Thursday 16 January 2014

axCut Laser Cutter - cracked it! z axes working, honeycomb bed installed - lovely jubbly!


Have finished installing the z-axes drives along with the honeycomb bed, and it has made such a difference.  I've been able to run some test cuts and finely calibrate the focal point (to within 0.1mm).  The host comms also seems to be behaving better (I'm convinced it's my windows laptop causing issues).

So... here's a video of it all working together - and it is working extremely well.  The test cut in the video is based on a friends wedding invite, and has converted into just 2223 lines of gcode - nice and compact thanks to the bezier curves!

The finished cut is very, very good - comparing it to the commercial reference (from same design file) it's as good, if not better (less wobble to the edges).  The low feedrate I've used may also be a contributing factor, but I'm still feeling rather smug.

Still lots to do on the hardware side (enclosure, cable chain for air assist, a rigid trolley), but for now, I think I'll take some time to play with cutting stuff!


23 comments:

  1. Im running from linux and I get the comms isues on my hobuilt laser cutter when the laser fires at certain powers for certain time frames... it's interferance for me... I managed my cables better, tried some shielding and used a usb cable with noise reduction and it helped a lot.

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  2. Laptops are generally not the best platform to run CNC from. They have power saving functions which are difficult or even impossible to disable, which can cause interruptions in communication with the port(s) used to control the CNC system.

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  3. thanks both - will try a shielded cable, but ultimately the RPI is going to run the jobs, so hoping that will help

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  4. Can this do raster and vector engraving?

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    1. theoretically both, but haven't tested either yet

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  5. Hello,
    Could you tell me where you bought the laser tube?

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    1. from ebay, user: http://www.ebay.co.uk/usr/cnsigntech

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  7. I cloned your git repository and took a look at all the work you have done. Absolutely fantastic. I bought an ebay laser last year but have always wanted to build one. I might implement a similar bed in my ebay laser with 4 steppers like you did. Did you develop anything to level the bed to the head at all 4 corners? If so it would be great if you could include the details in a future video.

    I'm going to price out the extrusion in the BOM. I printed a few of the STL files just to get a feel for the design. I am thinking I may take the parts from my existing laser (500x300mm) and use them in this design.

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  8. After looking at your videos further I see you are driving the 4 z steppers with a single driver. I thought you might be driving them independently hence my question above.

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    1. @xnaron - thanks the feedback, glad the git repo is useful... I didn't consider independent drivers for the z-axis motors (for auto bed levelling), but decided it was overkill. Certainly calibrating a laser doesn't appear anywhere near as sensitive as a 3D printer, so I think a manual one-off calibration of the bed is probably sufficient.

      If you're buying extrusions in the UK, I got mine from:http://www.aluminium-profile.co.uk/
      Cheap, quick service and everything cut to length with good tolerances.

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  9. Excellent work Damian! I was wondering if you could provide more info/links to the honeycomb bed and the optics setup you selected?

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  10. @tbone_atl - thanks, the honeycomb bed is from easycomposites:

    http://www.easycomposites.co.uk/products/core-materials/19mm-aluminium-honeycomb.aspx?LineItemId=801207a4-8268-43c6-842c-8c3f65a41579

    the optics setup is 25mm mirrors, 1.5" focal-length lens. Optics, 40W laser and PSU are all from: http://www.ebay.co.uk/usr/cnsigntech

    I ordered the complete set as a bundle to save on shipping - combined cost was just over £375 inc import taxes.

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  11. Great work! I'm thinking of following your lead and building one myself.

    In the video I see a stepper on the right side of the machine, but it doesn't show up when I render the OpenSCAD files, although I see code for it. I can't easily figure out why it doesn't render, can you give me any pointers?

    I did learn some new tricks looking at the OpenSCAD code (I had never heard of the attach library before). Lovely!

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    1. HI Ward
      Thanks - and had forgotten to add the 2nd y motor into the CAD model. I've just updated it and committed the changes. Towards the end of the build, I got a bit lazy and didn't add some of the smaller parts into the combined model - cable mgmt brackets, limit switches, etc! Will have to find some time to sync the CAD model with reality at some point...

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    2. Thanks for the addition!

      I was wondering about the other bits. Looking forward to your sync.

      Also, did you only use printed brackets/gussets or did you use some metal ones as reference angles?

      Keep up to good work, I really appreciate it.

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  12. I've been looking at the design and I'm very impressed. I'm thinking of working from it for my own build. I would like to scale it down ever so slightly though. I changed the sized of the bed in the code which I believe everything else calculated from and it looks good however the BOM gets way thrown off. Is that the only variable that really has to be changed to change size?

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    1. thanks and it should be as simple as that... will have a play tonight/tomorrow and see what might be going on. Have you forked the repo? if so, let me know the link and I'll clone a copy to review.

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  13. Im gathering parts for this build but i have a few questions regarding electronics selection. I noticed you changed throughout the build. i would rather now have to in my build and just go with what seemed to have worked best for you.

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    1. Sorry for the slow reply - got lost in notifications. The current electronics set is a common Arduino Mega 2560 + RAMPS 1.4 board, a cheap chinese stepper driver for the Z-axis (parallel wired to all 4 steppers), a relay module to power the laser PSU, the laser PSU itself (from China, came with the laser tube), an ATX PSU for the low voltage stuff and a Raspberry PI host.

      Would be great to see pictures of your build - are you sharing them online anywhere?

      thanks
      D

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  14. Excellent and helpful post… I am so glad to left comment on this. This has been a so interesting read, would love to read more here…. laser cutting machine

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  15. I have 2 questions for you. What are the stepper motors that you used for the bed. Also, what do you think of using a fiber optic cable to carry the light from the laser to Trolley.

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