Turbulent flow temperature control cuts cycle times at Warden Plastics
17/03/2014 Sumitomo (SHI) Demag
Fitting Sumitomo (SHI) DEMAG temperature control units on two of its highest output machines has enabled injection moulding specialist Warden Plastics to not only stabilise its process but also accrue significant financial savings by shaving 10% off cycle times.Besides providing contract manufacturing of extruded and injection moulded parts and products to the automotive, electronics, medical, construction, point of sale and vending industries, Luton-based Warden Plastics produces its own range of Biomedia branded biological filter media. One of these products, the Biomarble, is a spherical polypropylene filter used in industrial and municipal wastewater treatment plants.
To keep pace with rising demand for these filters, last September Warden Plastics decided to upgrade the moulding tool on its Sumitomo Systec 160-tonne machine from an 8-impression to a 16-impression tool. The increase in cavities meant more heat was entering the tool, and Warden Plastics quickly realised it needed some serious mould temperature control if it was to maintain a stable process at high speed.
"As more heat was entering the process, we were unable to run the tooling for any length of time due to overheating. Because of the size of the tooling and the speed of the cycle we needed a temperature controller with more powerful flow and heat transfer capabilities," says Mark Barrett, managing director of Warden Plastics.
Sumitomo recommended fitting two AEC TrueTemp TCU 300 9kW water temperature control units on the mould. These stand-alone units can be fitted to any make or model of injection moulding machine to provide highly accurate control for applications requiring a continuous supply of temperature-controlled water. Their innovative design promotes turbulent water flow to maximise heat transfer performance, delivering far more efficient and effective control than the indirect cold water systems that are widely used in the industry.
Nick Smith, processing and training manager at Sumitomo, explains: "Our TCUs use a powerful pump to create a turbulent flow action. This results in a high flow rate and better cooling capacity than a system with laminar flow. On these systems, the water temperature rises as the water circulates around the tool, whereas with our system, the temperature differential between the water entering and leaving the tool is minimal - just a couple of degrees. It's a far more efficient method of cooling."
Nick continues: "The direct cooling design also makes for far more efficient heat extraction than an indirect unit with a heat exchanger. Plus, direct cooling provides constant flushing of the tool circuit to minimise corrosion.
He adds: "All injection moulding machines use some form of basic temperature control, but the advantages of optimising this operation are often overlooked. Anyone wanting to improve process control and reduce cycle can benefit from a TCU - whatever their product or industry."
There are other companies who make direct cooling systems, but they cost approximately three times as much as the AEC unit. What's more, Warden Plastics has a lot of faith in Sumitomo's knowledge of its product and process.
"Sumitomo was able to demonstrate an understanding of our product. With their advice and optimisation, I was confident we'd be able to run the product successfully," says Mark.
Since installing the units, Warden Plastics reports that it is able to run a stable process, producing a consistent, repeatable product with zero defects.
What's more, the TCUs have shaved a second off the cycle, reducing cycle time from 12 to 11 seconds.
"When calculated across 5,236 units per hour on a 24 hour operation, this represents a considerable cost saving. We expect the TCUs will pay for themselves within a year," says Mark.
This was not the first time Warden Plastics had installed TCUs on its injection moulding machinery. Five years ago, the plastic moulding and extrusion specialist purchased two TCUs for a Systec 210 machine it uses to produce balloon sticks for one of its customers.
"It was a similar story to the Biomarbles," recalls Mark. "Following mould flow analysis, we optimised the design of the stick to make it faster to produce and to use less material, and the mould was upgraded from a 12-cavity to a 16-cavity tool. However, we found we had to slow the cycle to maintain and control the temperature of the mould itself; to achieve the designed and desired cycle time we switched to a bigger, better TCU."
Equipping the injection moulder with two AEC TrueTemp TCU 300 9kW units not only restored productivity, but took 1.5 seconds off the cycle time. "Cycle time is a key determinant for our profitability," comments Mark.
For more information, please contact:
Nigel Flowers, Managing Director
Sumitomo (SHI)
Accent House,
Triangle Business Park,
Wendover Road,
Stoke Mandeville
HP22 5BL
Tel: +44 (0)1296 739500
Email: nigel.flowers@dpg.com
Web: uk.sumitomo-shi-demag.eu/
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