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  • CNC hexapod

    Found this vid today, Check it out:
    http://www.cncinformation.com/CNCBlo...od-technology/

    Iv heard of this concept before, But this is the first large scale demo I have ever seen of it. Must have some intresting axis/rotation limits.
    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

  • #2
    With the forces involved in maching I don't see how they keep all those ball joints and swivels tight.Seems the least amount of slack would be a deal killer.

    Here's G&L's version-

    http://www.youtube.com/watch?v=7TowJZQi-qY
    I just need one more tool,just one!

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    • #3
      The rigidity of the hexapod comes from the opposing pistons or leadscrews. It's the same mechanism that drives a flight simulator, upside down:



      I mentioned a couple of times the Nova episode about making the replacement cases for the Constitution and the Declaration of Independence. It was a bunch of high-precision machining. The backplate itself, with all the lightening pockets, was milled by the giant hexapod at NIST.
      "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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      • #4
        The first hexapod I saw was a separate attachment bolted to the floor BEHIND a regular Bridgeport. The head of the Bridgy was turned around to face the rear. The struts of the hexapod went down to the floor. It was really great to watch in action. Wonder if they are still made?

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        • #5
          That is so cool? Hand coding G Code must be a treat? With processing power so cheap these days I am surprised there are not more of them around? Will EMC control one of these?
          I think this would be a good project for Sir John and Evan to co operate on?
          Should be a piece of cake? John has some ball screw cut off? Evan can make up some zero backlash nuts?
          Dave

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          • #6
            Originally posted by gwilson
            The first hexapod I saw was a separate attachment bolted to the floor BEHIND a regular Bridgeport. The head of the Bridgy was turned around to face the rear. The struts of the hexapod went down to the floor. It was really great to watch in action. Wonder if they are still made?

            Not sure if they are still made. I think they are. I have seen maybe two pop up on ebay.

            Of course the software to program is a killer.

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            • #7
              Originally posted by macona
              Of course the software to program is a killer.
              No doubt -- the Stuart platform doesn't look that hard, but the simultaneous multi-axis kinematics necessary to drive a hexapod are incredibly complicated.

              I posted several years ago that a hexapod control system would be the ultimate home-shop project. I've still never seen a hobbyist hexapod, but I've haven't been by CNCzone in awhile either...
              "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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              • #8
                Originally posted by wierdscience
                With the forces involved in maching I don't see how they keep all those ball joints and swivels tight.Seems the least amount of slack would be a deal killer.

                Here's G&L's version-

                http://www.youtube.com/watch?v=7TowJZQi-qY
                Thats rubbish, see what hexapods can realy do HERE

                john
                John

                I used to be indecisive. Now I'm not so sure , but I'm not a complete idiot - some bits are still missing

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                • #9
                  Originally posted by jugs
                  Thats rubbish, see what hexapods can realy do HERE

                  john
                  even better, someone posted this one, one of the last times a hexapod thread was posted here.
                  http://www.youtube.com/watch?v=quN37YskoaM

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                  • #10
                    I don't think the software is all that tough. You know where the cutter must be placed in three space. You know what the X, Y and Z is and the Roll, Pitch and Yaw. The cutting head is placed on a polygon (triangle) which is a face in a 3D mesh. The triangle is then translated in X, Y and Z and rotated in R, P and Y. The position of the face vertices determines the length of the sides of the triangles that connect to the vertices of the cutter triangle and connect at the other end to fixed 3D locations. It is calculated backwards from the vertices of the the cutter triangle using a 3D best line algorithm to the fixed points of the other end of the support trigons. That gives the length of the six variable sides of the three support trigons. All you do then is make it so, increment after increment.
                    Free software for calculating bolt circles and similar: Click Here

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                    • #11
                      Originally posted by mochinist
                      even better, someone posted this one, one of the last times a hexapod thread was posted here.
                      http://www.youtube.com/watch?v=quN37YskoaM
                      LOL! For those who don't get the joke -- those are hexapod (i.e., 6 legged) robots, which have nothing to do with a hexapod CNC machine
                      "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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                      • #12
                        I have some memory image that EMC2 supports hexapods and I've seen a few built, though not for milling, by hobby guys/girls.

                        Thanks for the video links, nice piece of machinery
                        Amount of experience is in direct proportion to the value of broken equipment.

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                        • #13
                          I have always wanted to build a hexapod... Some day. Yes - emc2 has kinematics that allow for a translation between actuators and xyzabcuvw.

                          http://linuxcnc.org/docs/html/motion_kinematics.html

                          this is a delta robot running emc - kinda cool.
                          http://www.youtube.com/watch?v=FgnxBaFFDi8

                          real hexapod.
                          http://www.youtube.com/watch?v=7hztl4eWpZM
                          read about it here
                          http://translate.google.com/translat...n&hl=&ie=UTF-8

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                          • #14
                            Originally posted by Jaakko Fagerlund
                            I have some memory image that EMC2 supports hexapods and I've seen a few built, though not for milling, by hobby guys/girls.
                            I'm not finding any with a quick Google search, but there apparently was some hexapod support in EMC in the distant past. Lot of comments like this on the EMC discussion list:

                            > As far as I know hexapod code is in EMC2, but does it (still) work? Back in
                            > march there where some mails about it. Unfortunately there was no success
                            > story follow up.

                            Edit: Sorry SW, I had that reply up on my screen for 15 minutes and cross-posted...
                            Last edited by lazlo; 03-24-2011, 05:24 PM.
                            "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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                            • #15
                              Originally posted by skunkworks
                              this is a delta robot running emc - kinda cool.
                              http://www.youtube.com/watch?v=FgnxBaFFDi8
                              That's very cool! He's planning to use it as a hexpod extruder head for a rep-rap
                              "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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