Polycarbonate parts breaking
Polycarbonate parts breaking
(OP)
Hey Guys,
Just after some info about an injection molded poly carbonate part we are having trouble with.
The part is a clear Polycarbonate price ticket housing for a retail store. It has been injection molded in clear poly carbonate.
The design has 2 plastic clips on the rear which clip onto a wire basket in the store. We chose poly carbonate because it is strong and durable and these items are used rigorously in store everyday.
During prototyping the parts performed well(3d printed parts), however during the 1000 part store trial, we have had some issues with these parts breaking.
We are finding that the clips on the rear are starting to become brittle and snap off when used. The reason why this is very confusing is that the parts are extremely strong, if you try to break the clips it is pretty much impossible. Yet out in the field we are finding that they are becoming brittle somehow and snapping. The break is always in the same point. So we are figuring that it is a design fault, but was wondering if anyone had information about how a poly-carbonate part could become brittle?
tks
-jon
Just after some info about an injection molded poly carbonate part we are having trouble with.
The part is a clear Polycarbonate price ticket housing for a retail store. It has been injection molded in clear poly carbonate.
The design has 2 plastic clips on the rear which clip onto a wire basket in the store. We chose poly carbonate because it is strong and durable and these items are used rigorously in store everyday.
During prototyping the parts performed well(3d printed parts), however during the 1000 part store trial, we have had some issues with these parts breaking.
We are finding that the clips on the rear are starting to become brittle and snap off when used. The reason why this is very confusing is that the parts are extremely strong, if you try to break the clips it is pretty much impossible. Yet out in the field we are finding that they are becoming brittle somehow and snapping. The break is always in the same point. So we are figuring that it is a design fault, but was wondering if anyone had information about how a poly-carbonate part could become brittle?
tks
-jon






RE: Polycarbonate parts breaking
Does it sit out in the sun all day?
www.nxjournaling.com
RE: Polycarbonate parts breaking
It does not sit out in the sun. And in most case breakages occurred on parts which had only been trialed for a few days. But again...we took parts that had one clip broken(there are 2 clips per part) and tried to break the second clip and couldn't break it!
RE: Polycarbonate parts breaking
Chris DeArmitt
Expert consulting & training
www.phantomplastics.com
RE: Polycarbonate parts breaking
RE: Polycarbonate parts breaking
So far, the problem has defeated some pretty smart people.
The worst part is that environmental exposure does not immediately craze PC or cause any other detectable change in it. ... but subsequent loading will cause immediate failure at low load, even if substantially displaced in time.
If you can't find who/what/how the stressor is being applied, and probably even if you can, you'll need to change to a different resin.
Mike Halloran
Pembroke Pines, FL, USA
RE: Polycarbonate parts breaking
Chris DeArmitt
Expert consulting & training
www.phantomplastics.com
RE: Polycarbonate parts breaking
RE: Polycarbonate parts breaking
Chris DeArmitt
Expert consulting & training
www.phantomplastics.com
RE: Polycarbonate parts breaking
* Styrene Block Copolymer
H
www.tynevalleyplastics.co.uk
It's ok to soar like an eagle, but weasels don't get sucked into jet engines.
RE: Polycarbonate parts breaking
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
RE: Polycarbonate parts breaking
www.tynevalleyplastics.co.uk
It's ok to soar like an eagle, but weasels don't get sucked into jet engines.
RE: Polycarbonate parts breaking
I just had a mental picture of mold release with aromatic hydrocarbons in it.
B.E.
You are judged not by what you know, but by what you can do.
RE: Polycarbonate parts breaking
Is the gate the same distance to each clip?
During molding, does one clip fill before the other? Check short shot.
Paul Kuklych
http://www.improve-your-injection-molding.com