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-   -   Can the X,Y zero be moved from right to left front? (http://www.mechmate.com/forums/showthread.php?t=3051)

Hans Wed 22 September 2010 18:01

Can the X,Y zero be moved from right to left front?
 
I am running out of space in the workshop. In order to fit the Mechmate in I need to move the Z,Y zero point.

Can the z, y zerro that in the design is at the right front side be moved to the left front side?

If this is possible how to do this?
Steel will arrive next week.

Hans

smreish Wed 22 September 2010 19:42

Hans.
The quick answer is yes.
You will have to make sure that you CAM software (sheetcam, vectric cut2d, etc) uses that bottom left corner.

The configurations in Mach 3 will have to be configured with x moves in the (-) negative direction and y moves in the (+) positive direction. This is because you will now orient your parts to move absolute of x in the negative direction and absolute y in the positive direction. OR, if you flip your design - it's the opposite. It's a game - not really fun to play - you just need to find which direction you need to go.

It's like 9th grade geometry all over again.

Anyway....with the combination of tools offsets and configuring Mach to set the other corner, you should be fine.

PS... pay close attention to the homing sequence if your using proximity sensors...you will need to configure which way is +/- there too.

riesvantwisk Thu 23 September 2010 12:52

I don't think that CAM software has anything to do with it.
It's just what you define in your controller (EMC or Mach3).

I have my bottom left as my 0.0 when standing in front of the machine looking over the longer axis. I know some people use bottom left, when looking over the short axis.

It's just a matter of telling your CAM software what is where. you can even use the middle of your machine as your 0.0!!!

smreish Thu 23 September 2010 13:05

Ries,
I guess I wasn't as clear as I typed. The 0,0 can be anywhere....what I was trying to emphasize in the CAM software was to be very aware of your UCS (user coordinate system) when building parts. If you build your layouts with the 0,0 in bottom right, you will have more work to realign it to your table when importing to Mach3 to run the file.

Can't tell you how many times I forgot the reset the UCS to bottom left in RHINO and when I imported the part, the 0,0 was in the center of the design and "out of limits" of the table....thus making me go back and rewrite the file with the correct UCS.

I guess the summary is to make certain your UCS is using the same 0,0 orientation.

Sean

riesvantwisk Thu 23 September 2010 14:22

Sean,

yes that makes sense :) I ususally don't have much problems with that aswell because I simple tell EMC where my 0,0 point is, but you don't want to have to to much away from 0,0.

So, to not to confuse Hans, yes you can have your 0,0 coordinate everywhere you like.

Hans Thu 23 September 2010 17:26

Sean, Ries,

Thanks for the clear info.

I can place the 0,0 anywhere I want it.
In my case on the left front side.
Just have to configure Mach3 - have to find out how when I am that far in the build.

Must be aware to place the UCS in the right low bottom. And inform my customer to do this before they send it to me.
And/or in Vcarve place the 0,0 in the right lower bottom before importing parts or start designing.

Hans

riesvantwisk Thu 23 September 2010 18:50

Hans,

EMC and I am pretty sure Mach3 will use two coordinate systems. If my memory serves me correctly, in EMC you have the following:

1) Absolute coordinates
2) Relative coordinates (where you touch off)

The absolute coordinate system is what Mach3 and EMC is using to setup it's soft limits, this makes sure that the controller (in my case EMC) will not run into your stop blocks, or go to somewhere it's not allowed to and cannot go to. This is nice, because when you jog around EMC will automatically de-accelerate before your limits.

The relative coordinate system is used where you touch off. The touch off position is usually the 0,0,0 place of you work piece. This is what EMC is using relatively to the workpiece.
You simply touch off where you set your 0,0,0 point on the workpiece in your CAD or CAM software.

To make matter a tad more complicated, you can touch of at any other position by telling your controller the relative offset, I sometimes do this manually.
In most cases touching off with a offset is used where you have a touch off plate. For example my touch off block is 12mm high. So when I do auto-Z my endmill touches off 12mm above my workpiece. By using a simple macro I will tell that this is the case and EMC will remove 12mm from the touchoff position and knows the real Z(0) point by removing the 12mm.

Ries

Note: EMC is in this respect far more advanced with it's kinematics module where you can even use a reversed tripod to run a endmill. EMC can calculate what it really needs to do on the steppers, and this doesn't have to be a linear movement. Here is a nice move on how that works : http://www.youtube.com/watch?v=LJYhz5aTMnA

Greolt Thu 23 September 2010 19:47

Sorry to jump in here but that terminology is likely to cause confusion.

Gcode has a G90 mode, absolute coordinate positions and G91, relative positions.

What you are describing are Machine coordinates and Offsets, (G54 G55 G56 etc) usually referred to as Work coordinates.

The video on the Artsoft site, called "Homing, Limits and Offsets", is worth watching.

Greg

riesvantwisk Thu 23 September 2010 20:28

Greg,

you are absolutely right, I was may be trying to explain it to simplistic in terms of terminology, I was indeed describing absolute coordinates (Machine coordinates) and offsets (relative/touch off)

Red_boards Wed 08 June 2011 23:34

This is a good place to find video answers for this sort of question:
http://www.machsupport.com/videos/


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