CNC machine monitoring camera/microphone for broken tool detection

I am looking for a cheap camera and/or microphone system that can automatically stop/reset my CNC mill if it detects a tool breakage. I want it to be quite cheap, and does not need to have any other features. In my mind, this seems like a no-brainer product that should be quite cheap (a few hundred dollars max). It would not even need to connect to the machine, it could just control a switch like this to hit the "reset" button when it detects tool breakage. Microphone would be cheapest/simplest, as all it would have to do is recognize the very distinctive sound wave profile/spike from a broken bit. With more advanced software, it should be able to let you know ahead of time as well, as it hears the bit get louder and louder. A camera could also do this, tho it may require image recognition/machine learning to see when a bit breaks (which coolant might also obfuscate too much).

The context is I am moving towards larger and larger batches/more and more automation. Last week I had a bit break early in an operation, leading two more bits to break (~$100 all in, and on another op coulda been much worse). The only systems I've been able to find for tool breakage detection are touch or laser sensors, both of which are very expensive. I don't need the zeroing features of many of these systems either, as I am rarely changing out tools.

If something like this does not exist, I may build it myself and would love to gauge interest or see if anybody would like to help out! I can post/share everything publicly as well. Would probably just build using Arduino and a switch like I linked to above. Would love any and all feedback!

----------------------

Think Snow Eh!
Ox

ianwatts said:

I am looking for a cheap camera and/or microphone system that can automatically stop/reset my CNC mill if it detects a tool breakage.

Click to expand...

AFAIK that's not a thing. What you want is a tool-setter in the machine that can be used for tool breakage detection. Renishaw and Blum are the big names, and you can use contact or laser.

Doing it reliably by sound is going to be a big ask, with all the other sounds in the shop and chips and coolant flying around. If you don't want to break check the tool after each use, you could use spindle load monitoring; have a macro check regularly that spindle load is within the anticipated range. Too high, and the tool is chipped or dull. Too low and it's gone.

Anyone here use the microphone/acoustic sensor setup.
Listen for cutting or not? Sometimes called gap sensors on a grinder.
Bob

mhajicek said:

AFAIK that's not a thing. What you want is a tool-setter in the machine that can be used for tool breakage detection. Renishaw and Blum are the big names, and you can use contact or laser.

Click to expand...

very expensive and don't need that level of accuracy or the tool-setting features yet, might be able to justify in the future

mhajicek said:

Doing it reliably by sound is going to be a big ask, with all the other sounds in the shop and chips and coolant flying around.

Click to expand...

maybe with very small tools or tool chips, but tool breaks are very distinct from the constant drones of machining or coolant (my shop also not very loud otherwise). could recognize it by amplitude, frequency, or combination of both

mhajicek said:

If you don't want to break check the tool after each use, you could use spindle load monitoring; have a macro check regularly that spindle load is within the anticipated range. Too high, and the tool is chipped or dull. Too low and it's gone.

Click to expand...

this seems like the best solution, do you know if it's possible with Haas machines?

Relative to all of the other engineering costs involved in automation, the blum/renishaw solution is pretty damn cheap. Not to mention that the tool probe does double-duty by dramatically reducing setup times.

Your optical solution may seem cheap on the surface, but getting it to work with the flexibility and consistency of the existing technology will cost orders of magnitude more than just buying something off the shelf.

ianwatts said:

this seems like the best solution, do you know if it's possible with Haas machines?

Click to expand...

If some presetter is installed on the machine, at least for $100; and there are measuring cycles on the machine - of course he can!

ianwatts said:

microphone system that can automatically stop/reset my CNC mill if it detects a tool breakage

Click to expand...

I think it will be much more reliable for you to measure the vibration for this. Such devices are quite common, but I probably never met a microphone.
One of our machines is equipped with the montronix ts100 system. There is a vibration sensor on the spindle, the controller allows you to set the allowable vibration for each tool.
We have never used it The machine is 20 years old, at that time the CNC did not yet have built-in vibration measurement functions.
I think you can find the right stuff on ebay for a few hundred bucks. Or less https://www.ebay.com/itm/2838363263...bLiDPgD9wdwqhG0aHXf6a9/eE=|tkp:Bk9SR8qGgeifYQ

Tool and work probing is about a $5k option on a new Haas, and can be added to an existing machine for a little more. That's pretty cheap, its tried and true, and it works.

If you roll your own solution, including design and debugging time (your time is worth money), how much would you spend?

Regarding the spindle load, Haas controls are already setup so you can set a spindle load limit per tool. I've used this to detect the dulling of a 1/2" endmill dynamic milling in Titanium and it worked great. You can have it then switch to a "sister tool" backup copy and keep going. If you want a macro to poll for a minimum load that should also be achievable, but more work.

A Metrol tool setter with .5 micron repeatability is under $200 from AutomationDirect, if you can put together a system cheaper than that with 1/2 the reliability I'd be most impressed. If you're planning on using Arduino parts I'd recommend getting a quote on a spindle before building because there's a very good chance it'd fail at some point and it only takes once to become more expensive than a Renishaw system.

You're trying to reinvent the wheel here. Don't. Buy the wheel.

Ian, If you are running a HAAS, I believe that they are equipped with a function that senses tool load, and will stop if that threshold is reached....

footpetaljones said:

A Metrol tool setter with .5 micron repeatability is under $200 from AutomationDirect, if you can put together a system cheaper than that with 1/2 the reliability I'd be most impressed. If you're planning on using Arduino parts I'd recommend getting a quote on a spindle before building because there's a very good chance it'd fail at some point and it only takes once to become more expensive than a Renishaw system.

You're trying to reinvent the wheel here. Don't. Buy the wheel.

Click to expand...

Yeah I've been a silly goose, somehow didn't think to look for cheaper versions . Agree that anything I do would be rife with error. Still hoping for someone to make an all-in-one machine monitoring camera + microphone that could do all of this and more for cheap.

M. Roberts said:

Ian, If you are running a HAAS, I believe that they are equipped with a function that senses tool load, and will stop if that threshold is reached....

Click to expand...

Yeah this seems like the best solution until I can get a tool setter setup, also good to stop before tools break.

ianwatts said:

Yeah I've been a silly goose, somehow didn't think to look for cheaper versions . Agree that anything I do would be rife with error. Still hoping for someone to make an all-in-one machine monitoring camera + microphone that could do all of this and more for cheap.

Click to expand...

The software to correctly interpret what it saw and heard would be the major undertaking. You'd have to get Google or Amazon interested to fund it.

You've heard of ShotSpotter? That microphone system sold to police departments for millions of dollars on the claim it could identify gunshots? It can't tell the difference between a gunshot, a car backfiring, or a dumpster slamming. They just report to the police that they heard a loud bang, the police go to investigate and report back what they found, and then ShotSpotter retroactively identifies it in their database as a gunshot or not based on what the police found.

There is one camera based tool setter that I'm aware of, the Dyna-Vision made by Big Diashowa. Afaik, only Yasda uses it. Attachment to either of those companies disqualifies the system from being within the same hemisphere as "cheap".

Mhajicek, image recognition I'd actually expect to be one of the easier portions of this goose chase by piggybacking off of OpenCV. Everything else would be the problems I see.

Sounds are complicated.
The sound of a 1/4" drill breaking is a lot different than the sound of a 1/4" tap or 1/4" endmill, which is also different than the sound of a 1/2" of anything, etc...
And what about "ambient" sounds? You can hardly hear our aluminum machines running when standing next to them while the cast iron cell is running 100 feet away... not to mention the occasional thing being knocked off a table.

I would think a camera could do it without too much trouble by comparing images snapped as the tool is loaded/unloaded from the spindle and seeing if they are approximately the same length or shape.

Taking into account for chips wrapped on a drill?


-------------

Think Snow Eh!
Ox

A problem with optical is that they don't much like coolant and chips on the lens or window and as Ox points out metal chips on the tool.
A problem with power guys is that they will turn off with too much power but few are smart enough to stop if not enough power is being used (broken tool and cutting air).
A problem with touch is that with something like a .006 endmill or 30 degree clear PCD you chip or break the cutting tool.
A problem with acoustic is that you need a way to memorize what it should sound like.

All these things a human on a B-port can do, computers not so much.

One more option; probe the last face cut by the tool before it was put away. If there's too much material there, the tool broke.

another vote for cheep tool setters, I've been using some that I got from eBay, i think they were <£30. no where near as good as a Renishaw, but they work well enough for basic tool setting and brake detection.

lumley32 said:

another vote for cheep tool setters, I've been using some that I got from eBay, i think they were <£30. no where near as good as a Renishaw, but they work well enough for basic tool setting and brake detection.

Click to expand...

are most of these models compatible across machines (I have a Haas Mini Mill 2)? Looking at this ETS, meant for a Tormach trying to figure out if it would work. Also looking at a really cheap option to play around with and test out, something like this