# Need help Routing half inch aluminum



## diego06310 (Aug 30, 2012)

Hi I have a Gerber CNC Router. Im trying to route 1/2" thick aluminum. I'm using a 1/4 router bit 63-725 18,000rpm @ 40ipm and i'm going 1/16 down per pass. Ive broken about 3 bits and messed up 1 collet by now. By the way i am using mist coolant.
Any one here have any tips or tricks.


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## old55 (Aug 11, 2013)

Welcome to the forum Diego. I'm sure someone will be along to give you a hand.


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## Quillman (Aug 16, 2010)

Not with CNC but with a kitchen router.


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## MAFoElffen (Jun 8, 2012)

I'm not a CNC'er, but... Thinking your speed is too high.

Just by machining calc's, wrought aluminum, such as 6000 series... milling factor is 165 feet per minute. With an 0.25" end mill, that calculates out to suggested tool speed of 2521 rpm.

I occasionally hand-route aluminum and I turn my router down to 10,000 (because that's as low as that goes) and use continuous flow cutting lube oil (not just mist) with carbide bits. Experience has shown me that if I go any higher with that, then I have problems melting the aluminum to the carbide and breaking bits.

Just an observation.


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## Semipro (Mar 22, 2013)

Hello Diego, glad you found us, it's great to have you as a member of the community, welcome to Router Forums.


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## fixtureman (Jul 5, 2012)

Slow the spindle speed and use a HSS bit they are more forgiving. .0625 is a little aggressive also


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## Dr Neon (Apr 15, 2010)

Hi Diego. Harder aluminum routes easier. 5000-7000 series is the best to use. Slowly, with adequate cooling (don't know how much your mist system puts out), and end mill bits that are designed to remove cut chips. A straight cut mill can keep the chips in the groove (especially when you are 3/8" down into 1/2" material) which will break bits every time. Spiral bits will pull the chips out.


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## ve3sqb (Nov 7, 2014)

first off, router bits do not have the correct geometry for cutting a metal. You have to have a end mill. Next the speed of the router may be too fast. Aluminum has a cutting speed of around 100 so the formula (cutting speed x 4)/diameter says it should be running at 1600. Coolant can raise this 2 or 3 times. Lastly feed should be .008 to .045 per tooth. The formula here is Feedrate=RPM x number of teeth x chip load. .008 is probably a little light and would gum up and .045 would be heavy steel mills. The 40ipm would be good for a 4 flute cutter but depending on how rigid the machine is, start low and work your way up.


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## diego06310 (Aug 30, 2012)

Thanks.


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