Cutting rubber

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rtibbs
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Cutting rubber

Post by rtibbs »

Looking to cut some rubber tire treads for a project. 6mm thick 60 durometer. Suggestions on cutting, should I adhere to a firm substrate, speeds, feeds?

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WNC_Ed
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Re: Cutting rubber

Post by WNC_Ed »

Typically in the industry tread rubber is sheer cut - think high pressure and thin blade.
Not saying it can’t or shouldn’t be tried on a CNC, but be prepared for a stinky mess.
Your best bet will be nibbling it down in thin shallow steps. I would use cheap bits that you are willing to toss after the cut.
Actually with rubber you are grinding/burning and not really cutting.
Definitely attach the tread piece to MDF, plywood or something solid.
If you use a drill bit to make holes for the attachment note that you are just making punctures. To get a “hole” in the rubber you need a hollow “punch bit”. Again it’s just a round spinning sheer.
You may want to try drilling a hole first to see what you are up against.
I will be interested in your results.
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Re: Cutting rubber

Post by ger21 »

Try gluing it to a sacrificial board, and freezing it.
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Re: Cutting rubber

Post by Mark Bolton »

The freezing it idea is the best. I would be very very nervous depending on your machine of all heck breaking loose at any random point when swarf or and overheat situation gobs onto the tool. At that point you will have a wild out of balance situation as well as a major chip weld situation. If your machine is not super robust I would fear the combination would likely cause some substantial damage if you dont plan some safety (break away) into your fixturing.

We have had some chaotic situations cutting foam that has no where near the density of rubber. Where a piece of foam will melt and bond to the cutter, then start whipping, and gob on some more. Thankfully the foam is soft enough to yield to the machine but we have a heavy steel machine, 10hp spindle. With something more "grabby" like rubber, I would be thinking twice.

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Re: Cutting rubber

Post by Philip Lutz »

Probably be much better the carve MDF in the inverse pattern for your rubber tread, then using that as a mold to "pour" RTV compound.

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rtibbs
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Re: Cutting rubber

Post by rtibbs »

Heeding your advice I opted for another way. I used a HD circle cutter to cut the tire 'treads'
Once I finish the painting I will adhere the tire to the wheel, turn the OD true and cut in the tread pattern. (I hope)
Wheel.jpg

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