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GWizard calculation suggests unreasonably deep cut depth


I suspect this has something to do with the way I’ve setup GWizard but I can’t find anything to indicate what I’m doing is wrong. I’m trying to cutout a profile in 3.175mm aluminum plate 44 BHN.

Using the CADCAM tab and 2D Profile I put my Depth at 3.2mm and my Min Inside Radius to 5mm.

Tool Diameter is 1/8″ or 3.175mm, 3 flutes,  with a stickout of 10mm.

Using these settings the Feeds suggests that I can do a 3.2mm deep cut at 800mm / min which is much too deep. Others with the same machine (Stepcraft 840) have been cutting aluminum with 0.3 – 0.5 mm deep cuts.

Where have I gone wrong?

  • Steven Furick asked 1 year ago
  • last edited 1 year ago
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Steven, a cut depth of 1 x Diameter is not all that crazy aggressive at all.  But, you’re in aluminum and using a router.  The issue isn’t so much the cut depth as it is the likelihood that cutting aluminum with a router is seldom done with coolant or even mist.  That leads to trouble as the aluminum wants to bond to the cutter and things soon break not long after.  On a “regular” milling machine we’d be using either flood or mist coolant, not so much to cool as to lubricate which prevents the chips welding onto the cutter.

This post gives more info:

10 Tips for CNC Router Aluminum Cutting Success

So what’s to be done?  Ultimately, if you insist on cutting aluminum without lubricant, you’re going to have problems.  Even spritzing it with WD-40 can make all the difference.  But, the Router crowd doesn’t want to deal with lubricant.  Absent that, take extremely shallow cuts, blast it with compressed air to clear chips immediately, and hope for the best.  You can get there, but it is likely to be painful.

It doesn’t cost much to rig up a mist system and the difference will be night and day if you cut much aluminum.

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Hi Bob,

thank you for the response! I will give the specified depth a try and I’m planning on using lubricant to do the cuts. The Stepcraft by default does not come with a coolant system but I have installed a drip coolant system. It may be fair to describe what I’m using as a router although it’s the HF-Spindle they offer which is rated for 500W 4k-20k RPMs. It seems like it should be enough for some light aluminum cutting with a 2 flute end mill.

My main concern was that the endmill would snap off without making the cut rather than the spindle binding which I’ve had happen with some hardwoods. If you feel like the results are reasonable I will give it a try.



PS The site says

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but there doesn’t seem to be any location to register.

  • Steven Furick answered 1 year ago
  • last edited 1 year ago
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Steven, the login is just the Wordpress commenting login.  If it isn’t asking you to login, it already has you logged in.  It works across all Wordpress sites.

Here’s another thing to consider–try 1/2 that depth at first and then increase if you’re feeling trepidation.  I am a big believer in working up to it.  There’s no hurry.  Keep a notebook on your results and over time you’ll dial in what’s best for your needs.  Glad to hear you have drip in the plan.

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