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IndustryArena Forum > CAM Software > BobCad-Cam > 4th Axis tool plunges before positional moves
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  1. #1
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    4th Axis tool plunges before positional moves

    Hello...Happy New Year!

    I don't know what to search for or what part of the process is messing this up so posting here.
    I use BobCad-for Cam and have a 4-axis router fed via Mach3.

    I am making several small pockets around a spindle. Every so often (even the very first move) this code shows up where it puts the tool down and then moves to the next pocket leaving a long straight cut in between pockets.
    It doesn't do it for every pocket and it does not show at all in the preview and simulation.

    I am still a CNC rookie but have made several parts similar without this. Not sure at all what could be causing this....CAD/CAM setup, Post, Mach3 setup...etc...

    It is zeroed off the top center surface of the spindle and is cutting .030" deep pockets. It should move to the next pocket and then plunge.

    I have seen where the red highlighted text threw a code (absolute to incremental) that drove the tool all the way through the part so not sure if there is something there causing this?

    Any thoughts to help an old school machinist get up to speed?

    (BEGIN PREDATOR NC HEADER)
    (MACH_FILE=HAAS - 3XVMILL.MCH)
    (MTOOL T1 S1 D.0313 C0. A0. H1.5)
    (SBOX X-3.25 Y-.625 Z-1.25 L3.25 W1.25 H1.25)
    (END PREDATOR NC HEADER)

    %
    O100
    (PROGRAM NUMBER)
    (PROGRAM NAME - THUNDERBIRD.NC)
    (POST - MACH 3 MILL NO ATC)
    (DATE - MON. 01/06/2020)
    (TIME - 06:24PM)

    N01 G20 G40 G49 G54 G80 G90 G91.1
    ;N02 G53 Z0.


    (Machine Setup - 1 Pocket)
    (FEATURE 2 AXIS)

    ;N03 T1 M6
    N04 S10000 M03
    N05 G00 G90 G54 X-1.9307 Y0.
    ;N06 G43 H1 Z.5
    N07 A 0.
    N08 Z.2
    N09 Z.1
    N10 G01 Z0. F10.
    N11 Z-.03

    N12 X-1.9251 A46.427 F15.
    N13 X-1.9221 A47.172
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    N154 X-2.0594 A-10.634
    N155 X-2.0597 A-10.944
    N156 X-2.0506 A-10.115
    N157 G00 Z.2
    N158 X-1.8547
    N159 Z.1
    N160 G01 Z0. F10.
    N161 Z-.03

    N162 X-1.8571 A.804 F15.
    N163 X-1.8721 A-.045
    N164 X-1.8709 A-.121

  2. #2
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    Re: 4th Axis tool plunges before positional moves

    What version of BC are you using?
    Is your A axis running in the X or Y axis?
    Why do you have ; semi-colon on some lines, these should not be there.
    Can you put your bccd file in a Zip folder and upload it?

    Regards
    Rob

  3. #3
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    Re: 4th Axis tool plunges before positional moves

    Quote Originally Posted by The Engine Guy View Post
    What version of BC are you using? Version 28
    Is your A axis running in the X or Y axis? X-Axis
    Why do you have ; semi-colon on some lines, these should not be there. I am not sure...the Cam puts them there. I haven't learned to code from scratch except for very simple shapes.
    Can you put your bccd file in a Zip folder and upload it?

    Regards
    Rob
    The ; only shows in the places in first post and between the tool changes (below) and the end of the program same as here. (N3199 and 3200)

    N3195 X-1.8204 A53.108
    N3196 G00 Z.2
    N3197 Z.5
    N3198 M05
    ;N3199 G53 Z0.
    ;N3200 G53 X0. Y0.

    N3201 M00

    (Machine Setup - 1 Profile Finish)
    (FEATURE 2 AXIS)

    ;N3202 T2 M6
    N3203 S22000 M03
    N3204 G90 G54 X-1.9358 Y0.
    ;N3205 G43 H2 Z.5
    N3206 A 0.
    N3207 G00 Z.2
    N3208 Z.1
    N3209 G01 Z-.03 F5.
    N3210 X-1.9083 A42.182


    I can share the code but this is all the offending parts...plus a few other spots where it sets the tool down before moving to next pocket.

    - - - Updated - - -

    BTW...thanks for looking!

  4. #4
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    Re: 4th Axis tool plunges before positional moves

    Using the BC-4X Mill and the Mach3 Mill No ATC Post.

  5. #5
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    Re: 4th Axis tool plunges before positional moves

    The code isn`t telling us anything, need the BobCAD .bccd file so we can see how and where it has been programmed.

    Regards
    Rob

  6. #6
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    Re: 4th Axis tool plunges before positional moves

    Got it...

  7. #7
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    Re: 4th Axis tool plunges before positional moves

    Reckon it may be the Post Processor, the Mach3 No ATC processor I have I know works and it is outputting different looking code to yours, it actually looks right

    Do you have homing switches on your machine and is the machine homed OK ?

    I have Zipped up a copy of my Mach3 No ATC Post Processor for you to try, should work, it has worked many hundreds of time for me :F

    Regards
    Rob

  8. #8
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    Re: 4th Axis tool plunges before positional moves

    I do not have homing switches. Homed OK? It is aligned accurately but the Machine Zero is really something I never use due to not having switches.

    I will give it a shot and let you know. I may not get to run the machine now for a day or so though..

    Thank you very much Mr.Guy!

  9. #9
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    Re: 4th Axis tool plunges before positional moves

    I'll run it when I can but it looks to me like it will still drop the tool at A0 and wrap 46.4 degrees for the start of the pocket.

    656. Block delete? " " This is where my post shows the semi-colon?

    N03 T1 M6
    N04 S10000 M03
    N05 G00 G90 G54 X-1.9307 Y0.
    N06 G43 H1 Z.5
    N07 A 0.
    N08 Z.2
    N09 Z.1
    N10 G01 Z0. F10.
    N11 Z-.03
    N12 X-1.9251 A46.427 F15.
    ;N03 T1 M6
    N04 S10000 M03
    N05 G00 G90 G54 X-1.9307 Y0.
    ;N06 G43 H1 Z.5
    N07 A 0.
    N08 Z.2
    N09 Z.1
    N10 G01 Z0. F10.
    N11 Z-.03
    N12 X-1.9251 A46.427 F15.

  10. #10
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    Re: 4th Axis tool plunges before positional moves

    This is the result...
    Attached Thumbnails Attached Thumbnails Thunderbird.jpg  

  11. #11
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    Quote Originally Posted by RakmUp View Post
    Hello...Happy New Year!

    I don't know what to search for or what part of the process is messing this up so posting here.
    I use BobCad-for Cam and have a 4-axis router fed via Mach3.

    I am making several small pockets around a spindle. Every so often (even the very first move) this code shows up where it puts the tool down and then moves to the next pocket leaving a long straight cut in between pockets.
    It doesn't do it for every pocket and it does not show at all in the preview and simulation.

    I am still a CNC rookie but have made several parts similar without this. Not sure at all what could be causing this....CAD/CAM setup, Post, Mach3 setup...etc...

    It is zeroed off the top center surface of the spindle and is cutting .030" deep pockets. It should move to the next pocket and then plunge.

    I have seen where the red highlighted text threw a code (absolute to incremental) that drove the tool all the way through the part so not sure if there is something there causing this?

    Any thoughts to help an old school machinist get up to speed?

    (BEGIN PREDATOR NC HEADER)
    (MACH_FILE=HAAS - 3XVMILL.MCH)
    (MTOOL T1 S1 D.0313 C0. A0. H1.5)
    (SBOX X-3.25 Y-.625 Z-1.25 L3.25 W1.25 H1.25)
    (END PREDATOR NC HEADER)

    %
    O100
    (PROGRAM NUMBER)
    (PROGRAM NAME - THUNDERBIRD.NC)
    (POST - MACH 3 MILL NO ATC)
    (DATE - MON. 01/06/2020)
    (TIME - 06:24PM)

    N01 G20 G40 G49 G54 G80 G90 G91.1
    ;N02 G53 Z0.


    (Machine Setup - 1 Pocket)
    (FEATURE 2 AXIS)

    ;N03 T1 M6
    N04 S10000 M03
    N05 G00 G90 G54 X-1.9307 Y0.
    ;N06 G43 H1 Z.5
    N07 A 0.
    N08 Z.2
    N09 Z.1
    N10 G01 Z0. F10.
    N11 Z-.03

    N12 X-1.9251 A46.427 F15.
    N13 X-1.9221 A47.172
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    N154 X-2.0594 A-10.634
    N155 X-2.0597 A-10.944
    N156 X-2.0506 A-10.115
    N157 G00 Z.2
    N158 X-1.8547
    N159 Z.1
    N160 G01 Z0. F10.
    N161 Z-.03

    N162 X-1.8571 A.804 F15.
    N163 X-1.8721 A-.045
    N164 X-1.8709 A-.121
    So most likely it is the "machine zero"
    That's biting you.

    When you are setting zero in mach3 3, get all your zero's set, then hit "reference all home". You'll probably see the numbers change (that's the machine zero)

    Change those numbers back to your set zero and try.

    Also, since you said you dont really use machine zero, just get rid of that G53 Z0.0 out of your post processor.

    Open the post in notepad, and then you will probably find that G53 in the "standard start of file" line...

    Look for it in the toolchanges and e,d of file lines....

  12. #12
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    Quote Originally Posted by RakmUp View Post
    Hello...Happy New Year!

    I don't know what to search for or what part of the process is messing this up so posting here.
    I use BobCad-for Cam and have a 4-axis router fed via Mach3.

    I am making several small pockets around a spindle. Every so often (even the very first move) this code shows up where it puts the tool down and then moves to the next pocket leaving a long straight cut in between pockets.
    It doesn't do it for every pocket and it does not show at all in the preview and simulation.

    I am still a CNC rookie but have made several parts similar without this. Not sure at all what could be causing this....CAD/CAM setup, Post, Mach3 setup...etc...

    It is zeroed off the top center surface of the spindle and is cutting .030" deep pockets. It should move to the next pocket and then plunge.

    I have seen where the red highlighted text threw a code (absolute to incremental) that drove the tool all the way through the part so not sure if there is something there causing this?

    Any thoughts to help an old school machinist get up to speed?

    (BEGIN PREDATOR NC HEADER)
    (MACH_FILE=HAAS - 3XVMILL.MCH)
    (MTOOL T1 S1 D.0313 C0. A0. H1.5)
    (SBOX X-3.25 Y-.625 Z-1.25 L3.25 W1.25 H1.25)
    (END PREDATOR NC HEADER)

    %
    O100
    (PROGRAM NUMBER)
    (PROGRAM NAME - THUNDERBIRD.NC)
    (POST - MACH 3 MILL NO ATC)
    (DATE - MON. 01/06/2020)
    (TIME - 06:24PM)

    N01 G20 G40 G49 G54 G80 G90 G91.1
    ;N02 G53 Z0.


    (Machine Setup - 1 Pocket)
    (FEATURE 2 AXIS)

    ;N03 T1 M6
    N04 S10000 M03
    N05 G00 G90 G54 X-1.9307 Y0.
    ;N06 G43 H1 Z.5
    N07 A 0.
    N08 Z.2
    N09 Z.1
    N10 G01 Z0. F10.
    N11 Z-.03

    N12 X-1.9251 A46.427 F15.
    N13 X-1.9221 A47.172
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    N154 X-2.0594 A-10.634
    N155 X-2.0597 A-10.944
    N156 X-2.0506 A-10.115
    N157 G00 Z.2
    N158 X-1.8547
    N159 Z.1
    N160 G01 Z0. F10.
    N161 Z-.03

    N162 X-1.8571 A.804 F15.
    N163 X-1.8721 A-.045
    N164 X-1.8709 A-.121
    Hello dear,

    Are you sure the emplacements origin in Z is OK?

  13. #13
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    Re: 4th Axis tool plunges before positional moves

    Hi Guys...
    Burrman...I can try resetting true machine Home and see what happens but honestly I have never done this and not seen this problem before. I have never checked out each and every code to see what it is doing and trusted it until proven otherwise (thus the driving tool all the way through the part comment). Mostly it has worked well when the simulation works right. But if that is what G53 is for I can wipe that out as I do edit code I get that part of it. Maybe that can be adjusted in the post as well to avoid.

    Lukedu...if you mean the fact that I am zeroing on top surface instead of rotational axis...I don't know. I found a reference that could cause issues....and I typically do use rotational center for zero but part is not perfect to size I need and wanted the depth from surface to be very close. And as I use various sizes of cylinder I would just re-zero to top of cylinder. Yes I know the depth may change as it wraps around part but we are talking thousandths of inches in variance. Not a big deal in wood projects.

    Thanks for the thoughts...will check them out.

    The real feeling I have is the CAM has decided to drop the tool before it gets to the pocket so I don't see where either of these issues is the culprit. Make sense? It cuts one pocket...raises the tool...moves x a bit...drops the tool...moves X a bit and A a lot....cuts next pocket.

  14. #14
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    Re: 4th Axis tool plunges before positional moves

    RakmUp;

    I believe Burrman is spot on. When BBCD programs a move (as opposed to a cut) it moves the bit (hopefully above the stock) to "Rapid" or "Feed" Plane, Then it zips around to continue the cut/ starts the next feature. If your z=0 point is the center of the axis of rotation, and rapids/ feed plane are too low (lower than the stock), the tool carves as expected, then will auger in as it goes from feature to feature, just as you show.

    The observation that gives it away for me is the bid drops BELOW the depth of cut as it moves in your pic. This should show on a simulation, and you should be able to look for GCodes programming Z below your depth of cut (assuming z=0 is center of rotation).

    Note:
    If you are "Wrapping" an axis to do rotary moves, things get a bit more involved, but judging by your pictures, you seem to have those issues figured out.

    -ShortTrack

    Go ahead, ask me why I think this is the issue. For even more fun, ask me how much firewood I made before I figured it out.

  15. #15
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    Re: 4th Axis tool plunges before positional moves

    I reckon it is the Mach3 post, I have just tested your file with a different Post Processor, it is one I use for 4th axis work so I know it works, well, on my machine controls anyway which are now Mach4 and simCNC, I don`t use Mach3 anymore, not that it is complete junk it`s just that the other two are better
    Here is some code from it :-

    N01 G00 G17 G40 G49 G80 G20 G90

    (FIRST CUT - FIRST TOOL)
    (Machine Setup - 1 Pocket)
    (FEATURE 2 AXIS)

    N02 G00 G53 Z0

    (TOOL #1 0.0313 1/32 FLAT ENDMILL - STANDARD)
    N03 T1 M06
    N04 G00 G91 A45.565 (Moving Incrementally to first position at full machine Z0 clearance height)
    N05 G00 G90 G54 X-1.9307 Y0. S10000 M03 (Changes to Absolute and moves to G54 position)
    N06 G00 G43 H1 Z0.5 (Moves to Stock Clearance height)
    N07 Z0.2 (Moves down to Rapid plane moves height)
    N08 Z0.1 (Moves down to Feed plane height)
    N09 G01 Z0. F10. (Moves down to top of stock)
    N10 Z-0.03 (Plunges the 0.03 into the stock)
    N11 X-1.9251 A46.427 F15.
    N12 X-1.9221 A47.172 Now it continues with the normal X and A moves

    If you think this PP may be of use let me know and I will do a version that does not have the G53 Homing moves in it for you

    Regards
    Rob


  16. #16
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    Re: 4th Axis tool plunges before positional moves

    OK guys...lot to try. The code looks better now but I'll try the center of rotation change first just to confirm.
    If that does not do it I will ask for the Post.
    But I won't get to try a cut until Saturday now. Life gets in the way of hobbies you know. Maybe I can see it in the code change and I will be able do that sooner.

    Thanks for all the effort and deep thought! It is very much appreciated.

  17. #17
    Ghost
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    Quote Originally Posted by RakmUp View Post
    OK guys...lot to try. The code looks better now but I'll try the center of rotation change first just to confirm.
    If that does not do it I will ask for the Post.
    But I won't get to try a cut until Saturday now. Life gets in the way of hobbies you know. Maybe I can see it in the code change and I will be able do that sooner.

    Thanks for all the effort and deep thought! It is very much appreciated.
    Another thing that could create that gouging and not show in the sims is not setting the origin of the stock to the same place you set it in mach.

  18. #18
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    Re: 4th Axis tool plunges before positional moves

    Interesting...re-posted only changing zero pick point to center of axis and I get no semi-colon due to your post but the program will drop the tool before it gets to a pocket. No real improvement....save the ";" And this is with your Post (Engine Guy)...I think the old one...V27?

    N03 T1 M6
    N04 S10000 M03
    N05 G00 G90 G54 X-1.9307 Y0.
    N06 G43 H1 Z.5
    N07 A 0.
    N08 Z.2
    N09 Z.1
    N10 G01 Z0. F10.
    N11 Z-.03
    N12 X-1.9251 A46.427 F15.
    ;N03 T1 M6
    N04 S10000 M03
    N05 G00 G90 G54 X-1.9307 Y0.
    ;N06 G43 H1 Z.5
    N07 A 0.
    N08 Z.2
    N09 Z.1
    N10 G01 Z0. F10.
    N11 Z-.03
    N12 X-1.9251 A46.427 F15.
    N03 T1 M6
    N04 S10000 M03
    N05 G00 G90 G54 X-1.9307 Y0.
    N06 G43 H1 Z1.125
    N07 A 0.
    N08 Z.825
    N09 Z.725
    N10 G01 Z.625 F10.
    N11 Z.595
    N12 X-1.9251 A46.427 F15.

    Burrman...to the best of my knowledge the pickups and tool setting match the CAM and I am guessing if the cut and gouges are cylindrically centered and exact same depth as pockets I should be OK on that front. I think I understand your point though. Thank you...

    Mr. Engine Guy...I am more interested in your post at this point. It did post the code that looked right. If I could bug you once more for a bit of your time. That won't satisfy my need to know why but it will help with this project...and many more down the road. I thank you again in advance.

  19. #19
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    Re: 4th Axis tool plunges before positional moves

    RackmUp

    OK, here is a sample Post for you, it should be pretty close, I have removed all the G53 Home moves and done a couple of other small mods that I thought might be better for your no limit switches setup.

    Anyway, give it a try, as usual at your own risk, go very carefully, set your Z high and just cut air for starters and try setting your WCS to the top of your stock as that seemed to work for your Mach3 setup before

    Regards
    Rob

  20. #20
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    Re: 4th Axis tool plunges before positional moves

    Quote Originally Posted by The Engine Guy View Post
    RackmUp

    OK, here is a sample Post for you, it should be pretty close, I have removed all the G53 Home moves and done a couple of other small mods that I thought might be better for your no limit switches setup.

    Anyway, give it a try, as usual at your own risk, go very carefully, set your Z high and just cut air for starters and try setting your WCS to the top of your stock as that seemed to work for your Mach3 setup before

    Regards
    Rob
    Awesome Guy (Rob)...can't wait to check it out! The whole post thing is interesting to me and I'll try and figure out what the differences are. I'll play it safe for sure...and try it on a couple other proven paths just to keep learning.

    Thanks much! Cheers...

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