For the vias, I drill a tiny hole, put a thin bit of wire (usually resistor trimmings) through the hole then solder both sides. A bit ugly, but solder has too much surface tension to flow through the hole. I'd consider trying the laser printer + photo paper method. There are loads of instuctions online on how to go about this, basically you laser print the design onto photo paper, then iron ontoby james glanville - Controllers
Thanks a lot for the mention of the drv8811, just ordered 5 samples As for the idea of all the motor drivers on the same pcb, I don't think its worth it at this point in reprap's development. Firstly, the extra connectors aren't terribly expensive, and I've found three smaller boards are easier to mount to the reprap than one big one. Its also easier to have a hot spare for tinkering, and be ablby james glanville - Controllers
I had a very similar problem with my GM3 motor, which I ended up resolving by using a different power supply. I did find a massive improvement when I put a hefty capacitor right next to the chip, I think in my case the problem was that as the motor switched on and off the voltage given to the chip fluctuated quite a bit. Check that any comms cables are either far away from any switching power cabby james glanville - Controllers
I did this in places because I ran out of threaded rod, but I found it took a lot of time and effort to cut the thread. In the end I just used a cordless drill with an adjustable clutch and a lot of oil, but unless the unthreaded rod is much cheaper its probably not worth it. Its also quite a bit of wear and tear on the tap, so factor that into the cost.by james glanville - Plastic Extruder Working Group
Hi, just thought I'd point out that some of those points are only true for some setups. With a constant voltage across it, the lower the resistance the greater the heat output. Your observation to the contrary shows that your drive electronics are not providing a constant voltage source. As the resistance decreases, more power is radiated from the transistor (I assume that's what you're using?),by james glanville - Controllers
I'm trying to use the non-5D latest gcode firmware from svn. I'd be interested in your current firmware, because adding an encoder is on my todo list. Jamesby james glanville - RepRap Host
Has anyone managed to get a dc motor-driven extruder working with the newer firmwares? Without the fixes listed above, I can see an led on the motor speed pin flash very quickly, so it thinks its driving a stepper. With the fixes, nothing happens on the motor speed pin. If anyone had any ideas they would be very much appreciated. Jamesby james glanville - RepRap Host
I get this error quite a bit, try holding reset, pressing program/flash/whatever, keeping holding the reset button for a few seconds, then letting go. When I do this, I only get the error maybe 5% of the time. Also, make sure you installed the sanguino libs correctly, and check you've selected "sanguino" under board type.by james glanville - RepRap Host
It sounds an awful lot like your pin configuration is wrong. Have a look at the pins.h file you're programming the sanguino with, and double check it's right, and there are no collisions with other functions. Remember the pin numbering doesn't correspond with the physical chip's packaging.by james glanville - RepRap Host
The current trend in controlling repraps seems to be storing the build instructions on an sd card. This has the huge advantage that all object -> instruction processing can be done at whatever pace - there is no need for any real time processing on the computer end. I have yet to try, but I think there is a simple python program floating around to send gcode to a reprap if you want to try now.by james glanville - RepRap Host
Counting the two bicolour leds as four discrete lights, one or two should light up at any given time. Try manually strobing the step pin, if all is well the lights will change. As for the dodgy board, is there a dead short across the board? Any change if you take out the DIL chip? Instead of load resistors, I use a spare 12v cabinet light I had, illuminates the build area nicely at the same time.by james glanville - Controllers
Although someone should probably fix the ambiguity, either value will almost certainly be fine. If this is halting your build, go for whichever you have on hand.by james glanville - Controllers
On the reprap configuration tips page, it says to measure the extrusion rate, then match the print speed. I found it was better to try many tens of lines and find the speed that left the extrudate under no tension or compression. I wonder if the warping effect could be ameliorated by choosing better speed settings. Also, I get less warping when the extrudate is at a higher temperature, I assume tby james glanville - General
Instead of trying to keep the print warm, I get the best results when I cool the object as it is being printed as much as possible. If you match the extrusion rate with movement speed perfectly, the plastic seems to freeze before it can warp. I use a pc fan pointed right at the tip of the nozzle. I'm currently having problems with insufficient insulation, so this cools down the metal too much, buby james glanville - General
Making a reprap from wood isn't too hard, provided you have access to a drill and a saw. You can even follow the darwin design so that when your printer is up and running you can slowly replace the wood with reprapped parts. My wooden reprap can be seen at if anyone's interested. Using paper seems tedious and slow, you could learn the skill needed to make the wooden parts in less time.by james glanville - Mechanics
This sounds an awful lot like the high current draw of both things is causing the voltage to wobble, disrupting comms. I'd try powering the arduino separately, or shoving hefty capacitors before each device.by james glanville - RepRap Host
The value of the capacitors is not too important - they're just there to smooth the output of the regulator. I believe the electrolytic capacitors from about 10uf upwards help correct low frequency wobbles in output voltage and the ceramic ones filter high frequency noise. You could try adding a resistive load to the 5v line, the motors will briefly draw no current as they spin, causing voltage fby james glanville - Controllers
You could try adding a hefty capacitor near the stepper drivers. I was getting weird loss of power issues until I added about 30000uF in capacitors to each board. There's probably a more elegant way though. The change in temperature reading I would guess is because the supply voltage to the microcontroller is fluctuating, though I may be wrong. A capacitor either on the microcontroller power suppby james glanville - Controllers
Rick: Can't help you much, but skate bearings are all (or at least mostly standard). 8mm internal diameter, 17 external diameter, 7mm depth if I recall. I agree it would be great to get write access, you could try pestering whoever over irc at #reprap on freenode, its a pretty active channel.by james glanville - Reprappers
Really nice, I'll definitely be stealing some ideas such as the square tubing corners. How are you tensioning the extruder bearing by the way?by james glanville - Reprappers
There's a local shop near me, but there are loads of cheap ones on ebay. |66%3A2|65%3A12|39%3A1|240%3A1318 works out at 29p each. Searching for "skate bearings" gives loads of results, for my design you need 30 (will be posting to the builders blog later today, have a look if you want to see how I've made my x and y axes.)by james glanville - Mechanics
I've been annoyed for a while at the friction my reprap has been experiencing, because it has limited how tight I can make the chains and have the thing move. I decided to replace all the bearings with skate bearings, and remake the axis, and thought I'd share my method. I hope that with very little friction, light milling will be possible. Anyway, for the y-axis (on my reprap this is the axis tby james glanville - Mechanics
Would you mind posting some pictures of the sprocketty things you made? Also, for the z axis I found it much, much easier to use 8 jockey wheels and 4 loops of chain (see my photos) because otherwise only a couple of teeth mesh properly, and getting the tensioning is a real pain. It's an added cost, but I wasted so much time with one loop. I assume this would also apply to ballchain, because youby james glanville - Mechanics
Photos are at # For the shaft to sprocket connections, for the Z axis I'm just tightening nuts each side, because the torque is really low. The white discs stop the chain falling off if the tension is too low, only a problem for the vertical axis. The X and y, I've drilled a hole in the rod and some holes in the sprocket, and just shoved a whole load of polymorph around the edges. I'm remaking tby james glanville - Mechanics
Annirak: trying not to hijack the thread, but feel free to pm me if you want some advice on bike chain - i've been using it for a while and have found some neat ways to tension things. Cost me £20 for sprockets and chain for three axis, not sure how that compares. For beaded chain though, if you could find a cog with the right spacing, you could loop the chain round a few times to increase sprocby james glanville - Mechanics
I'd be tempted to find or cut a plastic circle, then heat up the chain in a flame and wrap it around the disc. With luck this should melt little holes around the edge. You could also set up a jig to drill tiny holes around the edge of said disc to achieve the same effect. Both are fiddly though. You could always try and salvage sprockets from discarded blinds if you knew somewhere that would letby james glanville - Mechanics
While an endstop is essential, you could rig up some wire contacts in a pinch, at least for testing. Have you tried insulating the heater with glass fibre or increasing the voltage? What plastic are you using?by james glanville - General
@cpwebste: The reprap stepper board just passes through the min/max signals to the arduino/sanguino, theres no processing of the signal done by it. I presume this is just to neaten the overall wiring. The trouble I see with the stepgenie is that it is not easy to modify. The reprap stepper driver board 2 is a one-chip solution that looks a lot better.by james glanville - Controllers
It was standard copper clad board. If I ever make a toolhead based on this approach, I think I would use two power supplies so the electrode could be optically isolated from the control circuitry. However, I definitely need to get my almost-darwin to print better parts before I start experimenting more.by james glanville - Plastic Extruder Working Group
Could you extrude solder onto a pcb as a protective layer? I'm not sure how well solder resists etchant, but it might work. This is still not an additive process though. The other thought I had was extruding solder directly onto plastic sheets. I forget which plastic I tried ages ago, but i found it melted the plastic and sunk in quite nicely, with minimal smoking plastic. If this seems a workablby james glanville - Plastic Extruder Working Group