I'm also quite interested in this - I just had another PTFE thermal break fail on me, most likely because I mistyped an M104 command and overheated it. Any idea on the thermal conductivity of the ceramic you're using? PTFE looks to be around 0.25 W/(mK), and it works quite well as a thermal break. Some ceramics seem to go as low as 3 W/(mK), which will need a bit longer/thinner thermal break, bby Wade - Plastic Extruder Working Group
BobH - the noise, assuming your extruder controller is running the 5d Extruder firmware, is the 1 kHz PWM base frequency. You can change it to 64 kHz by adding the following line to your void setup() function in extruder.pde: // Change the frequency of Timer 0 so that PWM on pins H1E and H2E goes at // a very high frequency (64kHz see: // ) TCCR0B &= ~(0x07); TCCR0B |= 1; Be awareby Wade - Controllers
I've built two Darwins with the shaving and gluing technique, using a jig made out of polymorph plastic. The belts have held up fine (one is almost 2 years old now, and still printing), but due to the teeth spacing not being perfect, the belts sometimes skip under loading. It means I have to re-level the bed on the Darwins every once in a while, but hasn't been a serious problem. On the Mendelby Wade - Mechanics
Interestingly, permanent magnet brushless DC motors are more or less the same thing as stepper motors, they just have far fewer poles. So you can get similar results with a 3 pole motor BLDC (which is really a synchronous AC motor with some fancy drive electronics that take DC) and a 30:1 gear reduction, or a simple 200 step stepper and simple open loop electronics. Another factor in rapid protby Wade - Next Wave Electronics Working Group
Hey, ribbon cable is pretty standard - it's 0.05" between the cables. If you find any dead PC's around, you could snag some off the hard drive cables, or just order some up from Digikey. That said, pretty much any small wire will work for the extruder - no need to use ribbon cable.by Wade - General Mendel Topics
Nice looking machine! Send me an email at wbortz at gmail dot com if you'd like a set of RP parts for my extruder - maybe we can work out a deal. Wadeby Wade - Reprappers
The Arduino serial console doesn't send CR/LF's, so the 5D firmware doesn't recognize that a command is sent. Try Ralith's gcdump util if you want to send gcode straight up, or any terminal program that sends CR/LF's. The Makerbot firmware has a bit of a hack to ignore the lack of CR/LF's in the Arduino serial monitor.by Wade - Reprappers
mattkos - that wil get rid of particulates (ie, dust), but it won't do anything for vaporized styrene. I just stick with PLA - it works far better than ABS for me, besides being a lot more pleasant to be around.by Wade - General
Alibre Design has a free version that will let you do proper dimensioning. Unfortunately, it won't import STL or AOI files, but it does import STEP files quite nicely - there are some STEP assembly files for Mendel in Subversion.by Wade - 3D Design tools
It's nominally in mm of extruded filament (or inches if you're using Imperial). The volume is set by the E steps/mm setting in the firmware. Right now, most CAM assumes you only want a single width of filament, but you can adjust it using die swell or filament stretching and varying the E / distance travelled rate set up in your CAM software.by Wade - General
Is there any reason they need to be the exact same diameter? Just measure the diameter, and update your E steps/mm value accordingly. Besides, I doubt it's possible to get repeatable results without a lathe, but the big advantage of this design is that you don't need a lathe. I don't even use those bearing blocks, I just use some skate bearings in a vice with a hand held drill.by Wade - For Sale
Aren't those a bit low res and low torque for a Reprap?by Wade - For Sale
Alibre.com has some good CAD software - I liked it well enough to buy the cheap version, but they have a free version as well that's pretty good. It's more for mechanical engineering types, but it does the job. Blender is my next favourite, but it's more of a mesh modeller than an actual CAD package. AOI is similar to Blender, but crashes too much for my tastes. Openscad is a modeller forby Wade - General
I tried an 11 tooth spur gear purchased from SDP-SI, and while it worked, there was noticeable acceleration and deceleration of the filament as each tooth was engaged. Making a worm gear style pinchwheel (like Nophead's designs) worked out much better - smooth operation, great pull (16 kg on PLA), and easy to make - all it takes is a hand drill, file, and an M3 tap, plus a few skate bearings andby Wade - Reprappers
Hey, neat-o! Glad you guys like my design! Wadeby Wade - For Sale
Since you aren't selling plastic Mendel parts, wouldn't this post fit better in the "Vitamins" forum? Also, can anyone print 2.5 mm pullies yet? I thought 5 was the limit for reliability.by Wade - Vitamin Kit for Sale
Anton, that's an interesting CO2 analysis, and good info on the Wiki page. One more thing to consider, though, is the renewable aspect of PLA compared to ABS. Even if the CO2 situation is a wash, I think the fact that PLA can be biodegraded, and re used to grow more PLA makes it much more attractive for me. One of the main problems with traditional plastics is the fact that they do not biodegrby Wade - General
Yes, sounds like a tricky problem. I like the idea of the Journal of Negative Results - sometimes these forums feel a bit like that. Just for kicks, I tried using a flashlight, loupe, and my cell phone camera to get a photo of the ridges. It sort of worked, but you only see the larger bumps in the photo, which correspond to the full steps at 0.2mm. The smaller bumps at the half steps (0.1 mby Wade - Reprappers
This is one of the main reasons I only use PLA. There's a lot of talk about recycling ABS, but it really does not recycle well, even in commercial operations. PLA should recycle a bit better, as it doesn't loose so many volatile compounds during the melt process, and if it doesn't, we can always compost it. Composting PLA is not as easy as composting vegetables, but at least it's possible.by Wade - General
Ah, I see what you're getting at. Interesting! I had a look at some of my prints with a cheap loupe equipped with a mm scale today - all or them, irrepective of head speed or plastic flow rate, have a roughly 0.1 mm spaced ripples; which corresponds to my resolution (10 steps / mm). I think the head vibrates with the stepper timing. Since the plastic tends to stick to the bed immediately, Iby Wade - Reprappers
By default the home command should move all the way to the endstops, no matter where the head is in the machine. Perhaps you could attach the gcode file to this post, and I'll see if it looks ok. What firware version and host version are you running? Attach the Stl as well, sometimes they have odd offsets. Wadeby Wade - Reprappers
Curlrup, try measuring the difference between the commanded and actual moves, and the ratio might give you a clue. It could be that one of your stepper drivers is set to microstepping mode if it's 1/2, 1/4, 1/8 or 1/16 exactly.by Wade - Reprappers
Assuming you're not leaking plastic, it's easier to just measure the flow of plastic in to the extruder in order to determine how much plastic is coming out. My old extruder used the magnetic encoder to keep track of the drive screw; if you're worried about slippage, mount a separate measuring wheel on the filament independent of the drive system. With a good stepper based pinch wheel extruder,by Wade - Reprappers
Sircastor, well put. I was trying to say just that, but couldn't do it as eloquently. Thank you.by Wade - Administration, Announcements, Policy
Actually, that part I posted would not print properly if you chamfered the unsupported lower faces that were greater than 45 deg from vertical. 10 points if you can figure out why not. Still, it could be a useful addition. I'd have more use for a tool that would convert all the tear drop holes back to round. It's a non-trivial problem, if you don't have access to the design tools that werby Wade - General
I don't use the teardrops holes anymore - with a small amount of stretching, even fairly large holes print just fine. Check out the 16 mm diameter horizontal hole on this extruder body: Prints just fine.by Wade - General
On mine, I just moved the vert bearing 360 assembly inboard about 5 mm. The spacers are slack, but I think there's enough grip to hold the belt tension. If not, I'll trim the bars. Wadeby Wade - General Mendel Topics
Arduino 0017 works fine for me - I've been printing with the Makerbot firmware as well as the 5D firmware on Gen3 electronics with it. Did you install the libraries and edit the file as indicated in the installation instructions here: that might do it for you. Wadeby Wade - Controllers
You rocket scientists realize that there's an entire forum for printing wires embedded in plastic, right? The spoolhead guys are working on something pretty similar for a few months now: And Rhys Jones printed a working circuit with solder almost a year ago: I'm not saying you shouldn't work on this, just though I'd point out some of the prior work that's been done in the area. Maybe yby Wade - Kartik M. Gada Humanitarian Innovation Prize
Interesting stuff! You might want to work out the volume of plastic you're going to need, and how long it will take to print it. Could take a very long time, especially if you're using a threaded rod drive system.by Wade - General New Machines Topics