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News Release from: Gammaflux Europe GmbH | Subject: Hot runner feedback control - Power Priority
Edited by the Manufacturingtalk Editorial
Team on 24 December 2007
Control smoothed for hot runner systems
A further function in control algorithms of hot runner feedback control systems smoothes the power output without affecting the accuracy of the temperature control.
Gammaflux Europe has added a further function - 'Power Priority' - to the control algorithms of its hot runner feedback control systems Power Priority is designed to smooth the power output without affecting the accuracy of the temperature control
This article was originally published on Manufacturingtalk on 19 Mar 2008 at 8.00am (UK)
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This feature is especially important in low output systems where the heat output can fluctuate considerably.
Power Priority is the ideal control algorithm for hot runner systems equipped with small hot runner nozzles for low shot weights, said Gammaflux.
Such nozzles are being used increasingly in, for example, multicavity moulds, and are often no larger than 6 to 8mm in diameter.
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On account of their low heat capacity, such extremely small nozzles manifest very high heating and cooling rates.
Even for the hot runner control systems from Gammaflux, which work with a cycle time of only 20ms, this poses a challenge.
* Avoiding 'stringing' - if the power output is not smoothed, any heating pulse necessary for maintaining the required temperature and applied to the nozzle immediately upstream of its outlet, can cause stringing.
Stringing is a highly undesirable phenomenon that can adversely affect both the production process and the quality of the part.
Conversely, freezing of the melt can occur, which is just as troublesome.
The user can adjust the efficacy of Power Priority within a range of four settings - from 1 (light) to 4 (heavy) - and in this way obtain the optimum quality of feedback control for the actual application.
All LEC and TTC hot runner control systems from Gammaflux will be equipped with Power Priority with immediate effect.
The control algorithm can be readily retrofitted to existing control systems, during routine servicing and maintenance, for example.
The Power Priority control algorithm is based on the Triangulated Control Technology (TCT) developed by Gammaflux.
This technology optimizes the control process for each of the heating zones in three steps, as follows.
* Temperature measurement in 20ms cycles.
* Temperature evaluation with the self-adapting PID2 control algorithm.
* Transmission of heating pulse to the heating circuit via the high-precision phase angle firing control.
After substantial research and development, Gammaflux has now improved this technology to provide tighter-than-ever power and temperature control for small hot runner nozzles.
The extremely negligible fluctuation in heat output achievable with Power Priority without affecting the accuracy of the temperature control is a decisive factor for the optimum working of all cavities in a multicavity mould.
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