moving connection point

Discussion in 'General Electronics Chat' started by jjanes, Aug 21, 2013.

  1. jjanes

    Thread Starter New Member

    Aug 2, 2010
    18
    0
    OK I am coming to the people who have seen it all for the right way to do this.

    I have a 3d printer and on this printer is a what they call a heated bed it connects to 12V and is turned on or off by checking the temperatures with thermistors.

    These connections points or simply two solder pads on the bottom of the board and they simply soldered wires directly to these pads that move directly away from the board. This would be fine if it were not for one thing the bed moves via motors in a direction 90 degree off of how these wires come out of the heated bed.

    The connection point for the wires can move either to the left or the right about 110mm and they make no allowance for how this wire is to move back and forth, so it moves all the way out in one direction and the wires reach out that far then the bed may move back and the wires end up bending over themselves and eventually as in my case either break the wire or the solder connection to the pad on the heat bed.

    In my attempts to alleviate this mess I cut a slot directly downward where the wires eventually go to connect to power and this seemed to help a bit but the back and forth is still breaking wires.

    I have changed the connection point to a 90 degree connectorand it is angle straight down now and one end is connected to the heat bed and the other the wire it also has a close tolerence away from the heat bed also( the reason I went with the 90 connector to fix that issue.

    I still need to somehow compensate for that back and forth 110mm travel i have had 4 wire breaks in fewer days. Each time the break happens I have to tear it all up to fix it and then re calibrate all of it.

    So is there some kind of miraculous way to make this connection that will allow the wire to somehow swivel so the wire doesn't have to bend back over itself or something else that completely eludes me.

    I have attached an image the PS is the 12v supply the X's are teh connection points and teh dotted lines show the possible distances the X's can actually move and I need some way that will stay connected not break the wires or the solder connections by pushing and pulling the wires in crazy directions.

    Thanks for your help
     
  2. sirch2

    Well-Known Member

    Jan 21, 2013
    1,008
    351
    The normal approach is to put the wire in some kind of flexible trunking so that the radius of curvature is controlled and fix the trunking to the moving part to relieve strain on the wire itself, also fix the wires to prevent them bending at the connector. Wires with very flexible silicon insulation are available and often used for things like meter leads.
     
  3. Metalmann

    Active Member

    Dec 8, 2012
    700
    223
  4. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,013
    1,531
    Got an old wall phone with a 'coil cord' for the hand set? Use a piece of it for your supply wire. The coil cord will have four wires in it, just use them as two pairs wired together, for a larger amperage rating of the wire. http://www.belkin.com/us/p/P-F8V101

    And don't count on the wire and solder joint, no mater what wire you use. you need to use a "strain relief". This can be as easy as just gluing the wire insulation to the board, since that will make the glued point the new strain point. Or you could buy a fancy strain relief mount from a supplier.
     
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