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Author Topic: Define location of zero in Z axis, in milling.  (Read 2711 times)

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Define location of zero in Z axis, in milling.
« on: January 05, 2013, 05:03:37 PM »
Hello,

I'm a newbie and I just made all the limit switch work to perfectly,
thanks to the valuable support received in this forum (thanks Hood).

My machine is milling type, three axes, MDF table below, router above.

I purchased the system Craftman QuickRout (Router Bit Connector/Adaptor Kit),
and like update the compensation tooltable for bits of varying heights.

I do not want to destroy my bits.
I do not want to damage my machine.
I do not want my bits drilled base table.

I think about security,
and let me know your experience,
Where it is recommended to define the machine location of the zero z axis?
Limit up or limit down?

So also would like to know why up or down.
I have intention to cut materials of various heights.
My prejudice tells me zero down is better, I not sure.

I appreciate any related information.


Offline Hood

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Re: Define location of zero in Z axis, in milling.
« Reply #1 on: January 05, 2013, 05:49:35 PM »
Normally you have Z Zero in machine coords as fully up, this is so when you send to Home or reference the machine the Z will move up and clear the work etc.

Most people set the work offset Z Zero to the top of material although some router guys seem to set table top as zero and all work will be in a positive unit.

If using the surface of the material as Z Zero you can just jog down and touch off the material and zero the Z DRO, that will set the work offset to zero on the top of the material.

Hood
Re: Define location of zero in Z axis, in milling.
« Reply #2 on: January 06, 2013, 12:36:07 AM »
I thank you for your information, that has been enlightening for me.

Then I decided definer Machine coords the Z zero fully up. And so it was already.

Also connect an aluminum plate of 1/2" as a probe,
I saw the diagnostic screen, digitize the signal lights when I connect, and off when disconnected.

I have only one problem to solve:

I have not got the script for Auto ToolZero for:

1.- Table detect surface to configure workoffset Z=0  (to set table top as zero).
2.- Detect different height offset bits and update Tooltable.

I have no idea how to do this that I'm missing.
I think then able to use my machine.

I appreciate your time and attention.







Offline Hood

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Re: Define location of zero in Z axis, in milling.
« Reply #3 on: January 06, 2013, 02:57:00 AM »
Lots of tool zero macro info on the forum. I dont use them myself as I have made up a presetter that connects to Mach and I can set up all my tools in it and have the values entered into the tooltable, the only thing I then need to do is bring a tool down to the material and touch off it with a feeler gauge. Once I do that then all other tools are  set correctly.
Hood
Re: Define location of zero in Z axis, in milling.
« Reply #4 on: January 06, 2013, 08:25:28 AM »
I want to know, as you do that?  What is presetter?

Anyway, I'm trying to make a macro,
because I do not find the script Auto ToolZero for Table detect surface and Detect different height offset bits and update Tooltable.

best regards.

Offline ger21

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Re: Define location of zero in Z axis, in milling.
« Reply #5 on: January 06, 2013, 08:32:59 AM »
If you use the Big Tex Mach Blue screenset, or my 2010 Screenset, you don't need to set the tool table, as the tools are measured ans zero is set automatically. This does require a second probe plate mounted permanently on your machine for reference, though. But imo, it's much simpler tan messing with the tooltable
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html

Offline Hood

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Re: Define location of zero in Z axis, in milling.
« Reply #6 on: January 06, 2013, 10:56:30 AM »
I want to know, as you do that?  What is presetter?

Below is a pic of the presetter I made and also a pic of my screen in Mach.
I put a dummy tool in the presetter and bring it down onto the tip of it and press zero button and it zeroes the DRO. I then put in Tool 1 and bring the presetter down to it and press Set Z button, a window pops up and asks me what tool number and I enter that and it automatically enters the Z offset into the tool table. I repeat for all 12 tool in the toolchanger and then once that is down I place the dummy tool in the spindle and bring it down to the surface of the material and zero the Z DRO in Mach. From then on when I call a height offset for a tool it looks in the tooltable to see what it should be and sets the correct Z height automatically.
Hood