Just Another RepRap

Ok, I moved the rest of the pictures off of my wife’s phone, so here’s part 2 of the progress from this past weekend. Despite the fact that these are large 9-megapixel pictures, they should all look much smaller than normal since I’m uploading them via the web, so I’m able to use the thumbnail feature of wordpress. Click them for stunning detail. 🙂  (actually it looks like you have to click twice to get the full resolution.. me no like..)

The y motor bracket assembly:

The y-bearing-360 (left) and y-bearing-180(right) assemblies:

Then, I skipped part of the Y axis steps and put off affixing the Y axis components to the MDF and frog, moving on to the frame (I couldn’t help myself). Here’s the first side that I assembled, with the first piece that I’d printed for my Mendel on the top:

This is the Z motor bracket on the bottom, along with one of the z-leadscrew-base assemblies (this is the one that I had a stray extra bolt stuck in, from the last post):

The Mendel rests on the edges of the bottom frame vertex pieces. At some point I’ll probably put some foam padding on the bottom of the feet.

Once I built the second side (the next triangle, with another z-leadscrew-base and the z-tensioner assembly), I stood the two of them up next to each other (with the X axis behind them) to see what the tent-shape will ultimately look like:

Here’s a closeup of the base of that second triangle, showing the upside-down z-tensioner piece made out of PLA, and the z-leadscrew-base that had the opto spring mounted on top of it with the long screw (described in the last post):

Immediately after that I proceeded to put the two sides together. This involved taking a long threaded rod, putting it in the chuck of my hand drill, slowly feeding it through the pieces on the top (ensuring the proper distances the whole way, and placing washers and nuts on as I went). It was actually kind of fun. Here is the way-cool result of all of that work:

There ya go. Wow that doesn’t look nearly as good with those tiny thumbnails.  🙁

So there’s one last picture from last weekend.. While slowly drilling/driving one threaded rod through on the bottom (after the above pictures), once it made it through the z-tensioner piece (made out of PLA), the rod started to jam up and wouldn’t turn any further. Once I unscrewed it and looked at the rod, I saw the threads seem to actually have been changed/warped somehow.. Here’s the picture – the strange threads on the left are thicker than the normal threads on the right:

Yeah you can’t see that at all unless you zoom in. At first I thought maybe the metal from this rod scrapped against the metal from the crossing rod inside the z-tensioner piece, but I don’t think that’s it. Then I thought maybe the threads were caked at some very very fine level by melted PLA.. I tried screwing nuts onto the rod with two wrenches, but could only get so far before it became almost impossible to move. I also tried my tap and die set on the rod, but didn’t try for long before I gave up. I’ll have to take another look at that and see what I can do. Not crazy about being held up by that.

Hopefully more progress soon!

LOTS of progress!!

This weekend Laurie and I were planning on opening our pool early in the season (since last season at least 1/2 of the season was wasted by rain and us having to replace the old pool liner). Saturday we peeled back the pool cover to see that the liner was ruined again – it floated away from the sides of the wall. We called the guys who installed it last year, and they came out to look at it Monday. The upside? This weekend I had lots of time to work on my RepRap!

But as usual, I’ve got a bunch of catchup pictures to go through, this time with a few details.

So first I needed to put together the z-leadscrew-base assemblies. I had two z-leadscrew-base pieces from Nick McCoy (mccoyn), and two z-leadscrew-base pieces from me begging at work (although I only needed two in all). I’d decided to use both of the mccoyn pieces, and started out with the two trapped nuts for the z-leadscrew-base-bar-clamp connection. Because this PLA z-leadscrew-base was similar in quality to the x-carriage pieces I’d made, I found that I had to use a soldering iron to fit the hex pieces in the nut trap holes. Here are a few pictures showing that:

Success! Ok, so then the bad part. On one of those two, I’m supposed to sink a nut way down into a long hexagonal shaft, so that a long bolt can just barely engage the nut on the other side of the piece. Here is the nut resting on the top of that shaft (not pushed in at all):

So what the instructions say to do is to push it in as far as you can, then take a small M4 bolt, put an M4 washer on it, then screw it into the hole on the bottom side of the piece. The idea is you’ll catch the nut, then as you screw it tighter, the head of the bolt will push against the washer, and continued screwing will pull the nut down to the bottom of the hexagonal shaft. Then, you unscrew the bolt, and the nut is in place for the larger bolt to take its place (after going through another two pieces).

Yeah. So, that didn’t work out so well. The problem was that the hexagonal shaft wasn’t completely clean – it was still one of these pieces printed out of PLA that need work. So initially I couldn’t even get the piece to go down at all. Then I used a soldering iron to get it to go down as far as I could, turned the piece over, put in the small M4 nut, and pulled the nut down to the bottom.

The problem is, at the last second I probably turned too much, and ended up stripping the hexagonal shape at the bottom of that shaft. That left me with this:

Tragically that’s now stuck. The bolt is stuck in the nut, and trying to turn it just causes the nut to turn where it is. Still, that wasn’t the end of the world, because that hole was unused on one of the z-leadscrew-base assemblies, so, so what, one of them will have an extra bolt sticking out of the top where there should have been nothing…..

..but then I went to the next PLA z-leadscrew-base piece, to try the same thing on that, but as careful as I was, I had the exact same thing happen there. Worse, instead of using the small bolt, I figured I’d try using a longer bolt, as it might reach the nut easier. That of course meant I needed something for the bolt head to push against, so I threw on a bunch of mudguard washers I had which were pretty thick. All of THOSE are now stuck on that piece, making that entire piece unusable:

But luckily, I had those pieces from work! And they were made on that Stratasys printer, which used support material, so those holes were perfect! Look how perfectly these nuts fit into the nut traps in the piece printed with support material:

So here’s the z-leadscrew-base assembly that needed the long bolt coming out of the back. I still think this looks like a Star Destroyer:

Here’s the bottom of that piece:

Ok, moving on. Here is the assembled z-leadscrew that will eventually be mounted in the z-leadscrew-base. The z-belt will move along that geared pulley and turn the threaded rod, moving the X axis assembly up or down.

Then there’s the z-tensioner assembly, which has a bearing that you can slide up and town to add or remove tension to the z-belt:

The Y Idler Bracket assembly sits on the front bottom of the Mendel:

So then I finally got around to splitting the belts. The other day Casainho had posted on his blog about splitting the belts for his Mendel, and how he’d been apprehensive about it and eventually found that after all of that worry, it was easy. I too had been hesitating to cut the belts, putting that part off for a while. Well I have to agree, that was easy!

Here was everything set up, ready to go:

Then I built the belt splitting jig around the belt:

I placed the whole jig into a vise, and while wearing gloves pushed the blade into the slit, cutting into the belt. I grabbed the end, and pulled the belt into the blade.

After taking it off of the vise, I opened it up, and there ya go – a 5mm continuous belt (and more belt for later as spares!)

I broke this post up into two parts, because I have pictures that I took on my wife’s camera after this point, since my iPhone is 100% absolutely full with 5119 photos and movies. I’ll post those pictures later in another post.
(hint: it now actually looks like a Mendel!)

Huge milestone.. My entire X axis is assembled! (I’ve held rods alongside pieces many times when showing this to friends, trying to describe how in will work, and now I can just show you.

I’ll cut to the chase and show the final pictures first. Here is my mostly completed X axis assembly:

I still need to put on the belt, PTFE, and heater barrel. Six of the nuts on the carriage are still temporary regular nuts, whereas all of the others that are supposed to be nylock are now nylock.

Here are some of the pics leading up to that completed X axis.. (sorry that there aren’t more captions or descriptions – I’m trying to spend more time building than blogging.. 🙂 )

FIrst, here are pictures of the Vert Bearing 360 assembly:

I really like this next pic:

Ok, so when I ordered parts, the “mudguard washers” I originally obtained were way too small. The whole point was that they were supposed to extend out far to hold up a timing belt. I finally found a source (not McMaster) that had mudguard washers (fender washers) of the right size. These next two pics show the new washers and them in their correct place.

Ok. So next, there are pulleys that need to go on the stepper motor shafts, the insides of which have oval/rectangular holes intended for filed-down stepper motor shafts. (There are now some good alternatives on thingiverse that don’t require as much filing, but I’m not in a position where I can print new parts right now). So, I filed down the shaft on one of the stepper motors (and I’ll do the same for the next two soon). Here I clamped the shaft in a vise, after caking the base of the shaft in blue-tack, which is something like silly putty, to keep steel filings from being pulled directly into the stepper motor (it’s a big magnet, remember?).

Then, a few Dremmel cuts later and after lightly tapping with a plastic mallet (with the base of the stepper shaft supported by a clamped small hex socket), I managed to get the pulley on the shaft!

Here’s a ridiculously short 5-second video showing that:

So then I moved onto the motor bracket. Unfortunately I think I tightened one side of a clamp too much (on the rest of them I carefully went one side to the other), resulting in a crack in this piece (visible in this picture). Hopefully it doesn’t make that much of a difference in the end:

So I continued.. Here is the bottom of the motor bracket, with one of the two x-axis rods in place:

Then the top and bottom once the second rod was placed:

Here are two cylindrical spacer pieces that go next along the rods:

Next on the x axis rods, I placed the Vert Bearing 360 assembly shown earlier in this post:

Here’s another crack that doesn’t seem like it will be a problem:

And finally, here are the first two pictures of the assembled X axis again, along with other closeups. Sorry about the horrible lighting – I should take some of these outside or something.

Can’t wait until I get some free time to move onto the next steps. I might not get free time until Monday night though.

Getting closer!

p.s. I’m thinking that maybe I need to replace those thin sheets with pieces of tin or something – I hope not.