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Hot roll laminator - roll refurbishing

Madis Reivik

Hot Rolled
Joined
Jan 23, 2011
Location
Estonia
Hello !

We use hot-roll laminators here and during use the hot roll gets scratched

Similar rollers:
New, Used and Refurbished Lamination Rollers– VitechParts

I dont know exact material, its medium-hard rubber-like with surface working temp about 120deg Celsius

How can the surface be reworked, we need to remove about 0.5..1mm

Dont want to scrap used rollers as the replacement is 1000 bucks a piece..

Any advice ?
 
.040" of rubber off an unknown durometer roll across 30"...

I guess if someone told me I HAD to do it, and the job would repeat enough to justify the time/effort, I'd try to source/make a box tool and use a SUPER sharp cutting tool, either an upsharp aluminum insert with a tiny nose radius, or a hand ground piece of HSS (I'm no great shakes at grinding HSS, but I think I could handle this)...

If you're unfamiliar with box tools (I was until they were mentioned here on PM), this should give you some ideas. Obviously you'd need it radially mounted instead of axially, so that you could traverse the entire length of the part.

lathe box tool - Google Search
 
I suspect that freezing of the roller prior to machining may help. I've done it long ago when I needed to turn rubber parts occasionally (surface finish wasn't critical though).

P.S. I imagine liquid nitrogen as a flood coolant would be nice to try. :)
 
I work for a packaging company, and we have rubber covered rolls made / recovered all the time. The rubber guy just dry grinds the rolls to size.
 
Rubber/poly is ground, not turned.

You guys thinking you're going to turn it are in for a hell of a fight.

I would send it off to those that specialize in it, but if I had to do it I'd mount a heavy belt grinder to a lathe and go to town.

About a year ago I was at an auction and was trying to figure out what the hell one of the lots was. I took to long and they had a no sale on it with $1000 minimum. Turned out it was everything to strip, prep, rubberise and grind rolls to about 30' long.
 
The mystery in rubber rolls is the selection of the proper compound and the required Shore durometer needed to do the job. To do your job correctly, the ideal is an adequate lathe and a tool post grinder to fit your size roll. Feeds, grits, and type of bond in the wheel will divulge the right recipe. A compound-mount slack belt grinder will also work, depending on the final finish you need. Be careful of excess feed or bite, which may cause reversion of the rubber, (big mess). Keep the roll clean with a mild solvent between passes. You can't go wrong by finding a roll shop that knows how to do it. You might ask the manufacturer of the equipment.
 
I second the suggestion of using a tool post grinder on the lathe. We used to often grind 9 ft. long rubber covered rollers for a local plastic bag factory and had no problem grinding them dry.

Went into it plenty ignorant of such processes and used the wheel that happened to be mounted on the grinder at the time as an experiment, worked a treat, so we get no credit for any wheel selection, just dumb luck.

Had the feed rate rather slow, I do remember that, if old man memory serves, it took ~1/2 hour for a pass and we never had to make 2 passes. I'd certainly share speeds and feeds if I remembered the facts, but I do not any longer.

Prepare for the mess, might kill off a shop vac if you have lots to do, but worth it. We used to kind of joke we should just forklift the lathe outside for those jobs, but it was a beast of a lathe and wish I'd never sold it.
 
I have the shore-meter nearby, i try to measure the hardness.
So, a good bet would be cyl grinder with coarse open aluminium-oxide wheel ? Since I have to buy the wheel, share opinions about grit size.
I can use coolant but is it better try ?

P.S. I locate in Estonia, so there is no "roller refurbishing shop" available nearby and in Finland or Sweden, the attitude and price is awkward...

P.S.S. One old Soviet era anecdote - a man goes to local shop in Tallinn (capital of Estonia). "Excuse me, where can I get needles from sewing machine? " hmmm "from Helsinki I guess".
The irony is that although there were no sewing machine needles or bananas or meat in Tallinn in Soviet occupation, there were facilities that worked with pure tungsten or inconel details 4meters in diameter.
 
I worked in a spinning mill for a while And they had thousands of rubber rollers
When these were worn they had a centerless grinder with a drum that had emery cloth wrapped around it as a grinding wheel
Worked like a charm
Thats why I came up with a belt grinder And I have practised it several times
Peter
 
I occasionally grind rubber and polyurethane rolls with a TP grinder using a 36Grit induced porosity wheel (or also known as a "bubble wheel").Also made a wheel guard that has a vac cleaner hose attachment.
Have to play with the doc and feed depending on material, wheel and power available.
Generally start with .002"DOC and feed 1/4 wheel width per revolution and go up or down from there.
If I have a lot of material to remove I use a carbide tooth saw blade to rough cut as you can take a lot deeper cut but obviously a lot less feed.
 
...feed 1/4 wheel width per revolution...
What rubber roller diameters and lathe chuck rpms are involved in your case? What kind of surface finish do you get on rubber using this method?

Do you have the manufacturer's name/ product## of the wheels you suggested?

Thank you.
 








 
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