In the previous blog posts, I created the front and rear assemblies for the Y-axis. This time, I’ll use aluminium extrusion to connect the two assemblies and secure them. At the end of the post, we’ll have something that’s starting to look recognisably like part of a 3d printer.
First, I obtained some aluminium extrusion. The factory Taz-5 uses 20mm x 20mm extrusion, which has a central hole for suitable for an M5 bolt, and slots suitable for M4 T-nuts. I found it impossible to obtain extrusion with all these dimensions – so I settled for extrusion which is 20mm x 20mm, with a central hole suitable for an M6 bolt, and slots suitable for M5 T-nuts. Basically it’s fine, there are a couple of special modifications I had to make but nothing really significant or anything that caused a problem. The lengths of extrusion I used were 500mm for each of the two pieces.
The first thing to do is tap the holes in the ends of each of the two pieces of extrusion. I tapped to a depth of 50mm – this was probably a bit much, but it didn’t do any harm.
Remember I needed to tap using an M6 tap – the holes in the front and rear assemblies we printed are last time were only big enough for M5 bolts. This was easy to fix – I used a drill with an 6mm bit to expand the four holes in the front and rear assemblies.
I inserted the ends of the two pieces of extrusion into the left and right uprights of the motor mount assembly (the rear), and used two M6 bolts to secure them to the assembly. I didn’t tighten the bolts very much, as there’s quite a few other things to do.
Next step is to slide in the T-nuts required to secure all the parts – slide the T-nuts into the open end of the extrusion. This can’t be done later because you need to have one end of the extrusion open to slide these in.
On each side, you need:
- 4 T-nuts in the top slot;
- 2 T-nuts in the left slot;
- 2 T-nuts in the right slot;
- No T-nuts in the bottom slot.
The photo below shows a view from the side, where you can see the T-nuts in place.
After this, use a couple of M6 bolts to secure the remaining assembly to the other ends. At this point, you’ll be able to secure the extrusion to the plastic assembly not only using these M6 bolts (into the tapped end of the extrusion), but also on each of the left and right sides of each Y-axis upright. You should use an M5 x 10mm bolt into the T-nuts inserted to each of the sides. The image below shows how this should be attached.
Now use some M5 x 10mm bolts to secure the sides of the first assemblies attached – the inside is quite tricky, you might need a hex key rather than a screwdriver with a hex head.
Next, print four of the Y-axis mounts – these are available for download as STLs here. I’ve shown below what these look like when set out in Cura for printing.
Clear out the support material from the lower section of these mounts (if you’ve chosen to include this material), and these are ready to mount on the top of the extrusion. Secure each of these with two M5 x 10mm bolts – again, there’s no point in tightening these up just yet – their position will be determined by the frame for the X-axis and Z-axis, which I’ll blog about later.
At this point, both the front and back assemblies are attached to each of the 500mm lengths of extrusion – and each mounting point is attached by 3 different bolts, which makes for a very strong join. Also the Y-axis mounts are also attached, which prepare the piece to be attached to the main printer frame. The image below shows what’s been built so far. Hopefully you’ll agree this is starting to take shape as the Y-axis of a 3d printer.
Next time, I’ll look at starting to put together the main printer frame.