Problems feeding TPE pellets into small injection machine

[ABerlinMML]

Hello

I hope im in the right forum.

Would like your tips and ideas as I'm having great difficulty feeding TPE resin into the auxiliary injection machine.

the material is Versaflex OM1245 in 3.5mm pillow shaped pellets. the machines have screws from 16-25mm and a the largest feed port is an oval 22x25mm.

we've tried vibrators, vibrating inserts, augers, etc but it just bridges. The latest idea now is to try starve feeding using a masterbatch doser, eductor, line vac, belt, or vibratory conveyor.

Thanks in advance,
ABerlin

 

[Compositepro]

Your problem can only be solved through trial and error. You may have to dust the pellets with talc or similar powder to reduce stickiness or friction. An agitator in the throat of the feed hopper is often used. You may have to use two or more feeders in series to go from large hopper to a smaller one.

 

[ABerlinMML]

Thank you compositepro

I think youre right about the trial and error, the analytical approach does exist but i know what those calculation will tell me 'your feed port is 10x too small' however i can't increase much. what do you think about starve feeding and injection machine (as opposed to an extruder)?

 

[Compositepro]

If by starve feeding you mean feeding at a rate slower than the screw can remove pellets from the feed throat, then yes I think that would be very helpful to prevent bridging in the feed throat.

 

[berkshire]

ABerlinMML,

From my old feed mill design days, a rule of thumb derived by trial, and error, was that the smallest size of a chute was 8 times the largest dimension of a pellet. so based on that, your min dimension should be 28mm. so it looks like you are close , but not quite close enough.
You may need a " Bin Feeder" at the discharge end.
B.E.

You are judged not by what you know, but by what you can do.