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Thread: Engraving shows random lines

  1. #1

    Engraving shows random lines

    I have compiled a photo for engraving on my GCC Mercury 25W laser. I start up the laser at sees the little (!) guy engrave as was its life depending on it. Very satisfying view

    After the engraving was completed, I examined the result for quality and the like and found some odd stuff, I hadn't bargained for, as it seemed:

    Besides the very nice engraving, there were 3 or 4 random lines of random dots all across the engraving - also at places where there were no information in the file.

    I immedietly sent the file to the vendor and asked them to engrave the same file. It came out perfect by them.

    I now suspect 2 things:
    * Either there is a bug in the mainboard controlling the laser or
    * there is noise in my cable between the computer and the engraver.

    To add to the info, I use an USB->Parallel-cable, which seemed to be the only thing that would communicate with the machine.

    I use a laptop (which comes without an LPT-port) and tried a PCMCIA-card first. This couldn't communicate with the machine. Then I tried the parallel port in my USB-hub, which created odd offset-errors. Finally I tried the direct USB-LPT-cable, which seemed to work - until now.

    Any ideas?

    Best regards
    Peter

  2. Peter ,
    can you post a picture of the tile so we can get a better idea of what your problem might be?

    Tom
    Explorer II 30W & Corel V12

  3. #3
    Attached to this post is a scan of the engraving. The lines should be easy to spot, though I had to compress the image a lot due to file size limitations.

    Also attached a cut out enlarged.
    Attached Images Attached Images

  4. #4
    [quote=Peter Boyford;715115] . . . there were 3 or 4 random lines of random dots all across the engraving - also at places where there were no information in the file. quote]

    Peter, can you clarify the second half of the statement? Did you mean there were rows of dots OUTSIDE of the boundary of the graphic?

    This problem might be very difficult to track down. Is the USB cable a shielded cable? If you have any doubts about it, you might want to buy the best cable you can find to at least rule that out. Does the cable you are using have electronics built into the cable or connector shells? I assume there is, as USB is serial data. If so, it could be that the electronics are causing the glitches.

    Can you get a desktop PC (at least to do some testing?) In that case maybe you could get the standard LPT port to transfer data. (If it still fails to engrave correctly then you know the problem is likely in the laser system rather than in the PC/cables.) I have heard of several cases where laptops just would not behave like a regular PC when connected to CNC equipment. I'd certainly rule out the PC and cable first, as a desktop PC is cheap compared with replacing the mainboard. You don't need anything fancy to drive the Mercury - an older PC will probably do.

    The only time I have seen laser marks outside the boundary of the graphic was when the tickle threshold for the laser tube was misadjusted - meaning that the laser would fire when it was not supposed to. But I don't know if the marks you are showing within the boundary are indicative of a tickle problem. Have you contacted GCC with the photo?

  5. Laser Ghosts I call them

    At first I thought maybe you had the same problem I have been having the past couple of days. Everytime I tried to engrave something it would always leave "something" there that wasn't on in the file. I called my tech support people and the first question was, what type of material are you using? I was using Rowmarks brushed metal (very reflective I guess) Anyway, the tech said it was my laser bouncing off the material and hitting the cross bar or something and coming back down on the material. Make sense because I didn't have the issue with other substrate material now that I think of it. Something new everyday. Good luck, I am sure the Guru's here on the board will steer you in the right direction.


    Pinnacle M30, Corel x3, photograv

  6. #6
    If you figure this out, please post what you found. -thanks steve
    Pinnacle/Mercury 30w Corel x3. Laser Master 8.0v3 Photoshop

  7. #7
    Peter, I'm still pondering your problem . . .

    When you said "the vendor" did you mean your GCC distributor was able to plot it correctly?

    Unfortunately, you are running an unusual system - not many people are likely using the USB-to-parallel method. That puts you in a minority as far as debugging etc. If you run an unusual system, it will never have been tested by the manufacturer and any bugs will not have been found.

    Some years ago, when I bought my laser, the system requirement was Windows 95. When I reported a problem, I was told that they were testing internally with Win98 so I should upgrade (before they would look at the problem.) When the problem did not go away it was blamed on Corel - I should upgrade to Corel 11. (The problem did not go away either.)

    So if you are using an unusual configuration (and mine was not actually unusual) you may have difficulty in getting any technical support. The manufacturer is not likely to buy a bunch of converter cables to test, when the user base is tiny.

    The USB to parallel cables were designed for printers. Whether they work on a laser depends on how closely the laser interface mimics a printer interface. And the manufacturer may not even be able to answer that question . . .

    I'm not saying that it's the cable causing your problem - but until you prove that it is NOT the converter, you will probably have difficulty getting your problem in the queue for resolution. Just my opinion based on my experience in reporting problems.

  8. #8
    Join Date
    May 2008
    Location
    Granada,Spain
    Posts
    21
    Hello Peter,
    I have read your message and wanted to make a query.
    How to set the USB adapter to LPT?
    I also have a Mercury L30 and buy a USB adapter to Centronics the mark BAFO BF1284, to use my laptop, but do not get it to work.

    On your problem, I guess they will have it solved.
    But I think that may be due more to an accumulation of dirt on the encoder engines, I sometimes happens, it is a matter of cleaning up the dust is settled.
    Sincerely
    German
    PS: Sorry for the grammar, but I do not speak English and use google as a translator.
    GCC Mercury L-30 , PHOTOGRAV 2.11 , GIMP , InKscape

  9. #9

    poor engraving

    you didnt mention how old your machine was,
    i recently suffered a similar problem with lines over the image , they seemed to be evenly placed .
    after a lot of trial and error i managed to track the problem down to a defective stepper motor. having changed the motor the problem was solved.

    we also had a similar problem with a versa laser we hired short term and that turned out to be a loose rf board so worht just giving them a check to see if they are seated correctly , apart from that im at a loss but hopefully with all the posts you should solve the issue one way or another
    who dares wins? so throw it in your laser and see what happens it could make you a fortune or very poor .

    epilog ext36 75 watt on ETHERNET
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    line bending, flame polishing,thermo forming,guillotine cutting,bonding, 3 mtr CNC routing ,design ,project management
    and a partridge in a pear tree


    angry bank manager

  10. #10
    Join Date
    Oct 2004
    Location
    Cape Town, South Africa
    Posts
    3,922
    Looks like a data problem , the gcc's dl the whole file to the laser and noise in the transmission will give results like that. I would buy an old rubbish puter as a print server for sending....
    Before doing that however , I would also check that the problem is "random" , Ie send the file again and see if the lines and dots appear elsewhere or not at all, if they in the same place , there is another problem.
    The older mercurys had an issue in that the x motor has a badly sealed cover over the encoder , you need to pry off the cover , use a soft brush to clean the encoder and the reading eye assembly , replace the cover (it slides off , you can see the channel it slides off on , you need a small screwdriver to pry the ends away from the channel to slide it off)
    When you replace the cover , use masking tape to "seal" any gaps.
    Its real easy to remove the X motor and replace it , belt tension must be "TIGHT".
    Generally an X motor encoder malfunction will either "skew" the engraving or not let the laser initialise...but what you are getting can also happen
    Rodney Gold, Toker Bros trophies, Cape Town , South Africa :
    Roland 2300 rotary . 3 x ISEL's ..1m x 500mm CnC .
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    1600mm hot and cold laminator , 3x Dopag resin dispensers , sandblasting setup, acid etcher

  11. #11

    Exclamation

    Peter,
    I have the same machine that you have. I’m using a usb to serial cable which came with the machine and have had no communication issues. If you have that cable and the driver for it, that should work but, it’s very important that the com-port communication speed in the computer match your communication speed in your engraver. I have both set at 57,600. I’m not sure if that will resolve your problem with the engraving but, it could eliminate one of your possible issues. Hope this is helpful.
    Ralph

  12. #12
    Join Date
    Oct 2004
    Location
    Cape Town, South Africa
    Posts
    3,922
    Just another thing to try is reseat the RAM on the motherboard , or replace it , that too can lead to issues witn engraving.
    Rodney Gold, Toker Bros trophies, Cape Town , South Africa :
    Roland 2300 rotary . 3 x ISEL's ..1m x 500mm CnC .
    Tekcel 1200x2400 router , 900 x 600 60w Shenui laser , 1200 x 800 80w Reci tube Shenhui Laser
    6 x longtai lasers 400x600 60w , 1 x longtai 20w fiber
    2x Gravo manual engravers , Roland 540 large format printer/cutter. CLTT setup
    1600mm hot and cold laminator , 3x Dopag resin dispensers , sandblasting setup, acid etcher

  13. #13
    Join Date
    Oct 2005
    Location
    Moreton, Wirral, UK
    Posts
    3,287
    Just a mention on your image as I'm sure someone will have covered the line problem. The image you have engraved should be reversed. The picture you posted shows the cat in negative.
    Epilog 45w Helix X3/X5 Corel Microflame Generator (flame polisher) Heat Bender


  14. #14
    Exact same problem here!

    My first Mercury 25 watts showed same random lines not engraved and some graphic images have minor distortions.

    And on the same day, my second mercury 25 watts displayed "x motor malfunction".

    for the first mercury my dealer said to try re installing the driver. but I think it is more of a hardware problem. Maybe re aligning the beam? The rollers on the top of the carriage were replaced a few weeks ago and I did notice that the roller on the left side sometimes does not turn (seems like it is floating) when I slide the carriage frm side to side.

    waiting for more suggestions from you guys. soonest my dealer is available is after new year and I'm in the middle of a big job.

  15. #15
    Join Date
    Oct 2004
    Location
    Cape Town, South Africa
    Posts
    3,922
    Remove the X motors and clean the shaft encoders.
    Rodney Gold, Toker Bros trophies, Cape Town , South Africa :
    Roland 2300 rotary . 3 x ISEL's ..1m x 500mm CnC .
    Tekcel 1200x2400 router , 900 x 600 60w Shenui laser , 1200 x 800 80w Reci tube Shenhui Laser
    6 x longtai lasers 400x600 60w , 1 x longtai 20w fiber
    2x Gravo manual engravers , Roland 540 large format printer/cutter. CLTT setup
    1600mm hot and cold laminator , 3x Dopag resin dispensers , sandblasting setup, acid etcher

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