One of our HDPE extrusion machines had a bit of a fit, and managed to dump maybe 80 pounds of molten plastic onto the base of the machine. Access isn't easy, and the plastic surrounds cooling pipes, etc. I'm trying to get it out of there. What I've been doing so far is using a sawzall with a 10" long coarse blade and just cutting chunks out, but the pile of plastic is around 2' across, so I'm trying to figure out a fast way to get it out of there. I've already spent a few hours and only removed maybe 1/4 of it. It's harsh work, and I'm getting closer to the cooling lines, so I thought I'd ask for ideas as to how to get it out of there.

Mike

How about using an air-operated jack hammer which I used to break refractory linings previously?

Why was it dumping molten plastic unnecessarily?

I considered a jackhammer but I didn't think the plastic would be brittle enough to break apart the way cement, etc. does. Plus I worried about harming the machine.

As to why it happened, it is normal operating procedure here for the extruder to be turned on before the molds are brought into place. Normally this excess is caught on a piece of sheet metal sitting on the frame of the machine, but someone who didn't care or wasn't thinking, or whatever, allowed this plastic to fall into the machine again and again until it had piled up to the point where the machine won't work any more, and now it becomes my job to get it out of there. Nice, eh?

If a Jack Hammer is too much, what about a drill? Maybe risky to damage the cooling pipes.

Could you heat the plastic with a small torch or a heating element?

Can you disassemble partially the machine to gain more access?

It's interesting that you would mention a drill... as I just used that method today to get a bunch of melted plastic out of a 100HP shredder. The plastic was about 2" thick in a recess around 18" diameter, so I couldn't get a pry bar under the edges. I used a drill and chain-drilled 'fault lines' and used a pry-bar with a spud (a pry-bar with a pointy end) to pry in the drill holes to break the plastic up, and it worked like gang-busters. It _did_ leave small drill-dents where I hit the steel under the plastic, but that didn't matter in this case. I am seriously considering using a 24" long 'bell-hanger bit' to drill through my pile of plastic under the extruder.
Great minds think alike?

Glad to help, I had doubts on the drill but in brainstorming:

* No idea is a bad idea (until proposed, analyzed, and discarded if not good enough).

* The only bad idea is the one no one proposed.

There are also some good portable waterjet cutting companiess in southern ontario. We have had to call them in a few times to clean out the shredder.Good job and not too expensive.

RR

Mike,

I see the same thing in two plants I'm going to tomorrow.

In one case it was a small leak that entangled several control lines, hydraulic lines a motor and the steel bar grating. I watched one guy go at it with a reciprocating saw and give up. About 6 months later, it was gone and there were new hoses, etc. and checked plate in place of the grating. The other gets trapped by the machine and the adjacent building support and has been really big a couple of times. They have added a stainless steel chute to get it out of the trapped space and that makes cleanup much easier. Is this caused by plugging in the nozzles?

As far as how they clean it up, I'll ask them tomorrow and let you know.

use a hot knife

I did a Google search for '"hot knife" plastic' and got a bunch of things based on a soldering iron with a blade perhaps 1/2" long. That doesn't seem quite suitable. Are there companies making _big_ ones?

The other option is to have machine operator clean up there mess.We did that last time , it took them better part of 3 shifts to clean out the shredder. Guess what word gets around plant pretty quick of how dirty and hard it was to clean out. We have not had a problem since.

L8R

Yes: you can buy a hot knife that looks much like a kitchen knife or butcher knife for lack of better description.

Making the operators clean it out is an interesting idea... I'm not sure it would fly here, but I'd like to try.

I'll look harder for a large hot-knife.

Mike,

The answer I got was, "If you figure it out, let us know."

They use saws, chisels, drills, a cutting torch , etc.

The most sensible approach to clean up is probably like blasting. Drill a line of closely spaced holes and connect the dots until it gives. I spoke to one senior operator who does like was suggested earlier. He makes the operator clean it up and that particular operator won't let it happen again.

The bad part is that the piles mysteriously appear overnight and no one saw anything.

I'm a little late to the game, but you mentioned hammering wouldn't be effective because the plastic isn't brittle enough. How about blasting it with CO2 to make it cold/brittle and then smacking it. I never used liquid Nitrogen for this type of stuff because it gets so cold the metal may crack too, but I've sprayed down plenty of radiators with Nitrous Oxide to cool them. I think the CO2 route would be safe and would freeze the plastic quite well without harm to the metal and other lines.

Just evaluate first what else is around that could be damaged with the CO2 cold... wires?, rubber fluid lines?