Need help with a plastic selection or something similar

[lightitupgolf]

Hi I hope someone can help.

I am in need to find a material to replace the current material on my design of a LED golf ball. The inner core casing that holds the LED's is made from PC plastic how ever it cracks under a lot of force from getting hit by a golf club. I am in need of a material here that is clear, that can be made into a mould, that can hold at a min amount of heat as PC before melting and main thing cant be broken or can flex to stop the cracking under force.

Look forward to your reply.

Brad

 

[MacGyverS2000]

I see LED bouncy balls at the dollar store all of the time... seems like a form of rubber would hold up a lot better than PC under such extreme forces.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[lightitupgolf]

Thanks for the fast reply Macgyver. We tried rubber before but its melting point is too low for when the outer core of the ball is made. I was thinking a clear Urethane but im not sure if its melting point is high enough for the job?

 

[btrueblood]

There are clear-ish silicones with upper use temperatures above 400F. Dunno how well it can be over-molded.

 

[MatthewL]

Or perhaps a nylon or block polyether/polyamide? They can be translucent to transparent and have good heat resistance.

Matt

Quality, quantity, cost. Pick two.

 

[MikeHalloran]

PC is ordinarily incredibly tough and strong.

... unless it comes in contact with anything resembling a solvent.

The list of substances that can cause Environmental Stress Cracking in PC is too long to copy here, but you can easily find it.

PC doesn't ordinarily fail by cracking from stress alone; the cracking strongly suggests ESC as a cause. The problem is that the exposure can occur anywhere in time prior to the application of stress, so you could be looking at environmental attack by the overmolded cover, or by anything that's used to wash/clean the PC during manufacture.

This would be a good time to walk the production line and record all the substances used on or even in the vicinity of the PC. Bring along some samples of the PC part, swab or dunk one in each substance, then hit it with a hammer. The difference will be immediate and dramatic.





Mike Halloran
Pembroke Pines, FL, USA

 

[lightitupgolf]

Thanks to everyone for there in put. Mike this is very useful information as from what your saying I think there is no way possible the PC hasnt been exposed to something. They put glue around the core before the 2nd layer go's on, the 2nd layer is a rubber compound which probably reacts with is, The core holds resin and batteries which im guessing wouldn't help it either??

So with that info there is no possible way that PC should be used in this. I have cut open a new ball and the inner core was not cracked at all. then after a ball had been hit a few times I cut it open and the core is basically shattered.

So if thats the case. What is the best material to try? TPU, truebloods suggestion of silicone, matt and nylon or block polyether/polyamide or are there any better options?

 

[Pud]

So if thats the case. What is the best material to try? TPU, truebloods suggestion of silicone, matt and nylon or block polyether/polyamide or are there any better options?

Have a look at this stuff: Amorphous PA12

Should do the job. (I believe equivalents are available - by whom I don't know - sorry)

H

www.tynevalleyplastics.co.uk

It's ok to soar like an eagle, but weasels don't get sucked into jet engines.

 

[Pud]

Just in case you miss it - the density is 1.0, cf. 1.2 for PC so you get ~20% more per $, before you take a sharp intake of breath at the price! Much easier to process than PC as well.

H

www.tynevalleyplastics.co.uk

It's ok to soar like an eagle, but weasels don't get sucked into jet engines.

 

[MatthewL]

Here's another manufacturer, it looks like the chemistry is similar:

http://www.rilsanclear.com/en/key-features-benefits/index.html

As full disclosure, I work for one of Arkema's polyamide plants, but we don't make rilsan clear.

Matt

Quality, quantity, cost. Pick two.

 

[lightitupgolf]

Thanks for everyone's input. Im not sure what alternatives they have available in china but it gives me something to start on and im sure there engineers would no what they have over there that's similar?

The rilsan clear look very promising but how is the price on that?

 

[Pud]

Rilsan is nylon 11 - similar properties to nylon 12. Rilsan is also promoted as "green" as it is made from castor oil. Might be useful in today's marketing environment. Not sure if it's transparent though, as data sheets appear to be a bit of a secret (Have to sign up for spam marketing I suspect....)

Pricing of any polymer is dependant on geographical location.

H


www.tynevalleyplastics.co.uk

It's ok to soar like an eagle, but weasels don't get sucked into jet engines.