Lumen PnP Y-Axis Drag Chain Mount

prusaprinters

This is a mounting bracket to install a wiring drag chain for the Y-axis of an Opulo Lumen PnP. This mod is NOT compatible with the official Lumen kit wiring harnesses, because the harness routing is considerably longer, however, I believe it is a huge improvement over the original umbilical routing, which has issues sagging over the build surface.The lower guide bracket mounts along the lower of the left-hand extrusion rails.  The top mount installs in place of the original FDM-0010-01 “Y Gantry Mount” part.  The new umbilical mount installs opposite the top mount, onto the front 2 screws of the X axis motor mount, and is compatible with the original umbilical swivel arm, parts FDM-0046-01 and FDM-0047-01.  The two different versions of the mount are identical except for the angle of the swivel stops.  I suggest the 0 degree version, but you can print both and see which works better for you.  The original umbilical mount FDM-0007-01 is no longer needed.This design uses M4 hardware for attaching the drag chain to the brackets, and M5 hardware for attaching the brackets to the machine, M5x8mm + T-nuts for the lower bracket and M5x25 for the top mount and umbilical mount.  One thing of note when installing is to take care with how far the outer radius of the drag chain sticks out the back of the machine when the Y axis is moved fully to the back of the rail, as this will affect the ability to stand the machine upright if it sticks out too far.  This can be adjusted by moving the Y axis all the way back, loosening the M5 bolts on the bottom bracket and sliding the bottom bracket forward as far as it will go, then back just a little bit to relieve any undue strain on the top mount, then fasten the bottom bracket at that point.  You can also print a second bottom bracket and install it around the middle of the rail (right under the back of the chain when the Y axis is moved all the way forward) to better support the chain.This design was intended for use with the "uxcell R38 18mm x 25mm Plastic Semi Closed Cable Wire Carrier Drag Chain" which can be purchased on Amazon.  Other drag chains may also work, but check their dimensions.  The R38 minimum bend radius is especially important, as any smaller may cause kinks in the vacuum lines, and any larger will not fit between the two rails on the machine.  It is HIGHLY recommended that you get a drag chain with links that can be opened, and that it be mounted so that the hinges are in toward the machine so the opening latches are accessible from the outside.