Has anyone experienced Mold Masters hot runner nozzles with E-type torpedos? We are having big difficulties with the raw material Zytel 70g30 PA66. In my opinion this type of nozzles are not very convenient for the high glass fiber reinforced materials.
First at all, nozzles closes often with the frozen raw material. Increasing nozzle temperature doesn’t help. Because torpedos get bigger and close the gate. So raw materials burn due to high temperature. It is a nightmare to start the process. I would like to listen your advices.

Hello. I'm very embarrassed to suggest in this case because MoldMaster is our competitor. Anyhow I suggest you to reduce the contact between the tip insert and the tool , it should be helpful to take the gate temperature better under control.
Best regards

We often use this material(Zytel 70g30 PA66) for the injection tries,but the mold without the hot runner system.

If the nozzle closes when you raise the temperature it would seem that the set position is too close. Also as Roberto mentions reduce the contact of the gate insert with the mould. If the mould is designed as it should be with a separate water circuit to these inserts then run that circuit hotter.
If the torpedo is too close and you need to give more clearance then beware of stringing then the circuit round the gate inserts needs to be run colder. With nylons the balance is fine.

Thank you all. I think Roberto is right. The real problem is that we are loosing heat because we discover an another contact surface between tip and the mould. As far as I know there should be a plastic melt barrier which makes isolation between tip and mould. But in our case we have also contact in that point. So nozzles are loosing the temperature. We will try to fix that point with correcting the mould.

But anyway, Roberto don't worry about the competitor issue. Because we have so many Synventive hot runner systems in the plant as well. I like this group. Because people can openly discuss about technical solutions.

Erol. I think we have no problem with the points you mentioned. Unfortunately, We have no chance to change raw material type.

I will also check the cooling system. I will share the results with you.

For me it seems that the nozzle tip is worn-out due to the fact of glass filler material. Double check if your nozzle tip is in hot condition staying over or on the same hight like the mold surface! If not, you have no cooling problem, you have wearing on the tip and you have no posibility to open the gate! Thats why you have to increase the temp. You have to inspect every half year the nozzle tip hight. 0.5 mm is sufficient to get bad results and also bad inejction Points like vestige.

Regards,
Carlos

Hello all. Thank you for feedbacks again.
There were two main issues.
1. You are right that we had to dicrease the contact surfaces between mould steel and tip.
2. We found out that some torpedos were worn somehow and lost the shape which should transfer the heat. Therefore we could never achive to melt the plastic in front of the tip.

So actions were taken and related issues were solved. I would like to share some images for the actions. But I guess it is not possible here.

Regards
Şender