question hog's head removal

[corvairbob]

i need to ask this to the machine repair people that have to deal with this issue. i'm somewhat new the imm's i have worked in machine repair for 30 years but just the last 2 years around the imm's. i have had to remove at least 8 hog's heads in the last 4 months and my style may not be the correct way. so i'm asking this to you guys to see if i'm going about this the correct way and or if there is a better practice.

my way heat the barrels under the hog's head to 500 or more deg. and the take a wood chisel and beat the thing off the barrel, until i have removed enough to get the rest off. this sometimes requires nozzle band replacement and or t/c replacement and once the 1st heater band. all due to cutting the wires to them.

so tell me i'm going about this the hard way and what is a better way. i was thinking of getting one of those tire grovers to cut through the plastic and remove it that way but before i spend the money for one i would like to see what may be the correct way to do this. thanks for your help. bp.

[rickbatey]

Remember to shut the power off when you try to remove them! I've seen air chisels (pretty good if you have good air and solid flow), hot knives (Engel made them years ago, kinda like a large solder iron and were great if not too large), then your method plus heated by torch pieces. I've also saw a Sawzall used once because it stretched from tip to feed throat!!
One thing that makes replacement easier; run ALL of the heater and T/C cables on TOP of the barrel. The leak pulls the mass down against the hot heater bands allowing easier wire removal. Plus you know where all the wires are. There is a tool called Lasor I think that uses super heated wand with compressed air; not cheap and made for stuck rib removal but I've seen them work well.
Rick.

[cavity filler]

here in our factory (UK) we call them 'barrel monster' !
I wonder what other places call them.
But we have the same procedure for removing them. Some are easy (polypropylene) some are difficult (nylon).

[brentb]

What kind of resin is your "Hog's Head"? Removal depends a lot on this!
On small presses people call them " Frog's Heads".

Why not prevent them? There are press alarms that can be set for this. Molder's Choice, I believe sells a detector that can warn you when one starts.

Prevention is best and least costly. Check sprue bushing seating,nozzle tip and press hydraulics. This should be a thing of the past!

KOM

brent