Line bending temperatures
Name:
Laszlo Lipot I have conflicting information about the temperatures at which thermoplastics are hot enough to bend. I would like to add a table of temperatures to my line bending animation on http://www.notesandsketches.co.uk/Line_Bending.html and other further information.
Could anyone please give me the correct temperatures at which the following plastics may be bent by line bending: PC, PMMA, PVC, PE,PETG, ABS, PS, HDPE,PP. Would this be the elastic or the plastic temperature?
If possible, please also state what happens to the polymers when they are heated above the bending temperature, i.e. do they melt, melt and form bubbles etc.
I thank you for your help in anticipation.
Best regards,
Laszlo Lipot
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Hi Laszlo.
Nice presentation.
THe best terms to find the info you want is to look for "thermoforming" (process) and "softening temperature".
The following site is all right and it gives you the temperatures required. The ones yo're interested are identified as "Lower Processing".
http://www.plasticsmag.com/thermoforming.asp?fIssue=Mar/Apr-03&aid=3752
Take a look at the the Upper temp for the maximum temp allowable for thermoforming.
I am not sure what do you mean with elastic or plastic temperature.
If you are thinking that elastic temperature is a temperature at which the plastic part recovers a previous shape (shape memory), that does not happen in most plastics. Generally, it's a combination of materials and manufacturing conditions.
If the temperature goes beyond upper bending temperature, different things can happen, as it basically depends on the type of plastics (amorphous, semi-crystalline), family (PS, PP, etc) and some other factors.
For your presentation, I believe you don't have to worry about this. To learn more, it would be convenient for you to go around wikipedia, google books or get a book on processing of plastics.
MPS
Firstly, thanks for posting your question as I may have never had the opportunity to look at your excellent web site.
As the previous post, If you really want to know the details of bending temperatures, get the book.
Obviously it takes longer for the heat to 'soak' through a thick sheet, so it's not just about temperature.
Amorphous materials (P.C.)typically have a sharp softening point and crystalline (P.E. P.P.)materials may just get softer and softer as they get hotter. This makes it difficult to say at what point the 'plastic' has 'melted' We bend polycarbonate (Lexan) at room temperature. This is for machine guards. Regards, Robin Enderby
BMC Controls Ltd.