The larger stepper motors look like they should be powerful enough. Use the best on the X an Y axes, because they move the most. The extruder also needs power, but it moves the plastic slowly and so several stages of gear reduction will make a weaker stepper have enough torque to push the plastic through the tip. It looks like you have plenty of gears to pick from. I would leave the drive pulby rocket_scientist - General
Ben, Even the simple HDPE recyclers are going to be high in vitamin content, low on RP parts. To make something strong, long lasting and reliable will probably benefit from some custom designed and built metal parts. That means that for several generations of repraps to come, having even a soft plastic recycler will mean purchasing a kit of special parts, if not a full kit or prebuilt unit. Soby rocket_scientist - General
moon rabbit, it looks like someone will need to acquire a few and see if the inside diameter is large enough for the 3 mm plastic filament to pass, or perhaps shift to the 1.8mm filaments. My sister works for a microscope stain and medical lab reagents house, and they might have some use once pipettes that she can pull for me to test after they have finished with them. Mikeby rocket_scientist - General
Rich, I have not read the plastic sticking or not sticking theory thread, so this may duplicate existing comments, or be all new. But here is my best shot. When you put Kapton tape on polycarbonate, then aluminum, then glass, I suspect you will see the least warpage on the polycarbonate. My theory is that the polycarbonate has a little flex, so as a corner begins to pull up, the plastic undernby rocket_scientist - General
Ben, you can probably downsize the motor by adding a flywheel to the power train. That will provide instantaneous power when something tries to jam the cutter/blades/grinder without depending solely on the horsepower of the motor. And much cheaper if made from scrap plate steel. Blender: The blender may work best with denser objects. An intact, empty milk bottle is fairly low density, and tby rocket_scientist - General
For high current connections, I still prefer screw terminals to slide on connectors. In my car, the AC fan keeps burning through the spade style connectors. With proper termination of the heater power leads using a crimp or solder connectior you should have very reliable power transfer, and easy connecting and disconnecting of the leads when needed. I agree that stranded wire going straight intoby rocket_scientist - Next Wave Electronics Working Group
Thanks! Makes my humble efforts to design new and better glass nozzles and the Open Air reprap I want to build sound much more important and meaningful!by rocket_scientist - Kartik M. Gada Humanitarian Innovation Prize
I believe that the Chumby Hacker Board would make a great Linux single board computer for running a Mendel or other current generation reprap. Most of the IMX233 chip's general I/O are used internally for expanded memory, microSD card, LCD, etc. But there should be enough to run 3 axes and an extruder, just not a whole lot more after that. And it might be interesting to work on an EMC2 based reprby rocket_scientist - Next Wave Electronics Working Group
I believe it has been suggested before, but a meat grinder already as the variable pitch auger, and the advantage of the grinding body to mount the auger in. Replace the plate with one with fewer openings and perhaps use a heated aluminum plate to bind the granules into a filament. Mikeby rocket_scientist - General
That makes sense. Then you best bet is the modified code for your arduino. Mikeby rocket_scientist - Controllers
445builder, have you looked a EMC2 as the control software? I have not used it myself, but it is geared more towards many forms of CNC, and might even have a mode for laser cutting already defined. It only runs on full size laptop or desktop computers, but can probably be configured to send commands to a microcontroller running you X-Y stage stepper motors. Mikeby rocket_scientist - Controllers
I have already picked up colored and natural ABS, natural PLA, and HPDE filament for my own testing in glass nozzles once I get my McWire going. It is 3/4 constructed, but I still have to add the extruder, bed (probably heated bed) and make and connect the Gen2onaBoard electronics, so not quite yet ready to test. I will post my results here and in the glass nozzle thread. Mikeby rocket_scientist - General
Running the glass bead around the middle of the tub will take a little practice, but once perfected would make the strongest connection. You could even put springs on the vertical bolts to handle thermal expansion. The second approach should work, and will likely work better with roughed up edges for the ferrul to grip. On the other hand, the flange at the end is easier, I just need to work on geby rocket_scientist - General
Ryan, thanks for the update. It is really great when we get the suppliers and commercial people to post on these boards to help us and keep us up-to-date. Of course, I placed my back order before responding! I am nearly finished with the X-Y-Z table of a McWire, and I want a test controller to run a stepper axes or extruder forwards and backwards, and a temperature controller to test out the exby rocket_scientist - Controllers
Just had an idea. When pressing the replaceable orifice against the glass, it is hard to get a precise fit to prevent leaks. What about using PTFE or PEET washer as a gasket? It should be good through the entire temperature range, and compliant enough to seal the gaps if everything to smooth and clean. Mikeby rocket_scientist - General
Should help with the smell from over heated ABS, too!by rocket_scientist - General
As standard plexiglass or MDF cabinet would be fine if there was a fan providing negative pressure. I was wondering if it would help to have a furnace section that burned the dangerous gases, or possibly a used catalytic converter from the exhaust pipe of a car plus some propane or something to help keep the temperature inside high. Or maybe just activated charcoal from a fish tank filter to soakby rocket_scientist - General
If we need to go back to ground, signal, power to be compatible with board generations and cables, that will mean jumpering every opto-connector. I would recommend using the jumper on the signal as it is the lowest current of the three pins. I fully understand dumbing down the design to allow for reprap pcb milling. I had forgotten that that was a major goal for this board. Given that, yes thby rocket_scientist - Next Wave Electronics Working Group
I have also seen designs where there are two axles of circular saw blades that mesh together like a paper shredder. That would ensure that all the plastic was finely divided into small granules.by rocket_scientist - General
I believe that the borosilicate glass nozzles I have been experimenting with can handle 325C or even higher. But that does nothing to stop the decomposition and out gassing. Possibly a sealed cabinet with something to catch or detoxify the gasses. Mikeby rocket_scientist - General
Lanthan, Your schematic has the limits stops as ground, signal, power, but your PCB layout has them ground, power signal. When I ran optimize rats, it showed many shorts and missing connections, basically bridging that whole side of the chip. You need to decide if you want to use the schematic choice of signal on the middle pin, or the PCB choice of power on the middle pin. Sticking with the PCby rocket_scientist - Next Wave Electronics Working Group
Unless I left some hidden thermal stress, the glass should be quite strong. Especially with a balanced force around the circumference. However, if you break a nozzle following my instructions, I will send a replacement to continue experimenting with. I still think that some form a glass based nozzle is the way we eventually want to go. Mikeby rocket_scientist - General
True, I keep forgetting that it is easy to draw perfectly aligned rails, but not as easy to build them. I also wonder about adding X and Y offset screws to the top and bottom of one of each pair of vertical rails.If you get enough constraint with the design you that is great. If not, you have some ideas on how to add more.by rocket_scientist - Delta Machines
Buback, I wasn't cleat in my last post. In this case, I was referring not to the drawn out nozzles that I have made, but an unmodified glass tube that is ground down to a cone shape so that it will seal against a brass bolt with a similar taper countersink. I have attached a crude drawing of what I was thinking of. I tried doing this in Google Sketch, but it was faster in Word to do a 2D drawinby rocket_scientist - General
Greg, I find the concept of moving the table interesting. You have to be careful to let the hot plastic harden before you make any sudden moves, but the ability to have several fixed print heads sounds interesting. If you rotate the nut instead of the rod, then you need to have the stepper motor mounted on the moving surface, which probably adds more mass than you save by not rotating the dby rocket_scientist - Delta Machines
How about a MakerLegoBot that _extrudes_ Lego blocks?by rocket_scientist - General
Buback, Do you need a different nozzle? I have a glass grinder, so I can grind down the flange to 8mm. I can also make you one with a tapered tip that id larger than 1mm so that different nozzle plates can be pressed against it and still seal fairly well. The idea of putting a metal plate on the very bottom to create the orifice and heat the plastic right at the tip is good. I will have to tryby rocket_scientist - General
Martin, A beautiful, elegant design. I like the way you have carried the Darwin/Mendel approach of smooth and threaded rod with RP end connectors for the structure rather than the more specialized and custom machined pieces I saw in a video clip of a different polar robot. The first polar robot I saw working had the paired rods from each vertex aligned vertically, making a parallelogramby rocket_scientist - Delta Machines
aka47, if I understand correctly, you are recommending that we use a standard switch mode power supply controller, and externally measure the temperature and find what reference voltage/current needed to power that much energy into the windings. It would not have temperature feedback, but would be stable amount of power being added. This may be good enough, although we might need to change theby rocket_scientist - General
Thanks Sebastian. I think I will step out of the current sequential numbers being used by various 8bit AVR/arduino designs and jump to a new naming/numbering scheme for 32bit processor based controllers. Lets use 32GenX1..2..3 for 32bit microcontrollers on custom boards (eXperimental), 32GenS1..2..3 for SBC (single board computer) based designs, and 2GenP1..2..3 for pentium based designs that mayby rocket_scientist - Next Wave Electronics Working Group