Spindle Load Check for Dull Inserts

I've got a old QT250 with a 640T controller. Is there a way to use either spindle or Z axis load to detect dull tools? I have an operator who is smoking insert drills & the boss came up with this idea of controller detection. Anyone done this before? I've never used any type of load monitoring for tooling so this is first for me. Plus this machine is older with few bells & whistles.

Thanks in advance for any replies/ideas.

Brad

Does the machine have overload detection enabled? If it does this will cause the machine to basically reset with an overload detection alarm, its more used to tell when an insert has already failed and often saves the holder. If you turned down the detection rate enough for the drilling it may catch it before failure, however the drill will still be in the part potentially causing tool breakage due to the spindle stopping.

Tried doing it with the cutoff but it was too hard to detect when an insert would fail. You'd probably have more luck with an insert drill as its significantly more load, but it would definitely be trial and error as to what percentage you'd want the machine to alarm at. I wouldn't be too concerned with an insert drill stopping in the middle of the cut. It should be able to take that little bit of abuse no problem. You will just want to monitor z-axis load when you're cutting to see what it is during normal cutting, and what it is during worn insert cutting. The problem is any type of load spiking, which could cause a false alarm. You might get a spike from material fluctuation, or just any weird machine anomaly. There are certain overload tables you'll need to write at the beginning of the feed you want to monitor. Each axis has a writable field, but I'm not sure what they would be on your particular machine. Just ask your local Mazak application engineer or tech center, or pull out your 50000 page manual and start reading...

Possibly a simpler solution would be to give the tool a tool life in tool data? You can either count number of minutes in cut or number of cuts. The machine will soft alarm once it hits either minutes or number of uses depending on the user parameters. Again, user parameters are a little machine dependent so refer to your manual or ask your local Mazak dude.

E

Well I have seen many machines that stalled out due to wasted inserts. Mostly drilling though. I don't know if turning and boring in a lot of cases put enough load on the machine to make a noticeable difference until things are really really bad.

I always have thought that in the future machines will have IR heat cameras and monitor the heat signature of a particular tool each time it runs and you would be able to see it that way. Probably doable right now.

pmtool said:

Well I have seen many machines that stalled out due to wasted inserts. Mostly drilling though. I don't know if turning and boring in a lot of cases put enough load on the machine to make a noticeable difference until things are really really bad.

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Yea insert drills produce a ton of tool pressure in the z axis. General turning is hardly even recognizable on our mazaks unless we're doing od pinch turning. It would be nice to see a good upward trend in load as the inserts wear, but I have my doubts that it will be a steady linear increase. I'm worried it's more exponential as failure approaches which might not be repeatedly predictable. Let us know what direction you take as I'm curious on this one.

E

No idea about your lathe, but I use it on our haas mills when I'm using our seco high feed cutters. I find insert life drops off in rapid fashion then they break, and take out a holder. I just watched it running one day, and made note on the load meter when they started going south and set the limit a little shy of that (%65 for our setup). Works great, and I havn't lost a holder yet.

afc

BradLEE said:

I've got a old QT250 with a 640T controller. Is there a way to use either spindle or Z axis load to detect dull tools? I have an operator who is smoking insert drills & the boss came up with this idea of controller detection. Anyone done this before? I've never used any type of load monitoring for tooling so this is first for me. Plus this machine is older with few bells & whistles.

Thanks in advance for any replies/ideas.

Brad

Click to expand...

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on a mazak mill it is called afc or automatic feed control and the % is set where you set the tools on far right, most times if auto set it can be too high or low
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when afc button is on and overload detected the red light goes on and the feed will slowly reduce to 50% and if overload continues for 5 seconds a feed hold is active
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i would recommend reading your mazak operator manuals. afc is slow to react but if overload is high and more than a few seconds it will start to reduce feed. i have had it set where feed hold was activated. auto set just is a best guess. only experience will tell you if it can be higher or lower.
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afc works better with bigger tools. trying to measure less than 20% and especially less than 10% of spindle or axis thrust load is not easy for the machine to do. for drill bits it works good if over 3/8 dia tool.

DMF_TomB said:

.
on a mazak mill it is called afc or automatic feed control and the % is set where you set the tools on far right, most times if auto set it can be too high or low
.
when afc button is on and overload detected the red light goes on and the feed will slowly reduce to 50% and if overload continues for 5 seconds a feed hold is active
.
i would recommend reading your mazak operator manuals. afc is slow to react but if overload is high and more than a few seconds it will start to reduce feed. i have had it set where feed hold was activated. auto set just is a best guess. only experience will tell you if it can be higher or lower.
.
afc works better with bigger tools. trying to measure less than 20% and especially less than 10% of spindle or axis thrust load is not easy for the machine to do. for drill bits it works good if over 3/8 dia tool.

Click to expand...

Did this once on a Mazak mill when using a 2" diameter roughing endmill on a job (years ago). Worked pretty good. I dont remember exactly....but I think you can set the parameters to either measure spindle load or table load????

toolsteel said:

Did this once on a Mazak mill when using a 2" diameter roughing endmill on a job (years ago). Worked pretty good. I dont remember exactly....but I think you can set the parameters to either measure spindle load or table load????

Click to expand...

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2 settings thrust and spindle load
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i of course created a excel chart of all standard tools in standard tool holders with the % range to use for each tool for example
.75C which is a medium length 3 flute 3/4" dia end mill it is 12-17-25
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at 12% afc is too often reducing feed
at 17% afc is rarely reducing feed
at 25% the end mill will often chatter severely and afc might not reduce feed in time to help much
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in general i usually set it at a medium setting. usually auto set is usually at a high %. the longer a tool is sticking out the more the % needs to be reduced. normally a tool sticking out 2X can only take 1/8 as much. this is why any settings must take into account tool holder used, type of tool and especially length tool is sticking out of the holder
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even with twist drills it matter a lot. a 2" long drill and a 20" long drill there is a hugh difference is max feed rate it can take

Wow, thanks guys for all the replies. Sorry I did not mention my drill size, make & material. SECO SD504-0709-284-1000R7, 4xD .709 diameter, drilling a blind hole into 17-4PH H900 condition. Let me see if I can find the manuals & poke around the controller to find AFC functions.

Brad

No luck with the AFC on the controller. Still trying to find our manuals.