Saturday, August 14, 2010

Brutis is dead, long live Brutis!

Instead of focusing on Brutis, I am going to dedicate my time to getting the fully metric, 606 bearinged, NEMA 14 mini Mendel working 1st.  I think Brutis would have worked, but I am not going to touch it for a few weeks.  If you want the design files they have been uploaded to Sourceforge here.Take it as your own if you want.  Any questions don't hesitate to PM me.

I have my Mini Mendel put together, and have been trying to run the Bowden extruder.  I can already tell that unless someone does some very slick codeing, or we put a second booster motor at the hot end, it's never going to print at a quality level anywhere near even what Makerbot does, which is not exactly the highest of quality out the box.

Problem is they went with a boden for a very good reason, NEMA 14 are VERY low toque, and any height added to the trolley directly reduces you maximum build height.  I tried attaching a Prinstruder onto the trolley, but both it, and a Wades where HUGE on that little trolley (looked like an elephant riding a donkey).

I needed a smaller high torque extruder that could fit on a Mini Mendel X trolley.  I came up with this:

It's the Kysan/Makerbot gearmotor using the MK5 wormgear and a 608 bearing idler like a wades extruder.  I printed off a copy last night (something wrong with being able to print an extruder in 30 minutes :) ).  Even with the filament being a little off it was able to lift itself, and the gearmotor up a length of  HDPE filament, good sign on the grip end of things.  Added the hot end today, and tonight I am hoping to have my 1st extrusion with it, but that brings me to the sad news.

The thermistor port on my Extruder board just gave up the ghost.  Swapped the thermistor, reloaded the firmware, even taped the thermistor to the back of the board, nothing.  Thanks to some guidance from Kliment looks like I could install a thermistor off the A7 port and change the firmware slightly to take the temp from that port instead.  As a work around I took my Mini Mendel extruder board and put it over on my Makerbot.  I will do my exstruder testing off my Makerbot and deal with the soldering when i finish up the mini.

I hate Windows Movie Maker, it takes SO LONG to bring videos into the library, and then over 1 1/2 hours to process 15 minutes.  If anyone knows a faster option that allows for videos to be edited, double speeded, and and the ability to add titles, let me know.

Back to good news.  My 3 year old daughter decided she needed to be like daddy and take apart random pieces of electronics. Unfortunately she chose as her first victim my microphone (it was already broken). Didn't realize it until I found the outer casing of it reattached with silly puddy. She claimed to have fixed it, which amazingly enough meant the speakers where twice as loud, but the microphone still didn't work any more.

Birthday was good, got a Drill press from Harbor Freight for $60 bucks, and a new microphone.  Fun Stuff!


  1. I'm running a carriage-mounted Wade's on my Mini and I even posted a version designed for it on thingiverse, which I just finished printing. It leaves me about 80mm build height, but then my Mini is not so mini.
    I'm using these motors for all three axes, and they feel like they've got torque to spare.

  2. I just checked, and the motors linked above are just over the 19.4 oz-in of holding torque recommended for the NEMA-17s on Mendel.

  3. Mine are the ones from Phidgets

    17.35 oz-in here :)

  4. I almost bought those, but they would have costed more with shipping, and the pololu ones are higher-torque. As it turns out, they match my machine's color scheme better too.

  5. I don't know if you've noticed this, but the MakerBot gearmotor is quite large and heavy--are you sure the Mendel Mini will be able to move it without skipping steps?

  6. My extruder,plus the 2 bearings and 9 m3 screws, gear motor and hot end will still be lighter than a decent Nema 17 and the wades. Not by much, but every ounce counts.

  7. Any updates to this? Have you tried it? If so, does it work well? How does the extruder block mount to the carriage? I just got a good ABS Wade's after melting my PLA one with a hot motor, but now my stepper is skipping steps. I'm about ready to jump ship on the reprap side and try a gearmotor extruder with the makerbot toolchain, and this seems like it would be the extruder to go with.

  8. Just got off a killer 2 weeks at work (180 hours in 11 days). I haven't touched it for about 2 weeks now (Still catching up with the 3 days I have been off). If your waiting on it I will finish it up tonight. (I hope)

  9. If you are interested in a stepper based motor take a look at the small PM stepper based geared motors sold by, for example, Anaheim Automation (TGM42-075-40-12V-040A-50R-LW6) and Kysan (SKU 1040121). I'm using the TGM42 on a custom printhead for a Taig and it works very reliably with ABS (I have not tried PLA).