consumption under control.
As carbon footprint standards become a legal requirement in the near future, the use of these systems will be inevitable.
Conversion
Let us convert your machine park to servo
We will assess your existing machines and work out the conversion plan and payback period together.