The electronics isn't much more complicated you just need a more modern driver chip that does it all. If you go too modern then you run into leadless surface mount chips which gets you into solder paste and ovens. The main problem is that you probably need to go to a higher voltage supply so the cheap, off the shelf, PC supply is no longer an option as is the idea of running it from a single carby nophead - Mechanics
Have you checked the voltages around the MAX232 chip and the polarity of its capacitors?by nophead - RepRap Host
The library is here: I think I had to copy it to C:\Program Files\kicad\library to make it work. I am not sure if that is how it is supposed to be used.by nophead - Controllers
Yes it would need more torque with a belt. The studding gives a higher gear ratio so it requires less motor torque at a higher speed. Having said that stepper motor torque falls off with speed so more torque is available when using the belt, as the motor does not have to turn so fast. I would guess that frictional losses would be a bit higher with a studding drive. I think Forrest published someby nophead - Mechanics
"Power wiring too?" No you need thicker wire for the power.by nophead - Controllers
Yes it would useful if everybody that has had problems give a quick post recapping what problems they have had, or still have, regarding UCB PCOM interconnect and testing. Also if people who had no issues could also post we get an idea of the scale of the problems. We should also be able to put together a debugging flowchart that differentiates each of the problem people have encountered so farby nophead - Controllers
The main problem with stepper motors and studding is speed. To get steppers to go fast enough you need a high voltage constant current drive and low voltage high current motors (low inductance). The RepRap electronics is constant voltage drive into relatively high voltage motors so its not going to be very fast. Threaded rod drives use much bigger thread pitches than standard studding but are expby nophead - Mechanics
2 hours? We are talking about 5 one pin cables so that is 12 minutes per connection. I can see why it would take more than a minute per pin which is 10 minutes in total. Double it for somebody with no experience.by nophead - Controllers
Yes come to think of it I have had problems with RJ-11 model cables. You would think they were interchangeable between different modems but they are not. The biggest problem I see is being able to get standard cables the right length. If you look at Darwin the boards are quite close together. I have never seen RJ-11 cables less than a couple of metres. You can make them up yourself but you needby nophead - Controllers
OK I have not done much with Kicad yet but I will give it a go this weekend.by nophead - Controllers
Forrest, Yes rather than insulation you effectively have a heatsink at the top of the barrel increasing the gradient. That might be a good idea. I am not sure what the purpose of the fiberglass insulation is. Is it to keep heat in, or is it to stop heat radiating out and melting the workpiece? englewood, Yes I realised later you were talking about the position of the thermistor but I findby nophead - Controllers
I think some people have reported the connector holes being a bit tight.by nophead - Controllers
For TX and RX LEDs on the TTL lines connect the anode to +5V and connect the cathode to the line through a resistor. The MAX chip can drive a logic low at 3.2ma so if you have LEDs at both ends you need to limit the current to 1.6ma each. They will be dim but should be visible. For a red LED, assuming Vf around 2V then 3V across the resistor so 1.8K should do. To monitor the RS323 levels on theby nophead - Controllers
Forrest Higgs Wrote: "the brass plate that attaches the extruder barrel to the HDPE thermal break never sees more than about 120C and usually something like 90 when it is on 100% of the time." I assume you meant PTFE not HDPE? Is there a temperature gradient down your barrel then? I ask because I suggested to englewood that putting the heater at the top of the barrel rather than the bottom mightby nophead - Controllers
andreas Wrote: ------------------------------------------------------- > but for security-reasons I will implement a > mechanism to switch off the heater if to much > calculations have been thrown away. Good idea. Relying on software alone for safetly would not be allowed on a commercial product with safety approvals. It should really have a thermostatic cutout as a failsafe. Either thaby nophead - Controllers
The solution suggested in the wiki sounds easier to implement: clear a flag at the start of the measurement, set it in the interrupt handler and then test it after the measurement. If it is set the measurement was interrupted so discard the sample.by nophead - Controllers
I just attacked a milk bottle with a 3mm endmill at about 20000 RPM. It ripped into it and produced fine swarf.by nophead - General
I haven't machined any HDPE yet but I read somewhere that you can. The closest that I have would be Delrin / acetal. Perpex / acrylic makes the the nicest powder. The mystery metal loaded resin that I made my extruder body from makes a horribly fine dust that blocks up the pores of my vacuum clean bags.by nophead - General
Well my milling machine does a pretty good job of reducing plastic to dust. Not very fast, but probably faster than RepRap can extrude it.by nophead - General
Good idea Richard, I will try that first when / if it breaks again.by nophead - Mechanics
I think transparent pop bottles are PET not HDPE.by nophead - General
Ah, yes it is on the board BOM, but it doesn't go on the board. It is shown attached to the acorn nozzle in the parts picture in the wiki along with all the mechanical parts so I think it should really be on that BOM. It doesn't make much difference to most people but I am just building the extruder for now with my own electronics. It's out of stock at RS at the moment. I wonder if there is a suby nophead - Controllers
Presumably if you fed powdered material into a temperature controlled heating vessel at a constant rate and pulled a thread from it a constant rate then you would geta constant diameter filament? I am not certain but I got the impression that the pulled filament has different mechanical properties to the extruded one. Possible a bit clearer and more flexible, a result of the molecules being aligby nophead - General
I know nobody has mentioned this for a while but While testing my heater I managed to create about 8mm of .75mm filament by manually pushing the feed for about 10 seconds has hard as I could. I then pulled pulled the freed filament back and created about 0.5m of similarly sized filament by stretching with very little force in less than a second. 625 times more productive! That got me wondering aby nophead - General
Thanks Evan, Now I remember why I didn't get one. It is only available from RS and I haven't found a way of buying from them as an individual. I can't find any with a high enough temperature range from any of the companies I do deal with from home. Perhaps this is one for the RRRF, Zach? My plan was to measure the resistance of the heating element to measure its temperature. It turns out thatby nophead - Controllers
Yes why not, and the stepper outputs, then the machine will look very impressive when it is running. Like a sixties computer!by nophead - RepRap Host
I can't find the thermistor on the new BOM, I am sure it was on the old one. Does anybody have the part number?by nophead - Controllers
There is an open source project to convert Gerber to G code outlines here but it looks quite early in its evolution. I plan to try it on KiCad but have not got round to it yet.by nophead - Controllers
Kai, As Jonathon says we are running out of ideas here so perhaps we need to back track. Please can you confirm the following tests :- You can get an echo through HyperTerminal when you link pins 7 and 8 at the PIC socket (with the PIC removed of course) AND you don't get echo with the link removed. The comms port that you have HT set to is the same as the one in the stepper test. The PIC haby nophead - RepRap Host
Ah, I see. My cable does not bend near the ends because the solder wicks up it a bit making the ends stiff. Also the cable I had to hand (left over from a garage door opener) is 2.5mm rather than 3mm so perhaps a bit more flexible in the middle.by nophead - Mechanics