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Author Topic: NEWBIE- HELP PLEASE! WORK PIECE NOT SHOWING IN CORRECT POSITION  (Read 344 times)

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NEWBIE- HELP PLEASE! WORK PIECE NOT SHOWING IN CORRECT POSITION
« on: February 08, 2021, 11:11:27 PM »
Hello.  I am brand new to cnc and mach3.  I am trying to cut out my first project that I made in Fusion360.  Unfortunately my machine keeps showing the piece in the display mode in the wrong place.  A bit of background- when I turn my machine on I hit "ref all home" which brings my z all the way up, and my table all the way to the front of the machine (moving in the neg to get there), and the table all the way to the left (moving in the neg to get there).  I have home switches set up to do this. After that, I set my work zero's and than load the g-code.  In the attached picture of the display- my spindle is actually sitting directly over the the middle of my work piece- which is not what the display is showing.  After several hours of messing with it, I did hit run even though it said I was out of the soft limits on the y.  That was a mistake- the table took off moving to the right and away from me (y in the +).  Just being too impatient.  Luckily I was able to stop it before it crashed.
I did make a Turners cube just using the "circular pocket" wizard and had no problems.  After I set my work zeroes, and put the spindle over the center it showed exactly that on the display and cut the g-code flawlessly.
 I have been trying to figure this out for the last couple of days and have read so many different posts and watched so many videos that I am more confused than when I started.  I also attached the beginning of the g-code that is showing on mach3 when I load it.  Not sure it matters but i am trying to cut 1.5 by 3" blade out of a 3 x 5" stock piece.  I attached some pics of that as well.  Any all help would be immensely helpful- thank you.

Offline Graham Waterworth

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Re: NEWBIE- HELP PLEASE! WORK PIECE NOT SHOWING IN CORRECT POSITION
« Reply #1 on: February 09, 2021, 09:40:33 AM »
Jog the machine so the pink cross hairs are more to the lower left then press x zero and y zero then press regen toolpath
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Re: NEWBIE- HELP PLEASE! WORK PIECE NOT SHOWING IN CORRECT POSITION
« Reply #2 on: February 09, 2021, 12:21:38 PM »
Graham, thank you for taking the time to respond to my question.  It is greatly appreciated.  If I simply move the pink crosshairs I don't understand how that corrects my actual spindle position relative to my work piece (my current problem being that the spindle position is not correct relative to my work piece).  Wouldn't that just give me a different work home position, and one that isn't relative to my actual workpiece.  I am trying hard to do as much research as possible and improve my understanding- so again thank you.

Offline Graham Waterworth

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Re: NEWBIE- HELP PLEASE! WORK PIECE NOT SHOWING IN CORRECT POSITION
« Reply #3 on: February 09, 2021, 01:12:58 PM »
The problem is the way you have drawn the part in 360, the XYZ is in the opposite direction to the datum on your machine.

Your cad datum is front left of part.  Machines tend to be top right.

Most machine tools home with the table left front and up for the XYZ so you draw in your cad to the left of the X (Red arrow) front of the Y (Green arrow) and Z is top of work on a mill and in most cases bed of machine on a router.

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Re: NEWBIE- HELP PLEASE! WORK PIECE NOT SHOWING IN CORRECT POSITION
« Reply #4 on: February 09, 2021, 02:56:46 PM »
Ah . . . ok.  That is starting to make sense.  I need to move my datum to the top right corner of my drawing.  Do I have the orientation on the x & y correct in the drawing below?  Thanks!!

Offline Graham Waterworth

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Re: NEWBIE- HELP PLEASE! WORK PIECE NOT SHOWING IN CORRECT POSITION
« Reply #5 on: February 09, 2021, 07:18:23 PM »
Yes the drawing looks good, look up right hand rule for more details.

https://www.autodesk.com/products/fusion-360/blog/cnc-coordinate-system-made-easy/
« Last Edit: February 09, 2021, 07:22:37 PM by Graham Waterworth »
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Re: NEWBIE- HELP PLEASE! WORK PIECE NOT SHOWING IN CORRECT POSITION
« Reply #6 on: February 09, 2021, 08:54:51 PM »
Unfortunately I still couldn't get this to work.  Now my workpiece is incorrectly displaying on the bottom left of my table.  In the first picture the pink crosshair is an accurate representation of where my spindle is in reference to my table (in the middle of my x axis, and a little north of the middle of my y axis).  However, as you can see in my second picture, the workpiece is directly under my spindle- which is not what the display is showing.  I changed the datum in the CAM to the top right corner, and a zeroed my workpiece off the the top right corner as well.  Any other suggestions?  I would really appreciate your continued help. Thank you.

Offline Graham Waterworth

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Re: NEWBIE- HELP PLEASE! WORK PIECE NOT SHOWING IN CORRECT POSITION
« Reply #7 on: February 09, 2021, 09:19:42 PM »
Do you have homing switches on your machine?

Is the material in the CAD the same size as the material on the machine?

If the answers are yes then click home all.

Move the centre of the spindle over the back right corner of the material and click 'Zero X' then ' Zero Y'

Touch tool on top of material and click 'Zero Z'

Click Regen Toolpath
« Last Edit: February 09, 2021, 09:24:01 PM by Graham Waterworth »
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Re: NEWBIE- HELP PLEASE! WORK PIECE NOT SHOWING IN CORRECT POSITION
« Reply #8 on: February 09, 2021, 09:26:58 PM »
After posting the above, I went back and messed around with my mill some more.  I discovered that my table coordinates appear to be reversed.  In the attached picture you can see that my display shows my spindle over the bottom right of my table, when in actuality you can see that the spindle is over the top left of my table.  Thoughts?  How do I fix this? 

Offline Graham Waterworth

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Re: NEWBIE- HELP PLEASE! WORK PIECE NOT SHOWING IN CORRECT POSITION
« Reply #9 on: February 09, 2021, 09:32:10 PM »
If you press MDI and type in G01 G91 X1. F10. and press return the table should move to the left

Then type Y1. and enter and the table should move to the front.

If you are in MM then X25. F100 may be better
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