I’m looking for some advice for milling rubber. The rubber is around 90A shore hardness. To be specific, I’m planning on machining a 3/8" x 1.5" rectangular slot out of a hockey puck. It’s going to be purely functional, so it doesn’t need a good finish quality.
I’ve read this post:
And they recommended this: Hole and Cutout Settings:
1/8" 2 Flute 0.375" doc, 5mm/s, no finishing Pocket Settings:
1/8" 2 Flute 0.064 doc, 80mm/s, no finishing 20% stepover
But they don’t state how hard their rubber is and I’m not sure if that’ll affect the numbers. If someone can confirm that’d be great.
Hi! I’m the OP of that post you linked. The rubber that I milled was really soft. Like the tires of your car. I milled that soft rubber at really high speeds, as the material was more likely to rip and tear than actually make chips.
In the case of a hockey puck, I’d expect it to behave more like plastic, such as ABS. Slower, shallow cuts will probably be ideal.
Go to your local harps (or maybe whatever your regional grocery is) and get some dry ice. Lay the dry ice on your material prior to milling - freeze it to -90 with the dry ice - boom profit and easy milling. I actually do this on copper as well (on the manual mill) when drilling deep, or high aspect ratio holes.
Alright, time for results. I did my first test. I used a 2 flute 1/8" cheapo bit from amazon (costs less than $2 per bit). I ran with 1mm depth, and a feed rate of 2800mm/min with a 20% cut. It worked so easily that I’ll probably increase the depth to 1.5mm Kyle Wolfe did. I used no cooling and I only smelled a little burning rubber. My garage was -1C at the time and the puck was left there overnight and so also would have been that cold.
I noticed that it took about 20% longer than estimated, I’m guessing there’s limits within the current firmware for acceleration or top speed. It’s not a big issue though.
