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/
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