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having problems routing 1/2" aluminum

Darren123

New Member
any ideas will help. I keep breaking bits at my standard feed and spindle rates. Chip loads look fine, things go well for a time then they break. I thought I might not be cooling enough, but it seems fine.

any ideas?
 

Techman

New Member
what is your mist.. aluminum will stick to a cutter, and then cause it to break because it cannot cut. you need an aluminum mist to cut at full speed.

Something such as tap magic for aluminum or some a petrol product such as kerosene type stuff works ..
 

Darren123

New Member
I am going through all the way, at 4 passes, and 1 clean up pass. i have been breaking mid way through. I'm using a cutting fluid mist, fairly heavier than usual too.
 

The Big Squeegee

Long Time Member
When the aluminum sticks to the cutter it will build up heat as well as become harder to move through the material. An oil or wax will help to keep the aluminum from sticking. You can also increase the chip size by slowing the speed of the cutter or increasing the feed speed.

The kind of material will also make a difference. 5051 is a soft aluminum. 2024 and 7075 are much harder. The softer the metal the more it will stick to the tool.
 

JimJenson

New Member
When the aluminum sticks to the cutter it will build up heat as well as become harder to move through the material. An oil or wax will help to keep the aluminum from sticking. You can also increase the chip size by slowing the speed of the cutter or increasing the feed speed.

The kind of material will also make a difference. 5051 is a soft aluminum. 2024 and 7075 are much harder. The softer the metal the more it will stick to the tool.


I have found Crisco to be very effective on difficult materials. In regards to grades, aove is correct. 5051 has the lowest copper content, and 7075 is the highest. The T number following the grade is the hardness, typically these grades are t6. Other factors change the machinability of aluminum, for example if its been welded, the hardness will have been annealed out of the material as soon as the aluminum has cycled above about 4-500 degrees. As to the worst I have had the pleasure to worked with, extruded shapes (3XXX series) takes the title. Even that has tricks to make cutting and tapping simple.
 

briderx

New Member
1/2" aluminum should NOT need 4 passes.. You can do it in 1 if you know what you're doing. I run a 1/4" spiral upcut bit @ 126IPM @ 28000RPM and it cuts just fine. Make sure your mist is working correctly and turn it up a little if needed. I don't adjust my mist too much. Make sure your parts aren't moving on the table (tabs or onion skin methods..).
 

briderx

New Member
Forgot to add.. Often times, going too shallow with cuts will break bits.. 4 passes @ .5" comes out to 1/8" per pass.. Too much material being cut by tip of bit will break it in minutes. Your tip will wear really fast and break. Typically, you want to go to a depth of the diameter of the bit: 1/4" = 1/4".. Decrease your speed by 25% per pass.. So, .5" is 2 passes on 1/4" bit.. can be done in 1 if speed is slowed by 25%.
 

Jester1167

Premium Subscriber
The width of the bit = the max depth of cut in aluminum. 1/4" bit = max 1/4" depth. With deep cuts orient your two mister nozzles so that a majority of the time they are blowing down into the tool path not just on the exposed bit.
 

briderx

New Member
The width of the bit = the max depth of cut in aluminum. 1/4" bit = max 1/4" depth. With deep cuts orient your two mister nozzles so that a majority of the time they are blowing down into the tool path not just on the exposed bit.

Exactly. Don't have your mist nozzles directly opposite each other.. If the spindle were a clock face, one would be @ around 12:00 and the other @ 4:00. So, staggered. This way, you're getting fluid in all areas.
 
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