The store isn’t functional just yet, so don’t get all excited about the super cheap mendel kits ;)

Using a printed ruler, the process is pretty straight forward. There’s some trial and error involved, and it’s probably not 100% accurate just yet, but I’m happy with a percentage in the high 90′s.

Here are the results:

The one on the right was printed extruded Monday night before calibration. It’s all kinds of wrong. Y Z weren’t  moving enough, and X was moving way too much.

The one on the Left was printed last night after calibration. The results are quite obvious.

There’s still some extrusion work to be done. Since I’m not sure what this PLA is exactly (It was an engagement gift from MakerBot, all I know is that it’s ‘Prototype’),  a lot of trial and error going on.

As it is now, once extrusion stops, it wont start extruding again right away. There’s a 30-60 gap between stopping and decent flow. Once it’s going, it goes pretty well. Since Jordan built this extruder, I’m also not sure what diameter the nozzle it is, but I suspect it’s smaller than the 0.5mm I’m used too. Easy enough to figure out once I get a mic. I just need to adjust for that and see if I can produce better results.

My machines.xml entry and some photos are below the cut

I really need to make a div for posting code… until then:

That’s all I have to report.

Some things I’ve run into:

• If the carriage belt clamps are too tight, it restricts the carriage from moving on the X. I suspect a better carriage would fix this (Stronger material for sure)
• Trying to print a square, and get a rectangle. Not sure what that’s about yet. I’m guessing it’s a change in machines.xml and/or skeinforge
• Skeinforge is trying to print down in the negative on Z, causing the extruder to punch holes in the print area. Easily fixed, but strange. I thought skeinforge started from the bottom of the model, that doesn’t seem to be the case always. huh.
• My X drive pulley was loose, causing lots of skipping steps. I wish I had noticed that sooner.
• I’m not sure the PLA I’m using is worth a damn. I can’t get a consistent extrusion at all. Once it starts, it seems to do ok, but that isn’t kicking in until around layer 2. That wont do. I think I’ll get some ‘know to work very well’ PLA.

All that said, I think I’m pretty close to having something that works well.

My buddy Jordan decided he wanted it printing more than I did, and made it happen. That’s pretty awesome. It’s put a spark under my ass to get it going.

Here are his results:

That’s the Printruder II from Thingiverse printing some Black PLA. Looks like I might need to order a new tube, as Jordan reports there’s no way it’s coming unglued from the ABS.

I tried to figure out how to remove it, but It’s not obvious… If who ever added me to it, I kindly ask that it be removed.

Unless, of course, you all enjoy reading about video games and other random crap I post about now and then.

That said, I took a break from making my Mendel print. It was just something I needed to do. All that’s left really to finish is the extruder. I plan on working on it more this week, so naturally, I’ll keep you all posted.

The extruder gear will be here tomorrow, so it’s likely it will actually print something tomorrow. I’m ordering some ribbon cable this week as well, so I can wire it up all pretty. In the meantime, I’ll be happy with a working printer that has sloppy wiring.

Here’s a short clip of it printing pretending to print one of the Y axis parts:

Still a lot to do before it’s done by definition, but not long until I have it printing itself a sibling.

I wasn’t real sure what to go with.  You need an adhesive that will bond to the PTFE, and be able to withstand some heat. I stopped by the hardware store and headed to glue section. I was kind of disappointed  at the lack of documentation on most packages. I ended up going with Loctite® All Plastics.

I must say, this glue does an amazing job, and works perfectly.

The Mendel is near complete. The only thing left is wiring, and finding a gear that will work well in the extruder. I believe I have most of the firmware issues sorted out, but I won’t know for sure until it’s all wired up.

Progress was made though. Not as much as I had hoped for, but better than nothing.

The best result, is that the Z axis works. I was worried that there would be too much binding, or that the steppers I got wouldn’t do the task. The steppers work fine, and I was able to solve the binding for the most part. I do plan on turning the X axis around, so Z has more torque on X’s heavy side.

I shot a video, of course. As usual, it’s pretty boring, and this one a bit slow.
I’m using ReplicatorG and a Stepper Driver. I haven’t gotten the extruder board to move the stepper yet.

Back to the grind tomorrow. I’ll post more about these final build stages Sat. probably.

Once it’s finished, I’ll be offering kits (in many fashions, more on that later), and hopefully all custom electronics from Adam. Making our own to save cost, and be more awesome.

Adam’s driver uses an L298, and is based off a solarbotics schematic, and works quite well. With 5v going in, these steppers have an awesome amount of torque.

Keith from FUBARLabs also showed us how to turn ports on at the same time using Port Registers. That might not be necessary to get the job done, but we like it. See the code and an amusing video after the break.

Here’s the code to get the steppers moving. stepDelay can be changed to increase or decrease speed.

int step1 =  10;
int step2 =  11;
int step3 =  12;
int step4 =  13;
int stepDelay = 1;
int stepDir = 0;
int stepCount = 0;

void setup()
{
    pinMode(step1, OUTPUT);
    pinMode(step2, OUTPUT);
    pinMode(step3, OUTPUT);
    pinMode(step4, OUTPUT);
}

void loop()
{
PORTB = B0101000;
delay(stepDelay);
PORTB = B0100100;
delay(stepDelay);
PORTB = B0010100;
delay(stepDelay);
PORTB = B0011000;
delay(stepDelay);
}

And here’s the video of it in action:

That aside, I now have enough to put it mostly together. I ran into some problems during the build this morning. Kept forgetting washers. I must have taken but together and taken apart again at least ten times because of this. If you’re planning on building one, keep that in mind. The largest problem I can find is the X Axis. Specifically the motor bearing side. Even without the motor on, it doesn’t move well at all. Finding out what causing it to bind is proving pretty difficult. The other side is extremely smooth, and requires almost no effort to move. The other rather annoying issue is that the Z Axis seems to go down further than the frame (See beer caps in photo). Not sure what’s up with that.

So, I’m just about finished. All that’s left are elcetronics (Looks like I’ll be making my own, unless MakerBot restocks in the next week or two) and the Y Axis. Then it’s print time.

Here are the Z drive pulleys. I didn’t think they would come out so well, but they are pretty functional. I still might see if I can get some non-printed ones on the cheap.

Hoping to have it printing by the new year.