XY Axis Belt Assembly

Difficulty

Medium

Steps

7

Time Required

X Minutes

Sections

1

A big thank you goes out to Guy Charles Doppia who posted some instructions on the East 3D Gecko Facebook Group on how to tighten the XY axis belts. His method is what I present below, if I got it correct, and it makes great sense in the execution and gives me confidence in doing the job right. Time will tell once I get the machine running on how well I did.


Step 1

Gather XY Axis Materials

  • XY Axis Belts (2x) Bag C-13
  • M3 x 8mm Socket Cap Screws (4x) Bag C-13
  • Axis spacers, I used Duplo 2x4 plates
  • 2.5mm hex key, four bench clamps
  • There will be two bags of belts in the C-13 bag. I choose to use the bag with the smaller bundle of belts. My reasoning, and it turns out to be correct, is that the Z-Axis belts are the longer of the two sets. In the picture I used the bag on the right for XY axis.

Before we start, you will want to ensure the two belts used on the XY axis are identical lengths. This will help when it comes time to understand how much you have tensioned each belt. Layout the belts, aligning one end of each and then comparing the far end. Trim as needed so that they are identical. Cut only in the valley between the belt teeth.



Step 2

Attach one end of each belt

  • Next we will attach one end of each belt. On the left side of the block, attach a belt in the bottom position. On the right side, attach a belt on the upper position. Tighten those screws. Leave the other screws loose. The belts are not strung in the machine yet.
  • Now position the entire assembly vertical on your work surface. You may want to steady the assembly so it doesn't fall over, I choose to use clamps to my workbench.



Step 3

Prepare for belt stringing

  • I recommend securing the X-axis carriage so that it doesn't move. I used small clamps. You may use tape or a helping hand from a friend.
  • Insert the axis spacers. I used Duplo plates, you could use something else. The key here is both blocks are identical in size and the edges of the blocks are parallel. When inserted as shown in the picture, the X-axis rests on both blocks evenly.
  • We will first work on the bottom or Y-axis belt first.
  • Lay the top or X-axis belt in front of the work area and out of the way.



Step 4

String the Y-Axis belt

  • Wrap the bottom or Y-axis belt around the machine. This belt, as shown, heads left from the X-axis carriage, up the machine, across, down to the stepper motor and then back up and around to the X-axis carriage. The belt should be riding smoothly in the groove of all pulleys.
  • The belt will be wrapped on the lower pulleys as shown in the images.



Step 5

Tighten the Y-Axis belt

  • The loose end of the Y-axis belt will be threaded in the bottom of the belt capture part.
  • Before you tighten the belt holding screw, pull on the loose end of the belt so that it has tension.
  • When you add tension to the belt, the left side of the X-axis rail will lift slightly off the spacer block. This is expected and means you have tension on the belt.



Step 6

String the X-Axis belt

  • Wrap the top or X-axis belt around the machine. This belt, as shown, heads right from the X-axis carriage, up the machine, across, down to the stepper motor and then back up and around to the X-axis carriage. The belt should be riding smoothly in the groove of all pulleys.
  • The belt will be wrapped on the upper pulleys as shown in the images.



Step 7

Tighten the X-Axis belt

  • The loose end of the X-axis belt will be threaded in the top of the belt capture part.
  • Before you tighten the belt holding screw, pull on the loose end of the belt so that it has tension.
  • When you add tension to the belt, the left side of the X-axis rail should now set back down on the spacer block. You want to apply just enough tension that the belt sits down on to the block. This will indicate you have about even tension. If you over tension it, the right side of the X-axis rail will lift off the block.
  • Since you previously confirmed the belts are the same length, I'd expect them, after tensioning to still be close to the same length. There may be one or two tooth difference. The key is to tension them as indicated above so that there is about even tension and the X-axis rail is level.



Step 8

Tidy the extra belt lengths

  • You could cut the extra belt length off, however I'm not sure if I would need it in the future when I retighten the belts.
  • A couple zip ties and a pair of cutters is all you need for this step. These are not included in the kit.
  • Fold the access belt and then use a zip tie to hold the bundle.

I recommend moving the X-axis carriage back and forth, up and down and all around to ensure the system is smooth. Look at each pulley to ensure the belt is riding properly. You should feel some stiffness in the system as you try to move it because of the belt tension and the stiction of the stepper motors. Remember, the Y-axis isn’t captive, the carriages could still come off the rail, so be careful to not move the assembly too far in the direction opposite the motors.