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    Post Z height difference

    Hi

    I got a strange issue and can't find out what's the cause.

    I have a program which start with facing a part.
    First a face and it leaves 0.3mm stock
    Then a second facing op which removes everything from the top.

    Both ops remove material. And the rest of the program runs.
    But when I measure the top of the part to a pocket it's 3.3mm instead of 3,00mm.

    I triple checked tool offsets and so on. But offsets are spot on.

    Funny thing is when I start the second facing op again which removes the 0,3mm. It removes material and the depth of the pocket is spot on...3,00mm.
    But why doesn't the program remove the 0,3mm in the program?
    It where long days and I'm a bit tired. But I can't find the issue?

    I also checked if the second facing was included in the program. But it is! and it's removing material!

    I attached the beginning of the full program and only the facing op, which I run afterwards to correct it.


    program1.txt
    facingop.txt

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    Without reading all your code....check where you touched off as Z0 between the different programs

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    Z0 is for both the same. They both use the G54.

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    You are using tool 1 (T1 M6) with offset number 2 (H2).
    Is it correct?

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    How think is the material after the first Face operation? I looked through your code and it's messy as hell. There are K values expressed while Facing. Have you tried just simple Facing both sides to see? Arbitrary, unrelated to the question code is annoying.

    R

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    Quote Originally Posted by sinha View Post
    You are using tool 1 (T1 M6) with offset number 2 (H2).
    Is it correct?
    Correct



    Quote Originally Posted by litlerob1 View Post
    How think is the material after the first Face operation? I looked through your code and it's messy as hell. There are K values expressed while Facing. Have you tried just simple Facing both sides to see? Arbitrary, unrelated to the question code is annoying.

    R
    The code is what Fusion outputs.
    No idea how thick it is after the first op. I just finished all parts. But can't explain the above issue.

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    Quote Originally Posted by tcncj View Post
    No idea how thick it is after the first op. I just finished all parts. But can't explain the above issue.
    Well you need to check.

    Do you read and interpret G code?

    Why are there K values in your program? G18 is assigned.

    Are you on a VMC or HMC?

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    G18 is XZ plane, so I,K is appropriate.

    If the OP can recut tool 1 and get material removal, something's moving...

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    Quote Originally Posted by tcncj View Post
    Hi

    I got a strange issue and can't find out what's the cause.

    I have a program which start with facing a part.
    First a face and it leaves 0.3mm stock
    Then a second facing op which removes everything from the top.

    Both ops remove material. And the rest of the program runs.
    But when I measure the top of the part to a pocket it's 3.3mm instead of 3,00mm.

    I triple checked tool offsets and so on. But offsets are spot on.

    Funny thing is when I start the second facing op again which removes the 0,3mm. It removes material and the depth of the pocket is spot on...3,00mm.
    But why doesn't the program remove the 0,3mm in the program?
    It where long days and I'm a bit tired. But I can't find the issue?

    I also checked if the second facing was included in the program. But it is! and it's removing material!

    I attached the beginning of the full program and only the facing op, which I run afterwards to correct it.


    program1.txt
    facingop.txt
    Hello tcncj,
    Nowhere in either program are you facing the part to Z Zero, only a surface that is -2.0mm from Z Zero. Ultimately, the tool moves to Z0.0 then follows a circular path in the X-Z plane to Z-2.0, cuts the bottom of the pocket and then follows a circular path in the X-Z to move out of the pocket to Z0.0. Accordingly, unless the material top surface is right at Z Zero, or you use another program that actually faces the workpiece to Z Zero, you will get discrepancies equal to the variations of the top surface of the workpiece.

    If the faced surface you're referring to is the Z-2.0 surface and you're getting a discrepancy between that and another pocket feature, you need to post the code for the pocket feature. If the actual Z-2.0 surface is the surface that is varying, then its a mechanical issue, not programming.

    Not that it would cause an issue if the value of Tool Length Offset 02 is correct for Tool 01, but by what logic would have Offset 02 applied to Tool 01 and then pre-call T2?

    Regards,

    Bill

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    Quote Originally Posted by litlerob1 View Post
    Well you need to check.

    Do you read and interpret G code?

    Why are there K values in your program? G18 is assigned.

    Are you on a VMC or HMC?
    Fusion likes to do little vertical arc lead-in's.

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    Quote Originally Posted by jancollc View Post
    G18 is XZ plane, so I,K is appropriate...
    I understand that G18 is appropriate, but working in the XZ plane while doing a Facing op is ......confusing.

    Quote Originally Posted by thesidetalker View Post
    Fusion likes to do little vertical arc lead-in's.
    Software doesnt like doing things, when it's defaulted to something stupid like that, it needs to be changed.

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    Quote Originally Posted by litlerob1 View Post
    I understand that G18 is appropriate, but working in the XZ plane while doing a Facing op is ......confusing.
    Not much about that code and the OP's description that isn't confusing, at least to me. I interpreted the arcs as XZ lead in moves that the CAM stuck in, whether it was a default setting in Fusion or a choice of the programmer.

    The program is a PITA to read, I didn't bother to visualize every move, plus it's in metric and there are no numbers in the program that I can relate to the OP's description of the problem. Goofy use of the offsets, no idea of the control or machine.

    Just another day on PM.

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    Please...if you don't have anything to contribute...don't respond
    Something is not "goofy" if you don't understand it.



    Quote Originally Posted by angelw View Post
    Hello tcncj,
    Nowhere in either program are you facing the part to Z Zero, only a surface that is -2.0mm from Z Zero. Ultimately, the tool moves to Z0.0 then follows a circular path in the X-Z plane to Z-2.0, cuts the bottom of the pocket and then follows a circular path in the X-Z to move out of the pocket to Z0.0. Accordingly, unless the material top surface is right at Z Zero, or you use another program that actually faces the workpiece to Z Zero, you will get discrepancies equal to the variations of the top surface of the workpiece.

    If the faced surface you're referring to is the Z-2.0 surface and you're getting a discrepancy between that and another pocket feature, you need to post the code for the pocket feature. If the actual Z-2.0 surface is the surface that is varying, then its a mechanical issue, not programming.

    Not that it would cause an issue if the value of Tool Length Offset 02 is correct for Tool 01, but by what logic would have Offset 02 applied to Tool 01 and then pre-call T2?

    Regards,

    Bill
    Hello Bill,

    The Z zero is the top of my stock.
    I have 2mm stock which needs to be faced. First it removes 1.7mm and leaves 0,3mm
    Then in a second facing op it removes the 0,3mm.


    It's not a mechanical issue.
    All other features of the part are spot on.

    When I re-run the exact second facing op. It does remove the 0,3mm. Then it's perfect!
    But I can't understand why it doesn't remove the 0,3mm in the first place.

    The code is identical.
    Tool lengths are correct
    All use G54
    No mechanical issue with the machine Z, cutter or toolholder.


    Not that it would cause an issue if the value of Tool Length Offset 02 is correct for Tool 01, but by what logic would have Offset 02 applied to Tool 01 and then pre-call T2.

    I have only a 10 pocket carousal toolchanger.
    I have all my tools (+/- 100 offsets) loaded in the tooloffset table.
    And they are all pre-set in the G120 WCS
    When running a program I just edit the T numbers of the tools. So there is no need to set tool length after each program change.
    For example my T1 H1 is a face mill, but if I want to swap it out for a different cutter I just change the H1 to Hx. Offsets are already set. Modify the program to use a different cutter and check if T and H are correct.

    I can just walk to my tools, grab the tools I need and throw them into the toolchanger. And change the T number according to the pocket of the toolchanger. And I'm good to go. Offsets are already set.

    Matching T and H numbers doesn't make sense. It does if you like to measure tool offsets...

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    Well, I must admit that if you are running the exact same program twice and it is doing something different the second time consistently that does have me stumped. Or are you only re-running the 2D Face Op part of the program?

    As far as Fusion goes I have gotten tripped up a few times when going through the settings because things like "do finish pass", "multiple depths", "roughing pass", "stock to leave", or setting your heights different can all cause it to do things that aren't what you intended. And they each have settings once you choose them that allow you to input values that can move where it actually cuts around.

    But if you are saying you run the whole program once and it is .3 thick and you do nothing but run the program again and it removes the .3 that is very strange.

    Does it show up strangely in the Simulation?

    Also as to comments on the code being a mess, yes that is what Fusion does. I bitched about it but the bottom line was that the CAM is good at math so adding a ton of extra lines to make it swoop around doesn't bother it a bit. I have had hell of time trying to debug code because it basically does everything long hand so your controller doesn't need to do anything but read the line and move. Very controller and memory friendly but a total PITA to go through and hand edit. It's like binary.

    But changing just that setting for, I think it was tolerance band or something that is always set to .0004" in inches to like .001" will cut the size of your program in half as it sets less points. NYCNC guy did a video on it at one point. So just one check box can make things change drastically.

    Hope this helps some.

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    Quote Originally Posted by tcncj View Post

    Hello Bill,

    The Z zero is the top of my stock.
    I have 2mm stock which needs to be faced. First it removes 1.7mm and leaves 0,3mm
    Then in a second facing op it removes the 0,3mm.


    It's not a mechanical issue.
    All other features of the part are spot on.

    When I re-run the exact second facing op. It does remove the 0,3mm. Then it's perfect!
    But I can't understand why it doesn't remove the 0,3mm in the first place.

    The code is identical.
    Tool lengths are correct
    All use G54
    No mechanical issue with the machine Z, cutter or toolholder.
    You could mimic your enthusiasm for there being no mechanical issue, by stating with equal enthusiasm that there is no issue with the program. You have Posted the program and there is no issue; therefore you have to look elsewhere.

    There is absolutely nothing in the program examples you've posted that will give the result you're describing. As Sherlock Holmes said "when you have eliminated the impossible, whatever remains, however improbable, must be the truth." Accordingly, given that your program example indicates that the program is not the cause, it must be something else, however improbable it may be. However, once the program has been eliminated, then a mechanical issue (machine, or workpiece) is the most probable.

    If you run your facing programs, and then immediately ran them again (without the other machining operations being done), is 0.3 removed by the second iteration of the program? Following your description, then it would (highly unlikely in my opinion). Could it be that the workpiece is distorting (moving) due to the other machining operations that are carried out. You haven't stated how much metal (area) is removed during the pocketing operations.

    Quote Originally Posted by tcncj View Post
    Matching T and H numbers doesn't make sense. It does if you like to measure tool offsets...
    You will have a hard time convincing the generally informed and majority of that.

    At some stage you will have set Tool Length Offsets for all the tools you have, or use. Having some correlation between Tool Numbers and Tool Length Offsets makes a lot of sense, simply on the basis of reading the program yourself, or by others. Why do you think Sinha in Post #4 questioned the Offset Number.

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    Quote Originally Posted by Jaxian View Post
    Well, I must admit that if you are running the exact same program twice and it is doing something different the second time consistently that does have me stumped. Or are you only re-running the 2D Face Op part of the program?

    Does it show up strangely in the Simulation?
    Hello Jaxian,
    Both programs finish at Z-2.0, so it would make no difference which program he ran. In Simulation, it clearly shows the tool path tracking at Z-2.0 after the Z-1.7 pass. Accordingly, nothing in the program to cause the issue.

    Regards,

    Bill

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    Quote Originally Posted by Jaxian View Post
    Well, I must admit that if you are running the exact same program twice and it is doing something different the second time consistently that does have me stumped. Or are you only re-running the 2D Face Op part of the program?

    As far as Fusion goes I have gotten tripped up a few times when going through the settings because things like "do finish pass", "multiple depths", "roughing pass", "stock to leave", or setting your heights different can all cause it to do things that aren't what you intended. And they each have settings once you choose them that allow you to input values that can move where it actually cuts around.

    But if you are saying you run the whole program once and it is .3 thick and you do nothing but run the program again and it removes the .3 that is very strange.

    Does it show up strangely in the Simulation?

    Also as to comments on the code being a mess, yes that is what Fusion does. I bitched about it but the bottom line was that the CAM is good at math so adding a ton of extra lines to make it swoop around doesn't bother it a bit. I have had hell of time trying to debug code because it basically does everything long hand so your controller doesn't need to do anything but read the line and move. Very controller and memory friendly but a total PITA to go through and hand edit. It's like binary.

    But changing just that setting for, I think it was tolerance band or something that is always set to .0004" in inches to like .001" will cut the size of your program in half as it sets less points. NYCNC guy did a video on it at one point. So just one check box can make things change drastically.

    Hope this helps some.
    I'm also stumped, that's why I made this topic haha.

    Yes I only re-run the 2d face op.

    Finish pass, multiple depths, roughing passes. All is checked.
    But it can't be the issue because the full program and only the second face op are exactly the same.

    It doesn't show strange in the simulation. It shows it exactly like it should.



    Quote Originally Posted by angelw View Post
    You could mimic your enthusiasm for there being no mechanical issue, by stating with equal enthusiasm that there is no issue with the program. You have Posted the program and there is no issue; therefore you have to look elsewhere.

    There is absolutely nothing in the program examples you've posted that will give the result you're describing. As Sherlock Holmes said "when you have eliminated the impossible, whatever remains, however improbable, must be the truth." Accordingly, given that your program example indicates that the program is not the cause, it must be something else, however improbable it may be. However, once the program has been eliminated, then a mechanical issue (machine, or workpiece) is the most probable.

    If you run your facing programs, and then immediately ran them again (without the other machining operations being done), is 0.3 removed by the second iteration of the program? Following your description, then it would (highly unlikely in my opinion). Could it be that the workpiece is distorting (moving) due to the other machining operations that are carried out. You haven't stated how much metal (area) is removed during the pocketing operations.



    You will have a hard time convincing the generally informed and majority of that.

    At some stage you will have set Tool Length Offsets for all the tools you have, or use. Having some correlation between Tool Numbers and Tool Length Offsets makes a lot of sense, simply on the basis of reading the program yourself, or by others. Why do you think Sinha in Post #4 questioned the Offset Number.
    My first guess was tool offsets. So I triple checked everything. All good
    Same goes for the mechanical side. Backlash? problem with toolholder? Machine (haas) is bought new in 2017...but backlash could be possible. Checked...no backlash that could cause this. Toolholder, also good.
    That's why it is so strange that when I re-run the second facing op, all is good!
    Programs are also 100% identical and there are no mechanical issues. All other pockets are 100% within spec. It's only the facing op.

    Distorting...good point. I use talon grips to hold the part. But I leave 10mm stock at the bottom so it won't distort. I doubt it's moving. And other ops would run into problems if it would distort. Besides the part would pull out perfectly 0,3mm upward after the second facing op.

    CNC control issue maybe?


    About tool / offsets:
    I understand everyone does it their own way.
    But imho it doesn't make sense to match tools and offset numbers.
    For example: Why would I number a T50 with an offset of 50?
    Then for each operation/program I have to manually change the tool number to 10 or something below 10. When I tell the mill "get me tool 50 with offset 50" it will tell me "how about no, I only got 10 pockets in my carousel".
    Maybe it works different on machines with a different toolchanger? Because the tools are stored as "pockets" in the offset database.

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    Still haven't measured the thickness of the part after the first Facing operation?

    When I am trouble shooting a problem, I start over, and make sure the physical part is exactly what I programmed it to be after every Tool, after each Operation, one by one.

    I don't think the part is moving.

    But you come to a public forum and ask questions, and are so convinced that your way is right that you won't concede that it might be the issue, then you are helpless. I use different H values for specific tools sometimes. Not normally, but occasionally. In this scenario, you are stuck. Why not try something different than what you are currently doing?

    R

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    Quote Originally Posted by tcncj View Post
    But why doesn't the program remove the 0,3mm in the program?
    It where long days and I'm a bit tired. But I can't find the issue?
    Single step through the program in your machine and make sure the machine is doing what you expect it to be doing.

    Sometimes it can be something as stupid as running the wrong program, e.g. an older version of the same program. BTDT...

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    this almost sounds like a work shift was done and on re-set to run the second program it is reset to the original.
    i would look at the machine position and note it for the first face then also note it when the re-facing occurs and when the 2nd face is run by its self.
    Do the first re facing and the second re facing go to the same point or is there a difference ?
    If there is a difference do a re-set/restart at the second facing op in the original does this go to the correct place ?
    you also show 2 programs and yet they are the same program numbers and have the same n numbers for the operations is this a copy of the actual programs that are run in the machine or are the copy's of fussion ?


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