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My Experiences with a clone 3018 cnc

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  • My Experiences with a clone 3018 cnc

    Well I took the plunge a couple of weeks ago and bought one of those cheap chinese 3018 cnc clones off ebay. Total cost was $230.00 delivered. The units dont come with much in the way of assembly instructions, but a quick search of google turned up the instructions required to be able to put it together successfully the first time. The unit does come with a small usb key with some software and a bunch of other pretty useless stuff, but it also has Candle 1.1 for Windows. Although I primarily use Linux as my main OS on my laptop, I have a Intel NUC which sits to the side of my desk running monitoring software for the servers, so I fired up Candle on the NUC and connected it to the cnc eager to give it a try.

    First thing I did was confirm that the thing actually moved, and sure enough it did, but what I did not realise at the time was that it was not moving as far as it should have. As I was to later find out, these units come with grbl 1.1f installed on the boards, but most of the settings have not been configured, at least not the number of steps per mm, which in my case was set to 80, when it should have been set to 800! So the first pcb test which I ran, which I threw together to test things, was a soic8 breakout board that should have been about 25x 12mm turned out to be about 3x1mm or so.

    After I corrected the grbl settings, I then ran another test and this time the X axis distances where ok, but the Y axis was all over the place. Turned out, I had not tighted up the grub screws on the lead screw for the table properly. Doh! So after correcting that issue, it was time for yet another test and this time at least the distances where all looking good, but the quality was terrible. I was trying to mill about 0.5mm tracks, but the unit was taking off way more copper than that.

    So time for some more investigation and I determined that the Z axis assembly had probably close to 0.5mm of play in all directions, which is not good for a cnc. The Z axis is supplied already assembled on these units, so I had no reason to really look at it closely when putting the cnc together. I removed the Z axis and pulled it apart and discovered that the LM8UU bearings were very sloppy. I ordered some replacements and when they turned up yesterday, instead of actually using those new ones, I took the original ones apart and found that they were all missing quite a few balls. After replacing the balls using one of the ones I bought as parts, I reassembled the Z axis and it was rock solid. I did notice that there is still some play on the Z axis, which is coming from the 10mm rails for the Y axis, but I will be replacing those with 12mm linear rails as soon as they arrive.

    So I performed another few tests, this time from Linux using bCNC and although I still have a little way to go, things are looking very promising now. This is the soic8 wide to 2.54mm header that I did last night. Its messy as I went over it a couple of times, testing the accuracy and depths, but its a step in the right direction. I cut this with a 0.1mm 10 degree bit.

    pcb_success.jpg
    -- http://www.2000cn.com.au
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  • #2
    image_148530.jpg This afternoon I finally tried out a full circuit board. Its my very first attempt and I am still working out the feed rates and depths, but considering it was my first go, I think it turned out pretty well.

    I started and stopped it a couple of times editing the settings which is why the bottom left corner is missing tracks, but the board is only for my own use and easily fixed with some jumper wires.
    -- http://www.2000cn.com.au
    Business Web and Email Hosting and Spam filtering

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    • #3
      I put clone 3018 cnc in google to see what the machine you are using looked like and this thread was first lol

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      • #4
        Pretty good for a calibration run.
        Is your PCB bowed or just camera distortion?

        Also looks like you might need to increase track thickness on diagonal and horizontals to compensate for CNC tolerances.

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        • #5
          Ended up redoing that board seeing as it was my first attempt and there was quite a few tracks missing. I cut too deep initially and thats why some of the tracks were completely gone. This is how the board came out the second time. Have to say I am very happy with this second attempt.

          Board2.jpg

          As with most of these things, when I buy them, I do so just to use as a starting point. I will be modifying the system a fair bit over the coming months as the bits and pieces turn up. Today the Z Axis linear rails turned up, and hopefully sometime this week the X Axis rails will arrive too.
          -- http://www.2000cn.com.au
          Business Web and Email Hosting and Spam filtering

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          • #6
            Originally posted by ozfalcon View Post
            Pretty good for a calibration run.
            Is your PCB bowed or just camera distortion?

            Also looks like you might need to increase track thickness on diagonal and horizontals to compensate for CNC tolerances.
            Its just camera distortion. I think I took the photo through my magnifying lamp which caused it to look a bit strange.
            -- http://www.2000cn.com.au
            Business Web and Email Hosting and Spam filtering

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            • #7
              Looks great! Do you use a drill press for the through holes? Could the CNC do them too?

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              • #8
                Originally posted by Zzap View Post
                Looks great! Do you use a drill press for the through holes? Could the CNC do them too?
                I forgot to take a picture after doing the drilling and cut out. I do the drilling and the board cut out on the cnc as well.
                -- http://www.2000cn.com.au
                Business Web and Email Hosting and Spam filtering

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                • #9
                  Nice! Seems great value for DIY PCB prototyping

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                  • #10
                    Originally posted by cwispy View Post
                    Ended up redoing that board seeing as it was my first attempt and there was quite a few tracks missing. I cut too deep initially and thats why some of the tracks were completely gone. This is how the board came out the second time. Have to say I am very happy with this second attempt.

                    Board2.jpg

                    As with most of these things, when I buy them, I do so just to use as a starting point. I will be modifying the system a fair bit over the coming months as the bits and pieces turn up. Today the Z Axis linear rails turned up, and hopefully sometime this week the X Axis rails will arrive too.
                    Great work.
                    Just add a border to your PCB and ensure your fills are all grounded. Also add a board revision & logo for the finishing touches.

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