Energy measurement in injection moulding machines is no easy task. The potential sources of errors are extremely wide-ranging and extend from suitable measuring technology through to correct procedures as well as systematic evaluation and interpretation of the results, particularly when it comes to making comparisons.
The demands placed on injection moulding machines in terms of the power measurement devices used for energy measurement are correspondingly high. Frequency converters, switch mode power supplies, bridge rectifiers etc., for example, “break up” the current waveform and can invert it due to energy feedback. Power measurement devices that require sinusoidal waveforms for voltages and currents consequently deliver incorrect readings. This danger applies particularly in the case of inexpensive devices.
- Use only power measurement devices that can also evaluate non-sinusoidal voltages and currents
- Take safety considerations into account: only have measurements performed by the relevant authorised persons
- Only begin with the measurements once the machine has been running in automatic operation for longer than 15 minutes (without changes to parameters or malfunctions)
- Perform measurement for at least 30 minutes to reliably compensate for process-dependent fluctuations
- During machine comparisons of an identical process (mould, material, environment), ensure that an identical measuring principle (port) and identical scope of measurements (without peripherals) are used
- Use specific energy requirement as key parameter: take into account the performance of the machine
- Detailed further training: bring responsible employees up-to-date with ARBURG training course