Accessibility Page Navigation
Style sheets must be enabled to view this page as it was intended.
Scottish Plastics and Rubber Association Scottish Plastics and Rubber Association

Improved Production Efficiency in Injection Moulding

David Raine, Technical Sales Manager at Sumitomo (SHI) Demag UK

The message for moulders at the April SPRA meeting in Cumbernauld was that an aggregation of marginal gains from application of advanced moulding technologies can lead to savings in energy, improvements in durability and maintenance, increased productivity (cycle time reduction)and enhanced precision and repeatability.

David Raine, Technical Sales Manager at SPRA Corporate Member Sumitomo (SHI) Demag UK, in his presentation entitled “Production Efficiency – Active Technologies to maximise your success” encouraged moulders to look for potential marginal gains by applying the latest injection moulding technologies, an approach which has proved successful for the GB Cycle Team.

“If you break down everything that can impact on performance, and improve each little thing by just 1%, when you clump it all together, you’re going to get quite a significant increase in performance.”   Sir David Brailsford, Head of Performance Cycling Team GB

To illustrate how this philosophy could be applied just as well to moulding, David Raine described examples from Demag’s range of ‘Active’ technologies.

Energy Saving

Efficient barrel insulation can save around 20% in energy consumption.  activeDrive, with variable speed pumps, could give savings of up to 45% on longer cycle times but has less impact on fast cycling operations.  Moving from hydraulic dosing to electric drive dosing can give energy savings equivalent to a pay-back time of less than 2 years. activeEcon integrated energy control allows optimisation of energy consumption by quickly comparing different machine set-ups.

Durability and Maintenance

The activeQ mould protection system, for both opening and closing, prolongs tool life.  On hydraulic machines activeCool&Clean, involving a new filter and oil cooling concept, results in increased oil lifetime (40,000 hours) and lower maintenance costs.  Linear platen guidance systems also lead to reduced maintenance and higher precision (from platen parallelism).

cycle time reduction from independent drives

Cycle Time Reduction

Independent drive motors permit individual movements in parallel, rather than sequential, thereby cutting the overall cycle time.  activeAdjust, which optimises mould speed, can increase productivity by 3 – 5 %.

Precision and Reliability

active Dynamics, using servo cards instead of a CPU on an all-electric machine, provides short response times for injection, pressure hold and dosing (20 times faster than the industry standard) and increased precision and reliability.     By reducing response times from 2.0 ms to 0.1 ms, positional variation is thereby reduced from 0.70 mm to 0.035 mm.  Pressure drop from 1400 bar is reduced to a hod pressure of 250 bar in 0.045 ms.  For a simple cup mould with 0.25 mm wall thickness cycle time is reduced from 3.3 s to 2.8 s.

For unbalanced moulds, activeFlowBalance stops the injection stroke just before the cavities are filled, allowing the pressure to compensate.  This leads to a raft of benefits such as reduction in peak pressure, clamp force, flash and venting problems, all contributing to improved part quality.

activeLock
The technology that created most interest in the audience of moulders and students was activeLock.  Standard axial seating of the check ring on the screw tip is replaced by a rotary closing action, which gives a much more positive and repeatable shut-off, resulting in less variable melt cushion and less variable shot weight.

Improved Flexibility

Peripheral equipment such as robots can be controlled centrally with activeRemote while activeConnect links to external equipment and real time monitoring systems. Intelligent flow monitoring of coolant in mould cooling circuits is provided by activeFlo, which measures pressure drops to calculate flow rates and checks for blocking.  activeEnergy stops pumps and reduces barrel heating after a machine has been idle for a set period.  Payback time from this retrofit technology can be as little as 8 weeks.

Benefits of advanced injection moulding technologies

Summary

For an 8 impression tool on a hydraulic injection machine, application of the advanced technologies improved cycle times by 8%, reduced energy consumption by 10%, improved availability by 1% and reduced rejects by 0.5%.  These seem marginal gains but, put together, it resulted in a yearly saving of €2,400.

Report by Charlie Geddes, SPRA Hon Secretary, May 2013

Corporate Members

Events Diary

PDM Event

11 June 2019
Manchester Central Convention Complex

find out more

Technical Info from SPRA

  • Materials Thermoplastics, Thermosets, Elastomers, Additives.
  • Processes Moulding, Extrusion, Thermoforming, Ancillaries.
  • Design Product, Mould, CAE, Testing.
  • Applications Healthcare, Packaging, Electronics, Other Markets.
  • Environment Waste, Recycling, Sustainability, Legislation, Energy.
  • Business Issues Network, Seminars, Competitiveness, Innovation, Regulation.