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  1. #1

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    X axis is off center

    hiiiiii everyone!

    i'm fairly new to this, so I'm sure there's something simple im doing wrong, but all of my cuts on my 770 are off-center in X by about 0.2". i'm using a passive probe to set my work origin in the corner, and i believe i have my origin set correctly in fusion, using model box point. the fusion simulation looks correct, but when I begin my operation (say a contour), the bit will take a normal cut on the left side of the stock and then run in the air on the right side of the stock. i've tried to troubleshoot this the best i can, but i can't seem to figure out what this issue is. has anyone run into an issue like this before?

  2. #2
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    Re: X axis is off center

    Quote Originally Posted by didu View Post
    hiiiiii everyone!

    i'm fairly new to this, so I'm sure there's something simple im doing wrong, but all of my cuts on my 770 are off-center in X by about 0.2". i'm using a passive probe to set my work origin in the corner, and i believe i have my origin set correctly in fusion, using model box point. the fusion simulation looks correct, but when I begin my operation (say a contour), the bit will take a normal cut on the left side of the stock and then run in the air on the right side of the stock. i've tried to troubleshoot this the best i can, but i can't seem to figure out what this issue is. has anyone run into an issue like this before?
    What is the diameter of the probe Has this been compensated for ( setup ) in the control

    Is the machine work offset X and Y Zero position the same position in your drawing
    Mactec54

  3. #3

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    Re: X axis is off center

    Is your machine in the right WCS? I do this all the time, create a program in G54 and forget that I was last doing something in G55. WCS settings are modal so once you set it, it won't change unless you tell it to.

    Is your stock the right size? If you are starting with a piece that is smaller than what you told Fusion you have, this will happen. Since your WCS is set off one side, that side will machine correctly but if the stock is too short, the machine doesn't know that and will cut air on the other side. Usually I will set my WCS origin to the center of a piece of raw material to deal with minor saw cut variances and avoid this.

  4. #4
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    Re: X axis is off center

    Fusion defaults to oversize stock with the part centered in it. So if you're picking a stock box point origin it's not likely to be at the edge of your part. Use the 'fixed size box' and set it to your stock size as a way to eliminate that possibility. At this point that's what you need to do... eliminate possibilities one at a time until you find it.

  5. #5

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    Quote Originally Posted by mactec54 View Post
    What is the diameter of the probe Has this been compensated for ( setup ) in the control

    Is the machine work offset X and Y Zero position the same position in your drawing
    The diameter of my probe is about .15”. I don’t have a gauge ring to measure it perfectly so I just used a hole in a 123 block. I’m sure it’s a little off, but I don’t think it’s off enough to cause this error? And yes, I’m setting the origin to the same corner as in my drawing, and when I type in X0Y0 in the mdi it seems to jog to the corner of the work piece perfectly.

  6. #6

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    Quote Originally Posted by soofle616 View Post
    Is your machine in the right WCS? I do this all the time, create a program in G54 and forget that I was last doing something in G55. WCS settings are modal so once you set it, it won't change unless you tell it to.

    Is your stock the right size? If you are starting with a piece that is smaller than what you told Fusion you have, this will happen. Since your WCS is set off one side, that side will machine correctly but if the stock is too short, the machine doesn't know that and will cut air on the other side. Usually I will set my WCS origin to the center of a piece of raw material to deal with minor saw cut variances and avoid this.
    It’s funny that you mention not being in the right WCS because this was a problem I was having a earlier but I’ve since realized my mistake! I think my stock is set to the right size (I checked it with calipers), but I’m not confident so I’ll have to double check. Question here though, if I was a fixed size box for my stock and then have my model centered in it, wouldn’t it cut air all the way around the part? I thought that since the model is centered in it this would be okay, but I might be misunderstanding this… if I set my origin to the center, will it fix this? And how does probing work if I set my origin like this? Thanks!!

  7. #7

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    Quote Originally Posted by shred View Post
    Fusion defaults to oversize stock with the part centered in it. So if you're picking a stock box point origin it's not likely to be at the edge of your part. Use the 'fixed size box' and set it to your stock size as a way to eliminate that possibility. At this point that's what you need to do... eliminate possibilities one at a time until you find it.
    I think the issue is related to the way I’m setting my origin too, so for testing I wanted to try and change my origin to model box point. But when I do this I run into a funny issue and I’m not sure what I’m doing wrong. Say the stock is .23” taller than my model, so I want to remove .23” off the top of the block. I have my top height set to stock top and my bottom to model top. When I use stock box point it runs as it should (but off center). When I use model box point instead of the Z going down to -.23” to make the cut it runs at Z0. When I run this on the machine the probe just barely skims the surface of the part. Do I need to offset my Z height that the probe sets? Or is something else funny happening here? Thanks for the help!!

  8. #8
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    Re: X axis is off center

    Quote Originally Posted by didu View Post
    I have my top height set to stock top and my bottom to model top.
    That statement confuses me a bit. The stock top is the stock top. The model bottom should be the model bottom. I'd need to see what you are doing within the CAM software to see if it makes sense.

  9. #9

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    Quote Originally Posted by Kenny Duval View Post
    That statement confuses me a bit. The stock top is the stock top. The model bottom should be the model bottom. I'd need to see what you are doing within the CAM software to see if it makes sense.
    I can upload my file, but for an individual tool path, telling it where to start and how deep you have to go you have to set the heights. I think what I’m doing is okay but I can add my file so you can see.

  10. #10

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    Re: X axis is off center

    for anyone that's willing to poke around a bit, here's my fusion file!

    https://drive.google.com/file/d/1cfj...ew?usp=sharing

  11. #11
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    Re: X axis is off center

    Quote Originally Posted by didu View Post
    I can upload my file, but for an individual tool path, telling it where to start and how deep you have to go you have to set the heights. I think what I’m doing is okay but I can add my file so you can see.
    Heights aren't going to cause anything to be off center. Given that the work is happening from a fixed point IE the work coordinate then all the math is done from that point. If something is not located where it should be when the code is run that is indicative of either a mechanical problem or a geometry problem. I'm just trying to piece together what you are actually trying to describe.

    If you make an error in height settings you'll either have a problem of cutting too deeply, not cutting at all or crashing into the part. Off center doesn't really come into play.

  12. #12

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    Quote Originally Posted by Kenny Duval View Post
    Heights aren't going to cause anything to be off center. Given that the work is happening from a fixed point IE the work coordinate then all the math is done from that point. If something is not located where it should be when the code is run that is indicative of either a mechanical problem or a geometry problem. I'm just trying to piece together what you are actually trying to describe.

    If you make an error in height settings you'll either have a problem of cutting to deeply, not cutting at all or crashing into the part. Off center doesn't really come into play.
    Right! So I think my off center problem is related to having the work origin set to stock box point instead of model box point (although I could very easily be wrong!). So I wanted to try and use model box point instead, but when I do this I’m running into a funny heights issues.

    When my program is set to use stock box point as the origin everything cuts at the correct height, but it’s off center. When I look in the Gcode I can see that the bit moves down to Z-.23 to make the cuts and when I check this with calipers my machine is taking a .23 doc which is right! But when I use model box point, I can see in the gcode that my machine runs down to Z0 and begins the operation, which isn’t right. So when I run this on my machine the endmill is just skimming the top of the stock, because I probe the top of the stock to set my Z0 height. If I’m using model box point, when I probe the top of my stock to set my work origin, do I need to offset the Z height by .23 here? Or am I setting my heights incorrectly? I’ve watched a lot of tutorials and no one seems to talk about this issue so I’m just confused at this point

  13. #13
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    Re: X axis is off center

    Well that would be an issue if the stock is not exactly the same size as your model. Unless the Stock origin point selected is on exactly the same plane as the model origin point you are selecting then you are moving the heights around by whatever amount makes up the difference. Your file is not accessible on Google drive until you give me permission.

    Using a model box point would mean that you need access to that point to set the WCS. Just selecting it in software doesn't tell the machine you have moved it. You would have to set machine zero to that point. So if you know it is down -.230 from the top of the stock then you would probe the top of the stock then enter then move away from the stock in X or y and move Z down to .230 and reset zero or enter the appropriate value in the DRO to accomplish the same offset.. That now moves your zero position down from the top of the stock by that amount.

    Remember the machine only does what you tell it to do. If you tell it to drive a tool through the table it will do it...without remorse or consideration for your pride or wallet.

    I try to always set Z0 to the bottom of my stock. The reason for doing so is obvious once you mill off the top of the stock and something goes wrong. It's hard to set Z zero back to the top of stock that is no longer there.

  14. #14

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    Re: X axis is off center

    Sorry, I had the permissions set incorrectly! This link should work

    https://drive.google.com/file/d/1cfj...ew?usp=sharing

  15. #15
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    Re: X axis is off center

    Ok...there is nothing "wrong" with what you have done in the setup and tool paths. You are picking up the Left rear corner of the stock and the tool paths are calculated from there. Now I assume that what you are about it being off center is Z depth related and not XY correct?

    There is nothing there but a 2d surface of the top of the stock followed by a couple laps around the part to mill the stock down to the size of your part. I'm am baffled by what you call off center. As long as you are probing the left rear corner and the top of the stock to set the WCS to that corner it should work. If the depth of the Z cut is not right then you have to look at your tool length offsets. If the width of cut is not correct then you would need to address the tool diameter offset. If the whole cut is shifted in X or Y then we are back to the probing calibration not being correct or some mechanical issue.

    If the tools are defined correctly, the WCS is set to the top rear left corner then that code should run as expected.

  16. #16
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    Re: X axis is off center

    Quote Originally Posted by didu View Post
    The diameter of my probe is about .15”. I don’t have a gauge ring to measure it perfectly so I just used a hole in a 123 block. I’m sure it’s a little off, but I don’t think it’s off enough to cause this error? And yes, I’m setting the origin to the same corner as in my drawing, and when I type in X0Y0 in the mdi it seems to jog to the corner of the work piece perfectly.
    You can get a rough measurement with a cheap digital caliper it will be a nominal size

    There is nothing on a 123 block that you could use as a gauge to measure anything with, the standard 123 block has a much bigger hole than .150 most holes are tap 3/8-16 so that would have around a .312 hole

    Most standard probes are .200 this number has to be in you probing software for it to work correct or your offset will be incorrect
    Mactec54

  17. #17
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    Re: X axis is off center

    Quote Originally Posted by Kenny Duval View Post
    Ok...there is nothing "wrong" with what you have done in the setup and tool paths. You are picking up the Left rear corner of the stock and the tool paths are calculated from there. Now I assume that what you are about it being off center is Z depth related and not XY correct?

    There is nothing there but a 2d surface of the top of the stock followed by a couple laps around the part to mill the stock down to the size of your part. I'm am baffled by what you call off center. As long as you are probing the left rear corner and the top of the stock to set the WCS to that corner it should work. If the depth of the Z cut of not right then you have to look at your tool length offsets. If the width of cut is not correct then you would need to address the tool diameter offset.

    If the tools are defined correctly, the WCS is set to the top rear left corner then that code should run as expected.
    One thing you are missing his Probe has to be setup correct also for it all to work correct
    Mactec54

  18. #18
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    Re: X axis is off center

    Quote Originally Posted by mactec54 View Post
    One thing you are missing his Probe has to be setup correct also for it all to work correct
    I realized I missed that. I went back and edited to make it correct.

  19. #19

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    Re: X axis is off center

    Since I'm having a hard time explaining this let me record a quick video on my phone so I can try and show you

  20. #20

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    Re: X axis is off center

    Here's a quick video explaining the issue I'm having. I shot it pretty fast so it's not very polished but it should help clarify the issue I'm having. Also, I forgot to mention that I've checked my tool diameter, and it seems to be right (3/8 tool so .375")

    https://drive.google.com/file/d/1mxC...ew?usp=sharing

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