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Laser retrofit

Discussion in 'Laser Cutters' started by tonywish, Nov 14, 2015.

  1. tonywish

    tonywish New
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    Hello Guys,
    New member here. I have been a cnc guy for many years, have a 4x8 Camaster with Vectric software and WINCNC control board. I want to put a laser on the gantry to do engraving, possibly 3D and cutting. I will first have get the proper laser at a reasonable price than match it to my control card. I would appreciate any input from the members as to problems I will encounter and which laser to purchase and then how to hook it up and make it work.

    Thanks guys,
    Tony
     
  2. Tweakie

    Tweakie OpenBuilds Team
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    Hi Tony,

    You don't specify the type of laser you will be wanting to use.

    If it's any help to you, the basic details of how I fitted a CO2 laser to my machine are here; CO2 laser. | OpenBuilds

    Tweakie.
     
  3. tonywish

    tonywish New
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    Tweakie,

    Thanks for the response. I wanted to use a laser best adapted to my machine which is a Camaster 4x8 CNC router. I would like to cut plywood and acrylic and some lithographs. I looked at diode lasers as it looked as they were the best fit and easier but would not accomplish what I wanted to cut. I chose the laser but then there was the difficulty in the inherrant design, mirrors, lenses, etc. I like your concept and design. One issue is that my control card is WINCNC a direct competitor to Mach 3. WINCNC has indicated they have the capability, however will not guraantee any results as it is a diy project without professional engineering. So the hook up and control might be an issue.
    I like your design and build. Do you have a parts list etc. available?

    Tony
     
  4. Tweakie

    Tweakie OpenBuilds Team
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    Hi Tony,

    Sorry I have no parts list available.
    Because lasers are extremely fast acting devices it was necessary for Artsoft to develop a suitable switching method within Mach3. This was accomplished with the M11/M10 commands which switch an output (on/off) at the instant of axis movement. I have not used the WINCNC system but if it can switch an output without any delay you should have no problems using a laser with that system. The actual hook-up should be no problem either.

    Tweakie.
     
  5. tonywish

    tonywish New
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    Thanks Tweakie, I will continue the process in putting this together. Hopefully have something in the near future.
    Tony
     
  6. tonywish

    tonywish New
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    Tweakie,

    Here is a responce from our control board mnfg.
    The dedicated laser gate output from WinCNC is motion matched. So in vector or raster engraving the laser pulse is generated in perfect synch with the first step pulse of a move. The general purpose outputs are handled differently. If you were using a GP output to control the laser on/off, for cutting, then there would be a small delay (1-20ms) between the time the output is set high and the first step pulse is sent.
    Will this work for the speed?
     
  7. Tweakie

    Tweakie OpenBuilds Team
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    " The dedicated laser gate output from WinCNC is motion matched. So in vector or raster engraving the laser pulse is generated in perfect synch with the first step pulse of a move ".

    That sounds Just perfect. :thumbsup:

    Good fortune with your project.

    Tweakie.
     
  8. tonywish

    tonywish New
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    Tweakie,

    In your build you had three mirrors and two lenses. I see how the mirrors were used, however the lenses that are in the nozzle enclosure I can't see how they are installed. I take it there are two lenses in the enclosure. In ordering the lenses how do you specify the exact lens and when installing in the nozzle what is the dimension of the distance in between the lenses. Then the question of how far from the edge of the nozzle to the work piece or is this a trial and error situation.

    Doing as much home work as I can before I start laying out funds.

    Again thank you for your invaluable help.

    Tony
     
  9. Tweakie

    Tweakie OpenBuilds Team
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    Hi Tony,

    I only use one lens.

    The one in the build is plano-convex, Zinc-Selenide with a 40mm (approx.) focal distance.

    (The lens is just dropped down onto a ledge inside the silver ally tube, followed by a silicone "O" ring and then held in place by the black ally tube which is in turn secured with a grub screw. That assembly is then clamped inside the 3 sided ally part).

    I do have other, interchangeable, lens's - typically different focal distances and different materials such as Gallium-Arsenide but the ZnSe is used the most.

    Hope this helps.

    Tweakie.
     
  10. tonywish

    tonywish New
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    Tweakie, On the two photos of women engraved in your build can you detail more of the way each was done. I know it's partly PWM but you briefly mentioned other parameters. Tony
     
  11. Tweakie

    Tweakie OpenBuilds Team
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    Hi Tony,


    The first picture has been produced by using a series of equal sized dots placed in a pseudo-random pattern called ‘dot dithering’. The image is first reduced to 1 bit then dithering software (such as Photograv) is used to create the pattern. The laser then fires the equal power dots whilst raster scanning the image.


    The second is slightly different. It’s a real-time process where an 8 bit image is raster scanned whilst each individual pixel value is converted into a series of dots which the laser then fires onto the workpiece. In the lighter areas of the image the number of dots are few whereas in the darker areas the number of dots are many. The dots overlap each other (many times in the real dark areas) and thus ‘shades of grey’ are reproduced in the work. The actual image shown was produced using the Mach3 Laser/Impact Engraving plugin (to which I have made many changes over the years) and this pdf gives some more details of it’s operation.



    Tweakie.
     
  12. tonywish

    tonywish New
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  13. tonywish

    tonywish New
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    Tweakie, Can't open the PDF with the info. Thanks, Tony
     
  14. JustinTime

    JustinTime Master
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    Yeah, the link is corrupt. Try this link.
     
  15. tonywish

    tonywish New
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    I see this is linked with Mach 3. I have WINCNC which is a pretty formidable card and software. I will need to look at comparable parameters to see if there is any tweaking ( sorry for the pun ) to be done in WINCNC. Do you have any suggestions on what to look for and adjust besides PWM, power and speed. I will see if the proprieters will allow any changes as it is a pretty closed system. If not I kight have to make a complete system from scratch which I hope to avoid as I have a very capable cncsystem in place. Thanks, Tony
     
  16. tonywish

    tonywish New
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    In using wincnc ( similar to your Mach 3 ) I was told I need software to create the image then send it to wincnc to control the machine laser. I have a Vectric product ( Aspire ) which has told me it will not work with a laser. I am puzzled they said this, but nevertheless is there a software you know that would bridge the gap to send the coding to wincnc to operate and control the machine. I called photograv and they indicated that the output is a .bmp or .tif file which wincnc will not translate into a contol code to operate the machine. Very puzzling. Thanks Tony
     
  17. JustinTime

    JustinTime Master
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    Tony, I'm kind of confused about what you say. If Wincnc is similar to Mach3 than it can not process a .bmp or .tif file. Mach3 doesn't either. You need a software that translate the file to g-code which wincnc, or Mach3, can understand. I think Aspire does that. I'm sure Mach3 can control laser since Tweakie is using it and he has a laser machine.
     
  18. tonywish

    tonywish New
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    Aspire tech support said it would not function with a laser. I was asking what program would bridge that function. Tony
     
  19. tonywish

    tonywish New
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    Tweakie, On your build I noticed in the schematic you have two psu's. The DC is apparent as it is supplying power to the cooling fans. You also feed a 9v leg back to the control terminals of the main psu that powers the tube. What is the purpose of this? Tony
     

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