Improved reliability and parts quality? It's as easy as AFB!
26/11/2013 Sumitomo (SHI) Demag
An innovative option from Sumitomo (SHI) Demag allows injection moulders to optimise their processes and achieve significant improvements in quality. Dave Raine, Technical Sales Manager, outlines the secrets of activeFlowBalance.Jetting, sink marks, short shots, flash, voids and warping - just some of the problems that affect productivity and eat into profits. Many of these have their roots in the transition from injection to holding pressure.
Parts with multiple gates, parts with thin-wall areas at the end of the flow-path, and parts which are very small in relation to their sprue weight can all too often incur unacceptable reject rates.
Faced with these issues, the mould setter's usual remedy is to adjust filling speeds, pressures and change over positions to reach a compromise which achieves the best result given the issues faced. However, this solution is far from ideal.
Increasing the injection pressure can cause flash caused by pressure peaks and malformed parts due to stress. By adjusting the holding pressure and altering the switch over point, the pressure peak problems are avoided but only at the risk of 'short shots' - incomplete mouldings due to insufficient material.
A question of balance
The introduction of activeFlowBalance by Sumitomo (SHI) Demag gives manufacturers a unique tool to combat uneven and fluctuating filling of multi-cavity moulds. Suitable for a broad range of applications, the activeFlowBalance option allows mould setters to avoid the potential problems of uneven filling of the mould without extending the filling time. What would previously have been a complex injection profile, requiring many years of experience and training to implement, can now be achieved in under 1 minute, with minimum input from the setter or technician.
Once the injection process is complete, the activeFlowBalance function controls switch over, holding the screw at a fixed position for a pre-selected period of time before moving on to the standard hold pressure setting.
During the activeFlowBalance phase, no additional pressure to the material is applied, allowing the existing cavity pressure within the melt to equalise throughout all the cavities. As the pressure is allowed to stabilise across the system, pressure flows into the cavities which are under-filled, reducing the imbalance, and producing a more even fill pattern.
Maintaining an absolutely fixed screw position, with no additional pressure applied once the injection phase is completed, is only possible due to the drive and control systems offered by Sumitomo Demag on its all electric machines. The duration of the activeFlowBalance stage is contained within the entire period of holding pressure, so there's no increase in cycle time.
ActiveFlowBalance is available as an option on all IntElect Smart all-electric machines, and can be retrofitted to existing machines. This unique development delivers a much improved weight distribution, a more even fill, and - with clamp pressures reduced by up to 40% - less wear and tear on machinery and moulds.
The operator-friendly, intuitive controls make it easy to achieve consistently high product quality, even on challenging applications. No wonder that leading manufacturers of such diverse products as automotive components and medical devices trust Sumitomo (SHI) Demag - and activeFlowBalance - to help attain market-leading levels of productivity.
For more information, please contact:
Nigel Flowers
Managing Director
Sumitomo (SHI) DEMAG
Tel: +44 (0)1296 739500
Email: nigel.flowers@dpg.com
Web: uk.sumitomo-shi-demag.eu/
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