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 Extrusion, Single Screw
 pvc profile tooling requirements ?
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cadcamjim Member Posts: 1 |
posted October 17, 2003 10:58 AM
   
we are looking at running a job with the following. 2 1/2 " single screw 24:1 rigid pvc "white" approx 50,000 feet per yr. profile is flat on bottom 10 1/2" wide X .055 thk. Upper side has some prjections which can be jigged in position. We are running on open air tables. What type of leadin if any would we require to keep this running at a reasonable speed reducing burn.. ??? IS our extruder too small for this size of part ? Any help appreciated. Any help apprecaited . IP: Logged |
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Tom C Moderator Posts: 244 |
posted October 17, 2003 01:50 PM
All of your questions can be answered by using extrusion simulation to design and optimize the process. While there are other methods for design that range from expereince and rules of thumb to cut and try to complex calculations you can make yourself, nothing can outperform modern modeling tools for speed and accuracy. I represent Compuplast's suite of extrusion modleing tools and can provide service on a consulting basis. Please check out the web sites for Compuplast listed below.
Consulting: http://www.feedscrews.com/newsdocuments/177.doc Technology: Compuplast Extrusion Simulation Software: http://www.compuplast.com/ Weber Systems NDT Flite Technology Gimac Paulson Training Discuss extrusion topics at FeedScrewDesigns.com (Tom Cunningham a moderator) http://www.feedscrewdesigns.com/cgi-bin/forums/Ultimate.cgi?action=intro&BypassCookie=true IP: Logged |
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Steve H Moderator Posts: 261 |
posted October 17, 2003 02:34 PM
Shameless advertising Tom  Looks like you've been spending a lot of pocket money on modelling software, approximately, what do Compuplast charge for their various modules? Some more links: Modelling and Optimisation of Single Screw Extrusion (corrected link)
Steve H [This message has been edited by Steve H (edited October 17, 2003).] IP: Logged |
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Tom C Moderator Posts: 244 |
posted October 17, 2003 03:46 PM
Steve, If Extrusion software sold like Injection Molding (MoldFlow) software I would not even have time to participate in this
As you know, few care about true technology in extrusion. I hope to increase awareness which may consume my years, disapointed, extruded, and penny-less. Well, maybe it is not that bad, but some days ........ Each Compuplast module runs $10-$20K. Sounds like a lot, but it is well within the range that injection software sells. The second link you posted does not work. Tom C [This message has been edited by Tom C (edited October 17, 2003).] IP: Logged |
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Steve H Moderator Posts: 261 |
posted October 17, 2003 04:13 PM
I can see how you would want a return for an investment like that- I can't see a problem with a reply that adresses a posting. It's the commercial postings that neither inform nor educate that make me reach for the transfer button. Haven't had anything to do with IM, but reading some of the articles in IM magazine, it certainly seems there's more uptake of modelling software. Most extrusion processes seem fairly dedicated to one product on one line, whereas with IM, moulds are being changed fairly regularly. As well as new materials adding to the mix, I guess that's why Moldflow etc sells so well. I'll check that link out and correct it. Steve H IP: Logged |
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Tom C Moderator Posts: 244 |
posted October 17, 2003 04:58 PM
Steve, My theory is that IM is a go/no-go process. If it does not work there is not much you can do until the mold is changed, which can be a long expensive process. With this fast moving world companies don't want to take a change that the mold won't work the first time. In extrusion you can almost always get something out of the extruder. No matter how slow, or even how poor the quality. Additionally there are a lots of process variables that can be changed, so there is always hope that the process can be improved quickly. The latest in out battle for acceptance has to do with profile extrusion. Profile dies have similar problems to IM. Complex dies can take 10 re-cuts and 6 months to balance. We have been able to help significantly with the design process, typically 3 cuts. The most recent development is a semi-automatic die balancing that has the computer figure things out for you. It is cool. I'll post some information soon. Tom C IP: Logged |
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alpertl Senior Member Posts: 31 |
posted October 30, 2003 01:42 PM
quote: You should be able to get a couple of hundred pounds an hour out of the machine, which if I understand your description your part weight would be around .3-.5#/ft. If I'm right, and you can output 150#/hr (on a 2.5" 24:1 as long as there is ample barrel cooling), your line rate would be about 300 FPM, which would take you 166 hours without scrap for 50K/ft. IP: Logged |
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