RepRapPro Huxley x axis assembly

Goal

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

X axis assembled

Tools

You will need the following tools

• Phillips screwdriver

• Pliers

• Half round needle file

Step 1: X axis rails

RP parts Quantity

x axis parts 1 1 1 1 1 1 Hardware Quantity 265mm Smooth Rod 2 LM6UU Linear bearings 2

1. 4x3/8" 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.

Igus bushing trial fit

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 #4x3/8" screws, but will need to be drilled a little deeper for #4x1/2" screws.

Igus bushings in position

Now slide a smooth rod through each pair of bushings to ensure that 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:

x axis parts 2

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.

Fitting the X carriage socket set screw

X carriage socket set screw fitted

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!

X carriage in place

Step 2: X belt

RP parts Quantity

x axis parts 3 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 three 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.

X idler bearing assembly

X idler fitted

X idler M3 nut fitted

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 four 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.

X axis motor fitted

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.

X tensioning wire

X belt fitted

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