Printer Flexible Cable Installation

Advert

Printer Flexible Cable Installation

Home Forums 3D Printers and 3D Printing Printer Flexible Cable Installation

Viewing 14 posts - 1 through 14 (of 14 total)
  • Author
    Posts
  • #318770
    Journeyman
    Participant
      @journeyman

      Had an interesting time with my Prusa i3 style printer (Factory 3D) today. Trying to print a part that is essentially a 100mm dia cylinder but every time I tried the left hand side would print and the right hand side would be missing or very poor quality. As I am a newby at this lark I quickly decided that it must be down to an unlevel bed. Re-levelled and tried again – same result. After about 3 goes at levelling with the same result I decided it must be something else.

      Watching very carefully I noticed that the extruder motor was turning (I have a line drawn on the spindle) when the print head was on the left but not on the right. Just to confirm I went into the move axis mode and could extrude on the left but if I pushed the head over to the right I just got a very faint click from the stepper motor. Checked the plugs which were firmly on and concluded a broken wire which I confirmed with a test meter.

      A lot of faffing about later having undone the wiring loom to the print head and replacing the stepper motor cable I tried again. This time no extrusion at all. "Oh bother!" I said and went and had a cup of tea before something terminal happened to the printer.

      It turns out that standard stepper motor cables are all different, a bit of swapping the terminals in the Dupont connector around and all was eventually working again. Having spent most of the day being in turn confused, annoyed, frustrated and annoyed again I was wondering:-

      Is there a better way of cabling up the moving bits in particular the print head which needs to up and down and left and right. At present I have all the witres in a braided nylon sheath with spiral wrap to give it some stiffness. The wire broke somewhere near the termination point on the head but to me it doesn't seem to bend much at that location. I was thinking of using a cable chain or is there something else that can be done to prevent future breakages?

      John

      Advert
      #31540
      Journeyman
      Participant
        @journeyman

        How Do You Prevent Cacble Breakage

        #318774
        SillyOldDuffer
        Moderator
          @sillyoldduffer
          Posted by Journeyman on 26/09/2017 17:21:58:

          At present I have all the wires in a braided nylon sheath with spiral wrap to give it some stiffness.

          John

          Could that stiffness be the problem? Unconstrained bendy wires have more room to flex which distributes the movement along the length of the wire. Bundling them together might focus the stress at a particular point whilst the added weight also increases the potential energy of the wiring loom as it moves about. Not good if the combination of extra energy and stiffness is relieved by snapping something expensive.

          Dave

          #318784
          Neil Wyatt
          Moderator
            @neilwyatt

            I'm going to print a clip on support arm from the back of the print head to hold up the wires, and keep flexing to a minimum.

            #318794
            Anonymous

              Solder and crimp terminations are known failure points for wires if they're not supported properly. You need a cable tie or clip some way above the termination, so the wire doesn't bend, even a small amount, at the termination.

              Andrew

              #318795
              RichardN
              Participant
                @richardn

                It's not unusual to include an over length piece of filament (3mm is ideal, but I've seen a few pieces of thin filament used) within the bundle of wires to the extruded which is held in a clamp to the back of the extruded block- this give flexible bouncy stiffness, with all load taken on the filament (cheap enough to replace if it does break) but creates instant cable strain relief.

                #318850
                Journeyman
                Participant
                  @journeyman

                  Thanks for the ideas gents. I have managed to keep all the crimps on the fixed side of the cable clamps so no movement near plugs or sockets. Seems strange that just one wire should break completely, perhaps I managed to pinch it when tightening up the cable clamp on the extruder. I think the moving wires are always going to be liable to failure but I would expect them to last a little longer than this one has.

                  Neil is the cable support on Thingiverse or your own design? I am still leaning towards cable chain (cos I think they look good) but I have never used one and don't know if they are any better than the stiff loom style I already have.

                  John

                  #318854
                  Neil Wyatt
                  Moderator
                    @neilwyatt

                    Hi John,

                    I haven't designed it yet… I imagine a simple 'cradle' with a point at the back for a cable tie. heater and thermistor cables would have connectors supported on the cradle.

                    #318857
                    martin perman 1
                    Participant
                      @martinperman1

                      On industrial robots that I've worked on the cables are fixed in flexible cable trays on all axis so the whole cable moves as one, when the cable gets close to the motor it should then be held rigid to the motor with no chance of it moving to the connector joint, the cable should be kept straight as possible as well.

                      Martin P

                      #318858
                      Martin Kyte
                      Participant
                        @martinkyte99762

                        If you can arrange it constrain your cables in energy chain rather than bundling with ties wraps or spiral.

                        Definitely use cable clamps behind connectors so the the clamp to connector length cannot move.

                        Keep bend radii as large as possible for the sections that flex.

                        Probably a little over the top to use robotics cable which is designed so that the cores can slide a little over each other but if you so wich the Lapp Cables are your friend.

                        regards Martin

                        #318897
                        Journeyman
                        Participant
                          @journeyman

                          Whilst re-doing the wiring I also swapped out the hot end nozzle and tube. My latest print effort has a top surface that looks like a ploughed field!

                          surface.jpg

                          I was wondering if this could be down to the nozzle width, the new ones are much more pointed. The old one has a flat end approx 2mm dia the new one has less than 1mm flat.

                          nozzles.jpg

                          Should I make the flat bit bigger, easily done on the lathe?

                          John

                          #318906
                          Neil Wyatt
                          Moderator
                            @neilwyatt

                            No, the smaller nozzle will work fine.

                            Check your cura settings, especially filament width, that problem may be under-extrusion

                            Neil

                            #318911
                            Paul Lousick
                            Participant
                              @paullousick59116

                              Cable on moving parts of commercial machines use a cable tray/chain to guide the wires and cables. These provide protection and control the minimum bend radius. Similar to that shown below.

                              cable chain.jpg

                              Lots of 3D models available for download to make your own.

                              **LINK**

                              Paul.

                              Edited By Paul Lousick on 27/09/2017 14:18:00

                              #318920
                              Martin Kyte
                              Participant
                                @martinkyte99762

                                I already said that.

                                Martin

                              Viewing 14 posts - 1 through 14 (of 14 total)
                              • Please log in to reply to this topic. Registering is free and easy using the links on the menu at the top of this page.

                              Advert

                              Latest Replies

                              Viewing 25 topics - 1 through 25 (of 25 total)
                              Viewing 25 topics - 1 through 25 (of 25 total)

                              View full reply list.

                              Advert

                              Newsletter Sign-up