GF VALOX

[not related to]

We drop our GF VAlox parts into water, like our nylon. Now we set water temp at 190F for nylon. I here valox is 150F? Why so low? Does it matter. Dropping into water for 1 hour really strenghthens the parts(tensile)

[dg1952]

Hello.
Does Polycarbonate without GF also can be srtengthened by dropping it to water?

I made a mold for 75mm * 85 mm simple ring of 5 mm thickness.
I tried 2 materials- Polycarbonate without GF and Polyamid with 30% GF.

My customer said that the Polyamid rings are good for him but the Polycarbonated ones are not strong enough.

His method for checking is as follows-
He puts the ring in his hand and squeeze it with all his power. It can be bent a little but it should not be broken.

Now the problem is that if I will mold the rings from Polyamid I will have to use my machine which
is equipped with bi-metal cylinder- it is a 60 ton machine and 8 cavities as I planned - will be too much for it.
Another consideration is that this small machine is the one mostly occupied.

Does anyone can suggest other materials that will make this rings stronger?
Thanks , Dani.

[rickbatey]

Dani ,
The reason for the pc breaking is due to the knit lines low strength. Pa tends to weld better due to its semi-crystal structure. You can make better of parts by optimizing the process and tooling for a amorphous resin. Gate sizing must be increased, runner sizing upsized as well, removing any sharp corners/stress risers from mold and runner path. More mold temp as well as optimized fill rate and hold time/ psi. You could also add glass to the pc resin. It really depends on end use as to which resin will be better. A polyester resin may be a better choice due to cold impact and water swell.
Rick.