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  1. #1
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    Feb 2010
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    58

    What causes the singe/scorch look on the cut? (C02 Laser)

    Attachment 214006
    On these test cuts, I varied the speed, gap, power setting and air flow, in an effort to understand factors influence the formation of the patterns.. and I can't figure it out. The interesting part to me is also how the effect is always to the right or downward.

    There are times when it doesn't happen at all, other times it's very pronounced.

    Attachment 214008

    I thought it might be the direction of the air inlet but rotating it does not matter.

  2. #2
    Not enough air at pressure my friend.

    Click image for larger version. 

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    With more air you end up with it like this

    cheers

    Dave

  3. #3
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    Jul 2009
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    18
    The one reason could be air flow from the nozzle especial if there is no airflow through the cut. That is the reason of some smoke at the start of a cut.
    The second reason is bad alignment of the beam especially if the beam is not the same all over the bed.
    Firstly make sure that the beam is 100% parallel to the X-axis and Y-axis rail. No exceptions.
    Attachment 215046
    Secondly make sure that the beam enter the hole of the nozzle on top in the center. If not, then adjust the laser tube only, not the mirrors.
    Attachment 215044
    Thirdly adjust the downward beam to exit the bottom of the nozzle.
    Attachment 215042
    Lastly adjust the bed level to the nozzle by using a piece of wood between the nozzle and the bed. Distance should not vary more than 0.5mm on all areas of the bed.:wave:

  4. #4
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    Feb 2010
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    58
    The gap distance does vary on mine, due to the way the bed is constructed. The machine originally was designed to cut with the material laying on a solid surface, and that was changed by half inch aluminum angles of various lengths. Three 48 inch running the length of X, to 24", one at each end of X, along the Y axis, and 12" sections inside mid sections, held in place by 12" ceramic tiles as a base for the laser to hit.

    Attachment 217708

    On top of that I have stretched metal ('diamond pattern' like a grill) where material being cut can have air space underneath, and is held in place by magnets. This provides a pretty consistent gap in the prime cutting area.

    If I could find steel honeycomb, much like the aluminum variety, I'd be set, and could build a new table with the ability to draw air from the bottom.

    Attachment 217702

    Attachment 217704


    Though I must say, aligning that laser is sometimes a frustrating challenge.

    I did change the regulator to one that provides for more air flow and that seems to have done the trick as mentioned in an earlier reply.

    Thanks for the diagrams, and further explanation.

    On this page, and further- is where I built the beam combiner after changing the original tube that I had, for this RECI refillable tube.

    The Speed of Orbit »

  5. #5
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    Join Date
    Nov 2008
    Posts
    350
    When ever I cut wood on my honeycomb surface I get a lot of wood residue in the honeycomb pattern. I have to remove it with oven cleaner. The bottom of the wood gets some residue but the beam and material tend to shoot into the honeycomb and not blow back to the top of the material.

    A strong air supply could help blow material into the honeycomb but if it's blocked the residue will backup and blow against the top surface.

    You are burning wood when you cut so the material has to go somewhere that's why it's also important to cut with a beam that's has pinpoint focus into honeycomb with a strong downwards directed air source


    Sent from my iPhone using Tapatalk

  6. #6
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    Nov 2012
    Posts
    477
    Two things I've done that improve my cuts were to raise the honey comb about an 1/8 inch off the solid table, this let a lot off that burn debris like soot get sucked down under the honeycomb and out the exhaust and I also raise the material about a 1/4 inch above the honeycomb, for the same reasons. I get little to no charring, and no buildup or soot marks on the underside of the material.

  7. #7
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    Join Date
    Nov 2008
    Posts
    382
    hi there
    if I cut anythings I raise the material with 5mm SS rods
    greetings
    waltfl

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