Friday, August 14, 2015

Prusa i3 (Rework) Z-Axis Support Brackets- Build Log

This week, we will be focusing on the build process of Tech2C's Prusa i3 Z-Axis Support Brackets, which were the topic of last week's Thingiverse Reviews post. I think they do a fantastic job of keeping the hotend from vibrating. The build process is a bit complex, but the final product is worth it.

Above are the items you will need:

The printed parts (2 top brackets and 2 bottom brackets) from Thingiverse
4 M3 nuts (optional, you can use the old ones off the printer, but I wanted to replace mine)
4 M3x25mm screws
12 M10 or 3/8 in nuts
12 M10 or 3/8 in washers
2 M10 or 3/8 in threaded rods, 350 mm long
1 M10 or 3/8 in threaded rods, 410 mm long

I used 3/8 in rod for the 350 mm supports, 8 3/8 in nuts, and 2 3/8 in washers. I used M10 rod for the 410 mm piece, 4 M10 nuts, and 8 M10 washers. It doesn't matter what kind of washers you have- M10 and 3/8 are completely compatible with each rod. However, each rod length must have 4 nuts of the same type. I recommend using M10 rod for the 410 mm length, so you can reuse the washers and nuts used currently on your printer.

Threaded rod (of the hardware-store mild steel variety) is easy to cut with a hacksaw.

It is best cut while clamped between two wooden blocks, or when wrapped in a cloth and put in a vise, to avoid damage to the thread.

The next step is to mark the 410 mm threaded rod with a permanent marker at the middle (205 mm) and 15 mm away from the middle (190 mm and 220 mm). This is so you can center the rod with the Y Idler printed part.

Above is a shot of the back of the printer, before I began to install the supports.

The first thing to do is to move the bed all of the way forward, so it is out of the way. Then, you can begin loosening the nuts supporting the upper back threaded rod member.

Also loosen the Y Idler's tensioning screw.

Here is the time-consuming part. Spin the nuts towards the right end of the rod, and slowly pull the rod out, while keeping the Y Idler in the same position.

 Eventually, you can withdraw the rod after taking all of the nuts and the idler off.

Now you can begin to insert the 410 mm rod into the upper rear slots.

Begin with putting on a washer, a nut, a nut, and a washer. Spin the rod and keep the washers and nuts from spinning, moving them down the rod.

Continue spinning the rod, while adding the Y Idler, a washer, a nut, a nut, a washer, and feeding the rod through the last support.

Use 4 of the 6 washers and nuts previously used on the upper rear support rod. Thread a washer, a nut, a nut, and a washer on the left and right sides of the rod.

Put the bottom support pieces on the rear rod. (Add them in reverse of what is pictured here.) Use the last 2 washers and nuts from the upper rear support- put a washer, then a nut, on each side of the rod, securing the printed parts.

Use the marks made on the threaded rod to center the Y Idler. Make sure that the distance from the outside of the left Y Corner to the outside of the right Y Corner is 186 mm.

This is not the correct orientation of the bottom support piece. Be sure to flip it upside-down if it is in this position, in order to get enough length to attach the other rods in the future.

Now tighten the extension screw on the end of the Y Idler, and tighten the M10 nuts on the rear upper support rod.

The next step is to unscrew the screws holding in the Z Axis Top Right printed part and the Z Axis Bottom Left printed part.

Then insert the M3x25 mm screws where the original screws were.

Slide the top bracket parts on the other side.

Add the M3 nuts, and tighten.

The setup so far.

At this point, put a nut, followed by a washer, on each end of each 350 mm threaded rod.

Slide each threaded rod assembly into the printer. Add a washer, followed by a nut, on each end of each rod. 

Tighten the nuts. Also adjust the bottom support pieces if they are not centered.

And that's it. You now have a much more stable and sturdy Prusa i3 (Rework)!