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Silicon/Rubber molding for a Bracelet product

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Raminee

Mechanical
Dec 6, 2021
5
Hi all

I am looking to design a bracelet product where the middle part is made of a more flexible material like Rubber/Silicon.
My question is can a part as shown in the attached image be molded as one part ?
The part is more like a hollow tube in the shape of the letter "C"

Any comments would be welcomed.

Thanks

Raminee
 
 https://files.engineering.com/getfile.aspx?folder=5c221dba-00b3-47e9-941b-b76cf04df85d&file=Rubber_C.jpg
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Hi Raminee

I doubt the part can be moulded as one because I cannot see how you can remove the central core after it as been moulded, if the c shape wasn’t hollow then that would be a different story.


“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein
 
Because the part is split, it might be possible to have a multi-piece core that could be supported at the split area of the mold, and would separate in multiple layers to be extracted from the center hole. Tricky, but playing with the geometry (and not minding if there is some taper to the center hole) could make it work, especially in a cold, poured silicone rubber (it's quite flexible and could possibly be rolled off of the core). Alternatively, you are looking at soluble cores, which are tricky to produce, and don't function in a high pressure injection molding machine (not sure about that, but relatively confident).
 
Hi Raminee,
What will be the material of the part you displayed? I'm not asking the mold material.
The different material will decide which way will be used.


David
Mechanical project manager
JLFY technology company
 
Hello David,
As the title suggests it would be something flexible like Silicon or Rubber.
I would prefer Silicon but then again I am not a material/molding engineer.
However I want the part (once it is out of the mold) to hold its shape. So maybe a higher shore rating.
But not stiff. Something around 0.8 so that it would be flexible enough to open the jaws when it is being placed on the wrist.
 
Hi Raminee,
Silicon material is ok.
The silicon durometer I touched is always from 20A to 80A.
For doing it, the way is to use flow mold instead of injection mold.
(If the material of the similar design is metal, the best way will be bent machining if the R is enough)
Hope that can help you get some points.

David
Mechanical project manager
JLFY technology company
 
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