[tjamscad]

We have had to start shifting our Y-axis for new and old programs since we had the head replaced on our VR11. It doesn’t seem to matter if it is a 5 or 3 axis cut. We have to shift the Y-axis +.007 to +.010. We have no backlash in Y-axis.

[haastec]

We have had to start shifting our Y-axis for new and old programs since we had the head replaced on our VR11. It doesn’t seem to matter if it is a 5 or 3 axis cut. We have to shift the Y-axis +.007 to +.010. We have no backlash in Y-axis.

When you say you had the head replaced, I am thinking the whole 4th and 5th axis rotating head assembly. Is this what was replaced? Or what exactly was replaced?

[tjamscad]

When you say you had the head replaced, I am thinking the whole 4th and 5th axis rotating head assembly. Is this what was replaced? Or what exactly was replaced?

The the VR head assembly. Done by Haas.

[Machineit]

Again, you need to be more specific. If the spindle was changed there should be no change. If the entire head was changed, was the probing re-zeroed.

How you do find part zero etc.

There is no charge for extra words here, it's all free.



Mike

[tjamscad]

The VR11 head assembly (yoke, A and B axes). The operator dials in a pin and adjusts the fixture offsets. We do not have a prob. The Haas service techs made the adjustments in the control after the work was done.

[haastec]

The VR11 head assembly (yoke, A and B axes). The operator dials in a pin and adjusts the fixture offsets. We do not have a prob. The Haas service techs made the adjustments in the control after the work was done.

Once a new Y is set does it repeat?

[tjamscad]

Yes, and the change is done on the tool offset not the program.

[haastec]

Yes, and the change is done on the tool offset not the program.

Y work offset repeats, yes? This has nothing to do with tool offset.

If the work offsets you are setting now repeat then this is just something you will have to adjust your programs to.

I am not surprised that you have a different y position if the complete 4th and 5th axis assemblies have been replaced. You basically took a block hanging off the Z axis and replaced it with another block. Depending on what the tolerances of the blocks are depends on how much things change.

Another example would be replacing a T-Slot table on a standard vertical machine. Most people would expect to have different Z values if the table was replaced with a new one.

Now whether or not .007" - .010" is an acceptable amount of change is a question for the factory boys.

[tjamscad]

Y work offset repeats, yes? This has nothing to do with tool offset.

If the work offsets you are setting now repeat then this is just something you will have to adjust your programs to.

I am not surprised that you have a different y position if the complete 4th and 5th axis assemblies have been replaced. You basically took a block hanging off the Z axis and replaced it with another block. Depending on what the tolerances of the blocks are depends on how much things change.

Another example would be replacing a T-Slot table on a standard vertical machine. Most people would expect to have different Z values if the table was replaced with a new one.

Now whether or not .007" - .010" is an acceptable amount of change is a question for the factory boys.

Yes, changing the work offset fixes it for that job this time. In a month it will needed to be shifted that same amount again. It is doing it for old proven parts and on new ones.

[haastec]

Yes, changing the work offset fixes it for that job this time. In a month it will needed to be shifted that same amount again. It is doing it for old proven parts and on new ones.

Maybe I am missing something in your process.

Can you give step by step of how you set up and how your program interacts with the pin?

[tjamscad]

The program is based off of a pin in a fixture plate. Everything is from XYZ 0 which is the pin in the program. The offsets are set by using an indicator in the spindle to dial in the pin. From there we run a part and it is heavy by .007 to .010 on the back side of the part. After the operator check the first finished part he changes the Y-axis work offset for the finishing tool and reruns that part or runs a new part and checks it. Is there some kind of global offset (common on Fanuc) that we could have wrong?


Would this show me if it is a machine problem VIDEO0001 02 - YouTube

[haastec]

The program is based off of a pin in a fixture plate. Everything is from XYZ 0 which is the pin in the program. The offsets are set by using an indicator in the spindle to dial in the pin. From there we run a part and it is heavy by .007 to .010 on the back side of the part. After the operator check the first finished part he changes the Y-axis work offset for the finishing tool and reruns that part or runs a new part and checks it. Is there some kind of global offset (common on Fanuc) that we could have wrong?


Would this show me if it is a machine problem VIDEO0001 02 - YouTube

Based on your other comments, what you are running in the video will keep going back to zero on the indicator all day long right?

If yes, then do this:
Verify that a work offset is set to your pin like you normally do. Then without changing anything, cycle the power, rehome the machine and indicate the pin again. I predict that you will see the .007" to .010" difference you are noticing. If this is the case then I would suspect a possible problem with the home switch.

When you home the machine, have the display of the position screen that shows work offset, operator, machine and dist to go. Take note of the distance to go value each time the y axis is homed. That number should repeat. If it is fluctuating (say .007 - .010 maybe) then your issue resides in the homing process of the y axis. Most likely a switch issue, but could be something with the motor encoder as well.

During the homing process, the machine runs the axis until the switch is triggered and then backs off the switch to a value set in parameters. This is known as the grid offset. When the position that is backs off to fluctuates, the physical location of the y axis fluctuates with it.
Hope that helps and makes sense.

[tjamscad]

Based on your other comments, what you are running in the video will keep going back to zero on the indicator all day long right?

If yes, then do this:
Verify that a work offset is set to your pin like you normally do. Then without changing anything, cycle the power, rehome the machine and indicate the pin again. I predict that you will see the .007" to .010" difference you are noticing. If this is the case then I would suspect a possible problem with the home switch.

When you home the machine, have the display of the position screen that shows work offset, operator, machine and dist to go. Take note of the distance to go value each time the y axis is homed. That number should repeat. If it is fluctuating (say .007 - .010 maybe) then your issue resides in the homing process of the y axis. Most likely a switch issue, but could be something with the motor encoder as well.

During the homing process, the machine runs the axis until the switch is triggered and then backs off the switch to a value set in parameters. This is known as the grid offset. When the position that is backs off to fluctuates, the physical location of the y axis fluctuates with it.
Hope that helps and makes sense.

Ok, before I posted anything. I homed the Y-axis and made the orgin read zero on the screen. Then I moved the Y-axis around and re-homed it. The Y-axis went back to zero from when it was set the first time. Should that also tell me the switch is good?

[haastec]

Ok, before I posted anything. I homed the Y-axis and made the orgin read zero on the screen. Then I moved the Y-axis around and re-homed it. The Y-axis went back to zero from when it was set the first time. Should that also tell me the switch is good?

No, do the steps EXACTLY as I stated them please.

[tjamscad]

Thanks, haastec I will get to it hopefully tomorrow. They know what needs changed and its always hot. RUN IT!

[tjamscad]

OK, here it is

The machine is done running that order of parts. The fixture plate is still in the same location it was when we pulled the last part off. We checked X-Y pin location and it was off X-.003 and Y+-0002. Powered the machine down, when we turned it back on we used the power up restart function. We sent the machine to the X-Y 0 work coordinate to recheck the pin. We found it was X-.004 and Y-.0106 to get it back to zero. We set that as work offset X-Y 0 and powered the machine down, when we turned it back on we used the power up restart function. We sent the machine to the X-Y 0 work coordinate to recheck the pin. We found it was X0 and Y0 to get it back to zero. We did a dry run of the same part that just finished up. When it was done we rechecked the X-Y 0 work coordinate and it was off X-.0005 and Y-.0008.

The Y-axis home switch was replaced on 12/17/2014.

[haastec]

When you home the machine, have the display of the position screen that shows work offset, operator, machine and dist to go. Take note of the distance to go value each time the y axis is homed. That number should repeat. If it is fluctuating (say .007 - .010 maybe) then your issue resides in the homing process of the y axis. Most likely a switch issue, but could be something with the motor encoder as well.

What about this?

[tjamscad]

What about this?

.1379 (morning Yesterday)
.1381 (morning Yesterday)
.1379 (morning Yesterday)
.1395 (afternoon Yesterday)
.1394 (afternoon Yesterday)
.1397 (afternoon Yesterday)
.1399 (afternoon Yesterday)
.1389 (This Morning)
.1394 (This Morning)

[haastec]

Based on your feedback it appears as the machine is homing properly. I would like to see the distance to go values a little tighter, but it's definitely not the 7-10 thou you are experiencing.

So lets back up for a minute. Once you dial the pin in at zero and set your work offsets, how long (aproximately) will the machine go before you see a change? Is the machine powered down every night? Do you ever see the change before the machine is powered down? How long ago did you have the VR head assembly changed?

[tjamscad]

Based on your feedback it appears as the machine is homing properly. I would like to see the distance to go values a little tighter, but it's definitely not the 7-10 thou you are experiencing.

So lets back up for a minute. Once you dial the pin in at zero and set your work offsets, how long (approximately) will the machine go before you see a change? Is the machine powered down every night? Do you ever see the change before the machine is powered down? How long ago did you have the VR head assembly changed?

After the pin is dialed in the machine will run a complete job with out being changed (10-60 parts normally) The machine is only powered down when there is a power failure in the building. I'm not sure we ever see the change with out it being powered down. During this process we did notice a change or total .018 from the pin location, but that does include the powering down in the previous steps you recommended. The head was replaced between 12/17/2014 and 1/6/2015.