We have had a customer who was able to cylcle their Duraform living hinge
part well over 300 times. We've had luck with wall thicknesses as small as
0.010". Of course, these don't tend to flex as many times. Another
customer was very skeptical and felt that the parts would not last. Once
the parts were built, they were surprised at the number of times it would
flex. If you anneal the Duraform, it appears to increase the number of
cycles you can expect.
**********************************************************
David K. Leigh ph (254) 933-1000
Harvest Technologies fax (254) 298-0125
Rapid Prototyping Services www.harvest-tech.com
-----Original Message-----
From: Brent Stucker <stucker@uri.edu>
To: 'Thomas Wickson' <tom.wickson@mollenium.com>; RP Mailing List
<rp-ml@bart.lpt.fi>
Date: Tuesday, September 07, 1999 3:13 PM
Subject: RE: Living Hinges
>Tom and others,
>
>Have you had any success making living hinges from DuraForm? If so,
>what are the design constraints and geometries you find work well. If
>you haven't tried it with DuraForm, what would you recommend, based
>on your experience with living hinges from nylon?
>
>Thanks.
>_________________________________________________
>Dr. Brent Stucker
>Assistant Professor
>University of Rhode Island
>Dept. of Industrial and Manufacturing Engineering
>Gilbreth Hall, 2 East Alumni Ave.
>Kingston, RI 02881
>ph: (401)874-5187
>fax: (401)874-5540
>stucker@uri.edu
>web: http://www.egr.uri.edu/ime/RMC
>
>
>
>-----Original Message-----
>From: Thomas Wickson [SMTP:tom.wickson@mollenium.com]
>Sent: Tuesday, September 07, 1999 3:23 PM
>To: RP Mailing List
>Subject: Re: Living Hinges
>
>Bob
>I would like to differ with one of your points about living hinges
"Currently
>there is no technology available to prototype living hinges without actual
>injection molding.".
>Living hinges can often be prototyped in SLS fine nylon material. The hinge
>design may need to be adjusted slightly for the prototype.
>Tom
>
>Fusioneng@aol.com wrote:
>
>> In a message dated 9/7/99 10:34:40 AM Central Daylight Time,
>> adirondackdesign@mindspring.com writes:
>>
>> << Does anyone know what the best material is to
>> use for injection molding a living hinge? The
>> maximum number of cycles on the hinge will be
>> about 2500.
>>
>> Thanks for your time.
>>
>> Barbara Ryan
>> **************************************************
>> Adirondack Automated Design, Inc.
>> Kent Lakes, NY
>> >>
>>
>> Barbara;
>> There are 2 materials typically used for living hinges in plastics.
>> polypropylene and nylon. both work well. There are specific grades
formulated
>> specifically for this job. I don't normally recommend polyethylene or
>> copolymers for this task even though the material suppliers somtimes
>> recommend them anyway. There are alot of tricks and pitfalls to their
design
>> and injection. I would recommend going to a mold shop with experience in
this
>> area. Currently there is no technology available to prototype living
hinges
>> without actual injection molding. We can assist in your design and
>> implementation as one of the leading innovators in this technology (ie..
>> living hinges). We can supply 3D Keltool inserts with a typical delivery
of
>> 8-10 days for cavity inserts from customer supplied masters models and
10-12
>> days from approved 3D cad data. Which can be quickly inserted into a
moldbase
>> by your local neighborhood moldshop typically 20-30 hours of labour to
finish
>> up mold (ie.. Drill ejector holes, fit into pockets and final fit shut
>> offs... etc). We have build many 3D keltool molds for living hinges.
Typicall
>> a 3D Keltool mold in unfilled polypropylene will last a minimum of 1/2
>> million shots with proper care and design. When it come time for
ultra-high
>> speed high speed multi-cavity Production tooling we can assist there
also.
>> Regards
>> Bob Morton
>> Fusion Engineering
>>
>> For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
> << File: tom.wickson.vcf >>
>
>
>For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
>
For more information about the rp-ml, see http://ltk.hut.fi/rp-ml/
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