CNC Mill spindle turns on in the middle of tool change and other sindle issues

[Hunter.sayre]

Hello everyone,

im having some weird intermittent spindle issues with my mill and i need some help figuring out how to fix it


Problem #1 the spindle turns on and starts spinning inside of the atc during a T#m6 and also during a manual tool call through the setup page in the cnc12 software as shown by these two videos

https://youtube.com/shorts/_Pfwe73tUJs

https://youtube.com/shorts/NccKBGbkNyQ

restarting the machine doesnt immediately resolve the issue once it starts happening it wont stop until the machine is off for an extended period of time this has basically rendered my tool changer useless since i bought the machine right now i just program everything as tool one and constantly change tools to tool 1 for everything

problem #2 occasionally the spindle will get stuck in a orientate loop where given a M3 or by also using the spindle on and off button on the control the spindle will orientate to the home M19 position and stay there regardless of the rpm value given as shown in this video

https://youtube.com/shorts/OGjxMNSu8uw

problem #3 the spindle will turn on but not at the correct rpm
this one is pretty self explanatory when running a proven and good program the spindle will turn on but instead of for example the program being written for 4000rpm the spindle will only be running 200rpm i stop the program and restart it without changing anything and it runs just fine


a note on the centroid report it is older but it is from the time that the videos and pictures were taken

picture folder

[cncsnw]

What brand and model spindle drive do you have? Where is is located?

If you temporarily set the G30 Z position safely above the fingers (e.g. up an inch, at -3.570"), and dry-run tool changes without any tools in place, does the unexpected rotation still occur?

Does the unexpected rotation always occur right at the point where the control would have unclamped the drawbar?

Some of your sequencing problems (failing to release orient and run normally) may be due to errors in your M function macros. Your M3, M4 and M5 macros should all include "M95/19" so that they will cancel the spindle orient request when you program a normal spindle start or stop.

The control was evidently updated with an MPU11/LegacyAdd system in 2022. It would previously have had a CPU10-based control, probably ca. 2002. Did you own the machine at the time of the upgrade? Or did the previous owner have it updated, and then sold it? Do you have any support from your local/regional dealer or tech rep?

[Hunter.sayre]

See attached photo for the spindle vfd….

I’m not sure about dry running the tool change that’s not something I’ve tried or know how to do

Yes the unexpected rotation always happens at the point the drawbar is supposed to release and sounds like it releases


I bought the machine after the upgrade from a local shop that I used to work at the original Linux pc ended up dying and he had his centroid tech do the upgrade… I had the same tech come over to look at it at the the time the atc had a high chance of picking up the wrong tool when rotating backwards and mixing the tools up he took care of that problem but wasn’t sure if anything he did would take care of the spindle problem I attempted to contact him a few months ago to look at it again and i haven’t heard back from him so I settled to go the diy route or atleast get a little bit more direction

[Hunter.sayre]

Is this something that installing the newest version of the cnc 12 software will/can fix are there default plc programs for atc functions?

[cnckeith]

there are no issues like this with the v4.20 version of software you are using so i doubt an cnc12 software upgrade to a newer version would do anything to resolve it.

who did the upgrade? sounds like you have unresolved configuration issues.

I see you have a legacy upgrade kit installed while these work great but there are lots of PLC program details that need to be worked on to get things right as the old linux plc program is not a 'drop it in and it runs' type of thing for use with the v4.20 on the machine now. when doing a legacy upgrade often the most work of the job is fixing up a new plc program to work with the existing hardware that the legacy kit is connected to.

frankly on this machine i would have NOT recommended a legacy upgrade as the old PLC and old servo drive is just a bit too old for my tastes, while it would have been more work and money to do a complete overhaul of the control system the results would have ultimately been better when considering everything.

[cnckeith]

looking at the videos , looks like the hand shaking between the orient card and the plc/tool change macro is where you are going to find the issue.

[Hunter.sayre]

Bill Meyers is the guy who did the upgrade I attempted to call him a couple of days ago to get on his schedule but unfortunately he hasn’t responded yet

The shop that the mill came from is usually a pretty busy shop and this mill was their #3 mill so I believe the thinking in the upgrade was that it would be the “cheapest” and quickest way to get it running again
But after running into the issue of the tool changer miss counting when going backwards and occasionally picking the wrong tool the shop decided to stop running the machine and bought a new one so they ultimately didn’t run into the more crazy issues

I bought the machine from them for what he had in the upgrade which was 10k

Unfortunately for me the only coding I even remotely understand is G&M code so I’m going to have to rely on either bill to get back to me or someone else to put the rest of the leg work in…

Over the weekend I was also rigid tapping and had a spindle slave position error which makes me feel like there’s something off with the encoder as well or something along those lines