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Thread: Fiber laser - not smooth engraving

  1. #1

    Fiber laser - not smooth engraving

    Hello,

    I have a Raycus 50wt + 200*200 table.

    Material: Stainless steel painted with black powder polymer paint.

    A task: get smooth bright engraving.

    The parameters were selected for that engraving:
    - 2 loops:
    Line Width - 0.05
    90power\400speed\20freq\0angle
    - 2 loops
    Line Width - 0.05
    42power\2000speed\20freq\90angle

    Engraving goes well, but smooth engraving does not always go well, there are time to time lines with different shape of color in different places of engraving, I think its probably knocks out more material or I am mistaking with this. Also I remove the vibration of ventilation, it helps but sometimes still lines ((
    And sometimes it’s good, there is no lines at all, and sometimes there are in different places. I already tried to change different modes, angles - the problem does not go away (
    Please tell me how to solve this problem.
    Thanks in advance for your reply.

    05.jpg
    04.jpg
    03.jpg
    02.jpg
    01.jpg

  2. #2
    try the changes in blue:

    The parameters were selected for that engraving:
    1 loop
    Line Width - 0.06
    90power\1000 speed\50freq\45* angle cross hatch
    - 3 loops
    Line Width - 0.1
    35 power\2000speed\50freq\90angle

    the line width will keep heat down while still cutting okay, and the cross hatch should help remove the coating more efficiently, and eliminates one loop-
    the reason I raised the freq is because, as I understand it, the wattage of a fiber laser determines it's lowest capable frequency, watts=freq... I'm curious if you'll notice any change..
    the 3 loop run is a cleanup pass, intended for bare metal- lower power the large line spacing will run a good cleanup pass with less heat, hopefully keeping the metal from darkening. Might do well to make it a cross-hatch too, with only 1 or 2 loops..

    You may require several runs to clear the coating out well, but hopefully not


    ========================================
    ELEVEN - rotary cutter tool machines
    FOUR - CO2 lasers
    THREE- make that FOUR now - fiber lasers
    ONE - vinyl cutter
    CASmate, Corel, Gravostyle


  3. #3
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    Also, insure that you don't have stray vectors. appearance looks like you might..... Those can leave blank spots in hatch.
    Changing the hatch angle can move them or eliminate also.
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  4. #4
    Quote Originally Posted by John Lifer View Post
    Also, insure that you don't have stray vectors. appearance looks like you might..... Those can leave blank spots in hatch.
    Changing the hatch angle can move them or eliminate also.
    Can you please explain about ~Stray vectors~ ? What they are and does change of the hatch always eliminate them.
    Thanks in advance.
    Last edited by Maxim Pernatiy; 10-25-2019 at 3:26 AM. Reason: missing worg

  5. #5
    hatch routines: EZcad has a-
    uni-directional (hatch icon with diagonal lines), engraves left to right only, slow but very precise and clean-
    'ring hatch' aka 'island fill', where it engraves the outlines outside-in-
    and then the 3 bi-directional hatches, which EZcad calls bi-directional, optimized, and optimized 'gong'-

    These are the main 2 everyone uses, left optimized (all blue), right bi-directional (longer, blue with red ends or NO ends depending on your version)
    hats.jpg
    -- I just hand drew these, they're easier to 'read' than the screenshot versions...

    note, the 'gong' hatch is the icon with the broken lines, more later--

    The optimized hatch is different from all the others in that the ends are connected, meaning the laser's always firing when it changes direction, AND, the fact that it doesn't engrave white space, it only engraves what needs to be engraved. This saves gobs of time because (a) the laser runs faster with connected ends as it doesn't have to slow down to stop and re-start the next line, and (b) because the other routines engrave whole entities in one pass- example, the letter O, optimized will follow and engrave only within the lines needing engraved, the other hatches will sweep the entire O.

    While optimized (I call it the 'fast hatch') is very fast, it comes at a price: First, This hatch, and sometimes the 'gong' hatch, will create the stray vectors John speaks of, so you have to watch for stray lines that don't belong, they WILL engrave!
    Second, the connected ends make for hotter engraving along the edges, which can cause issues. Third, the fast hatch can and will move in different directions, depending on which way is faster. This is great for deep engraving, but for aesthetic engraving, when a hatch that ran downhill connects to a joining hatch that run uphill (for example), the hatch cuts can look different, due to how the cut lines reflect ambient light. This is what happened during this test engrave (had the laser about 2 days )
    hat3.jpg
    For the final engraving on this I used the uni-directional hatch-so smooth it almost looks acid etched-
    hat4.jpg

    The 'gong' hatch- it's essentially a dead even split between the other 2 hatches: Like the fast hatch, the ends are connected but ONLY along outer borders, the inner borders are not connected, because it sweeps entire entities, one direction only. So it's a bit faster because half the hatch is connected, and runs cleaner since the hatch runs one direction, no mis-matched lines. Works well if the extra edge heat isn't causing problems. BUT, beware of stray lines...

    I don't know about anyone else, but I nearly always the basic bi-directional hatch on everything except black anodized aluminum, for that I use the fast hatch in most cases..

    I'm not sure which hatch you're using but I recommend the bi-directional.

    A final note on white-space and sweeping, and "ALL CALC" ... All Calc means everything engraves in ONE sweep. In many cases it's a time waster, but when you have entities within entities within entities-- A bullseye target for example, engraving with basic bi-directional will sweep each target ring individually. If there's 4 rings, that's 4 sweeps. But the outer sweep covers the whole target anyway, so using All-Calc on a target, all 4 rings engrave in ONE sweep.

    Hope all this helps!
    ========================================
    ELEVEN - rotary cutter tool machines
    FOUR - CO2 lasers
    THREE- make that FOUR now - fiber lasers
    ONE - vinyl cutter
    CASmate, Corel, Gravostyle


  6. #6
    Hello Kev,

    Thanks for your reply.
    I have test using your parameters:
    1 loop
    Line Width - 0.06
    90power\1000 speed\50freq\45* angle cross hatch
    - 3 loops
    Line Width - 0.1
    35 power\2000speed\50freq\90angle

    and get the result with big black points(its black paint, as I think, because the material is painted stainless steel by black paint)
    here is the picture of the result:
    1_1.jpg


    I have also try to reduce line distance to 0.03 using my first parameters and change all angles to different ones:
    - 1 loop:
    Line Width - 0.03
    90power\400speed\20freq\-45angle
    - 1 loop:
    Line Width - 0.03
    90power\400speed\20freq\45angle
    - 2 loops
    Line Width - 0.03
    42power\2000speed\20freq\90angle

    It helps, but still have lines(left bottom angle of the star, there is vertical line):
    03.jpg

    I need bright engraving without paint residue and lines, its my target.
    Maybe I need for the first many loops with low line width, in order to keep heat down and remove black paint and residue of it and then many loops of polishinig with low line width too?
    Thanks in advance.

  7. #7
    Also one of fiber machine setup specialist on my side tell me that the reason of the lines may be due to vibration and unstable head of the laser.
    For the first I remove all vibrations with my fiber, put a rubber gasket under the fiber, under the table with fiber and make a vibration test while doing the enagraving. The vibration is 0.
    The unstable head reason I dont quite understand and dont know how to test for it also.
    For all my engravings I am using the following type of Hatch:
    04_1.jpg

    Also I have tested with my first parameters using unpainted stainless steel, and still get the vertical line in star ( :
    The parameters were selected for that engraving:
    - 1 loop:
    Line Width - 0.05
    90power\400speed\20freq\-45angle
    - 1 loop:
    Line Width - 0.05
    90power\400speed\20freq\45angle
    - 2 loops
    Line Width - 0.05
    42power\2000speed\20freq\90angle
    05_1.jpg

    The mail goal is to get white bright engrave with no black paint residue on painted stainless steel.
    I think I just need a few procedures:
    1. Paint removing until stainless steel
    2. Paint mess removing
    3. Polishing until white color

    Also it Tykma manual there is no parameters for "Ablating"(or it uses different name) and no parameters for "Frost" for stainless steel. The frequency in Tykma is too high too as I think. As far as I know Raycus operating 20-80KHz.
    Last edited by Maxim Pernatiy; 11-20-2019 at 3:05 PM.

  8. #8
    One of your issues may be the 50 watts you're pushing- I know there is a scientific reason, and a calculation for, the lowest frequency a fiber laser is capable of, but I'm not smart enough to know what they actually are- -- but the laymans calculation is simple: A fiber laser cannot fire at a frequency (in kHz) any lower than it's wattage-- which is to say, your 50w laser cannot or will not (not sure which is more accurate) below 50kHz. Likewise, my 30w fibers can't fire below 30kHz, and a 20w laser can't fire below 20kHz. This could be why 20w fibers are fairly efficient when metal engraving because a 20kHz beam 'digs' better than higher freq. beams. Even though you can enter numbers lower than 50kHz, your laser is likely ignoring them (like mine do)

    Lasering stainless takes some practice, because it's NOT very forgiving, if you warp it, it stays warped; if you discolor it, you can maybe lighten it a bit but usually it stays discolored. For LIGHT etching of stainless, low power/high speed and lowest possible frequency is necessary to prevent discoloring. (high frequency adds substantial heat) Also, wider hatch spacing, like .07 to .10, using a 45° hatch

    As to your vertical lines, I have no idea what would cause that while engraving within a hollow object. If it were engraving say, the letter O using the fast-hatch, that would make sense because fast hatch will engrave in different directions, and where 2 sections engraved in different directions meet there can be a visible line. But your engraving is only moving one direction in an open graphic. It's as if your mirrors are slightly changing position in that spot. Maybe they are?

    There's a couple of things to try. First, what are your laser's TC settings? If they're not set reasonably correctly weird things can happen. My 2 ebay lasers I have set identically, and both engrave nicely, and fast.
    This is their TC settings (under the speed/power settings)--
    tcsets.jpg
    My Triumph fiber's settings are close to these, but when I first got it I experimented with some settings that seem to work okay, but if use those settings on the ebay machines, they engrave much slower, and the engraving quality suffers, edges look ratty, etc... You might enter my settngs and see if it helps. (there's a section in the EZcad manual that explains this in more detail)

    Another option is to try the 'all calc' setting in the hatch menu:
    acalc.jpg
    What all calc does is engraves everything that's hatched as a group as if were a filled box, the laser starts at one end, and makes a continuous sweep to the other end, with no stops and re-starts. The result should be very smooth...

    Finally, you might try the Auto Rotate hatch function:
    ARO.jpg
    how to make this work for you, is run one single hatch, or one cross hatch, started at 0 or 90 degrees. If using a cross hatch, set rotate to 15 degrees like in my pic. DON'T run extra loops or 'counts', keep them set at 1 (extra loops don't rotate, only extra PASSES rotate )
    If using a cross hatch at 15°, then 6 passes will automatically run an equal full circle of hatches in 15° increments, pretty high-resolution. Or you can get the same results running 12 single hatch passes..

    Or set rotate to 30° and run 3 cross hatches or 6 single passes... you get the idea! With than many passes, be sure to run fast at lower power...trial and error time

    With all the hatch overlaps, and revised TC settings, getting rid of the paint should be easier, And there should be NO vertical lines left over. If there are still vertical lines, I would assume you either have a bad controller, or one of the galvo motors has a problem...
    ========================================
    ELEVEN - rotary cutter tool machines
    FOUR - CO2 lasers
    THREE- make that FOUR now - fiber lasers
    ONE - vinyl cutter
    CASmate, Corel, Gravostyle


  9. #9
    I have the following TC settings:
    01.jpg

    I've change the TC settings to yours and get different color result(no white):
    03_1.jpg

    And when I change the TC settings and check "All calc" I receive the following:
    02_1.jpg

    The big color change, and in first case, its like metal scale.

  10. #10
    Its weird, but when I move my laser head table block (i have portable fiber) from my iron workshop table to the floor - there are fewer lines in this case, but they are still exist. Maybe the reason is inside the laser head table block or something like that, or laser head itself. (
    Last edited by Maxim Pernatiy; 11-22-2019 at 5:04 PM.

  11. #11
    Already have a good microscope, please advice the procedure and parameters for check factory driver defaults and galvo motor check.
    Thanks in advance.

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