Mazak, Quick Turn 15 T2 The measurements are moving

Hello everyone.
We have a Quick turn 15 with T2 control.
Our problem is that every two days or 3 the measurements move 12 mm.
I would like to know if there is any parameter to fix
Thanks in advance
Greetings

If the pitch of the lead screw on the axis that moves is 12 mm, the home position is changing.

Possible causes:

Sticky slow down switch.

Crud on switch or cam that operates switch.

Coupling between motor and lead screw has slipped due to crashes, and the marker pulse on the encoder is too close to where the limit switch operates.
I normally set it up to be a half turn from where the switch closes.

Bill

12 mm? Wow. You have a mechanical issue, nothing a parameter change will fix. Is it in both X and Z? It may be something as simple as a sticking switch. Make sure it is going to home position correctly. Look at the home return switches at the plus end of your axes. Check for chips or goo and clean them off.

I had a simular problem ones.
On my machine the slow down switch was to close to home position so sometimes the ballscrew took an extra turn when homing.
Moved the slow down switch a few mm and all was fine.

But as stated before, also make sure the condition of slow down switch is good.


Ps.
The home function has no switch to indicate home position.
It has an slow down switch and then it turns the ballscrew slowly until the encoder is in the correct angle.
If the slow down switch is in the wrong position it will move the home position by one turn on the ballscrew.

Hi.
The 12 mm is on the X-axis, it doesn't mistake me for zero home.
There is another more serious problem, if the energy jumps away if they erase all the parameters..
This is not nice for us

Does it move 12mm during the day whithout a restart of the machine?

For the paramater issue you have to replace batteries.
You have 2 or 3 batteries on the boards depending on what version of the harware you have.
The original batteries are 3,6v NiCd batteries but can be replaced by any 3,6v NiMh.
I used holders for 3x1,2v AAA batteries with cabels from the boards to the holders.

If you dont replace these batteries they will leak and destroy the boards

It moves when I turn it off,For the battery we change it.

Does it change the exact same amount each time? Or just close

OK, since I don't know your machine config I'm going to make some guesses. Homing usually works on a switch which gives you approximate position. Indicates you are within 1/2 pitch of the ballscrew of home. From that switch closure it moves, either way is possible depending on your software. When it senses the index pulse (one per rev) it sets home position. A couple of possibilities. The switch is dirty and that makes for uncertainty on when you start the home cycle. More likely is that you are missing the index pulse. Causes could be a weak battery for the encoder, bad connection or the chip logic which senses the index is bad. I'm guessing that the shift in the home position is n*pitch of the ballscrew. I like the idea of Li-mh if you can find the correct voltage but they charge different than the Ni-Cd's. Cleaning the switch with 'LPS' or other contact cleaner may help. HTH

Gobo said:

Does it change the exact same amount each time? Or just close

Click to expand...

Always from 11 to 12.

ss_user said:

OK, since I don't know your machine config I'm going to make some guesses. Homing usually works on a switch which gives you approximate position. Indicates you are within 1/2 pitch of the ballscrew of home. From that switch closure it moves, either way is possible depending on your software. When it senses the index pulse (one per rev) it sets home position. A couple of possibilities. The switch is dirty and that makes for uncertainty on when you start the home cycle. More likely is that you are missing the index pulse. Causes could be a weak battery for the encoder, bad connection or the chip logic which senses the index is bad. I'm guessing that the shift in the home position is n*pitch of the ballscrew. I like the idea of Li-mh if you can find the correct voltage but they charge different than the Ni-Cd's. Cleaning the switch with 'LPS' or other contact cleaner may help. HTH

Click to expand...

Tomorrow I try to clean the guides, it can be the dirt that creates these problems

ss_user said:

Li-mh if you can find the correct voltage but they charge different than the Ni-Cd's.

Click to expand...

Yes they are but it is close enough and I have done it successfully on 3 T2/T3 systems and one T32-6.
NiCd and NiMh always have the same voltage.

ss_user said:

OK, since I don't know your machine config I'm going to make some guesses. Homing usually works on a switch which gives you approximate position. Indicates you are within 1/2 pitch of the ballscrew of home. From that switch closure it moves, either way is possible depending on your software. When it senses the index pulse (one per rev) it sets home position. A couple of possibilities. The switch is dirty and that makes for uncertainty on when you start the home cycle. More likely is that you are missing the index pulse. Causes could be a weak battery for the encoder, bad connection or the chip logic which senses the index is bad. I'm guessing that the shift in the home position is n*pitch of the ballscrew. I like the idea of Li-mh if you can find the correct voltage but they charge different than the Ni-Cd's. Cleaning the switch with 'LPS' or other contact cleaner may help. HTH

Click to expand...

so these pictures tell you how it works on MAzaks. T2 probably doesnt have mask distance parameter to avoid your situation, but T32 has a mask , when machine is jumping ball screw pitch(when dog switch OFF coincides with Z pulse)

the idea is next: when DOG is made and then released , machine should be somewhere in between those Z (one revolution pulse). They (Mitsubishi) give you formula for machine to stop at next Electrical HOME, to do it successfully, that L number must be less then ball screw pitch ( 12 mm ) and more then distance when Servo can actually stop axis (factors like inertia). Then, you have your home position offset and that is where machine stops after Electrical HOME, final stop is MECHANICAL STOP.


so what you do is next: go to machine parameters and make MECHANICAL HOME offset 0 (ZP ), than go to DIAGNOSTIC screen and watch you DOG switch. Move axis manually towards you and then manually towards HOME position. When DOG switch is made and released( record position when it is released) ....say it was 12.4.....then move it towards you again and home it. Now you have to make the difference in between when dog switch is released and home, somewhere around 6 mm. in this case it is guaranty that any fluctuations in DOG limit switch will not affect Z ( one revolution pulse ), and now, after this amazing procedure, you bring your boring bar holder against spindle and clock it with dial indicator. Knowing X axis stroke you now adjust ZP parameter , to make sure you have right X axis stroke.

by the way, it is taken from Mitsubishi M300 CNC control connection manual. Google it and see, it is very well explained.

sounds like a sticky home switch right on a grid "point"
move dog 5 or so mm and replace home switch