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  • #16
    Originally posted by Qiaozhi View Post

    If the drill head is actually resting on the PCB surface, how does this arrangement stop the copper from being scratched?
    It does leave scuff marks, but without damage. A little polishing with steel wool or a brillo pad and its clean. Thats with a plastic nose cone.

    The Elektor floating head looks like it uses a metal nose. The high priced routers from Accurate CNC use a polished stainless steel nose, shaped like a horse shoe.

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    • #17
      Originally posted by Qiaozhi View Post

      During my searches I also came across references to a spring-loaded milling attachment. Can this be used to achieve the same result?
      Qiaozhi, Do you have a link for the spring loaded attachment?

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      • #18
        Originally posted by woodbob123 View Post
        If somebody in the uk want's to build one would be happy to go 50/50 you do electrics and electronics and i can build head and do machining. Have workshop with lathe and milling mc's. Made a start with cnc a few years ago with a compumill and compucut but never finished it off.
        That sounds a great idea. Let's do it!

        It doesn't need to be a large machine for PCB milling and drilling. Let's say maximum working area of 8" x 6", unless of course you want to make PCB coils.

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        • #19
          Originally posted by Altra View Post
          Qiaozhi, Do you have a link for the spring loaded attachment?
          Probably link you posted in post #8 lead to such things.

          Citation:

          "I attached a second slider on the Z-axis. This slider is forced down with 2 springs and is upwards floatable. This flotation allows constant depth engraving across the material surface even when the material is not perfectly flat. The engraving depth is adjustable with a precision screw ring."

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          • #20
            Originally posted by Altra View Post
            Qiaozhi, Do you have a link for the spring loaded attachment?
            Here's a video ->
            http://www.youtube.com/watch?v=RYLtL1R440E

            Do you have an idea of how much torque is required for the stepper motors?
            You can purchase lots of 3 stepper motors at a time on the UK eBay site for £75 plus shipping. These motors have a torque rating of 3Nm (425 Oz-in).
            http://www.ebay.co.uk/itm/3-X-Steppe...item3a65573448

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            • #21
              Thanks for the link. That looks pretty cool, not sure how good it would work on pcbs? If it was cheaper I might order one.

              Those motors will do pcbs and widgets without problems. The motor drivers are more critical.

              Add:
              This is a good starter kit, although the motors are a bit smaller. He also has ones with larger motors.
              http://www.ebay.co.uk/itm/Value-CNC-...item231ee73085

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              • #22
                Originally posted by Altra View Post
                Thanks for the link. That looks pretty cool, not sure how good it would work on pcbs? If it was cheaper I might order one.

                Those motors will do pcbs and widgets without problems. The motor drivers are more critical.

                Add:
                This is a good starter kit, although the motors are a bit smaller. He also has ones with larger motors.
                http://www.ebay.co.uk/itm/Value-CNC-...item231ee73085
                Part of the challenge has got to be designing and building our own custom stepper motor driver board ... and then using the prototype circuit to mill out its own PCBs.

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                • #23
                  Hi Altra, how can you positioning drill to start drill trough hole PCB (after changing grinder to drill) if you use floating head. Do you remove floating head for drilling hole, cause drill is pretty invisible under plastic ring? Or this is all software solved if PCB remain on constant position?

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                  • #24
                    Originally posted by WM6 View Post
                    Hi Altra, how can you positioning drill to start drill trough hole PCB (after changing grinder to drill) if you use floating head. Do you remove floating head for drilling hole, cause drill is pretty invisible under plastic ring? Or this is all software solved if PCB remain on constant position?
                    From what I've seen in some of the videos, you drill all the holes first, then mill out the isolation tracks. The PCB is left in place during the changeover.

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                    • #25
                      I'm surprised no-one has mentioned the Lego CNC machine on youtube ->
                      http://www.youtube.com/watch?v=Cf6mWQ8QreA
                      Not powerful enough for milling PCBs, but amazing none the less.
                      There's also another one made with Technik (search for it).

                      Now ... look at this beauty ->
                      http://www.youtube.com/watch?v=CQzoG...eature=related
                      It's being used to cut some gantry supports. So it's upgrading itself!
                      I've never seen such a clean and spotless workshop.

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                      • #26
                        Originally posted by Qiaozhi View Post

                        Now ... look at this beauty ->
                        http://www.youtube.com/watch?v=CQzoG...eature=related
                        It's being used to cut some gantry supports. So it's upgrading itself!
                        I've never seen such a clean and spotless workshop.
                        Yes, impressive spindle motor, I wish to have such one.

                        Do you know good converter from some graphic format as .jpg, .gif etc. to GERBER file?

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                        • #27
                          When you make a pcb on cnc. You have three files for a single sided board.

                          For example you draw your pcb using Dip Trace.

                          First generate a gerber file for bottom copper layer mirrored.
                          Second generate a gerber file for board outline.
                          Third generate an NC drill file.

                          Next you import your files into a program which can convert these to G-code.
                          I use Kcam, there are others. Once you are satisfied that everything lines up.
                          The pcb is secured to the table with clamps, tape or a vacuum. Using manual control you position the spindle near the lower left corner of the pcb. The x and y axis are zeroed in the cam program. This point becomes your "Home" position and everything is referenced to this point.Now you manually move the spindle over the pcb material. The z-axis is lowered until the nose cone is resting on the surface, plus another 0.20" or 5mm. This allows the head to float. The z-axis is set to zero. Now you press the home button. The z-axis raises above the surface, the spindle then returns to home position(0,0).

                          I generally cut the the isolation for the traces first. When this is done the spindle returns to home. Now change the tool to a drill bit. The drill bit is set so that it extends at least the pcb material thickness below the nose cone. Now you open the g-code file that was created from the nc drill file. Turn on the spindle and start the process. It will drill all the holes and return to home. Next step is replace the drill bit with a carbide router bit and cut the board outline.

                          The above is a general description and many variations are possible.

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                          • #28
                            This is amazing! Yet alarming!
                            http://www.youtube.com/watch?v=quN37YskoaM

                            P.S. Turn the sound off its like being at the dentist.

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                            • #29
                              Originally posted by Altra View Post

                              This is amazing! Yet alarming!
                              http://www.youtube.com/watch?v=quN37YskoaM
                              Indeed, for very advanced CNC-enthusiast only.

                              Comment


                              • #30
                                If we have BW picture (jpg, tiff, giff...) of PCB from say one old electronic magazine, what is the best way to convert it in GERBER file for routing PCB?

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