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Venting the extrusion mould
2/28/2012 |
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Extrusion mould specialist fhw-moulds GmbH of Bottrop/Germany presents a special solution for removing air from extrusion moulds and proves its innovative strength. This brand new, optimized product is perfectly adapted to blow moulders' requirements for improved cycle times.
As the mould closes around the parison and is inflated and pressed to the cavity wall by air blown into it, air is trapped between the parison and the two mould halves. This trapped air must be removed. In order to expedite this venting process, conventional moulds are often equipped with vents at the parting line for expelling any trapped air, sometimes with the help of vacuum. The downside of this method is the fact that air can only be removed locally and the introduction of a vacuum leaves small marks on the finished part.
Specialist fhw-moulds has developed a new solution for this problem: the extrusion mould for a 20 litre jerry can is now vented in all four corners of the mould and vacuum can be used to increase the ventilation effect. The vent is cut across the entire height of the mould corner so as to eliminate the occurrence of marks on the finished part. This way, entrapped air can be removed quickly and effectively.
During extrusion blow moulding, cycle times are highly dependent on mould cooling times. The new mould design with corner venting allows significant cuts in cycle times. "Thanks to optimized cycle times, the additional costs for this special mould have a very short payback time," Jean Ingenbrand, Managing Director of fhw-moulds points out. An additional benefit of this solution is that exchangeable corners can accommodate different designs of hollow plastic products, which translates into more versatility and cost-efficiency for blow moulders.
Website: www.fhw-moulds.de |
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