Table build 480x480mm motion

New Home Forum ZenXY Your Builds – ZenXY Table build 480x480mm motion

This topic contains 26 replies, has 5 voices, and was last updated by  G. Burkhardt 5 months, 1 week ago.

Viewing 27 posts - 1 through 27 (of 27 total)
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  • #78172

    G. Burkhardt
    Participant

    Looking around here got me infected with the sand table bug and I have now officially started my build.

    It will be a regular x/y table (no H-type kinematics) with 2 NEMA17 steppers and direct belt drive for X, indirect 2:1 belt drive for Y.

    I got a set of four 8mm dia 500mm long linear bearing sets for $40 and hope they will be rigid enough for this purpose.

    TBA6600 drives and a Planet-CNC motion controller that I happen to have from another project.

    The somewhat strange foot is intended to match the design of my Norwegian chairs.

    Right now I am printing some of the smaller components and will start machining some of the frame and foot parts soon.

    One thing I am not sure about yet is the plate that will carry the sand surface. Would a 1/8″ aluminum or glass plate do the job? Right now I am planning to use a 1/2″dia x 1/2″ long Neodymium magnet and a 1/2″ steel ball. What distance is optimal?

    Some pics attached…

     

    #78217

    Bill
    Participant

    Love the chairs… You should have no trouble with either aluminum or glass for that span, you could even go with thin plywood or melamine. I used a recycled back panel from a bookcase that was maybe 4mm thick with mine and although I’m smaller than you it isn’t by much. The shorter the distance between magnet and ball the better. I’ve got 10-12mm.

    #78980

    G. Burkhardt
    Participant

    Some progress…

    Machined the table mechanism base (from 3/4″ bamboo plywood):

    Printed all the small pieces:

    All electronics installed and partially wired. The steppers are moving, still need to connect the start/stop/pause buttons and home limit switches.

    #78986

    Ryan
    Keymaster

    Holy Moly, I thought I was freakish about wiring….I am glad I am not the only one! Perfect!

    #79005

    G. Burkhardt
    Participant

    Ryan, it looks like you could see the linked new pics in my last post. But now I can not see them anymore myself. Weird, but maybe has to do with the Google+ Photo link.

    Anyway, here again as attached pics:

     

    1 user thanked author for this post.
    #79014

    Barry
    Participant

    I really miss the old picasa photo sharing, so much easier.  For G+, you have to right click the picture in a new window/tab.  Then copy and paste that link to share.  Doesn’t work everywhere because the link doesn’t end in .jpg, but works here.

    #79026

    Ryan
    Keymaster

    That is odd, I can see it with my account but If I log out they disappear. Barry to the rescue.

    #79029

    Jeffeb3
    Participant

    You can test it by opening the page in a private window. If you can see it there, we can see it too.

    I have been thinking I’m going to start using imgur instead…

    #79032

    Ryan
    Keymaster

    Yup lots of private windows. Any change I make I check both ways, the one I have only done probably 3 times is sign in as a fake user to see exactly what you guys see.

    G+ is shutting down really soon.

    #79050

    G. Burkhardt
    Participant

    Ah, that explains it. I had similar trouble on another forum with pics.

    And I am missing the good old times with Picasa. I still use the desktop app, though.

     

    Yes, I am trying to keep the wiring clean but I had to mill recesses into the base board anyway for space reasons so the wiring channels did not really take any more effort. I closed them with super sticky aluminum duct tape. Holds on tight but can still be removed when needed.

    I decided to laminate a sandwich board for the sand surface from 2 thin (0.8mm) aluminum sheets with an 1/8″ fiberboard core and use my table glass (1/2″ thick) to keep it flat while vacuum pressing. Should be rather stiff and avoid sagging under weight or magnet force but I am not sure yet if I can pull that lamination process off.

    I read about a thin foam surface to help the ball rolling. Would a non-slip drawer liner do the job? I still have a roll of that.

     

    #79057

    Ryan
    Keymaster

    I would not put anything in between. the strength of the magnet drops off by the cube of the distance. Every .1mm counts. I use baking soda, so there really is nothing to impede the motion.

    #79064

    Barry
    Participant

    Yup lots of private windows. Any change I make I check both ways, the one I have only done probably 3 times is sign in as a fake user to see exactly what you guys see.

    G+ is shutting down really soon.

    G+ is shutting down, but I don’t think they’re killing off photos.  At least I hope not.  I have almost 13 gigs of photos!  That would take minutes to download!!! ????

    #79068

    Jeffeb3
    Participant

    I thought it wasn’t until april though. I hate that google shuts things down. I’m going to miss inbox.

    #79077

    G. Burkhardt
    Participant

    Yup lots of private windows. Any change I make I check both ways, the one I have only done probably 3 times is sign in as a fake user to see exactly what you guys see.

    G+ is shutting down really soon.

    G+ is shutting down, but I don’t think they’re killing off photos. At least I hope not. I have almost 13 gigs of photos! That would take minutes to download!!! ????

    I hope not as well. while I have only edited pics on Google and the original on the PC, but there are many forum posts with links and they all would be broken 🙁
    Oh well. Nothing permanent in the brave new cloud world.

    As for the foam mat under the sand, I am not sure where I read about that. Maybe not such a good idea, after all.

    I will try the baking soda. Given that I am in dry SoCal I guess the likelihood of clumping is small. I have also a bag of fine grit brass powder and some black dyed sand that I may try. But I am getting ahead of myself. Maybe I should first finish the table…

    #79411

    G. Burkhardt
    Participant

    It’s Alive!

    No sand surface yet, but the mechanism and electronics are assembled and working.

    Short video here: View file

    This is running with 10,000mm/min just to see what it can do. Obviously a bit high for a ball to follow.

    Noise is probably as good as it gets. At lower speed like 2000mm/min it is much quieter but the melodic whistling of the steppers can still be heard.

    #79454

    G. Burkhardt
    Participant

    Oh, one more question…

    What is a reasonable acceleration setting as to not lose the steel ball? Something like 200mm/sec^2  ?

    I will probably find out but would be good to know beforehand.

    #79546

    G. Burkhardt
    Participant

    Just noticed, I lied in the thread title….while the free length of my 500mm guide rods is 480mm (10mm on each side to hold them), the linear bearings are about 40mm long and that leaves only 440 x 440mm as useable motion range. Oh well, not so bad.

    #79935

    G. Burkhardt
    Participant

    So, it is running (without cover, feet and housing). I ended up getting an 1/8″ acid etched (frosted) glass sheet for the sand surface and the distance between the magnet and the ball is only 4.5 mm.

    Here my first test runs. The experiment with the Blues Brothers image was a bit overly ambitious (2mm mace trace distance with a 1/2″ ball). But even that looks interesting.

    Short Clip:  https://www.dropbox.com/s/rgd0jhy9576auan/SandTableFirstRun.mp4?dl=0

     

    2 users thanked author for this post.
    Ryan, BT
    #80008

    Ryan
    Keymaster

    Nice! I really need to get some lights on mine, they really add some depth and contrast.

    #80025

    G. Burkhardt
    Participant

    Nice! I really need to get some lights on mine, they really add some depth and contrast.

    Oh yes. It makes a big difference in appearance, even if I don’t have the cover frame finished yet that will mask the direct view of the LEDs.

    And I found the LED dimmer necessary. At full intensity, the LED strip (I used “warm white”) is way too bright. I removed the little dimmer PCB and pot from the plastic housing and installed directly on the baseplate so that I can adjust brightness with a knob reaching under the table. Similarly, the Start/Stop/Pause buttons, power switch, USB bulkhead connector and SD card slot are accessible from underneath the baseplate. I do not have a display or other user interface.

    BTW, below is the maze trace pattern for the picture. Clearly too detailed for a 1/2″ ball but works in principle. I tried it with an 1/4″ steel ball but the magnetic attraction is too weak and the ball gets left behind.

    Attachments:
    1 user thanked author for this post.
    #81526

    G. Burkhardt
    Participant

    Some progress:

    Added some reflector tape and a diffuser strip to the (later hidden) light strip.

    DSC01552

    Glued automotive sound deadener sheets (the waffled silvery area) wherever possible in an attempt to quiet the thing down.

    DSC01554

    Started cutting and glueing up the legs and ring foot from walnut segments.

    DSC01550
    DSC01557

    2 users thanked author for this post.
    #82956

    G. Burkhardt
    Participant

    Finished! This was a fun project. I like the combination of woodworking and technology application.

    Thanks to everybody here for some ideas and advice!

    Foot is sanded and finished:
    DSC01558

    Assembled with baseplate, tabletop and enclosure frame:
    DSC01576

    Complete table:
    DSC01568

    Detail vies ow the joints:
    DSC01571

    Now back to the living room. In spite of my best sound management efforts, the steppers can still be heard but are kind of acceptable. I guess I am not going to run the machine all the time, anyway.

     

    #82963

    Jeffeb3
    Participant

    That is beautiful. I love the curved finger joints.

    #82968

    Bill
    Participant

    I put a couple of these on and it made quite a bit of difference.

    #82975

    Ryan
    Keymaster

    That is sexy!

    #83122

    G. Burkhardt
    Participant

    Thanks guys,

    here a quick video:  https://youtu.be/ADVOGcGJWzs

    #83183

    G. Burkhardt
    Participant

    I put a couple of these on and it made quite a bit of difference.

    Hmm, interesting. Looks like a pair of anti-parallel silicon diodes in each stepper winding loop. I don’t understand what the 0.7V drop over the diodes will exactly do to smooth the stepper noise but I ordered a bunch of such 1N5404 diodes to try it out (I could not use the pluggable version anyway). Thanks for the hint!

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