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Author Topic: which way is xy as i stand at my mill?  (Read 5180 times)

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which way is xy as i stand at my mill?
« on: March 19, 2012, 10:08:19 AM »
As I stand in front of my Taig CNC shouldn’t tool path xy starting point be lower left when I setup my milling job? Mach 3 tool path shows lower left but when I start the cycle (I’m doing air cuts just to be safe) I have to reset everything to upper right. I did have to reverse my x axis to move in the right direction, but that shouldn’t effect where xy starting point is?
Re: which way is xy as i stand at my mill?
« Reply #1 on: March 19, 2012, 11:57:30 AM »
I know you will get replies that show the famous (infamous?) hold your hand in front of you, etc, etc.  It always confuses me.   But, if you have a CAD program look at the orientation picture - Y + is AWAY from the corner, X + is to the RIGHT, Z +(not shown on orientation picture) is UP.

And I know someone will disagree with me.  But, it works on my TAIG, words read left-to-right (I am assuming you are using English as your reference), Cut pieces are oriented Left to Right for proper placement, etc.

And so the discussion begins.

Bob@BobsShop

Offline BR549

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Re: which way is xy as i stand at my mill?
« Reply #2 on: March 19, 2012, 02:29:41 PM »
The standard for a knee mill type, Standing in front of the machine, is for the "TABLE" to move LEFT with a X positive move AND the "TABLE" to move TO  you with a Y postive move.  Z positve moves AWAY from the table.

As to Part ORIGIN , X0 Y0 it can be anywhere you want it. AND you can work in ANY quadrant you choose to. BUT the standard is to have the Origin at the lower left of your part program.

Now the nice thing about standards is that there are SO MANY to choose from. (;-)

Just a thought, (;-) TP
Re: which way is xy as i stand at my mill?
« Reply #3 on: March 19, 2012, 04:57:57 PM »
I like to think; Draw the CAD part with the 0,0 at the lower left corner and then place the material on the router or mill table with that in mind. I have mach3 .xml files that set my axis's either way.

Depends on the size parts I am cutting, the direction I programmed the repeated cuts (I do contour passes, 3d back and forth stepping over every pass). My cross slide seems to be faster, quieter, stronger and only uses one ball screw so I tend to use that as my X. But sometimes working on a very large piece I swap them and machine the other direction. I just think having the Lower left corner being Zero, Zero and Drawing to suit and then machine to suit keeps it simple (KISS)

As Terry states, make your own standards just learn to fully understand how to make it work for your needs.

Offline RICH

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Re: which way is xy as i stand at my mill?
« Reply #4 on: March 19, 2012, 05:25:09 PM »
Quote
And so the discussion begins.
That's for sure......i was going to say what is done here, but after thinking about.....heck,  nobody is from Lithuania in here so how could they ever understand why I do what I do. :D
RICH
Re: which way is xy as i stand at my mill?
« Reply #5 on: March 20, 2012, 09:54:26 AM »
Tks for the replies. Something I should have added at the beginning, I cannot change where the start point is. I zero x,y,z for lower left and start the cycle and Mach 3 runs it as if it was in the upper right. I’m using Cambam for my gcode, so I tried different starting point in the drawing and different orientation of the drawing. It always runs from the upper right.
2nd question, I have the Abnormal condition LED on   “IJ mode is incremental” is this due to the .002 backlash I have set in Mach 3?

Offline BR549

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Re: which way is xy as i stand at my mill?
« Reply #6 on: March 20, 2012, 11:07:10 AM »
SOunds like you need to change the origin point in CAM BAM to match how you want it on your machine.

THe abnormal light is just telling you that you have the IJmode set to inc instead of abs.


(;-) TP
Re: which way is xy as i stand at my mill?
« Reply #7 on: March 10, 2013, 11:31:22 AM »
Another old thread in FAQ, a year, or so so let's update it and nail this issue down. Here's my take.

A drawing, whether on paper or in a CAD program, usually have the axis set up as we learned in grade school, e.g. upper right quadrant are positive values. Thus, in effect, our pencil is the quill moving over the table.

However, the mill is moving the table beneath the quill, e.g. it is NOT moving the quil itself. Hence, moving the table to the far right and away from you finds the origin, or 0,0 of your drawing. Thus, the table moves to the left for +X (in effect the quill moving to the right) and toward you, for a +Y value (in effect moving the quil up the Y-axis).

Confused yet?

Machine center (X,Y) on a FADAL mill is usually center of travel of the table however, when milling a job, it is convenioent to relocate this to be coincident with the 0,0 of the part itself. This is especially handy when you have multiple vices on the table because then you set up offsets from the first jaw for each subsequent vice, e.g. a job with four vices on the table with each set 6 inches apart means you incerment the X-value by the with of the vice plus 6 inches for each subsequent job.
« Last Edit: March 10, 2013, 11:46:56 AM by jbeech »