Haas 4th axis position Q..

So I have a 4th axis for my old VF-1. No control box, wired straight to the machine, machine control drives all commands.

Here's my issue, I have never used this in the 5 years i've had the machine. So now I have a job to work thru.

Power up machine zero all axis, machine position reads all zero's, xyza..

put in fixture indicate flat straight position reads 14.803 from A0. Enter value into work offset G59 A column, reads -14.803.

Call it a night and go home...

This morning power up, zero all axis, position confirmed on screen. Fixture is rotated off in A no biggie I know machine A0 and the fixture are 14.803 off from each other.

Go to MDI, Go G90 G59 A0; cycle start. Indexer moves off another 14.803 and not back to the G59 A0 position to make the fixture straight.

I repeated this power up scenario several times and it appears that after re-zeroing the A axis that the position screen has A0 in the machine but the indexer never comes back to the same position. It only moves a few degrees from where it is sitting before power off and then it's new zero position never brings the fixture back straight.

So I reindicated and now the new A value is 4.805 between machine A0 and the fixture being straight. What gives???

Is this indicative of a mechanical issue with the 4th axis or a brain issue in my head? LOL! It appears I will have to reindicate the 4th each time I power up. This doesn't seem right. Is there a setting i'm missing??

I'm all ears...

You need to zero "A" and see if it is at the same location on the platter each time. Mark a line or something then keep homing. Second, you did not say what 4th you have or if you set the machine parameters correctly for that particular unit. Each one has different parameters.

Mike

Parameters I know nothing about. They were set from the previous owner and they could be wrong. All I have done was to "Enable" it in Parameter #43.

I have the 5C collet type, S/N 195427, not sure of the model number and I have no manual for it. This does not have the red/ black box, it's plugged directly into the machine.

Once I zero A. indicating the fixture straight and put the value into my work offset I can run the program and it will repeat the correct A moves I have assigned in the program. Currently G59 A is set to -4.805. and if I position to A90. in the program it moves to A94.805 on the Machine Position screen and A90. on the Work Position screen.

If I go to MDI and input G0 G90 G59 A0; and read it I would expect it to go to G59 A0 which is set at -4.805 making the fixture straight, but it does not. It moves back to Machine Position A0 and the Work Position reads A-4.805. That tells me that is is not reading the G59 A value and calculating for it's offset value of -4.805 during the absolute move (G90).

Also if I handle A axis to say 45 degrees, fixture severely slanted, then power off the machine and restart it. When I go thru the Auto Power cycle to zero the machine the A axis will physically move a bit while the side dial comes back to it's zero number position and stops, but the fixture won't physically come back around to the previous location it was at (-4.805). The Machine Position reads zero but the physical location of the fixture is at like 38 degrees.

Any Idea where to go from here?

Thanks,

sagespecialized said:

Also if I handle A axis to say 45 degrees, fixture severely slanted, then power off the machine and restart it. When I go thru the Auto Power cycle to zero the machine the A axis will physically move a bit while the side dial comes back to it's zero number position and stops, but the fixture won't physically come back around to the previous location it was at (-4.805). The Machine Position reads zero but the physical location of the fixture is at like 38 degrees.

Any Idea where to go from here?

Thanks,

Click to expand...

When homed, the 4th axis will always go to the same exact location, its home, not where you have your offset set. When homed, not told to go to your offset home, does it always go to the same place?

Mike

The side dial always comes back to zero, Machine Position at zero, but the fixture rotation doesn't visually come back to the same place if the power has been cycled.

If the power is not cycled, both the side dial and the fixture will repeat back to the same place.

It acts like it only needs a 1/4 rotation to find it's zero position when homed, after the power has been cycled, regardless of where the fixture is physically rotated too prior to turning off the power.

There must be some sort of roller type microswitch in the 4th axis to tell the control when the 4th is nearing its home position (within one revolution of the motor), at which point, the control waits for the index pulse from the encoder.

I'd suspect a faulty or gummed up microswitch. I've never had the covers off my 5C heads yet to know where they've got all that stuff crammed in.

Hi Murry

Yea I was able to get my parts done but I would really like to figure out what is going on. It just doesn't seem right...

I don't know where to find the parameters as this thing is pretty old. maybe i'll try the HFO and see if they have a record or can point me in the right direction. I'm also going to pop the cover off and see what I can find.