Cracks post crimping for Plexiglass V825 molded parts

[Lori Li]

Hello,

We had some molded parts made of Plexiglass V825. After the parts get crimped together at 270F, it developed delayed crack over time. Does anyone have experience dealing with this material? in particular why it cracked post crimping?

Thanks,
Lori

 

[davidh729]

Acrylic (PMMA) has a tendency to craze, which is probably what you're seeing. This is usually caused by an applied stress or a combination of an applied and/or residual stress and some other factor like UV or chemical exposure. With enough residual stress you could probably see crazing just from stress relaxtion, which is basically creep. It sounds like the forming process is adding enough stress into the part that whatever is happening later on is causing crazing.

Dave Hyman
Mechanical Engineer