Living Hinge Design for Celcon M90 ( Acetal Copolymer)
Living Hinge Design for Celcon M90 ( Acetal Copolymer)
(OP)
I am designing a 90° bend living hinge, But it is cracking, can anyone help or send me design guidlines for living hinge with Celcon material.
thanks
Maninder
thanks
Maninder






RE: Living Hinge Design for Celcon M90 ( Acetal Copolymer)
see http://pl
this reference gives more detail on the why's and how's:
http://en
RE: Living Hinge Design for Celcon M90 ( Acetal Copolymer)
You might get a few cycles (e.g. 5 -10) if you're lucky and have a good design. Acetal usually requires such a thin section to keep the stress down that it becomes impractical to mould.
As btrueblood mentions - PP or PE is a more suited to hinges of this type.
Cheers
Harry
RE: Living Hinge Design for Celcon M90 ( Acetal Copolymer)
There is lots of data out there on design, but it is pretty straight forward.
No sharp edges.
Gate on one side only so material MUST flow through the hinge and MUST NOT stop and form a weld in the hinge.
The hinge should not be to thick.
The land of the hinge should not be to short.
It is best if it is bent through maximum angle while the part is stll hot (ie automatically as the mould opens) so that the molecules are aligned parallel and to each other and perpendicular to the axis of the hinge.
It works best on fairly straight linear molecules. Anything that draws down well into a fibre will work. The higher the optimum draw down for fibre production, the better it will tend to work as a hinge. PP likes very high draw down ratios when making fibres. From vague memory, about 10:1 vs 6:1 for nylon.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Living Hinge Design for Celcon M90 ( Acetal Copolymer)
Design looks fine, no sharp edges, thin cross section, length of hinge is ine too. I took the guidlines from 'Designing plastic parts for Assembly' by Paul A Tres.
After the initial moldflow analysis, I out that the gate location of my part is not right, which cause to form a weldline across the hinge.
Also I am getting the help of Ticona to get into the root cause of the failure.
RE: Living Hinge Design for Celcon M90 ( Acetal Copolymer)
RE: Living Hinge Design for Celcon M90 ( Acetal Copolymer)
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.