Those will be fine. The polou/stepstick is a true current limiting stepper driver so the motor specs when it comes to current/voltage are not relevant. The polou drives the motor at a much higher voltage, 12V or 24V probably depending on your design and since the motor is rated for 3.1V this means it only needs a fraction of the amperage for the same holding torque. 3.1V and 2.3A is what you caby John Meacham - General
One "quirk" of many of these inexpensive calipers is that they never turn off (mine is exactly like the one in that listing and has this quirk), the power button blanks the display, but it is still drawing current doing its measurement thing. The button cells can be a little expensive or hard to find uso I rigged up a holder for a single AAA battery with a real off switch and glued it in place. lby John Meacham - General
The only disadvantage I can see is that the resistance will be doubled so you will need a higher voltage to push the same amount of current through the motors. With real drivers like the polou this won't be an issue as they take care of this automatically unless the voltage required to get the torque becomes more than whatever your main voltage is (12V usually) . I don't see that happening on theby John Meacham - General Mendel Topics
Yup. looks like an issue with my ABS. I put some PLA in there (from ultimachine) and it started printing up a storm. Video of it printing: pictures of the result: I still have a fair bit of tuning to do as you can see from the gear I printed, but it is usable. I like printing yellow on the blue tape as the first layer looks just like a blueprint for the final object Johnby John Meacham - General
Hmm... okay. Maybe my extruder isn't borked then. I had issues with my cupcake CNC chewing up the ABS from this roll too occasionally so perhaps it was just not a good roll to begin with. I always assumed the extruder was just finnicky. Would picking up water cause it to soften like this? Can I dry it out somehow? I am near the beach so am in a somewhat humid environment. ultimachine sent me soby John Meacham - General
I found the Wilseyed mounting option works perfectly for the J-Head nozzle too. I am glad I figured that out before spending too much more time futzing with the retaining washer. It is by far the most straightforward and I like how it doesn't obstruct the view of the extruding tip. I am screwing the set screws into PEEK instead of PTFE, but I imagine that won't be an issue.by John Meacham - General
I ran into this same issue. So, if I understand things, some software expects E to specify the length of the extruded filament, and other software expects E to specify the length of the filament taken into the extruder and skeinforge may do either depending on its version? Hmm.. that doesn't seem like a good situation, if both are going to exist, we should figure out some way to indicate which wby John Meacham - General
A long time ago I got a cupcake CNC, one of the first hundred, and it was good. I recently built a prusa mendel and had a whole roll of the ABS I bought back when makerbot was new, however the hobbed bolt just chews through the stuff, I am exhausting things to rebuild on my extruder so I am starting to wonder, did my ABS go "bad" somehow, or is the ABS today different than the ABS that was firstby John Meacham - General
I would like to see the updated accessible wades extruder made available.by John Meacham - Plastic RepRap Parts for Sale
Hi, I am working on my second 3D printer (a prusa mendel) and had a recommendation. The "official" power connector is said to be a XLR connector[1] which makes very little sense to me and is actually possibly dangerous to recommend. XLR connectors can generally take only 2A, though some can get up to 10A. You can't really tell from looking at one what type it is. The things were not meant for hiby John Meacham - Controllers
Geometry, There are various mathematical ways of obtaining precise movements from imprecise tools, perhaps the most famous and first was "Watt's linkage"[1]. We have the advantage of being able to order a precision ground straight rod, which we can then use as a guide for straight line motion. However, this was not always the case, In the past, they used clever linkages that mathematically guarenby John Meacham - General
That's great! Does the RapMan use a Z-axis like the cupcake cnc? 4 threaded rods? I wonder if I can improve things with it too via a similar technique.by John Meacham - General
Any reason why this page is locked? it has not been updated since 2009 but it would be great if we could keep it up to date. In particular, I am looking for the part numbers for springs suitable to use in the extruder. Johnby John Meacham - General
Yup. pretty much exactly what I had in mind. Did you have to double up pins for the heater or is one good enough?by John Meacham - Plastic Extruder Working Group
I was building my extruder and thinking about the standard pinout idea brought up on this forum earlier. I liked the idea of DB9 until I actually prototyped a board with the connector on it and stuck it on my extruder, it is pretty big and clunky when you actually look at it and doesn't have enough wires. I think I am going to go with a different plan. I was going to use a 2x7 shrouded IDC conneby John Meacham - Plastic Extruder Working Group
Not with modern electronics that can limit how much current goes into it. The ultimate limit is how much current the motor will take. (how many amps). The stated voltage is how much voltage applied directly to the motor will drive it at its highest current. As in, what size battery you can just hook to the leads and not burn it out. However, you can also limit current by actively turning on and oby John Meacham - RAMPS Electronics
Cool. I would like a full set if possible. Is paying via paypal okay? I am planning on building a prusa model, it looks like I will want the 36.5mm PEEK insulator then, is that correct? I have a working cupcake makerbot, so am okay experimenting with the state of the art with my next build which is why I wanted to try out the J-head. It also just seems very elegant to me compared to some of theby John Meacham - Wanted
Is anyone selling a J-Head style (this is the current state of the art, right?) hot end in the US? thingfarm sells them in the EU but I was hoping to find a local less expensive supplier. (though, I still want metric. I metricized my workshop a while ago to make collaboration easier) is what I am looking for, or something of similar design/performance.by John Meacham - Wanted
Hmm.. doing the calculations, without a heat sink we can provide about 250mA, so we probably want a heat sink to at least be able to provide the 500mA it expects from the USB port. Plus we will be powering the motor drivers directly from the main board which will be good. Though, I worry about us driving those PWM power MOSFETs directly from the avr pins, power mosfets can draw a lot of currentby John Meacham - RAMPS Electronics
So, it appears that people have issues because the 5V regulator on the arduino mega burns out trying to dissipate 12V. So something I am going to try is just adding a 7805 directly to the RAMPS board and feed 5V power to the mega directly. So, instead of +12V -- D1 -- Vin I will have +12V -- D1 -- 7805 -- AM-VCC | GND A TO-220 7805 should be ableby John Meacham - RAMPS Electronics
Hmm.. that is really cool and gives me an idea, if you have the skirt, why not just fill the thing with a warm viscous fluid occasionally. perhaps dilute gelatin. the print would pause every now and again for you to top it off. This would work much better for a machine that has a moving printhead like the ultimaker than one with a moving platform though due to sloshing.by John Meacham - General
Apparently a diffusion pump is pretty easy to make, here is one made of glass: It certainly looks 3d printable, probably want to do it upside down unless you can print a support material. perhaps with a steel cup at the bottom for heating until a reprap that can print in metal is made. Then all you need is a roughing pump, the liquid ring pump certainly looks like it might work. worth checkinby John Meacham - MetalicaRap
I think I will probably be much less ambitious than you for my initial attempts I have a suitable roughing pump, and a small vacuum chamber (2 cubic feet more or less), I think I will simply start by getting a relatively weak e-beam working and some suitable deflector grids running pointed at a phosphor target. Over my small chamber, I'd only expect a small amount of deflection, but it shouldby John Meacham - MetalicaRap
Hi, I find the ideas behind the metalicarap really interesting. I built a plastic printing reprap a while ago and am very happy with it, but always wondered if there was a good path to printing in metal. It just so happens I had the idea of building a farnsworth fusor in the back of my head for a while, and the set-up has a lot in common between the two. A few questions, what sort of vacuum dby John Meacham - MetalicaRap
10 1 meter lengths of M8 rod for $17, it seems like a great deal, but I worry when something seems to be a fifth the price of competing places... does this look like it will work for a reprap? I am attempting to populate my workbench with a nice collection of metric odds and ends so have been looking for *cheap* metric assortments I can get in california. If anyone has any recommendations I'dby John Meacham - Mechanics
I have completed the wonderful cupcake CNC kit and am happily extruding objects. I hope to start work on a real next generation reprap soon. It seems a shame to just have it sitting there a lot of the time, I should have it spitting out reprap parts to give out. It would be cool if there was some site for people to sign up and list what parts they need, once people that have repstraps/raps prinby John Meacham - Reprappers
I made a dead-simple but quite useful circuit for testing the stepper driver boards independently of the rest of the system. I was able to track down problems with the stepper boards quite simply relative to trying to use the motherboard to drive them during testing.by John Meacham - Controllers
I am afraid this won't work because you cannot detect collisions on a RS-485 bus, even if you could, collision detection is quite tricky, requiring things like sending jam signals and minimum packet sizes that depend intimately on the length of your cables and your bus speed. The reason is that RS-485 is a differential bus, it is driven in both directions (high and low) if two different thingsby John Meacham - Controllers
Since the boards both have ICSP headers and we need programmers anyway, why are we bothering involving the arduino software at all? it adds a lot of complication and has issues with 64 bit architectures. If you simply provided 'hex' files on the web site for the whole firmware for both boards, we can just use avrdude and burn the whole shebang in one go without having to bother with the arduino sby John Meacham - Controllers
You know, I am looking at the new extruder controllor board 2.2, and it seems _perfect_ for the brains of a robot! H-Bridges for the wheels, analog inputs for sensors, servo controllers for the wiggly bits, mosfet drivers for the circular saws . I may order a couple to use as a general platform for experimentation. I have an old toy car that is begging to get some better brains in it.by John Meacham - Controllers