Bridgeport with Eldrod Z axis kit and Fagor scale (All Issues Resolved)

[martyscncgarage]

My task was to remove the old motor, Elrod Z axis kit, and reinstall it on a new Bridgeport Head the customer purchased from Hardinge.
All that went well.

Today it was noted there were issues with the machine homing to Z properly. Getting 411 full power without motion. Seems his tiny Z+ limit switch was flakey. He replaced it.
The Elrod Z axis kit also has a Fagor scale so one could unlock the quill from the ball nut and use it manually. None of this was necessary because the customer never uses the machine manually. He only uses it as a 3 axis CNC mill.

There is a custom cncm.hom file in the machine. Seems replacing the limit switch has caused some problems.
We'd like to disable the Fagor quill scale, and I we simply install a standard mill cncm.hom file All axis home to + direction

Anyone have any experience with the Elrod Z axis kit WITH the optional Fagor scale on the Z?

See current attached report and photos of the machine and error messages.
The customer is 3 hours away from me. But completely capable of making minor changes in this respect.

Thanks in advance.
Marty

[tblough]

Marty - I'll jump in on this tomorrow when I'm back at my computer.

[martyscncgarage]

Marty - I'll jump in on this tomorrow when I'm back at my computer.

Thanks Tom
Trying to understand Elrods homing process. This weekend is fine if time permits.
Marty

[cncsnw]

You can leave leadscrew compensation turned off. When you look in the cnc-z.tab file, you will see that there were no corrections there anyway. To reduce clutter and future confusion, you could delete the cnc-?.tab file(s) as well.

The incremental move in cncm.hom, a couple lines below N40, is there to give the option of setting home back up closer to the switch, in cases where backing off the switch to the next index pulse cost too much Z travel, or prevented a power drawbar from fully engaging.

As long as you only run the homing macro once, it should work even with a positive travel limit of zero (since software travel limits don't apply until home has been set on that axis). However, if you try to run the homing macro a second time, after it has gotten as far as setting home on Z ("M26/Z"), then you might well get a travel limit error.

You could avoid that problem by putting a small positive value in the Z plus software travel limit. Alternately, if you don't need to move back up closer to the switch, you could edit the cncm.hom file to change the incremental move distance to 0.0.

[cncsnw]

The rest of the logic in the cncm.hom file is there to:
1) Ensure that the quill is unclamped from the ballscrew iff the Z is to be manual, and that the quill is clamped to the ballscrew iff the CNC Z is to be used, and
2) Home the fourth axis iff a fourth axis is installed, regardless of what letter label it may have.

The quill-clamp check presumes that the micro-switch is wired to INP7.

[martyscncgarage]

Thanks, Marc.
Yes, there is a power drawbar, so the more Z+ the better.

[martyscncgarage]

The rest of the logic in the cncm.hom file is there to:
1) Ensure that the quill is unclamped from the ballscrew iff the Z is to be manual, and that the quill is clamped to the ballscrew iff the CNC Z is to be used, and
2) Home the fourth axis iff a fourth axis is installed, regardless of what letter label it may have.

The quill-clamp check presumes that the micro-switch is wired to INP7.

He takes the fourth axis off, goes into setup and turns it off there when not in use. He turns it back on when plugged in.

He never has nor never will use the quill in the manual mode.

[tblough]

Marc has beaten me with most of the answers. Below is my cncm.hom file which does essentially the same thing:

Code: Select all

M92/Z
G91 G1 G20 Z0.120 F10.0
M26/Z

M91/X
G91 G1 G20 X-0.060 F10.0
M26/X

M92/Y
G91 G1 G20 Y0.100 F10.0
M26/Y

; Check for rotary table homing
IF #50010 ; Prevent lookahead from parsing past here
IF [#20104 == 78 || #20104 == 77 || #20104 == 64] THEN GOTO 1000 ; "N/M/@" for 4th axis turned off

M92/$[#20104]
G91 G20 G1 $[#20104]30.596 F1800.0
M26/$[#20104]

N1000

As CNCSNW posted, the G91 moves are to reclaim as much travel on each axis as possible. Especially on Z where you only had 5" to start with and the Elrod kit eats up another 0.4" or so of that, and the Index pulse could be up to another 0.2" more. To set mine up, I comment out the G91 on the Z line, jog Z close to the top, hit e-stop to disable motor power, and then push/pull the z-belt to move Z up against the hard stop at the top. Then I back off 1/4 turn (0.050").

With Z now positioned at what I want to be the home position, I use the I/O screen to watch the Z +Limit switch while adjusting the limit switch position. With that done, turn off e-stop and home the machine. I then note about how much Z has backed off to find the index pulse and change the G91 line accordingly. It usually takes a few tries (power down control/restart/re-home) to get the G91 adjusted to just before the limit switch trips.

Don't forget to reset the soft limit for Z- once you've adjusted the limit switch/G91 settings. I jog close to the bottom of the travel, disable the motors, manually move Z till it bottom out, check the machine Z coordinate and then set the soft limit about 0.030 above that. It's all about getting as much travel as possible.

As for the 4th axis, I also leave mine off and unattached from the machine when I'm not using it. F1 Setup/F6 4th axis on/off disables it in the control. See Parameter 131 on how to configure this. The home file uses #20104 for the axis label since it could be A, B, or possibly C (although I don't know why since you have circular interpolation on X/Y). My G91 in the rotary homing routine actually position the t-slots on the rotary table perfectly horizontal/vertical. Yeah - I have CDO. It's like OCD only the letters are in the correct order.

Thanks for posting the home file routine on your customers machine - I may steal the disable/clamped checking at the start. I have some users who forget to re-attach the quill before they power down the machine and the next person is usually clueless when they start it up and it fails to home.

As for the scale (Elrod calls this Smart-Z), that's controlled by parameter 130 which sets how the axis behaves when disconnected. Bit3 allows the use of the glass scale for position information when the motor is disconnected. If you never disconnect the Z, just change bit 3 to zero if you want, but it doesn't hurt to leave everything connected and enabled. That way the option is there if he ever wants to try it. It should not interfere otherwise - as Marc pointed out, the problems are with the axis comp file, not the scale.

[martyscncgarage]

Tom, your .hom file looks a little confusing to me. It shows a Y axis to me and your rotary axis, but no mention of Z. What am I missing?
Is this what you are referring to?:
M92/$[#20104]
G91 G20 G1 $[#20104]30.596 F1800.0
M26/$[#20104]

I am very new and weak to variables.

[tblough]

Sorry Marty I edited the original post to add this as well. Z axis is a that the top of the file, then X, Y and finally the rotary table. The rotary table uses variables because the axis label could be A, B or even C depending on how the rotary table was oriented, and if the person selecting the axis designation was a stickler for detail.

From ISO 230-1:2012(E)