RE: Thermal degradation of polymers?

From: Russell Harris (rharris@dmu.ac.uk)
Date: Wed Aug 01 2001 - 12:20:43 EEST


Mick,
I've done a lot of studies on the morphological properties of parts by rapid
tooling methods for injection moulding.
The time between each shot can be around 10 minutes (mostly cooling down the
mould) so for the sensitive polymers I purge and reload another shot before
next injecting.
I am not aware of any specific work relating to barrel residency time and
rapid tooling with respect to the morphology of the mouldings.
Russ

Russ Harris
Research Fellow
Rapid Manufacturing Group
Queens Building
De Montfort University
Leicester, UK
Tel. +44(0)116 2551551 ext.6649
Fax. +44(0)116 2577071
www.cse.dmu.ac.uk/RMG/Welcome.htm

-----Original Message-----
From: Michael Priest [mailto:M.L.Priest@tesco.net]
Sent: 01 August 2001 00:05
To: rp-ml@ltk.hut.fi; Advantage Prototype Systems
Subject: Re: Thermal degradation of polymers?

Thanks for the advice. I have the results from the material manufacturer,
but I was wanting to know if anyone had carried out any independent research
in this area.

Mick Priest

Engineering Dept.
Warwickshire College
Leamington Spa
UK

-----Original Message-----
From: Advantage Prototype Systems <protoinfo@advproto.com>
To: Michael Priest <M.L.Priest@tesco.net>
Date: 30 July 2001 13:45
Subject: Re: Thermal degradation of polymers?

>Michael, Each polymer reacts differently. Polyethylene is one that has
>very little change after prolonged heating. There are some flame retardant
>materials that will degrade in minutes. The best thing to do is check
with
>the material supplier for there research.
>
>Mike Burg
>Advantage Prototype Systems.
>www.advproto.com
>
>----- Original Message -----
>From: Michael Priest <M.L.Priest@tesco.net>
>To: <rp-ml@ltk.hut.fi>
>Sent: Sunday, July 29, 2001 9:56 PM
>Subject: Re: Thermal degradation of polymers?
>
>
>> Hi all,
>>
>> Bearing in mind that rapid tooling mould cycle times are often longer
than
>> conventional tooling, a molten polymer will remain static in the barrel
of
>> an injection moulding machine for a greater length of time than in a
>> production environment. Has anyone established any links between the
>> prolonged heating of a molten semi-crystalline polymer in the machines
>> barrel and the mechanical properties or shrinkage that results in the
>> mouldings? I would assume that after a period of time the polymers
>molecules
>> would degrade and the properties and shrinkage of the moulding would be
>> affected. Any suggestions?
>>
>> Mick Priest
>>
>> Engineering Dept.
>> Warwickshire College
>> Leamington Spa
>> UK
>>
>>
>>
>>
>>
>> For more information about the rp-ml, see http://rapid.lpt.fi/rp-ml/
>>
>>
>
>

For more information about the rp-ml, see http://rapid.lpt.fi/rp-ml/

For more information about the rp-ml, see http://rapid.lpt.fi/rp-ml/



This archive was generated by hypermail 2.1.2 : Fri Jan 04 2002 - 09:57:35 EET