That sounds a little... contrived. You'd need a braking nut on the leadscrew, and you'd need some sort of rotating and braking system on the supporting rails for the stage... they'd have to be mounted on a bearing to allow them rotate with the stage, and then locked in position when linear motion was required again. Two new and complicated mechanisms, for the AX axes, which in turn need to supporby Ru - Mechanics
QuoteWaiting for some commercial company to come along and do all of the hard work for us will not further the goals of reprap, if the goal of reprap is to produce a 3D printer for the masses. If it is just to produce a good 3D printer without regard to market share... Someone has to do the hard work to bootstrap a reprap. That's the major barrier to adoption right now. And you know, I don't caby Ru - General
QuoteInstead of 3mm welding rod, you could use nylon fishing line I remember looking at nylon when reading up on thermoplastics and looking at other things which might be extrudeable. Isn't its glass transition point *significantly* higher than any of the other materials people have tried? The problem with using a baby-size printing head is that suddenly everything is going to take waaaaay longby Ru - General
Quotewhen you cut away a scaffold, you have the imperfection on the overhang A little careful work with a sharp knife should take care of that. Take a look at the sprues and flash you get in injection molded or cast parts, for example. I used to make airfix kits quite a few years back; cleaning up plastic parts it dull, but it can be done quite neatly. I'm pretty certain that you could extrudeby Ru - Mechanics
I made a comment about 4+ axis printing a little while ago: To summarise; the problem isn't a mechanical one, its a software one. Calculating toolpaths when you add extra axes is going to be very, very, very hard. I think just making generous use of scaffolding parts that can be easily trimmed away is the best direction at this point. I've been fiddling with my own toolpath generator a little,by Ru - Mechanics
Quote...and that's why all schools today use Linux? A school isn't looking for cutting-edge mass installations, they're looking for a company (like Microsoft) that will take their money and give them a product that simply works. Works reliably, in a way that Windows does, and Linux does not The schools do not want linux because it is not what the staff are familiar with. Windows support is commoby Ru - General
That might make a nice, fast way to do infilling. Certainly easier to work with than injecting resin into a mostly hollow shell, or whatever.by Ru - Plastic Extruder Working Group
QuoteIt's not the macine that may cause the faultiness, it's most likely the software I guess. The flexible drive shaft is the single most unreliable part. The way forward is a rigid gearmotor-to-drivescrew connection. There have also been a couple of stepper-to-driveshaft connection breakages too, but I think those were reprapped parts and so replaceable with bits made from something strongerby Ru - Reprappers
QuoteHm. Ru, I found your post quite entertaining. It was a bit defensive though, and some of your response points were flawed (probably due to the emotions that controlled the reactions) Messages of negativity and doom and how everyone is wrong are quite commonplace in open source projects. Whether they're correct or no, they really get to me. The patronising and paternalistic tone of 'you'reby Ru - General
QuoteWhat does Linux have, 3%? And actually declining, according to some estimates Now that one is a blatant troll But moving swiftly on. QuoteRepRap is failing. Designs diverge further from the standard on a daily basis Where's the failure? I'm not seeing it. The heart of the reprap is the filament extruder and the techniques by which it might be used. Who cares what platform it is mounted oby Ru - General
Quotethe play between the shafts and the coupling might lead to problematic amounts of backlash That shouldn't really be a problem in this case... the drive shaft only ever turns one way, and you can always use nophead's strategy of starting the extruder and wiping the nozzle before a build is actually begun to the drive has a chance to spin up and remove any 'slack' in the connection. The mainby Ru - Mechanics
Quotejoining in the crackpot spirit of the thread; with accurate temperature measurement it should be possible to detect loss of feed. That's true, although there'd be a small lag between the feed halting and the power drain of the heater decreasing, and so the print might still be screwed once the jam has been sorted out. Perhaps you could work out some cunning logic to backtrack a bit to resuby Ru - General
QuoteSometimes the *eggs* I get at the market have some psrt of code printed onto them Pretty much all the ones here do... I'm not sure whether that particular piece of bureaucratic idiocy is the fault of the UK government or the EU. A quick look at a handy egg shows the print has significant distortion (so no cunning flxible print heads or contour following), and looks dot-matrixed. I imagine iby Ru - General
QuoteAnother problem with this idea is that the filament moves very slowly, so unless you have a very high resolution encoder you only get feedback relatively infrequently I'm curious; how much resolution do you actually need? The magnetic encoder board seems fairly high-res at 1024 steps, if I remember correctly. This is the direct motor output which is then geared down by quite a bit, and usedby Ru - General
There are various reasons you might pause the build briefly. A short pause lets the previous layer cool slightly... someone (I'm assuming nophead) made a martini-glass type model without inter-layer pausing, and it got sufficiently hot that it sagged, ruining the print. There's also the possibility of a nozzle cleaning step, whereby the nozzle is driven over a cleaning brush or blade to remove aby Ru - Reprappers
QuoteIt would be a simple way of seeing how fast your filament is being pushed into the mechanism But wouldn't the motor encoder already do this? It wouldn't work in circumstances where the filament was not being moved by the drive screw, if the extruder housing wasn't forcing the filament onto the screw hard enough, for example. Aside from that case, you know that one tick of the encoder reprby Ru - General
There was an amusing, if very NSFW article on The Register about some of the flaws in cuil. Really, really NSFW though. Or those of a sensitive disposition. Its hard to be excited about something that has been released in such a clearly broken and unfinished state. What on earth were the developers thinking?by Ru - General
Quoteit's pretty much built like a cnc setup so it's fling it around w/o a problem. Good stuff. I'll be quiet then Quotethe reason i'm using it is because i'm feed up of those hobby geared motors Sounds like a sensible plan. Let us know how it goes... Car window motors seem dead easy to get hold of. I hadn't considered using them for anything before.by Ru - Controllers
Quotei'm running a 5amp motor because i'm trying to increase the speed of extrusion. Seems... excessive. You'll probably need your own DC motor driver for something that big. The interface is simple enough, so I'm sure you can find something you can attached to the arduino and run using the existing firmware. Motor power is only part of the problem... the little GM3 puts out a surprising amounby Ru - Controllers
All things are possible, if you're willing to hack the firmware to suit your needs. It might be easier just to pick up a smaller motor thoughby Ru - Controllers
QuoteChanging nullcartesian to cartesian in my preferences fixed the problem. What is nullcartesian for, anyway, and why is it the default? It just does a build preview, and no actual IO. It means the software can run and be tested without needing a real cartesian bot attached to it.by Ru - RepRap Host
QuoteI wonder if a set of 1/4" steel waterjet RepStrap parts would be much different in price than the plywood ones from Ponoko You might not want to use these for the X axis/Y axis/Extruder, as they'd make a pretty heavy head to move around, and you might need new motors.by Ru - RepLab Working Group
Quote2.can i use UF5408 instead of 5404(as 08 seems much better) Forgive my ignorance here, but what makes it better? It seems to have much higher voltage tolerances, but are they actually necessary? Quoteso say if i use motor with 4A rating ...then you'll probably destroy the L298. 2A per phase is the limit of the chip, and you don't want to be running things at their limits because they wonby Ru - Controllers
Have a think about how long it will take to fill that build volume, too! The big, complex parts of darwin currently take many hours to print on the hydraraptor, which I suspect is the fastest repstrap currently running. Making objects 12 times bigger is likely to mean build times on the order of several days! And keeping the reprap running that long without a fault is going to be tricky, to sayby Ru - Reprappers
QuoteHey Steve. I like the ratcheting push rivot thing! How are these removed? If I recall, you can grab and pull hard. The teeth slip before they break. Course, that might not be the case in whatever material we use. Also, these may be tricky to fabricate well, as they have lots of little overhangs. I guess you could make flat T shaped ones without any difficulty.by Ru - Mechanics
It may well be that the higher resolution encoder is overkill. You might well get away with a much coarser resolution encoder on the shaft output anyway, without gearing. And for a few bucks, its the sort of thing you could just try out Also consider that encoders are the sort of thing that you can add much later, or upgrade at will. Yes, they have a big impact on build quality, but the extrudeby Ru - Controllers
QuoteAlso, what exactly is the function/purpose of the diodes? Is it to make sure that a current doesn't flow from the motor back into the chip and fry it? I did a little research on what goes in to a good H-bridge motor driver, to see what sort of work is required to replace the really expensive bits like the L298. Turns out motor control is an unpleasantly complex problem. Amongst other thingby Ru - Controllers
Yeah, the infrastructure associated with waterjets is significant. There are always plasma cutters of course... they're not as neat, but they are the sort of things that are affordable by mortal man. Not that they'd be hugely useful in such a small build area, but if you wanted to do sheet metal cutting they're certainly convenient compared to water or laser alternatives.by Ru - RepLab Working Group
QuoteIs heating the object feasible It is tricky, to say the least. And you have to have some extruded structural parts *inside* the heating volume (ie, the extruder head), which means you'd have to make them out of higher temperature plastic such as HDPE which is itself more prone to warping... and for a reprap, you'd need to be able to fabricate most of the heated volume container, and so onby Ru - Plastic Extruder Working Group
QuoteWhere's that then? I've been looking around on ebay for a lathe for a little while... if a lathe is small and potentially courierable for a sensible sum of money, it tends to sell forby Ru - Plastic Extruder Working Group