short shots on a new tool

[JWD89]

We have recently had a back-up tool made for one of our most run parts. The tool was supposed to be manufactured identically to the original (original is 3/4 years old) to ensure that they can both run on identical settings.

Since running the tool we have had issues with short shorts mainly on 1 cavity only. But recently on a different cavity. We have been removing plastic from the tips every few weeks to remove potential contamination / carbonisation (thinking this may be the issue) but last week the problem happened so often we cleaned the tips 3 times.

We have checked the cavity temps and they are all the same within 1 - 2 degrees. Our technicians and even the tool room manager are now stumped as to what the problem could be.

Can anyone help?

Its worth noting that when we have cleaned the tips they seem to be a lot smaller than the original tool (obviously the tools are not identical).

Thanks,

Jamie

[Pilot]

hi,
Ii is not so much informations… Which hot runner nozzle tip do you have? Do They have torpedo, or needle or nothing inside? how big the parts are.... OK. By my opinion you have nozzle with torpedo. It can be blocked by piece of dirt.
Than you will have no ballanced cavities.

[Jendalf]

Hi,

yes,

and...check all diameters and holes in the tools. Saddle diameter, nozzle/input diamaters. Wall thickness of the part will also tell You if the tools are same...let the tool itself measure at CMM and compare.
j

[JWD89]

Pilot / Jendalf,

Thank you for the advice. I can appreciate the information was a bit thin.

To update we checked the plastic removed from the tips with a magnet last night and the tips instantly stuck to the magnet. It turns out that (swarf) metal shavings from the adjacent tool room have been making there way into our material bins and eventually building up and getting stuck in the tips. I have just ordered some magnets for the hoppers and we will be taking a lot more care in managing our materials.

Thanks again,

Jamie

[Jendalf]

Hi,

good that You found something.

Sometimes I found IM as a medicine.
"When You are hearing the hoof claping behind You, don´t expect You will see a Zebra :)"

at IM, actually You can :)

J.