cnc mill repairs

[mikkhh]

Some 30-40 year old cnc mill had tooling setup error and mill crashed into jaws hard. After that there is spindle error. I was like okay, this has to be something with the spindle motor module.








Pulled the module out, fuses checked good. Then checked igbt module with multimeter diode mode and found out short between W and N legs . There should be not full on short circuit there. Then pulled the igbt module cover and looked inside for signs of burn or perhaps the schematic is just plain wrong.


https://www.ic-components.com/blog/6MBP1...asheet.jsp

This case there is actually burn visible under the gel.


Next step of action is trying to find another working igbt module, replace optocouplers (find if and where are igbt drivers, if possible replace them too) on board and check other parts of the igbt driving circuit. Maybe the igbt failed because of bad controls ? .

My theory is not good, I am not good at reading schematics (things I fix most of the times there are no schematics obtainable) but I have fixed all kinds of electronics before. I first first tv power supply board when I was 16. I have been involved with these things for over 10 years.

All that diagnostic took actually less than hour - started at 16.30 drove away 17.30.

[Rawze]

(From What I can see, the beer is talkin' )...

Unless there is stuffs that I cannot see in the photos ... those FANUC drives are doomed to fail / fail again. That motion control system cabinet is not designed correctly. There are missing support components for those drives either because the maker of that CNC was a cheap-scate, and tried to cheat the system, putting those drives at risk ... That, or they were absolute dumb-arsses and don't know how to design a CNC mill motion control system properly.

The irony is that they almost got part of it right on the front-end .. but then they cheaped out on the things that counted the most towards protecting those drives properly.

- I.E.> WTF good is it to put a line reactor without proper amp-traps in the system to go with it? .... WTF???!!> .. and WHERE THE H@#ELL is the dynamic braking unit?>> WTF!!?>>. Any feed-rate above 30-40% on the table with a heavy part is going to torture those drives every time it reverses direction!.

WHO makes this machine?.. some back-water third rate CNC tooling company?. <-- because I sure hope like all s#ell that it is not a major brand doing things this badly. That F$in thing looks like the inside of some teen-age kids science project.. and not a professional CNC controls system cabinet design at all.