Why do plastic warp when heated

  • Thread starter hihiip201
  • Start date
  • #1
170
0

Main Question or Discussion Point

I have noticed that, in the plastic extruded from 3d printers, plastic fork that i put near the fire during bonfires, whenever plastic is heated they tend to warp(curve up) why is that the case?


thank you
 

Answers and Replies

  • #2
256bits
Gold Member
3,114
1,133
Uneven heating of the plastic object.
 
  • #3
20,134
4,209
I have noticed that, in the plastic extruded from 3d printers, plastic fork that i put near the fire during bonfires, whenever plastic is heated they tend to warp(curve up) why is that the case?


thank you
The plastic consists of very long-chain flexible polymer molecules, consisting of hundreds of molecular segments. The ordinary equilibrium configuration of these molecules are coiled into a ball, with the chains intertwined. However, during the manufacturing operation, the part undergoes very rapid deformation, and the polymer chains become elongated relative to their equilibrium configuration. Then the part is rapidly cooled (below the so-called glass transition temperature) before the molecular chains have a chance to relax back to their equilibrium configuration. So the polymer chains in the final part are "frozen in" in an extended configuration. When the part is heated again above the glass transition temperature, the chains relax, and this relaxation results in a deformation and a warping of the part. This behavior is very common in the polymer processing and man-made fiber processing industries.

Chet
 

Related Threads on Why do plastic warp when heated

  • Last Post
Replies
1
Views
490
Replies
7
Views
2K
  • Last Post
Replies
1
Views
2K
Replies
3
Views
753
  • Last Post
Replies
24
Views
4K
Replies
1
Views
1K
  • Last Post
Replies
20
Views
5K
  • Last Post
Replies
7
Views
3K
Replies
7
Views
2K
  • Last Post
Replies
11
Views
4K
Top