Connecting the X-Axis Carriage
So we’re done with the stepper end and idler end, and it’s belt tension block. Now we need to get the x-carriage sorted so the hotend has something to attach to! I’ve gone with a bronze bushing carriage, which is another one of Toolson’s designs. He has also created an LM8UU version too. I did actually print both as I was going to do some testing, but ended up breaking the LM8UU version so concentrated on getting what I wanted to be a final setup from the start. I also liked the more minimalist design of the bronze bushing version.
Check out the video below which shows the part being printed, impressive stuff! This was a final print after a couple snapped when trying to get the bushings in. This part is going to take a lot of abuse, so best to print it will high strength material, or a high infill. My final print was at 85% infill.
The end result is shown below, with the bronze bushings inserted into their sleeves. These should clip in with a little force, and are designed not to be clamped in – to allow them to self align together. To stop them from coming out, they should have some retaining fasteners added to them – which are the black M3 screws shown in the image.
The retaining fasteners are secured to the part using the same drill and tap technique used on the y-axis bushings and also the z-axis bearings. You can find images of that technique in the P3Steel Build Log (#06) – Y-axis Carriage Clamps blog post. Similar to the y-axis clamps – they shouldn’t cover the 8mm hole, and are there only to stop them from coming out, they should not clamp down on the bushings too much.
Carriage and Belt Installation
Time to install the belt for the x-axis. You can do this prior to adding the x-axis to the printer frame, or after. I have done this before as I knew the measurements from a previous run, plus it’s easier to photograph! Slip the carriage onto the two smooth rods which should be installed on the stepper end of the x-axis. The blank end of the carriage should face forward, and on the back there is a neat little arrow printed on the part which should point up (or so I assume!!).
First off I installed the four retaining M4 bolts which go on the back and secure the hotend mount to the carriage. You can add this after if you like. Then you will need another 1m of GT2 6mm belt. First add one end into the printed teeth part so it grips the belt as per below. To do this you will need to push it in with some pliers.
Loop the belt round the idler, back through the top of the carriage and round the stepper gear and back to the carriage. It should then match up with the printed teeth. There you should then push it in with some tension on the belt. Enough to take the slack and for the tension block to be able to pull it tighter if needed.
Z-Rails and X-Axis Tension Block
Once the x-axis is complete, you will need to insall it onto the z-axis rails. These are the final 8mm smooth rods which need to be installed from the top, down into the LM8UU bearings of each x-axis end and then secured into the holes in the stepper motor mount plates of the z-axis. The z-axis smooth rods are held in with friction alone. You may need to shuffle the idler block end so the x-axis moves smoothly up and down. Below are a couple of shots of the tension block in place on the z-axis rails. Ignore the black parts – they were from a test print!!
With the z-axis rails done. Check the x-axis movement by moving it back and forth on the rails. It should move smoothly back and forth.Now we need to install the z-axis lead screw into the x-axis ends, and the z-axis stop mechanism. You can see these installed below. I have skimmed over this part, but will cover it in more detail along with more info on the z-axis installation.