New machine couple of questions

I just took delivery of a nakamura tmc3b with a fanuc 6t
Powered it up today and noticed a couple of things.
I can only view a program in edit mode. When the program runs in memory mode it just shows the command screens or position screen but not the active program text like my other nak with 6t.

Also occasionally the turret will unclamp but the turret will not turn. I then press reset and the program stops and that is when the turret starts spinning and never stops. Sticky relay maybe?

Maybe first issue is a parameter bit change?
Thanks

there are no parameters relating to showing the program screen.
does the program show when you press PROG button? if not maybe the button connection is dirty or the circuit is bad. in this case remove the alpha-numeric keypad and check it for corrosion or dirt and also check the button pad underneath is making a good contact with the circuit. basically the black pad under the button shorts the terminals of the circuit together when pressed (and sends a signal to the controller). sometimes the black pad can be dirty or worn away due to years of use, or the circuit underneath can be damaged.

for the turret issue you'll probably have to remove the turret to see how it is activated but probably a proximity switch is either bad or out of adjustment.

Yes the program button works as I can use it to toggle between the position screen and the command screens.

When in position screen and I press it to takes me to the command screen and not the program screen. The only thing maybe the button is next to the command button (I think) so when pressing the prog button it is sending a ‘command’ button signal causing the command screen to show. That’s the best I can think off.

Thanks for the tip about the sensor on the turret. One thing I have noticed is it only does it on the first tool change of the program. I mdi tool changes or press turret index all day long and it is flawless.

What I have also just noticed it is seems quite inaccurate compared to my other nakamura.

The repeatability is really bad about +0.1mm in X
It would seem based on my quick tests that it is back lash cause when I bring a tool holder up to a dial indicator it will take a few clicks (0.1mm per click) on the hand wheel in the reverse direction before the turret moves. I also notice it doesn’t move 0.1mm per click eg I moved the turret 0.4mm actual and the dro on red 0.8mm, each time I moved another 0.1mm I would get actual movement of anything from 0.05mm to 0.08mm

I jump up and had a look to see if I was getting consistent ball screw movement when I move from 0 to 0.1mm and it seems ok by eye but that movement is not transferring to the turret.

Next step is I guess to look at ball screw support bearings and the ball screw itself.

Your thoughts.

on the 6B-series there are separate buttons for position, program, offset & command.
command is used when the MDI rotary switch is selected and toggles between next block and MDI
program, offset and position should show 3 different screens with no toggling.
if you get a toggle between the next block/MDI command screen and position screen when you press the program button it could mean you have a short somewhere in the keyboard matrix and possibly a logic fault on whatever board the keypad is connected to. either way you'll have to pull it apart to see what's going on.
if you have access to another 6 series, swap the keypad board over and see if the problem goes away. if not you have a fault on the board where the keypad cable is connected.

Quote:

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Originally Posted by Deano7/11

The repeatability is really bad about +0.1mm in X
It would seem based on my quick tests that it is back lash cause when I bring a tool holder up to a dial indicator it will take a few clicks (0.1mm per click) on the hand wheel in the reverse direction before the turret moves. I also notice it doesn’t move 0.1mm per click eg I moved the turret 0.4mm actual and the dro on red 0.8mm, each time I moved another 0.1mm I would get actual movement of anything from 0.05mm to 0.08mm

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This is a lathe ... X is a diameter
- so 1.0mm of turret movement in X is actually Ø2.0mm of display
then 0.1mm "click is a 0.050mm of turret movement

To check backlash, (only move turret in X- direction ) bring dial to zero mark, set machine to X0
- go past zero, ( move turret in X+ direction ), bring indicator to zero mark, ....backlash is the difference in X positions ( best to use the .001 increments )

This should be checked at varying points, as it may be larger in the more often used areas of the leadscrew ( indicating wear )
- if backlash is equal over all areas of the leadscrew, software adjustment will correct some of it, but it could indicate a problem exists for another reason ie, leadscrew nut, end play(thrust bearing) etc

Great replies guys thanks. A spare keyboard was supplied with the machine so I will try it and see .

Thanks for the tip re x as diameter. Didn't even think of that, simple things hey. Will double again and see where I end up but still think there is some sort of backlash as it takes a few 0.1mm clicks before I see any movement in the reverse direction.
The machine was a production machine up till 3 years ago when they closed down and the machine sat not used since then.

if the slide doesn't move immediately when you reverse the direction you can adjust the backlash with a parameter. you will probably still need to change the way you program jobs and take up any movement by moving past a point then moving down/up to it, otherwise you'll still get steps on a part, especially when doing complex curves with multiple arcs that change direction. but remember backlash is really only an issue where you change direction in the middle of a cut. if you can move off the part, change direction and move back to the part then just do that and you wont have steps on the part. it's pretty common on old machines to have to do this kind of thing to get around backlash issues.

Had a play around with the backlash settings tonight. They were set on 0014 and 0015 but to get them to where I was happy I had to change to 0320 in x and 0090 in z. If I understand this right that's .32mm in x and .09 in z. That huge amount in x is concerning. Might try and see how big a job it is to pull out the screws and thrust bearings and send them to the local linear bearing joint and see if the ball screws can be refurbed or the need to be replaced.

Quote:

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Originally Posted by Deano7/11

Had a play around with the backlash settings tonight. They were set on 0014 and 0015 but to get them to where I was happy I had to change to 0320 in x and 0090 in z. If I understand this right that's .32mm in x and .09 in z. That huge amount in x is concerning. Might try and see how big a job it is to pull out the screws and thrust bearings and send them to the local linear bearing joint and see if the ball screws can be refurbed or the need to be replaced.

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Don't remove them until you are really sure

attach a clock onto the chuck, set dial onto turret face.....push/pull manually along Z for free play......record any amount of play
- do same to end of Z axis lead screw......if values are the similar, then look to thrust bearing adjustment/replacement ( may be simply a tightening of the locknuts on the end )
- do the same for X ( dial onto side of turret )

Quote:

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The repeatability is really bad about +0.1mm in X
It would seem based on my quick tests that it is back lash cause when I bring a tool holder up to a dial indicator it will take a few clicks (0.1mm per click) on the hand wheel in the reverse direction before the turret moves. I also notice it doesn’t move 0.1mm per click eg I moved the turret 0.4mm actual and the dro on red 0.8mm, each time I moved another 0.1mm I would get actual movement of anything from 0.05mm to 0.08mm

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Strange, you had 0.1mm repeatability ( that's only 0.05mm linear slop ), Then you say you adjusted (0320-.0015=) 0305 um ....ie 0.1525mm slop ....yes, something doesn't add up

I adjusted the x and z backlash as I mentioned but w
Once I rans a typical backlash program it was shown my settings were very wrong I should have searched the net and ran a program prior to adjusting the back lash. I ended up returning the bl setting pretty much to where I started to get a consistent result. I will investigate more.

One other thing I noticed is when I turn the machine on and home it I consistantly get a 0.08-0.11 on the x dro. Is this normal?

I pulled the cover off the back of the turret to see if a sensor was faulty or out of adjustment and so far it all seems good. The unclamp sensor was outputting 24v and the clamp sensor was 0v so the cnc should be getting the right signals. I will look further down the line to see if the relay is playing up or a bad connection. It came with spare relays so can change it out easy enough.

Quote:

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Originally Posted by Deano7/11

I just took delivery of a nakamura tmc3b with a fanuc 6t
Powered it up today and noticed a couple of things.
I can only view a program in edit mode. When the program runs in memory mode it just shows the command screens or position screen but not the active program text like my other nak with 6t.

Also occasionally the turret will unclamp but the turret will not turn. I then press reset and the program stops and that is when the turret starts spinning and never stops. Sticky relay maybe?

Maybe first issue is a parameter bit change?
Thanks

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Your control will be a 6T Model A. With this control, the program could be viewed page by page in Edit Mode, but when Auto Mode is selected, only the Current and Pending Block is displayed. Other screens are available in Auto Mode that displays position and distance to go etc. It wasn't until the B Model control came out, that a whole page of the program was viewable in Auto Mode.

Regards,

Bill

Thanks for clearing that up bill.

I think I have found the tool changer issue. It is the ccw contactor. It was not pulling in when it was getting its signal so I pushed it in manually and it worked. I should have noticed earlier that it was only playing up in the ccw direction.

Now to sort out rs232 connection