Stars are rounded and not pointed like in preview?

New Home Forum Mostly Printed CNC – MPCNC Troubleshooting – MPCNC Stars are rounded and not pointed like in preview?

This topic contains 7 replies, has 4 voices, and was last updated by  Jeff 3 weeks, 6 days ago.

Viewing 8 posts - 1 through 8 (of 8 total)
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  • #110644

    John B
    Participant

    New build, crown test flawless but when I run a job cutting stars on an American Flag they come out rounded and of different shapes over the course of the 50.

    Designed in Estlecam, run on Repitier Host. Looks sharp in preview on Estlcam.

    I think I have conservative speeds and feeds as suggested from basic setup on this site.

    Could it be a setting? Using a 1/4″ 90 degree v bit, should I use larger v bit (I thought this would make larger, deeper cuts)

     

    Advice would be appreciated.

    Thank you.

     

    John

     

     

    #110650

    Ryan
    Keymaster

    Either your Vbit has a rounded tip or you started the Z axis too low.

    #110653

    John B
    Participant

    Thanks for the quick reply. The bits are brand new and show no signs of rounding. They are 90 degree, no ball-end.

    As far as starting Z too low, I used a z touch plate to zero with the correct offset 19.28mm. When I removed the plate it move to virtually touching the top of the workpiece before I started the file.

    Estlecam carve paths are set to automatic, so not sure what is meant by starting z too low. Are there other settings I should be using?

    Attached is a screenshot of the v bit used, a 1/4″ into pine.

    Thanks in advance for advice.

    John

    #110655

    Ryan
    Keymaster

    I would do a test cut and take a little video. One star. What you say means it should be perfect, other than you are not using a finishing pass.

    That is a pretty large bit to move that fast and that deep, something isn’t right.

    A screenshot of the actual cam paths would help of the gcode itself. The screen you show is nothing like what actually happens.

    #110894

    Jeff
    Participant

    It almost looks as if you Z depth per pass is too high. Looking at that image you shared shows the 1/4″ bit with a maximum cutting depth of 6mm your Z step is set up for 6.35mm. From my tests Ii found that if I go less than the bit diameter I get a much better cut. For instance, I have a 1/2″ 90 v groove bit and make 1mm passes they look much better than if I were to go full bore right out the door. Does it take longer? Sure, but I get a much better cut and I always run the program twice to clean up anything it might have missed. (for the life of me I still can’t figure out how to do a finishing pass in estlcam when it comes to carving).

    #110900

    David Walling
    Participant

    It almost looks as if you Z depth per pass is too high. Looking at that image you shared shows the 1/4″ bit with a maximum cutting depth of 6mm your Z step is set up for 6.35mm. From my tests Ii found that if I go less than the bit diameter I get a much better cut. For instance, I have a 1/2″ 90 v groove bit and make 1mm passes they look much better than if I were to go full bore right out the door. Does it take longer? Sure, but I get a much better cut and I always run the program twice to clean up anything it might have missed. (for the life of me I still can’t figure out how to do a finishing pass in estlcam when it comes to carving).

    Regarding the finishing pass…

    All you need to do is select the same bit in the ‘finishing bit’ dropdown when you have the tool path selected. If the tool that you choose has values in the yellow ‘finishing’ fields, then estlcam will add a finishing pass. I found if you select a bit that does not have values in the ‘finishing’ fields, then it won’t run the finishing pass even if you have a bit selected.

    I hope that makes sense.

    #110901

    David Walling
    Participant

    “Z-axis too low”

    What he means is Your Z-axis starting position, or 0 point, was either too low or too high. I’ve found when running V carves that you want the tip of the V-bit just barely touching the top of the work surface. I’ve you’re too high or too low, then the cut doesn’t make pretty points.

    #110924

    Jeff
    Participant

    Regarding the finishing pass…

    All you need to do is select the same bit in the ‘finishing bit’ dropdown when you have the tool path selected. If the tool that you choose has values in the yellow ‘finishing’ fields, then estlcam will add a finishing pass. I found if you select a bit that does not have values in the ‘finishing’ fields, then it won’t run the finishing pass even if you have a bit selected.

    I hope that makes sense.

    It does make sense, but the carve properties doesn’t have that drop down, only a carve pocketing tool drop down.

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