Sometimes, Stuff happens...

Sometimes, Stuff happens...

Joined: October 28th, 2014, 1:06 am

March 6th, 2017, 7:00 am #1

This happened to me a few days ago.


Fortunately, the actual part underneath all that mess was just fine.



I'm not sure what the material was. It was a former piece of form-tooling that I'd saved when the mold was replaced. It was some sort of plastic, that I know. Any ideas how I should adjust the feeds and speeds to get cleaner chips?
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Joined: November 17th, 2014, 11:09 am

March 6th, 2017, 1:21 pm #2

Lower the speed, use an endmill with fewer flutes, take deeper cuts with less overlap.

Just assuming the stuff is somehow melting and fusing together...
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Joined: February 2nd, 2017, 2:27 pm

March 6th, 2017, 1:46 pm #3

This happened to me a few days ago.


Fortunately, the actual part underneath all that mess was just fine.



I'm not sure what the material was. It was a former piece of form-tooling that I'd saved when the mold was replaced. It was some sort of plastic, that I know. Any ideas how I should adjust the feeds and speeds to get cleaner chips?
When milling plastic, an air-jet to keep things cool is a huge help. Doesn't have to be a cold-jet, just keep air moving at the tool/material interface and you'll reduce stuff like this. Also remember that plastics have much lower melting temps and softening points than a chunk of metal. Sometimes you have to dial it waaaay the heck back go slow and gentle.
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Joined: October 2nd, 2014, 6:07 am

March 6th, 2017, 3:02 pm #4

This happened to me a few days ago.


Fortunately, the actual part underneath all that mess was just fine.



I'm not sure what the material was. It was a former piece of form-tooling that I'd saved when the mold was replaced. It was some sort of plastic, that I know. Any ideas how I should adjust the feeds and speeds to get cleaner chips?
http://cheezburger.com/9016311552
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Joined: October 28th, 2014, 1:06 am

March 6th, 2017, 5:28 pm #5

This happened to me a few days ago.


Fortunately, the actual part underneath all that mess was just fine.



I'm not sure what the material was. It was a former piece of form-tooling that I'd saved when the mold was replaced. It was some sort of plastic, that I know. Any ideas how I should adjust the feeds and speeds to get cleaner chips?
The plastic I normally run, (the red stuff you see there) doesn't need any coolant, so I initially ran dark plastic without it, but I when I saw smoke, I knew I needed coolant. The part above was run with full flood coolant. The scrap I was using had been fully machined, so I knew it was machinable, I just didn't expect that.
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Joined: November 19th, 2014, 12:50 pm

March 7th, 2017, 5:55 am #6

This happened to me a few days ago.


Fortunately, the actual part underneath all that mess was just fine.



I'm not sure what the material was. It was a former piece of form-tooling that I'd saved when the mold was replaced. It was some sort of plastic, that I know. Any ideas how I should adjust the feeds and speeds to get cleaner chips?
As snowtroll said, much lower speeds and much higher feeds. You want big thick chips. This is true for most plastics, except acrylic which needs special care and handling.

Also, be careful because PVC can move around like crazy when you heat it up.


And actually, realistically most people are very conservative with feeds - I rarely see somebody feeding too fast, but see people feeding much too slowly all the time.
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