X Carriage and X Axis Assembly (Videos 15 and 16)

Recap: I'm building a Prusa Mendel 3d printer from a kit I purchased from nwreprap.com using a series of videos.

Videos  15 and 16 walked me through the process of assembling the X Axis components.  The steps are broken down into:

• mounting the X carriage on the linear bearings
• mounting the fan on the X carriage
• mounting the extruder on the X carriage
• attaching the X stepper motor
• assemble the X axis idler
• attaching the X axis idler
• installing the X belt

Mounting the X carriage on the linear bearings

The X carriage is to be attached to the linear bearings with four zip ties.  I suggest placing the X carriage on the linear bearings and sliding it back and forth a few times to make sure it slides smoothly before attaching it.

X carriage sitting on top of linear bearings.

Later, the extruder will be attached to the X carriage using 2 M4 hex bolts.  Now is a good time to install the 2 M4 hex bolts into the X carriage.  There are 6 holes in the X carriage, allowing for 3 possible mounting options for the extruder.  Study the picture below and insert the M4 bolts into those two holes.  Use 2 M4 washers.

M4 bolts have been inserted into the X carriage.

Mounting the fan on the X carriage

There is a small 30 mm fan in the nwreprap kit. It is to be attached to the X carriage to keep the hot end cooler. The fan is attached to the X carriage with 2 14mm M3 bolts. The bolts pass through two holes on the fan and into two holes on either side of the X carriage. Nuts are not used here. I suggest you use the two holes on the fan closest to the wires. Mount the fan on the right side of the X carriage (some of the photos below show the fan mounted incorrectly on the left side) .  The silvery sticker on the fan should face toward the X carriage.



Underside of the X carriage showing heads of M4 bolts, the M4 washers and the fan attached to the left side (incorrectly).

At this point you can attach the X carriage to the linear bearings with zip ties.  Make sure that the two mounting points for the belt clamps are facing the front of the Prusa Mendel (away from the Y axis stepper motor).



X carriage has been attached to linear bearings.  Fan has been moved to the right side of the X carriage.

Mount the extruder on the X carriage using 2 M4 nuts and tighten.  Take care to orient the extruder stepper motor toward the right - it should be over top of the fan.  You may need to raise the two X axis smooth rods to allow the hot end to fit.  You do this by turning the Z axis stepper motors.



Extruder has been attached to X carriage (viewed from the left-front)

Extruder has been attached to X carriage (viewed from the right-front)

Extruder has been attached to X carriage (viewed from the rear-top)

Extruder has been attached to X carriage (viewed from the rear-level)

Extruder has been attached to X carriage (viewed from the front-level)

Attaching The X Axis Stepper Motor

Prepare the X axis stepper motor by sliding the pulley onto the shaft and securing the 2 grub screws.  Orient the teeth of the pulley as close as possible to the body of the motor.



Pulley has been installed onto the X axis stepper motor.

Attach the motor to the X motor mount using 3 14 MM M3 bolts and 3 M3 washers.  Orient the motor so that the wires face down.

X axis stepper motor has been attached.

Assemble the X axis idler.

X axis idler is prepared starting with locating a short M8 threaded rod.  Slide the following onto the M8 threaded rod: M8 nut, fender washer, M8 washer, bearing, M8 washer, fender washer

X axis idler before installation showing (L-R) fender washer, M8 washer, bearing, M8 washer, fender washer, M8 nut.

Attaching the X Axis Idler

Attach the X Axis idler to the X end idler printed plastic piece by passing the short M8 threaded rod through a hole in the X end idler and securing with an M8 nut on the other side.

X  axis idler has been installed

Installing the X Axis Belt

You'll need the remainder of the timing belt, 2 belt clamps, 4 M3 14mm bolts and 4 M3 locknuts. 

Parts for X axis belt installation

 

Attach one end of the belt with a belt clamp to the X carriage using two 14mm M3 bolts and 2 M3 locknuts.  Pass the belt around the pulley on the stepper motor and around the bearing on the X idler.  Attach the other end of the belt to the X carriage using the last belt clamp.  The belt should be stretched pretty tight.  Cut off the excess belt.  In the video I see a slightly different X carriage that has a tensioner.  Slide the X carriage back and forth to make sure nothing binds.

 

X carriage with both belt clamps installed.

This is how the Prusa Mendel looks at the end of Video 16: