Backing material for a one-shot mold?

  • #1
Hi,

I currently have a fragile metallic cylindrical mold (wall thickness ~1 micron) into which I want to injection mold a thermoplastic polymer at about 150 MPa (3.14 Mlb/sq.ft). The mold and polymer together will form the final part. However, such injection pressure far outstrips the rupture stress of the mould; so I'm looking for some sort of backing which I could use to support the mold while injecting; but which I can then remove afterwards - ideally via some kind of solvent.

Unfortunately, due to the nature of the mold material, I can not use anything which requires a temperature >150°C (>300°F) to remove it.

Initially I considered some sort of epoxy, but it seems the only way to remove a crosslinked thermoset is via heat; and that really doesn't suit at all.


Any suggestions?



All the best,

Phil
 

Answers and Replies

  • #2
11
0
How about a 2-part firm silicone? It's used in dentristry, is pretty inexpensive if you hunt around, and gives you a few minutes of very soft pliability (warm plasticine) before setting to the firmness of a shoe sole in under 10 mins. It'll provide 1-time support and slip off a treat when you're done.

http://www.amazon.co.uk/dp/B007DKSH9Q/ for instance
 
Last edited by a moderator:
  • #3
I don't know 150MPa is really high. As in you'd have to be careful even with cement.

http://www.theconcreteportal.com/images/constrelation/stressstrain2.JPG

21755 psi. That would break apart a cement mold. Is there a reason you have to use this mold? Sounds like recreating it out of stronger materials would be better.

Normally large volume plastic molds are made from machined steel.
 
  • #4
13
0
Do u want to use a solvent to lower viscosity of melt ? what is the radius of the mold?
which is the thermoplastic ?
 

Related Threads on Backing material for a one-shot mold?

  • Last Post
Replies
0
Views
2K
Replies
0
Views
3K
  • Last Post
Replies
8
Views
2K
  • Last Post
Replies
1
Views
4K
Replies
0
Views
2K
  • Last Post
Replies
4
Views
746
  • Last Post
Replies
0
Views
2K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
10
Views
4K
Top