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Author Topic: Mach 3 Lathe setting up tools and offsets. hair already gone...teeth next...  (Read 23984 times)

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I have installed the X and Z limit switches on my machine this evening. I have not wired them in yet, but the hardware portion is done.
Got them wired in and lighting up the "led" on the diagnostics page.

Now I have to figure out how to instruct mach to home the axes.
A bit of progress. I found that g28 will send the machine to Z home (+14.000) and then X home (+4.000) Seems odd that Z homes first. Seems it should home X first for clearance and then Z. Is there a way to change this?

Also- I thought that I should be able to just press the "home all" button and it would home itself. Cant seem to figure that out...

Note, although switches and wiring are done, and I know they are functional. I am not runnning these tests on the machine. I am trying to figure out homing out of the shop (in the basment) because its bedtime here and I am just running mach on a laptop...

Offline Hood

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...maybe when I get the wee lathe up and running fully I can, big lathe is just too big to be able to set up a camera for that.
Yes please...show us how you set up and use your tool table too!:)  You make it sound so easy and I'm sure it is once one gets "over the hump."

I will see if I can mock up something on the wee lathe as tools and make a quick video. I only  have one holder for the toolpost so cant use that and  I also only have a threading  tool small enough to fit in the holder anyway. I should be able to make up some sort of gang tool mock up in the next few days and try and make a video.
Hood

Offline Hood

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I never could figure out why my G52 offsets ended up being ~1.9 inches away from each other per tool, when the tool block is on 1" centers. Never made any sense....

I use G52s with my gang tool holder, but then mine is set up for drills only, so the X offset never changes, and I just manually edit the G-code if the drill lengths change (I have a whiteboard with a corner dedicated to the drill offsets).

As to your offset being off, now you mention it, I think there is actually a bug in the tool change macro.
I noticed that if after doing a tool change where the X offset changed alot with minimal Z movement, the X axis would loose lots of steps/stall. It's like Mach was ignoring the X axis maximum speed, and setting speeds via the Z axis settings.
For example, if the X-axis had to move 80mm and the Y only 10mm, it would move the Y at rapid speed, and X would stall as it was expected to move at speeds far higher than it should.
I worked around it by adding extra lines to the G-code that move the carriage into the approximate place that is needed after the tool change.

I suspect the issue is something in the tool change macro, however I've never had a chance to look into it in any more detail, and given how cold it is outside, I'm taking the "if it's working, it doesn't need fixed" approach!

I am wondering how you are doing things when you say you think its the macro. If using offsets are they all in your code? If they are then I would imagine you have Mach set to Ignore Tool Changes. Is that the case? If it is then the M6start macro will not be used at all. Maybe you have the offsets in your macro instead and have it set to Auto Toolchange?
Hood

Offline Hood

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A bit of progress. I found that g28 will send the machine to Z home (+14.000) and then X home (+4.000) Seems odd that Z homes first. Seems it should home X first for clearance and then Z. Is there a way to change this?

Also- I thought that I should be able to just press the "home all" button and it would home itself. Cant seem to figure that out...

Note, although switches and wiring are done, and I know they are functional. I am not runnning these tests on the machine. I am trying to figure out homing out of the shop (in the basment) because its bedtime here and I am just running mach on a laptop...

The guy that made up the lathe screenset a few years back didnt reckon homing was much use on a lathe and that is probably why it doesnt act like most expect it should. It is also one of the reasons I made up my own screenset after about 2mins of trying to use the lathe screenset. Easiest thing to do would be to open the screenset with Screen4 or MachScreen and change the HomeAll button to a VB button then save as a new named screenset. Open Mach and load the new screenset and then go to operator menu then to Edit Button scripts and the HomeAll button will be flashing. You can then click it and in the editor window you can paste the following, that will home X then Z, personally I prefer Z then X but its just my preference.

DoButton(22)
DoButton(24)
Hood

Offline mc

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I am wondering how you are doing things when you say you think its the macro. If using offsets are they all in your code? If they are then I would imagine you have Mach set to Ignore Tool Changes. Is that the case? If it is then the M6start macro will not be used at all. Maybe you have the offsets in your macro instead and have it set to Auto Toolchange?
Hood

I still use manual tool changes with a QCTP, as it's only the drills that are ganged.
One of the reasons I use G52 is to avoid having to click start between drills.
I'm sure there is a better way to do things.
Ok! I made a bit more progress.

First- G28 does not stop on a home switch for me. it just kept going...


But, I now have Mach3 homing the Z and X (manually) by pressing "set home Z" and "set home X"

This works, but I would have thought "home Z" and "Home X" would have been the correct commands....

Anyway, is their a way to go in and change the rate at which the machine travels to home Z and Home X? My machine only has max 30IPM, and it appears that when using "set home Z" and "set home X" that it only wants to travel at .29IPM! painfully slow! Sure I can jog over to a better spot and start from there, but I would rather just hit the buttons and have it travel over at 10IPM.

Does it make sense that I maight write a macro that I can assign the "home all" button to, that will home X at 10IPM and then home Z at 10IPM? Also, could this macro be written to then assign a number to the home locations IE: Z 4.00 and X 16.00?

Mabie this is what the G28 "home location coordinates" are for? or mabie not, I have not been able to use G28 sucessfully. It seems that when I do G28, that it just goes to the numbers I have put into the "home location coordinates" boxes, and does not stop at the actuation of the switches and then re write the home locations to be the numbers in the "home location coodinates" box, like I thought it would have.

So many questions...
Under Config, Homing/Limits, set the % of G0 speed at the far right.
Russ
Excellent info Overloaded!

I can home at 100% on this machine because the max IPM is 30. The machine has a 5:1 ratio by design. I believe they wanted high res and decent speed with the original servos.