X-Gantry Assembly

This is part 3 of my X-Gantry Upgrade, for the previous article follow this link. Yesterday I printed the smaller parts needed for the gantry, and today I plan to complete the X-Gantry Assembly.

X-Gantry Right

This is a large piece and Slic3r says it is going to take over 5 hours to complete printing.  Barring any unforeseen mistakes by myself, this should go fairly easily, it will just be time-consuming. I have decided I am going to do my cleaning routine that I usually only do after a failure, to try to prevent any issues.

After preparing the print bed and the extruder I added my object and started printing. As usual, I switched to an online game while I waited so I can monitor the print and the printer itself, you can never be too careful.

X-Gantry Belt Tensioner

Belt Tensioner for X-GantryEverything went smoothly with the X-Gantry right end. So, I have decided to try to complete the X-Gantry assembly tonight. Things went so well with the other parts that I have decided to do the cleaning step before this print as well. Who knows, maybe I will just make it part of my “process”. This print will only take a little over two hours.

The print out went well, except I am not sure exactly what happened to the axle, but the flaw appears even with the top of the tightening knob.  My best guess is that the slicer did not slow the print for the first few layers and they overheated and basically sagged out from the axle.  I am planning to use it anyway, since it seems to fit with the other parts. Unfortunately, I just realized while dry-fitting the parts that I will need to reassemble the printer to print out the “Cap” for the axle.

X-Gantry Assembly

After putting the printer back together to print the axle cap, I am ready to take it apart again and upgrade the X-Gantry.  There is a definite temptation to just start shoving the parts together, but after the Cap incident, I decided to analyze this a little more.  There is a definite order for putting this together to avoid doing it over and over, and there are specific parts you have to salvage or have duplicates for.

Salvaged parts from X-Gantry

1 x R6RS bearing
2 x LM8LUU linear bearings
1 x Extruder head              (no need to disassemble)
4 x M3-16mm Hex Screw (currently securing extruder head)
1 x GT2 belt                         (try to leave it glued to the extruder head)
1 x GT2 Gear
1 x NEMA-17 motor
2 x Linear shafts

Disassembling factory X-Gantry

  • Remove the 3/8-16×1″ bolt that holds the XIDLER on the gantry. Set aside the R6RS bearing.
  • Remove the four M3-16mm screws from the NEMA-17 motor with the GT2 Gear.
  • Remove top two M4-8mm screws and lift off the top handle.
  • At this point I powered up my printer and ran negative Z-index until the X-gantry reached the top of the Z-index linear shafts. If you are feeling nervous you can turn the lead screw clockwise by hand until the X-gantry reaches the top.
  • Lift the x-gantry off and set down on the table.
  • Remove the eight M3-25mm screws holding down the bearing mounts and set aside the 2 LM8LUU linear bearings.
  • Cut the 4 zip ties holding the 2 linear shafts to the x-gantry, slide off the extruder head with the GT2 belt attached and set aside.

Assembling Proto-Plastik X-Gantry

  • For both end pieces, put an spacer in the linear bearing hole, then tighten in place with a threaded retainer.
  • Put a LM8LUU into the opposite end of the linear bearing hole, followed by another spacer and threader retainer.
  • Connect the acme threaded retainer to the left end piece with two m3-16mm screws. You may need to put a M3 nut on the screws and tighten them down, mine threaded tightly into the plastic.
  • Use a 5/16″ drill bit to clear the full length of the linear shaft holes in the right and left ends. I did this by hand, not with a power tool, you don’t want to risk making the holes any deeper.
  • Insert the linear shafts as far as they will go in both end pieces.dry fit x-gantry to check width
  • Check that the assembly fits on the Z-index linear shafts still attached to the base and that the lead screw can start in the acme threaded retainer.
  • If the holes in the ends are too far apart, or the acme lead screw binds, you need to clear the linear shaft holes a little better. The depth of the holes is correct so there is probably just some schmutz in them.
  • Put the x-gantry linear shafts in the left end of the x-gantry.
  • Put the extruder head assembly on the linear shafts and put the linear shafts in the right end of the x-gantry.
  • Slide the tensioner over the x-gantry lined up with the hole for the axle.
  • Push the end of the belt into the slot on the right end with the R6RS bearing inside it.
  • Pass the axle through the tensioner and the bearing to hold it in place.
  • Screw cap to axle with a M3-5mm screw.
  • Adjust the GT2 Gear on the NEMA-17 motor shaft down until it almost touches the motor housing. I literally used a sheet of paper folded in half to maintain the spacing while tightening the set screws.
  • Push the other end of the belt into the slot in the left end of the x-gantry, then push the gear through the circular hole in the left end and the GT2 belt.
  • Tighten the NEMA-17 in place with the four M3-16mm screws.
  • Turn the tightening knob until the GT2 belt is fairly tight.
  • Put new X-Gantry on the Z-index linear shafts and turn lead screw to lower gantry enough to replace the top handle.x-gantry assembly installed

X-Gantry Upgrade Conclusion

It has been a long night, but I now have my new gantry in place. Unfortunately, it is probably sagging about as much as the factory one, which I was hoping this upgrade would help with. However, this gantry has connection points for adding the anti-sag truss, which should fix that problem.  Another issue that I have noticed is that the print width has gone from about 160mm (6-1/4″) to about 140mm (5-1/2″).

Hopefully, tomorrow, I can figure out how to increase that, but now it is time for bed…

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