MACHINING RUBBER ? 1

[Judge]

Hello,
Has anyone got any information on machining rubber?
We make rubber lined impellers for pumps for the mining industry. Occasionally, the customer requests that the outside diameter be reduced. Making a mould for this infrequent request would not be cost effective, so, we send the impeller ( diameter 1.5M) to the machining department, where they set it up on a vertical borer and grind 100mm off the diameter using a hard metal type grinding wheel. This process is very time consuming & sometimes can take up to 12 hours.
Can anyone suggest an easier way?
Any information would be greatly appreciated.
Judge

 

[SOLIDMODEL1]

I can't tell if you're machining the rubber or the metal by the description. Either way, investing in spacers within the mould which will take up the difference between the existing inserts and the item may be an option.

Conrad.

 

[FatherBear]

Another possibility would be using a heated wire. I used this process with numerous foam parts. Rubber would be a much slower operation than foam, but it can be done. A wire is heated by connecting it to an electric power source. There are inexpensive machines available or you could make your own. It depends on how often this operation is done as to whether or not it would cost effective for you to consider this method.

 

[SOLIDMODEL1]

In response to FatherBear,
Melting rubber after curing reverts it to an unusable state and would leave a tackey surface finish suseptible to premature fatigue.

If you need to machine rubber, then used a very very sharp thin strong blade with lots of soap solution.

 

[gummi]

Our main products are roll recovering. We do machining rubber cover for every of our products. The best thing to get the most rubber out is by knife on lathe machine. We use grinding machine only for finishing the surface.

 

[coolbreeze]

We've been sucessful at machining rubber at extremely low temps. Freeze the part and go for it!!!

 

[patternmonk]

We've tried machining rubber just recently and found that running at high rpms 5000, at slow feed rates 10 ipm with a very sharp carbide cutter and small step downs .05 inches. One problem we had was with part deflection (the rubber bending out away from the cutter) so you have support the thin walled areas by fixturing. These were small parts with about .900 material in the z and .250 in the x and y.

Patternmonk