X axis assembly

Goal

By the end of this stage, your X axis will look like this

id=”" align=”aligncenter” ”300″ caption=”X axis assembled” [1]

Tools

You will need the following tools

• Phillips screwdriver

• Pliers

• Half round needle file

Step 1: X axis rails

RP parts	Quantity	id=”" align=”aligncenter” ”300″ caption=”x axis parts 1″ [2]
	1
	1
	1
	1
	1
Hardware	Quantity
265mm Smooth Rod	2
LM6UU Linear bearings	2
#4×3/8″ self tapping screw	4
M3 nut	1
M3 washers	4
M3 socket set screw	1
Igus bushings	4

We will start by fitting the Igus bushings into the x ends.
These bushings need to allow the Z smooth rods to slide easily, without much slack. In order to achieve this, you will need to fit an Igus bushing into position and slide a smooth rod through it.

id=”" align=”aligncenter” ”300″ caption=”Igus bushing trial fit” [3]

If the fit is too tight, remove the igus bushing, then remove a small amount of material from the X end, (using the half round file), and try the smooth rod through the bushing again. Repeat this procedure for all 4 bushing positions, then use the self tapping screws (with an M3 washer on each) to secure the bushings in place, (but do not over tighten the screws, the bushings should remain free).

The holes for the smooth rods are very deep and tend to be very tight fitting; you should ream these out before assembly.

NOTE: the screw holes may need to be drilled out a little deeper using a 2.5mm diameter drill bit. DO NOT force the screw in or you could damage the printed parts. The holes are long enough for #4×3/8″ screws, but will need to be drilled a little deeper for #4×1/2″ screws.

id=”" align=”aligncenter” ”300″ caption=”Igus bushings in position” [4]

Now slide a smooth rod through each pair of bushings to ensure it slides easily, but without too much slack. If the smooth rod is stiff, you have either over-tightened the self tapping screws, or you need to remove a little more material from the X ends.

Run a 5.5 mm drill through both Z-axis threaded rod holes; these holes must allow the threaded rod to slide through easily.

You can now insert the smooth rods into the X motor end, and slide a linear bearing onto each rod, (you may need to de-burr the end of the rods with a file to get the bearings on). The smooth rods go a LONG way into the motor mount; make sure they are both fully inserted before you go further.  As with the Y axis smooth rods, if the linear bearings are a little tight, place the smooth rod into an electric drill, then spin the rod whilst rubbing it with a scouring pad. The linear bearing should slide freely along the rod, but without too much play.

Add the X idler end, at which point your X axis assembly will look like this

id=”" align=”aligncenter” ”300″ caption=”x axis parts 2″ [5]

You can now click the X carriage onto the linear bearing on the lower smooth (it should be quite a tight fit, so may need some force to get it into place), then you can fit the M3 nut and socket set screw.

id=”" align=”aligncenter” ”300″ caption=”Fitting the X carriage socket set screw” [6]

id=”" align=”aligncenter” ”300″ caption=”X carriage socket set screw fitted” [7]

NOTE: The socket set screw is not there to retain the linear bearing, but is used later to pull the X belt tight. DO NOT screw the set screw so far into the X carriage to cause delamination of the printed part!

id=”" align=”aligncenter” ”300″ caption=”X carriage in place” [8]

Step 2: X belt

RP parts	Quantity	id=”" align=”aligncenter” ”300″ caption=”x axis parts 3″ [9]
	1
Hardware	Quantity
T2.5 toothed belt	1
Galvanised wire	1
NEMA14 stepper motor	1
M3x16mm screw	7
14 tooth T2.5 pulley	1
623 bearing	1
M3x10 socket set screw	1
M3 washer	1
M3 nut	3

Insert one end of the toothed belt into the 3 teeth printed into the X carriage, then route the belt through the X motor end, back through the top half of the X carriage, through the X idler end and back to the X carriage.

Assemble the idler bearing assembly by sliding the idler cover, the 623 bearing and M3 washer over the M3x16mm screw, then fit this to the X idler end.

Now fit the 14 tooth pulley to the motor shaft with the flat on it, and use the M3x10mm socket set screw to secure the pulley to the shaft. As with the Y axis motor, ensure the pulley teeth are facing towards the motor body. You can then screw the motor to the X motor end using the 4 M3x16mm screws.

NOTE: It is common for the corner of the X axis motor housing to foul against the Z smooth rod, causing the Z axis to bind. Please assume this will happen and file before installing the motor!  To resolve this, file the corner of the motor body facing the Z-rod ( and don’t be shy, you can remove a couple of mm without damaging the motor) until it clears the Z smooth rod.

id=”" align=”aligncenter” ”300″ caption=”X axis motor fitted” [13]

Loop the galvanised wire under the M3x10mm socket set screw fitted to the X carriage, then count 17 teeth from the loose end of the toothed belt and fold it over on itself so the end reaches the 17th tooth and slide it into the X carriage with the wire through the belt loop.

NOTE: Do not tighten the belt at this stage. This will be done when the X axis assembly is fitted to the Z smooth rods.

Step 3: Set X axis length

Before moving on to assemble the Z axis, ensure the distance between the Igus bushings is within 1mm of the distance between the Z smooth rods (which will already be installed on the frame assembly at this point). To do this, insert the two M3x16 screws on the idler side of the X axis along with 2xM3 nuts in the rectangular slots (if you can see the rods in these slots then use a flat headed screwdriver to nudge them back a little). These are used to push on the ends of the smooth rods to make adjustments to the distance. Measure the distance between the Z smooth rods at the top, then adjust the X axis assembly to suit.

Next step

Z axis assembly