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How do you guys measure wear on your endmills?

jools

Aluminum
Joined
Mar 28, 2017
Hi All

I'm just wondering how you all measure wear on your endmills? I don't have an optical comparator so was wondering what the best way is with normal measuring tools that I have around the workshop.

Cheers in advance :-)

Jools
 
For many situations, it's actually an "inferred wear", where in production size changes are noted on the parts, and at intervals cutter comp is adjusted. When judgement and past performance indicates, the cutter is swapped for new, the comp reset, and the cycle restarted.

In other cases, direct observation is made of changes in surface finish on parts, or unacceptable increases in part internal corner geometry require endmill change from tool corner breakdown.

And then there's the 'ol run it until it breaks method...

What are your circumstances? Is this just looking for a level of edge dulling to use as removal criteria?
 
For many situations, it's actually an "inferred wear", where in production size changes are noted on the parts, and at intervals cutter comp is adjusted. When judgement and past performance indicates, the cutter is swapped for new, the comp reset, and the cycle restarted.

In other cases, direct observation is made of changes in surface finish on parts, or unacceptable increases in part internal corner geometry require endmill change from tool corner breakdown.

And then there's the 'ol run it until it breaks method...

What are your circumstances? Is this just looking for a level of edge dulling to use as removal criteria?

Circumstances for me have been that I have been using without comp and have been using the 'use it till surface finish looks shit' method. What I'm trying to do is to move my Fusion360 CAM programs from just being processed'in-computer' to utilising wear so I can adjust part size, especially when thread milling. To do this I was hoping to get a line in the sand starting point; somehow measuring the endmill when it's new for a baseline.

I'll hold my hands up and say I haven't come from a machininst background so things like this, and learning from those who have, are particularly valuable to me.

So are you saying in general you would just pop a new endmill in, see what she cut's then adjust from there? I suppose it matters little if a part being out of tolerance is caused by machine or tool. Especially if adjusting the tool diameter can bring it back within tolerance.

Jools
 
Quality endmills (I use mostly YG-1 finishers, roughers I don't care what exact size they are), IME, are on-size within a tenth or two so unless it's a very tight-tolerance feature I do just pop one in and let it cut. There are other reasons why a feature might be off-size though so even if the endmill is perfect, the feature might not be. So, first part out of the machine gets measured then wear comp applied as needed.

Threadmills, OTOH, can't be trusted to cut a specific pitch diameter without comp-ing, since the diameter of the tool at the tips doesn't necessarily imply a certain pitch diameter. Threads don't have sharp corners at their crests and roots, while threadmills (unless using a pitch-specific threadmill) usually do have sharp tips, so you need to comp for the difference.

HTH.

Regards.

Mike
 
I program all my tools (well, a few exceptions but I digress) at nominal and computer comp for roughing, then use wear comp for finishing. Basically as stated, run at zero (unless critical features, expensive mat'l, then I might put in + comp so I *know* it will be oversize) comp, check part, adjust comp to get part within print tolerance. All that said, a nice magnifier/loupe will do wonders for checking tools for sharp corners, chips, coating wear etc. I am kind of spoiled now as we have a micro-vu so I can zoom in to around 190x to really really see what the tool looks like. :)
 
Doesn't really matter how well you measure the tool if there is runout, which there will be some, it will cut oversize.

If I'm really concerned about scrapping the part I will throw some + wear in the control(just to be sure it stands off the finish size), measure, adjust and rerun.
 
looking at the wear land with a loop may be the best way. A .015 land may be all some steels can handle.

Often end mills can be cut off and end resharpened to restore new condition for half price of a new one.

Running them till they fail slows down performance.
 
Just a note.
Measuring the working end of a new carbide end mill with a manual micrometer is a great way to ruin it.

Cutting tools cost real money and no one wants to toss not used up after a easy job run.
When an end mill comes out we use a good loupe or stereoscope to classify it. Blue marker is good but used, red marker ok as a rougher. Class three is the regrind bin.
Bob
 
Hi All

I'm just wondering how you all measure wear on your endmills? I don't have an optical comparator so was wondering what the best way is with normal measuring tools that I have around the workshop.

Cheers in advance :-)

Jools

Somoeone just posted about a digital microscope. Looks pretty awesome for $120, and a relatively cheap investment for a machine shop. Half the tools I program I can barely see with my old tired eyes, not to mention to see # flutes or if they are sharp! :(
 
Thanks all. Sorry I haven't logged in for a while to see this.

Seems that a cut and measure approach is the best way then and is what I'll do for the future. I've set my machine and CAM up now to use the 'wear' function so I'll crack on with that.

I did it a couple of times on a thread that was tight and got it to fit nicely :-)

Thanks all

Jools
 
Just a note.
Measuring the working end of a new carbide end mill with a manual micrometer is a great way to ruin it.

Bob,
Ruin the end mill or micrometer? Curios why you would say this, I've been doing this (carefully) for years and don't believe I have ever damaged either.
 
The end mill.
Do you have a 500X scope or make and measure carbide cutting tools?
Even a new untouched carbide endmill has chips out of the cutting edge, Not sure your allowance.
Use to get prints for Carboloy that said "no visible chips on cutting edge".. we had to ask them to define "visible".
Bob
 








 
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