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Phlatprinter #53 in France, first cuts !

Discussion in 'General Phlatprinter 3 Chat' started by kfrtoad, Jun 12, 2011.

  1. kfrtoad

    kfrtoad New Member

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    Hello everybody.

    I finally managed to do the first cuts with my new Phlatprinter.
    Most of the build went smoothly, thanks to the great video build log from Mark and Trish.

    It is almost mesmerizing looking at it finally working ! I still have trouble cutting tabs though so I delayed testing the "engraving" function.

    http://www.youtube.com/watch?v=onYGJ7Od25s

    You can see in the video that the router bit started barely touching the 3mm depron sheet but wasn't lifting enough to cut tabs (i forgot to put tabs in the inner circle but there were a few in the outside of the shape) and that it "dove" into the sheet on the way back to zero after finishing the cut. And I did select 3mm depron in the materials as well as in Sketchup before generating the GCode.

    Is there a breakin period before all axis work smoothly ? It looks like my Z axis is going deeper and deeper during the cuts and sometime when I jog it with the keypad there is a slight delay before it moves.

    Cheers,

    Laurent
     
  2. TigerPilot

    TigerPilot Well-Known Member

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    Laurent, welcome to the board.

    Did you make sure your calibration is correct? It sounds like a calibration problem. Make sure that when it supposed to travel 2" it really travels 2" and not more, which looks like what happens to you.
     
  3. kfrtoad

    kfrtoad New Member

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    I need to check that. The settings file I used is fine for X and Y but I didn't check Z ... my bad.
    The strange thing is that it doesn't seem to be constant. It looks like the bit is going deeper and deeper while cutting.

    Will get back to you on this.

    Thanks.

    Laurent
     
  4. theothers

    theothers Administrator Staff Member

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    Laurent,

    Congratulations on completing your Phlatprinter 3 Build! :doubleup:

    From what you described, it sounds like your Z pulley may be loose.

    Looking forward to seeing your creations!

    Mark and Trish
     
  5. GasPipe

    GasPipe New Member

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    Congrats on the French build kfrtoad!!!

    Now I see why the PhlatBoys put "International Headquarters" in their Phlatboy News intro.


    Total Phlatprinter newb here, but experienced machinist.

    Watch the pulley as you move the z-axis, and if it moves before your axis does there is something sloppy there. Just maybe a grub screw on the pulley or something like the others said. I think I saw something about that in another thread.

    Good luck and let us know how goes.
     
  6. kfrtoad

    kfrtoad New Member

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    There I fixed it .... Now I have to finish putting the Z assembly back together ...

    The problem came from the set screw of the big pulley that was loose and the pulley was sometime skipping, that's why it seem to be digging in the material.

    It took me a while to manage to get that pulley off since it kinda locked in the wrong position on the axis. After prying it out with a giant screwdriver I remembered something from the built (I knew should have posted the numerous pictures (2 to 3 per step) I took while assembling) ... I had problems with the set screws.
    The allen wrench seemed too small or too big and none was a perfect fit. I used the one that were provided in the kit and out of desperation even tried european sized one but it looked like the set screw hole was right in between. That is why I replaced the one on the small pulley in the video with a regular screw.
    I might have to do the same on the big pulley since it won't tighten properly now.

    Anyway I will test it again in a few minutes to see if I have better control of the vertical axis after this adjustment.

    Laurent
     
  7. kfrtoad

    kfrtoad New Member

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    I replaced the set screw for both pulleys and it looks OK. No more slippage.
    But I am still loosing steps on the Z axis. The bits comes back to where it was at the start of the cut but maybe an 1/8th of an inch lower than before, making a small hole in the material. I start and zero the machine before the cut with the tip of the tool an hair from the surface of my depron sheet.
    Could it be the steps/units value ?
    I have X : 432.516, Y: 423.051, Z:800.906
    Does that sound right ?
    I read in another thread that steps/unit shouldn't be that high (above 700) but how do I pick a value ?
     
  8. rcav8r

    rcav8r Moderator Staff Member

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    You may want to check and see how free your Z-axis movement is. For some odd reason mine is fairly stiff. I believe my anti-backlashnut is out of spec as it is hard to turn on the threaded rod even when it is out of the assembly. My work around was to swap the pulleys. Small one on the stepper, large on the rod.
    As expected I had to adjust my steps ( I forget the exact value, and can look up at home). To get it close I just took the ratio of the pulleys and inverted them, then applied that to the existing steps; well I think that's what I did. Then go thorough the calibration process on the Z to zero in on the setting. My Z is about 35 IPM which, in the grand scheme of things, really doesn't slow the cutting process much even when using V-tabs.

    To check and see how free the Z-axis is, remove the belt and try to turn by hand. Should be rather easy. Mine takes quite a bit of effort.
     
  9. kfrtoad

    kfrtoad New Member

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    I am not "loosing altitude" on the Z axis anymore. The set screw for the small pulley was not tight enough (I think I busted the thread but it is holding right now) and the torque when going up was enough to need a few rotation before actually moving up.
    Thanks all for the help and advice.

    Laurent
     

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