machinery feature | Profile dies Free flow analysis
Plastic Flow has just released a ‘pay per execution’ (PPX) version of its extrusion die design software, PolyXtrue. This version of the software is hosted
remotely ‘in the cloud’, so is free of charge. The user only pays for the executions that they submit. There is also no need to generate a finite element mesh in this version of the software. In the PPX version, users import their die geometry, specify material and define
processing conditions. No meshing is required. After creating this ‘job submis- sion file’, it is e-mailed to Plastic Flow. “Our experts will generate the mesh,
execute the analysis and send the results back to you,” said Mahesh Gupta. “You will then plot all the results in the PPX version, just as in the full version of PolyXtrue.”
Using the software in this way help users to avoid the typical investment needed
At the same time the vacuum pumps
have been replaced and provided with frequency controls.
Avoiding drool Die build-up (or ‘die drool’) in profile extrusion is often unavoidable, and can affect extrusion efficiency if not addressed regularly. Surface imperfections, equipment shutdowns and other problems can emerge if dies are not properly maintained. Davis-Standard has come up with three simple
Modelling an ABS/PS profile revealed faster flow (in red) through the ‘C’ section, and slower flow through the main ‘J’ section
rules to help avoid this potentially costly problem and improve die performance.
The first is to keep it clean: polishing all die parts
that come into contact with resin – specifically the pin and bushing – can keep downtime to a minimum. “Do this on a regular basis, preferably at every
shutdown,” says the company. “A well-kept tooling and die set will cause fewer headaches in the long run.” Secondly, review your process. A hotter resin will
have lower viscosity (and lower die shear exit stresses) but will tend to burn more easily. This affects the
when purchasing die design software. Instead, Plastic Flow charges a small fee for each simulation. “For this small fee, you get complete
insight into the flow intricacies of your die,” said Gupta. “With this, you will avoid the costly mistakes that are difficult to correct once a die is cut.” To get a free copy of PolyXtrue PPX, click on the link below. ❙
www.plasticflow.com/PPXDownload.php
solubility of process aids, leading to die build-up. Running processes as cool as possible, while avoiding melt instabilities, will help limit build-up. “Heating the die/bushing itself, if possible, will also
reduce exit stresses while avoiding overheating the bulk of the resin,” says Davis-Standard. The third tip is to pay attention to resins. Those with
high levels of filler or process aids tend to accumulate because of the stresses experienced at the die exit. This can be solved by working closely with the resin manufacturer, in an attempt to reduce the use of these additives.
“Find the right tooling and parameters for your
process,” says the company. “Die geometry is impor- tant, as are processing aids and die coatings.”
Click on the links for more information: ❙
www.mtu.edu ❙
www.plasticflow.com ❙
www.rwth-aachen.de ❙
www.greiner-extrusion.com ❙
www.sip-windows.com ❙
www.davis-standard.com
AMI Strategy Seminars
These one-day seminars are given by an AMI director and provide invaluable insights into market trends and industry strategies. They are held in small groups and provide ample opportunities for questions and discussions.
19 June 2012: Vienna, Austria 25 June 2012: Chicago, USA
16 October 2012: Cologne, Germany 5 November 2012: Philadelphia, USA
Click here to download our 2012 brochure
www2.amiplastics.com/Seminars
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