I've been using it for a good while now, and I have to say I'm still pretty happy. I've used about 3kg of the 5kg I bought, and have totally solved first layer problems by moving to a glass + pva bed. The only downside is it's hard to clean the black out of the hotend when changing colours - it mostly purges, but then you get the odd black fleck for the next half metre or so of the next colour. Dby james glanville - General
In terms of the vref pin, you don't actually need to calibrate it that way. The method I use is: set potentiometer to about 30% if it skips steps, increase the current if not, reduce the current until it does then you have the current that just skips steps, so turn it up just a bit for safety.by james glanville - Huxley
It's been talked about here a few times, I think some of the suspected problems have been: hard to get rotational accuracy at large radii without gearing steppers down difficult to program for (IMHO by far the hardest bit) probably impossible to remove the mandrel not necessarily better: printing a torus would still be tricky because the inside would need support material, like it would on a norby james glanville - Mechanics
I would have thought that a small hole in the side wouldn't let in very much moisture at all, and you could just add a load of desiccant to the box. This way, you'd dry out the pva, not just stop it absorbing more water. I have no plans to try pva any time soon, but it'd be a cheap experiment.by james glanville - Printing
You don't need safety glass - any old glass will do. I'm sure you'll find it much easier to get the glaziers to cut a scrap of window glass to size.by james glanville - Australia, Sydney RUG
Personally I'd go for a resistor based bed - they're so easy to make, just epoxy all the resistors on the bottom of an alu sheet, and wire them up. Mine tops out at 144W, which keeps it easily at 70C with a light breeze, but could probably do an awful lot more if I bothered to insulate the bottom of the bed.by james glanville - General
My darwin used bike chain for all the axes - it worked well. There was no detectable backlash (I used jockey wheels as the sprockets). It never printed terribly well for other reasons, but the drive system was good enough. I just tensioned the chain a load (over the 40cm long loop, it was very hard to significantly deflect in the middle by hand). I'm considering adding a milling head to it, sinceby james glanville - General
Do you mean to switch the power before it gets to the psu? if so it'll be absolutely fine, 30A at 12V will draw 1.5A at 240V, so you'd struggle to find any mains-rated switches that wouldn't work.by james glanville - RAMPS Electronics
Most people use mechanical microswitch endstops now, and they're easier to find - you can get them at any electronics shop, or I personally use the small ones in old computer mice.by james glanville - For Sale
Oh I am sorry, I got this from the rss feed, and didn't see that you were in Illinois. I hope you get your problem sorted soon, but I can't be of any assistance.by james glanville - Illinois, Chicago RepRap User Group
Where are you located? I'd be interested if you were local (UK for me), but it would help if you said where you were.by james glanville - Illinois, Chicago RepRap User Group
I'm not too bothered about the lack of spools - when I've used faberdashery I've liked the constant radius far more than repraper's uneven tension when coiling spools. That said, repraper is for me far better value for money now I've solved all the sticking problems by using hot glass with a pva coating.by james glanville - General
I'd recommend against using those, the idea is that they hold the z threaded rods straight, but in fact you want the z rods to wobble around unconstrained, while the x-axis is rigidly held by the z smooth rods. I just ended up with a load more z wobble when I installed mine.by james glanville - General Mendel Topics
I'm intrigued by the concept, but I do wonder if it'd be easier to improve print quality and print them on a normal reprap vs printing them on this. If someone were perusing this, I wonder if you could make the inner core into 5 parts: Cut the core into three slices, so that there are two almost-semicircle pieces, and a rectangle with rounded sides. Cut this into three, so that when you have prby james glanville - General
Why not just shove a 40mm fan behind the motor? Dirt cheap, and they keep the motor very cool so that they won't melt a thing.by james glanville - Mechanics
I print pla onto heated glass covered in a very thing dilute layer of pva glue. It works briliantly, with a flat glossy bad and good adhesion. If you're using pla, give it a try.by james glanville - Reprappers
There are a fair few problems with that design: Those motors are reasonably powerful, but have very little torque, and operate at a high rotational speed. They'd need to be massively geared down to the right speed, and the necessary torque increase, and the gears would add prohibitive backlash. To get absolute positioning, you'd need a >15 bit code to get actual positions if you didn't use eby james glanville - Developers
Well I get nice m8 printed nuts with a 0.5mm nozzle at 0.2mm layer heights. I do tend to run an m8 tap through them (easily done holding the tap by hand) to reduce friction when I run them onto a rod, but they're pretty good as-is. You should be able to get much smaller threads with your smaller nozzle.by james glanville - General
Sounds like you might need a fan on the motor - I certainly need to use one. Either print a fan holder from thingiverse, or just attach it behind the stepper with the same bolts (the holes have the same spacing for 40mm fans) and with some washers as spacers. Fixed the problem for me.by james glanville - Reprappers
Could you modify the design to use roughly-cut panels of sheet material with 3d printed corners/sides? That would be an easy way to cut down dramatically on the printed part size.by james glanville - General
Also if you solder, it might seem to work then fail later - I had "successfully" soldered the wires a few cm from my old hot ends resistors, only to have them fall off weeks later, either temperature fluctuations or creep. if you don't have crimps to hand, wire wrap seems to work well, just wrap a few dozen turns of wire around the joint.by james glanville - General
I don't think using shredded plastic directly will work for repraps - nowhere near the required volumetric accuracy. The boat is cool, but the quality of printing is lousy (not hating on it, clearly was good enough) so i'm not sure there would be much to learn from it. I suspect the plastic is full of air bubbles which are fine there, but wouldn't extrude from a fine nozzle cleanly.by james glanville - General
Yep that's the one, massively useful I find because I can tweak first layer speeds on the fly if i'm printing with a weird plastic, or slow the print down if it looks like I'm printing too fast to cool down. There's a bit of a lag before the number has any effect, I think because it only applies the scaler when the buffer empties.by james glanville - General
Unless you're printing things that take up a lot of the bed area, but have a small volume, you can just fill the bed with as many as possible, and you're easily talking 10+ hours of printing, so an eject thing is less useful. I frequently fill up my prusas bed with parts before I go to bed, and it's finishing printing the next morning, so it's no hassle or wasted time.by james glanville - General
My understanding was that the arduino uses the hardware spi pins (it does on my ramps), just that sd cards are really really slow via spi. It'd be interesting to know whether the bottleneck is serial rate/usb overhead/slow sd cards, so we could fix it.by james glanville - General
Well you can do this manually with pronterface easily, just pause, then move x or y enough to get it out of the way, do what you want, hit resume. (Don't home it, because you don't want to introduce inaccuracies from the endstops.) Since this is the sort of thing that needs manual intervention anyway, I would have thought an automatic system wouldn't save much time.by james glanville - Developers
Things like ambient temperature and any sources of wind affect temps quite a lot, could be it was a warmer day? You could check what the voltage is across the mosfet that switches power - if it's more than a few tens of mV, you could replace it with a lower voltage drop one to increase power?by james glanville - General
It's better to pick cut a jig or something vaguely to what you want, then use it very carefully, if everything is the same that's good enough. My prusa2 started life as a v1, so all the lengths are randomly off, but it's fine.by james glanville - Reprappers
Be really careful, it's not like a normal plastic that'll do a little bit of long term damage, you'll be in the hospital or worse if you overheat a large amount of it. HCN (hydrogen cyanide) won't be absorbed by carbon filters at all.by james glanville - General
I can't offer you parts, but get the newer prusa2 style z couplings (nophead style). They're just so much better.by james glanville - Canada, Vancouver RepRap User Group