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Thread: Top dumb things you've done on your CNC

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    Top dumb things you've done on your CNC

    I can go on and on, but here are a few:

    1 - I drilled some holes to hold some parts down with screws. After fastening the screws, I mistakenly didn't deselect the drill op in the second program. I actually milled off one screw head, but by the second one the bit was ruined.

    2 - When I first started using OneCNC, I didn't know how to configure the post-processor. For some reason the park Z was at 300 (probably because it's set up in metric initially). I heard my stepper stall for a few seconds, then my Z came crashing down into the table, burning a hole in it! This had actually happened to me a few times with VCarve, where my material was very thick (I only have about 5.5" of Z travel).

    3 - The ubiquitous "press start" without turning the spindle on scenario... I've conditioned myself to turn the dust collector on first, then the spindle, then Start. This will be automated eventually...

    4 - The absolute/incremental I,J thing in Mach3....

    5 - Ever forget to tighten that collet nut? It's not a pretty sight...

    6 - Wrong parameters - Sometimes I type too fast, and don't bother to check what I type. Like cutting the full depth instead of setting a DOC, adding an extra zero to the feedrate, setting the plunge too high... all with equally disastrous results.

    7 - Not cleaning the dust out of my old controller. Even Jeff at xylotex said he's only seen one other instance of a phase in an axis drive go bad. It had to be me.

    8 - Impossible to weld aluminum to steel? You wouldn't think so looking at some of my bits when I first started!

    9 - Sometimes I'll do some operations on one piece using two different CAM programs. Like for quickie stuff, I'll use Cut2D. For more intricate stuff I may use OneCNC. I'd forgotten a couple times to set the work origin 0,0 to center in Cut2D, with the predictable nightmare results.

    10 - "Oh sure, the router should easily cut through that nail..." Nope - another ruined bit!


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    Community Moderator Al_The_Man's Avatar
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    Accidentally use M4 instead of M3 and wonder why a new cutter doesn't work?
    Al.
    CNC, Mechatronics Integration and Custom Machine Design (Skype Avail).

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


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    Community Moderator ger21's Avatar
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    Try to cut at 1000 ipm and 1500 rpm, because you missed a 0.

    1/2" carbide bits shatter into quite a few small pieces.
    Gerry

    Mach3 2010 Screenset
    http://home.comcast.net/~cncwoodworker/2010.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)


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    Registered Drools's Avatar
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    #5 yep.
    #3 yep but the S-PID does that now.
    #1 yep but because the tool path came too close to the screw I had holding the material down.
    #6 yep.

    Good gcode management is essential as I have ruined material by not using the revised gcode.
    I have done my share of bit snapping due to stupidity. I have thought about making a check list sign and attaching it to the router.
    Another big one I used to do was forgetting to set the proper bit/plate offset in the Auto Zero macro. For example when doing a PCB, I set the plate offset to 0 and let the bit touch the copper on the PCB. Well if I forget the plate is set to 0 and start a wood job then I’m air cutting which is ok but still a PITA.
    The Auto Zero for X/Y is different as you can get the wrong 0,0 position if the bit/plate is set wrong, which might cause cutting into a hold-down.
    Gerry said in a post, get to know the software really well, it does pay-off in the end.
    Thank You.


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    Latest one was I left a razor blade on the part I was cutting and was running a drilling path sure enough it landed right on the razor blade. Spun that blade really fast. Fast enough to turn the razorblade blue and make a burn spot on the table.
    My CRP 48 x 48 build [URL="http://www.cnczone.com/forums/open_source_cnc_machine_designs/144173-crp_4x4.html"] CRP 4x4[/URL]


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    My favorite:
    Put all clamps in place align part and start program without actually tightening any clamp. walk away to do something (never made any scary sounds) come back a minute later to see very interesting designs cut in project.


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    Yep, i have learned (several times now) that quick is NOT fast.
    "quickly" load the next job and program and hit start....without changing the tool offsets to the new jobs tools.
    I hate it when i break a very nice new carbide cutter (or any cutter for that matter)


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    Registered Drools's Avatar
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    Also bit handling is important, carbide bits do not react well when hitting the concrete floor.
    Thank You.


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    Quote Originally Posted by ger21 View Post
    Try to cut at 1000 ipm and 1500 rpm, because you missed a 0.


    1/2" carbide bits shatter into quite a few small pieces.
    Nice! If you had 2 flutes that would have been a chipload of .333!


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    Registered IBBruin's Avatar
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    I'm glad to see the veterans making mistakes. I thought I was the only one.


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    Pushed a turret of of square in manual. Bib boob secretary was walking by giving me the eye. I was training a new set up guy at the time. Oops.


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    1.- Ran into a screw.

    2.- Reached the E-Stop box (wired) to have it at hand during a certain job, then accidentally dropped it causing an unwanted stop.

    3.- Did a profiling of a small circle without bridges, causing the remaining piece to get caught between the bit and the walls, ruining the piece.

    4.- Changing tools and forgetting to load the new g-code, goodbye workpiece.

    5.- Ruining a lot of material trying to find the reason for inconsistent engraving width before realizing my v-bit was dull to the point of concavity.


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