Y-Axis(Bed) Assembly PDF Print Email

For this part you will need:

  • 6x M3 Nuts
  • 3x M3x10mm Cap Screws
  • 4x M3x22mm Cap Screws
  • 2x M3x8mm Grub Screws
  • 4x LM8UU Bearings
  • 8x Small Zip Ties
  • 1x T5 Pitch Belt, 840mm Length
  • 1x NEMA 17 Stepper Motor
  • 1x Thick Sheet for Bed
  • 2x 8mm Smooth Rods, 406mm Length
  • 4x lm8uu-ymount printed pieces
  • 2x belt-clamp printed pieces
  • 2x belt-clamp-nut-holder printed pieces
  • 1x belt-pulley printed pieces


In this part you will be putting on the rods for the y-axis, the bed onto them, and then the belt to move the bed .  You may want a pair of pliers to help pull the belt tight.  You will need a 2.5mm size allen wrench to tighten the cap screws and a 1.5mm one to tighten up the grub screws.  You will need something to take a measurement so that you can make sure that the rods run parallel to the frame.  This is where we'll end up after this step:


 To begin with, we will want to get the LM8UU bearings and y-mount pieces and put them together by snapping an LM8UU bearing into each piece just like in the picture below.  Put two of these onto each of the smooth rods.  You will now put the smooth rods onto the frame.  Turn the rod-clamps on the top front and back threaded rods towards the top so that the smooth rods can go through them on top of the threaded rods.  Slide both the smooth rods into the rod-clamps.  Turn the y-mount pieces on the rod so that the flat part faces up, then set the thick sheet for the bed onto the top of them.  Move the y-mount pieces and smooth rods around so that the holes on the plastic pieces line up with the outer holes on the thick sheet.  The next two pictures show which holes they should line up to.  Once they are lined up, put a zip tie through one of the holes in each one.  Put another zip tie up through the other hole.  Put the end of each zip tie through the head of the other one and tighten down the zip ties a bit, but not all the way yet.  Do this to the rest of the y-mount pieces as well.

Loosen up the nuts against the bar clamps a bit so that the bed can be centered more easily.  Pull all the zip ties tight.  The picture below shows how this should look.


 Move the bed so that it is centered in the frame.  Tighten down one of the rod clamps.  Measure the distance from the inside part of the frame-vertex-foot to the smooth rod near that clamp.  Position the other end of the smooth rod so that it is the same distance and tighten down the rod-clamp on that end too.  Double-check that distance again once the rod-clamp is tighened down.  Slide the bed all the way towards one end.  Tighten down the rod-clamp on this end of the other smooth rod.  Slide the bed to the other end of the frame and tighen down the last rod-clamp.  Once all the rod-clamps are tightened down, slide the bed back and forth to make sure that it moves freely.  If it does not, reposition one of the last two rod-clamps that you tightened down to make sure that the two smooth rods are parallel.  Next, you need to adjust the belt-guides so that they are in the center of the bed.  Slide the bed to each end and use the two holes in the center of the bed to line up the belt-guide pieces.  The picture below shows the alignment.  Do this to both ends and snug down the nuts against the bearings in the belt-guides.


Now the y-bract piece that the motor will go on will need to be positioned.  Loosen up the nuts on the bottom part of the piece and move it up against the belt-guide, then tighten down the upper nut.  The bottom part of the piece will now be into position so tighten down the nuts up against the bottom part.  Put the motor onto the y-bract piece with the three M3 x 10mm cap screws.  Make sure that the motor shaft points towards the center to the frame like in the picture below.  Take the belt-pulley piece and put an M3 nut into the two rectangular holes so that the hole in the nuts line up with the holes on the side of the pulley.  Put a grub screw into each hole on the side and start them into the nuts.  Make sure the grub screws do not go through to the center or it will block the motor shaft from going on.  Push the belt-pulley onto the motor shaft and  line up the teeth with the teeth on the belt-guide.  Once it is into position, tighten the grub screws down against the motor shaft.  If one side is too tight, the pulley will be crooked.


 The next part that will be put on is the belt.  Turning the frame upside-down make make this part easier.  Start by putting a two M3 nuts into each of the belt-clamp-nut-holder pieces and two M3 x 22mm cap screws into the belt-clamp pieces.  Feed the ends of the cap screws up through the holes in the center of the bed and thread the cap screws into the nuts in the belt-clamp nut holders.  Do this to both sets of holes in the middle of the bed.  Do not tighten them down yet, just get them started onto the nuts.  Put one end of the belt through the space made between the bed and the belt-clamp piece an inch or two and tighten down the cap screws so that it holds the belt into place.  Put the flat part of the belt against the bed so that it's oriented properly.  After one end of the belt is secure, run the other end of the belt around the nearest belt-guide, then the belt-pulley you put onto the motor shaft, around the other belt-guide, then through the gap between the belt-clamp and the bed.  Take a look at the belt to make sure that it doesn't have any twists in it.  Once you are sure the belt is in the right place, pull it tight and tighten down the belt-clamp against the belt.  You have to pull it really tight, but there is too tight also.  The clamps and belt should look like this:


After the belt-clamps are tightened down, make sure that the belt is still tight, on both belt guides, and the belt-pulley on the motor.  Slide the bed back and forth a few times.  If the bed is hard to move, the belt is too tight and it needs to be loosened up a little.  It's hard to tell if the belt is too loose until we try and print, but make sure there is no slack.  If the bed slides back and forth pretty easily you are ready to move onto the next step.

Go to the next step where we'll put on the z-axis rods here