Adventures In Metal: Ongoing Questions

[Metal]

So I decided to start an ongoing thread, rather than keep going with my roughing bit thread with nonrelated questions.


Question1: In mach3, when I tell the mill to go to zero, it zeros the Z axis first, which has nearly lead to disaster several times, it seems stupid to bring the bit down to the metal then rake across it and hope a clamp isnt in the way, is there a way to tell mach3 to zero the Z /LAST/ ?

//edit: also can someone correct the spelling in my thread title because I'm a moron?

 

[RJSakowski]

If you are talking about referencing, the z axis homes first as the home position on the z axis is usually at the uppermost position (tool withdrawn from work). How do you have your DRO set up? In the Tormach flavor of Mach 3, there was the option of referencing each axis individually.

If you have set a work zero, you should zero each axis separately. If you give the command, G0 X0 Yo Z0, the mill will move in a straight line to 0,0,0. You will want to lift the Z axis to a safe distance before commanding G0 X0 Y 0 followed by Z0 on the next line of code.

 

[Metal]

I probably worded that terribly, thanks though.

I have limit switches setup, I can reference the machine home at will, and it does the Z axis first, then the other two, great, this is fine because the Z home axis is always going to be above the work and it'll never hit anything.
I was talking about the work home, when I click on "go to zero" underneath the DRO within mach3, it goes to the Z axis zero first, I want it to do it last so that incase I had to move off of my work to replace the tool, I dont have to bring the mill back to the vicinity of the work before clicking on it, having the Z axis lower first and risk snagging the edge of my workholders as it returns to work zero.

@ billy: i'll be all over the place with this one, though the mill is a cnc I really dont have a ton of idea what i'm doing here, I'd appreciate it if you left it here as I dont want to keep creating threads on particular topics and pollute the whole board.

 

[Bill Gruby]

I see your point. I won't move it. Your Title has been fixed and you are not a Moron, you have fat fingers like the rest of us. LOL

"Billy G"

 

[TomS]

If you are talking about referencing, the z axis homes first as the home position on the z axis is usually at the uppermost position (tool withdrawn from work). How do you have your DRO set up? In the Tormach flavor of Mach 3, there was the option of referencing each axis individually.

If you have set a work zero, you should zero each axis separately. If you give the command, G0 X0 Yo Z0, the mill will move in a straight line to 0,0,0. You will want to lift the Z axis to a safe distance before commanding G0 X0 Y 0 followed by Z0 on the next line of code.

I hear what you are saying. My work around is I have a DRO on my quill so I set the DRO to zero when I set my Z axis machine zero. Before clicking the Go to Zero button I raise my quill with the manual feed wheel. Before clicking Cycle Start I reset my quill back to zero on the DRO. This may not be the proper way to do it but it works for me. I'm interested to hear what the CNC gurus have to say.

Tom S.

 

[Metal]

Yeah thats sort of where I am, without the quill, because I dont have much Z axis, I have to move the mill off the part, replace the tool, then I can move it back, it seems like best practice /should/ be "if zero is closer to the part, it should be done last" as there could be any number of extrusions and such between where it is and where it needs to be.

 

[RJSakowski]

Yeah thats sort of where I am, without the quill, because I dont have much Z axis, I have to move the mill off the part, replace the tool, then I can move it back, it seems like best practice /should/ be "if zero is closer to the part, it should be done last" as there could be any number of extrusions and such between where it is and where it needs to be.

Metal,
Take a look at the website. Apparently, this problem has been discussed considerably before.
https://www.machsupport.com/forum/index.php?topic=15381.0

 

[JimDawson]

I was talking about the work home, when I click on "go to zero" underneath the DRO within mach3, it goes to the Z axis zero first, I want it to do it last so that incase I had to move off of my work to replace the tool, I dont have to bring the mill back to the vicinity of the work before clicking on it, having the Z axis lower first and risk snagging the edge of my workholders as it returns to work zero.

I think you can set up a tool change position in Mach3. Then use the Go To button to get there, if it works right, it should park Z first then do the X-Y move. Another option could be to put in a a couple of lines of G-code at the bottom that moves the tool to a tool change position, then just run that block of code using the Run From Here button.

 

[Wreck™Wreck]

I have never used mach3 or any open source machine control software, however I would never dream of pushing a "Work Home" button with the tool in the spindle and the work piece mounted.

Does this machine not have a manual rapid jog feature?

 

[rdean]

If I understand correctly when pressing "Go To Zero" you want the X & Y to move to their "0" position and then the Z last.

Setting "Safe Z" is what you want set to work coordinates and a distance you want the Z to rise to before the X & Y moves. I use this quite often.

Ray