PonokoXAxisAssembly

Assembling the Ponoko RepRap X Axis

Please, read the instructions through before you start.

The X axis assembly consists of a motor bracket, a carriage and an idler housing all transfixed by 4 off 500mm x 8mm diameter bright steel rods. The X motor bracket can accept NEMA 17 or NEMA 23 stepper motors. Use washers under the heads of all screws unless told otherwise. Where nuts can freely rotate, there should also be a washer between the nut and the plastic.

DO NOT remove protective paper from the 3mm slides used in the exchangeable extruder socket. You're reading the instructions through, right? You'll find it mentioned here.

Start by assembling the X carriage. You will need to locate the lasercut components shown on the right, together with the appropriate fasteners:

• 17 off M3x16 screws
• 1 off M3x20 screw
• 19 off M3 nuts
• 22 off M3 washers

Put an M3 washer on each of 2 M3x16mm screws, insert them through the rear panel of the carriage as shown and fit nuts.

Bring the back of the carriage upright and slot the nuts into the cavities of the carriage base as shown. Note that the laser cuts on a slight slope, so if the nuts won't go in from one side, turn the part over and try again. Note also that the nuts do not want to go into the holes, and sometimes need encouraging with tweezers or similar.

Here is a close-up shot showing how the nuts fit into the slots and the screws clamp everything together. As the washers may extend past the lower edge of the workpiece, you can't just flatten it on the bench and assume everything will come out level. You have to adjust it carefully.

Do not do up the screws to full tightness until all the parts of the carriage are in place. You may need the wriggle-room.

Do not over-tighten the screws. This breaks the acrylic and means you either have to glue the bits together or hack a new part out of acrylic manually. Either will slow down your progress somewhat.

Put the washers on 3 M3x16mm screws and put them into the 3 holes on the side piece. Fit it to the base, then add the two M3x16 screws and nuts (don't forget the washers) to the right side of the carriage. Then repeat with the left side, but only fit the lower two of the screws to the back of the carriage on the right hand side (shown unassembled in the photo):

Gather the remaining long M3 screw and thread the nut, opto flag holder and washer onto the screw to make a kind of mechanical shish kebab. Do not fit the opto flag into the holder yet. We do that last as they're fragile and tend to bump into things during calibration.

This is what the kebab looks like. The first nut is because we need a funny-length screw. You could just truncate the screw I guess.

It's hard to show on the photos, but the chain clamps are actually on the inside of the box-like carriage structure. If you choose to use split washers (more in a sec.), put them on the screws first. Then ordinary washers.

No point in doing the clamps up fully yet - we put the chain in them a bit later.

If you have some split washers handy, you might want to fit them on the screws that retain the chain clamps first. We don't know yet. They might help the chain stay firmly gripped as it beds in, or may give too much and let the chain slip. Experiment.

... and after all is done, your X carriage should look a lot like this one. Put it aside and save it for the next step, which is adding the socket for the exchangeable extruder. If you have the "redux" kit, the extruder is fixed with bolts through the obvious holes and there is no socket, so you can skip that part. Exchangable extruders are handy if you want to run different materials regularly.

Assemble the extruder socket or Skip straight to the X Idler assembly

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-- Main.VikOlliver - 23 Oct 2008