Here’s a bit more progress that I made today. I finally got around to cutting the bed, circuit board holder, and other pieces out of MDF (medium density fibreboard).
I don’t have easy access to a plotter, so I needed to print the dxf file for the thick sheet template out on multiple pages and arrange them together correctly. I thought it would be easy to find software that did this, but I didn’t find anything easily at first. Eventually I found some shareware package for windows called CADViewX Lite, which had a demo called CAD Open in Word that let me open a dxf file and print it across multiple pages (with hash lines). It didn’t work as nicely as I’d have liked, but with a few measurements and careful alignments I was able to lay out the pages on the MDF and tape them down with single and double sided tape:
The MDF sheet I had was an unwieldy 2′ x 4′, so first I cut off the relevant area:
Many cuts with the jigsaw later, I’d cut out the five pieces (scotch taping the template down again to the newly cut sides as I went). I’ll drill the holes and jigsaw out the internal ovals later.
Here’s the bed that the Mendel will print on:
I also was cutting rod today. Here are the fully completed smooth rod pieces, which make up the X, Y, and Z axes:
Those were cut out of 3 original rods. In addition to the 3 original smooth rods, there are 9 threaded rods that need to be cut into many pieces. I was able to get through one of those today, resulting in 3 threaded rod pieces:
Unfortunately the cutting drains the rechargable battery on my Dremel like crazy. I went to the store looking for a spare rechargable battery (quite naively) and of course no one carries them locally. I considered buying a 2nd Dremel that was corded, but even if I can only cut 1-2 rods every 3 hours, I’ll still get them all done pretty quickly, so it didn’t seem worth it. (I may just do more cutting with a hack saw, but it’s a pain). I did order a spare battery online – it’ll probably arrive by the time my Mendel is fully completed. 🙂
Oh, one more off-topic thing.. Last week when I ordered some red and black wire for the power connections from sparkfun.com, I saw they had some stepper motors that looked to both be NEMA 17 and have more holding torque than the ones I’d purchased from makerbot.com (at least that’s what I thought after a quick calculation.. I might be wrong). We’ll see when they arrive – they were cheap enough that it won’t break me if I bought four extra steppers for nothing – I’ll find a home for them.
Next up – a lot more cutting of threaded rod, drilling holes in the MDF, more assembly of the X carriage, and a bunch of electronics work to redo the boards I have for Mendel.
Huzzah! There is good in the world. Progress continues.
In my previous post, I described how my place of work had asked for the MakerBot (which I was using as a RepStrap) back; it was originally made available to Chris and I as part of a “technology library”. I’d still had six pieces left to go (as it turns out, actually seven).
Good people came to the rescue. mccoyn built and sent me two z-leadscrew-base pieces and a z-motor-bracket:
Seeing those parts actually completed out of PLA, I’m greatly encouraged. My most recent attempts had all jammed up at some point during the long builds. I’ve told the next person that received the MakerBot that they need to rebuild the heater barrel assembly (this time actually using a new heater barrel and nozzle, because that seems to be completely gunked up), so maybe the original RepStrap will be able to print those parts out too someday – I hope never to find out, as I want to print those parts on my Mendel. 🙂
In parallel with mccoyn‘s offer, I’d had a discussion with key people at work (I’ll omit names as I’m guessing they’d prefer that). Luckily I was able to thank the person responsible for ordering the MakerBot in the first place and setting up that technology library; hopefully I conveyed just how thankful I was for this. I also managed to get permission to have a few parts printed at work with a commercial Stratasys 3D printer. When it turned out that I actually had overlap between some of those parts and mccoyn‘s pieces, I decided I’d use mccoyn‘s and put the ones from work in the shoe box of spare parts (if not directly onto Chris’s Mendel, which will be the first set I start printing once I have my Mendel working, soon to be followed by a set for my brother Jon – who already has one piece. 🙂 ).
Here’s an example of what the z-leadscrew-base printed on the Stratasys printer looked like (this was printed with ABS, and there was some support material used and washed away in a bath after):
I received offers from at least two other people privately to potentially supply me with pieces if I needed them (when they got their printer working). Thanks to all!
Ok, so on to building. First, I spent an evening midweek figuring out exactly which items I had to order for wiring. Adrian’s excellent video illustration helped clear up any confusion I’d had about what went where. My spool of ribbon cable and lots of connectors will arrive probably around Monday, just in time to completely miss the weekend. That’s ok though, because I have a lot to do before I get to wiring.
First was cutting the metal rods and studding. I’ve put that off for a while, and just started on it last night. When I purchased the non-studded (smooth) rod for the X, Y, and Z axes, I went with A2 steel (even though I’d heard people say it was a pain to cut). It turns out it was relatively easy. A while back, in anticipation of this, I’d purchased a diamond cutting wheel for my Mendel for around $15 (maybe that’s overkill – I have no idea):
Here’s a quick video showing the sparks it created:
Before filing it down, here’s what it looked like after the cut:
I was supposed to cut it to 406mm (with a tolerance of +/- 1mm). I think I did pretty well:
The battery on my Dremmel needed recharging, so I was able to stop long enough to post this entry. Rather than building up a long post, I think I’ll just post this one now and follow up with more later. Another thing I’m doing this weekend is making an attempt at cutting out the MDF bed pieces with a jigsaw. There is a nice laser cutter at work that I might be able to talk someone into letting me use to cut pieces out of MDF, but it’d be nice if it was doable at home. Either way I bought a 2nd piece of MDF at Home Depot today after Emily and Alicia’s first-Saturday-of-the-month building time (this month they made a rain guage). But I digress. 🙂
More later. Once again, thanks mccoyn and unnamed person from work, both of which spent lots of time printing me pieces! I swear I’ll pay it forward!
Well, it’s been three and a half weeks since my last real description of any progress. In that two-posts-ago post I’d described the “crisis” of potentially losing the Makerbot before I was done printing pieces. As the circumstances of my last post pointed out to me rather harshly, that doesn’t really qualify as a crisis. Still, that issue was averted, as I was able to bring the Makerbot into work for the 3D printing class, then get it back out of the building.
Since that time, I’ve gone from having 20 pieces left to having 6 pieces left, but once again I’ve run out of time, as we received the expected request to return the Makerbot. I feel bad because it’s been in my possession almost 100% of the time, and Chris barely was able to use it (though he assures me he feels bad because he was able to enjoy actually having free time over the past few months while I did all of the hard learning for us, but I don’t know if I believe him. 🙂 ). Being completely frustrated with constant extruder stall failures, I called Chris on Saturday and asked if he wanted to take the Makerbot for the few days that we have left, which he did.
Our hope had been to finish the parts for my Mendel, start printing parts for his Mendel with the Makerbot, then when my Mendel was assembled print half of his Mendel pieces with my Mendel to halve the print time. Instead it looks like we’ll be printing his entirely with my Mendel, once we find a way to get that done. As I said, we’re 6 pieces down (we still need the y-motor-bracket, z-motor-bracket, two z-leadscrew-base pieces, and two belt-split-jig-bracket-universal pieces). Maybe Chris will figure out something I’m missing on how to reduce friction enough to keep the extruder motor from stalling and he can actually print them out, but he’s dealing with the same machine I was, so I’m keeping my hopes in check.
Anyway, let me document more of the success I’d actually had during that time. As usual, pictures and video…
When I had twenty parts left, I tried printing one of the z-leadscrew-base parts out of PLA, but it failed. Here I was, 18 minutes into the destined-to-fail print:
..and here is a description of the failure:
So here let me take a second and describe what I’ve now learned about how to somewhat recover from a stalled extruder motor (at least temporarily). If you’re printing and the extruder motor stalls (meaning you’ve probably got some sort of jam beneath the extruder in the heater barrel or insulator), and you know it was supposed to be printing rather than just traveling (because the head is moving slower, or you’re on the perimeter where it’s supposed to be printing, etc), press the pause (||) button in replicatorg (DURING A TIME WHEN IT WAS SUPPOSED TO BE EXTRUDING, NOT JUST TRAVELING). I used to think the pause button was almost useless because it kept the extruder motor on, so you’d end up with some huge blob of plastic ruining your piece. However, in this case it works to your advantage. Now that the bed is paused, you can grab some pliers, grip the filament as hard as you can, and push it hard into the extruder (I used to attempt to do this while the bed was moving, which sometimes worked but more than often would push the nozzle into the piece itself, causing it to catch, miss steps, become misaligned, etc). If you push hard enough, eventually you’ll hear the stepper motor “catch”, as you added just enough pressure to move the motor past the threshold where it couldn’t push any more, and the motor will start up again. Plastic will start extruding, and you can click the pause button again to resume printing. Unfortunately this is a temporary fix, since whatever caused the jam is still probably there and it’ll jam up again soon. This can help though if you just spent 1 hour and 45 minutes of a 2 hour build watching it print fine, just to see it almost fail at the end.
Ok. So here’s a piece that printed extremely well – y-bearing-180-inner_2off:
By the way, every time I see that piece I think of this building in Boston:
I was about to bring the Makerbot in for the 3D printing class I mentioned two posts ago, and wanted to do a few ABS prints to remind myself what it was like (I’d been printing with PLA for so long that I’d forgotten what it was like). While PLA is excellent and wins in many categories, ABS does have its advantages too – one of which being that it extrudes in a closer-to-solid state that seems to allow you to print insanely fast with it. (However, don’t take my account as a source of any real information on this! I wouldn’t be surprised if some people have PLA printing super fast on their RepRaps, perhaps with modified extruders (or even the regular Mendel extruder).. or maybe speed doesn’t even enter into it).
Here is video of me printing the x-360-z-bearing-plate_2off piece in ABS, which I’d also attempted in PLA but I’m going with the ABS piece:
So I packed up the Makerbot (weeks ago), and brought it into work for the 3D printing class that I’d actually been looking forward to since around October. The talk was by Dr. Zoz Brooks, who you can see on the TV show “Prototype This!” on the Discovery channel. It was a great talk, and after in the hands on section we saw all of the hardware at work and I was able to show the Makerbot to everyone (along with all of the parts I’ve made for Mendel so far).
As I said above, I was able to take the Makerbot back home after that. Then Laurie threw me a surprise party for my 40th birthday. Two of the RepRap-related gifts that I got are visible in this picture: the PLA in the front from Cheryl, and the Terminator bobblehead on top from ChrisR. Chris’s public statement with the joke was something along the lines of “So Jeff talks to everyone about the RepRap, but he sometimes leaves out the best part of the whole thing – it’s a self replicating robot. The inevitable conclusion, of course, is that this will eventually lead to Skynet and the destruction of mankind. So this is to keep him honest and remind him of what he’s making.” 🙂 (I disagree that I’ve ever left that part out, but why ruin a good joke).
Part creation continued.. Making two x-360-z-bearing-plate-mirror_2off pieces at once:
I made a much better z-axis-opto-spring than I had a month or so ago:
Comparing the two versions I made of the z-axis-opto-spring:
Again, as I said before, the default Makerbot ABS settings I’d grabbed from somewhere have the motors move extremely fast (maybe I’d slowed things down for PLA – I don’t remember). Here’s video of extremely fast printing of the y-bearing-360-outer-left_1off piece:
Here is a piece that might be unnecessary but I printed anyway, bed_height_spacer_31m:
And here’s another piece that might be unnecessary, but it was easy enough to print – x-cable-clamp_1off:
That’s it for successful parts. 🙁
Here’s video showing how incredibly beneficial it is to mount the extruder controller board above the plastruder, so you can see the idler wheel actually turn:
Here was a failed attempt to print a z-motor-bracket_1off out of ABS:
I’d gone through enough motor stalls that I was curious about what exactly the geared DC motor looked like inside, and before returning the Makerbot I figured it was worth taking a look. For anyone who’s interested, here’s what the inside of the motor looks like so you don’t have to open your own:
When taking the bearing off the shaft of the gearmotor, I realized that one side of the gear had actually broken off. In case it was adding resistance to the turning of the motor, I left it off.
Last two things.. First, the M6 nut on the heater barrel allows failure cases like this to live longer and remain undetected – here’s the heater barrel completely covered by plastic:
And finally, here’s the plastruder rebuilt by me (possibly for the last time, assuming I’m able to move onto my Mendel by somehow getting the last six parts I need):
The next thing I’ll do when I have free time is assemble more of the pieces I have (I should be able to complete the X axis, at the very least).
