Pointedstick Wrote: ------------------------------------------------------- > That's a pretty slick-looking machine. perhaps, but at its core, still a mendel. Nothing new here, move along... The description is so full of bull crap... 150mm/s to 300mm/s build speed? Who builds at that speed? maybe for travel moves but... None of their videos show anything CLOSE to that speed!! THey claim sby destroyer2012 - General
>I had the option of making it closed source and not giving it away at all. Giving it away? You mean, contributing to the reprap community, right? You have spent (allegedly) 1000-2000 hrs (thats a pretty big difference... between 1000 and 2000) on this design. Do you think it is ready yet? Have you predicted every possible thing that could go wrong and accounted for it? No, you use electronicby destroyer2012 - General
I have a feeling that a lot of the software tweaking that we do is a consequence of having to account for environmental effects. If we had a heated chamber and if the tip of our hot end was regulated at the chamber temperature (a temperature gradient, perhaps? Top is at 220 to melt ABS then the bottom is at 100C, chamber temp) then we wouldn't have to worry about cooling, etc. Since they use supby destroyer2012 - General
Steering this abortive discussion back into productive territory: the mojo seems like a good goal for reprap. Make a small device which can produce high quality objects, and do it for much less than 10K. What does the mojo have that warrants that price tag? Why can't we do what it does? Several differences I see off the bat: 1)support material -two-headed repraps are in the wild, the softwareby destroyer2012 - General
Ok so according to this it takes five hours to print a 2x2x2 inch cube. Anybody have time estimates for the same job on their machines?by destroyer2012 - General
wow, throw away extruders? But it's more expensive than new makerbot extruder+filament.. and this is what they are throwing away? Who the heck would buy this.. its not THAT much cheaper than uPrint is it? What takes up all that space inside? This thing makes little sense....by destroyer2012 - General
On the topic of small nozzles, has anyone made a smaller one? Has anyone done 0.1mm? I'm curious if anyone has tried using syringe needles or something, and whether it's worth it to try.by destroyer2012 - Reprappers
You should mount a fan on your extruder and make a duct so it blows exactly at (or ideally just below) the nozzle. I used a piece of sheet metal to mount a corner of the fan and then foil tape (more rigid than duct tape; it's my new favorite tape!) to make the actual duct. Looks ghetto as hell but works well and doesn't cool the bed down much at all.by destroyer2012 - General
I had the same idea, but it ended up costing about the same as a kit in replacement parts/ failed parts/ time spent. THe most expensive parts are going to be the motors and electronics, and you can't make those yourself anyway. And getting threaded rods/drill rods is going to be pretty expensive unless you scavenge old printers, but you can't count on those having the same rods/the right rods anby destroyer2012 - Reprappers
I just realized that you use 1.75 mm filament. Yes it would be much easier to deform that, the spur gear design may not be transferrable to 3 mm users such as myself. Sadly I think 1.75mm filament isnt rigid enough for use with a bowden tube, so I probably won't benefit from having that spur gear (and my comments about excessive tensioner force might be more applicable?). But that won't stop me fby destroyer2012 - General
Ok now that I've seen that picture I'm convinced. What kind of tensioner do you have that it doesn't squish the back side of the filament? Seeing that makes me want to change my extruder gear... SO does this work with PLA too or does the PLA break under that level of distortion? That's the only problem I can see; the filament being weakened and breaking when trying to retract or something...by destroyer2012 - General
So has anyone reprapped an air multiplier? Does it work? How did you do it/what support structure is best? I've seen some designs on thingiverse but they didnt look like they would print well on a reprap.by destroyer2012 - Let's design something! (I've got an idea ...)
What I mean is.. you have a lot of flat surface on those teeth. If you are putting some force on your filament to mash it against that gear, it's all being wasted on pressing the filament into those flats! A larger diameter drive gear is definately better for higher speed but in my opinion it needs sharp teeth. I get that the edges of those flats bite into the filament (what else, magic?) but thaby destroyer2012 - General
Yes this idea is fairly old. What I would be more interested in is: actually tiny and cheap to make "pixels" for this to work with. Besides, even if the pixels were tiny you would still need to have an object made out of smart elements. How structurally sound could this object be? How many different materials could you build with? Probably not many. 3d printing would still be useful.by destroyer2012 - General
I really like your method though I think I'm going to try making an ultimaker nozzle with your groove seal techniqueby destroyer2012 - General
The answer is torque. With an odd number of rotors you have more spinning one way than the other way. With an even number the spins cancel out. You could do 3 but then you'd need to have a counter-spinning weight or a tail rotor to act against the torque or else the whole thing constantly spins.by destroyer2012 - Let's design something! (I've got an idea ...)
however in the 50s they didnt have tiny computers to control the duct apertures like we have now. Perhaps with computer control an unstable and difficult to control aircraft like that could be a lot more feasible. A lot of the reasons why "regular helicopters" are what we are stuck with now is because it's a self stabilizing design and thus easy to control. Because we are not limited any more toby destroyer2012 - Let's design something! (I've got an idea ...)
Tbh I didn't try too hard to get the seal tight I just twisted the acorn nut HARD into the barrel (like, I held the barrel with pliers and torqued the nut a lot to try to get the brass to seal itself). I also used a nicrome and jb weld heating element and slathered the jb weld all over the joint between the acorn nut and barrel. works well for abs, haven't tried with anything else.by destroyer2012 - General
Well maybe the air multipliers will Compensate for the power loss you get from channeling air through ducts... Although I kinda doubt it. Well even if you did have the same number of fans it would still be more crash resistant. In fact I'm not sure if air multipliers would even help create more lift than you'd get from just powering fan blades directly. I do think it's worth a try though... Besby destroyer2012 - Let's design something! (I've got an idea ...)
you can drive a stepper directly from the arduino without a need for a stepper driver. If you don't need a lot of torque then this is probably your best bet (and fairly cheap too, arduinos are like $35 each, and you already have a stepper). Check this out:by destroyer2012 - Let's design something! (I've got an idea ...)
now that would be cool. I wonder if we could make the quad copter powered by a single fan in the middle blowing air into four air multiplier ducts.. then control the thrust of each by managing the apertures to each duct. Then you could have a gas powered quad copter that was not obscenely heavy... Plus it would be super safe and crash resistant because the spinning part is hidden in the middle.by destroyer2012 - Let's design something! (I've got an idea ...)
if we had a good way to measure the diameter of the outgoing filament, i bet having movable rollers would not be too hard. Maybe a laser pointer going through a glass rod with a webcam looking at the resulting gap in the laser line (sort of like a 3d scanner). Or just have the webcam look directly at the extruding filament (but that might be much noisier). Then, just adjust the position of theby destroyer2012 - Let's design something! (I've got an idea ...)
That spur gear looks dubious to me... I've asked this before and I'll ask it again: Why not just hob a bolt? It's really not that hard especially for a machine shop to do. Hobbed bolts are guaranteed to bite into the filament and provide way more grip than your extruder motor can push (which is good! Nobody likes stripped filament) I think that gear's going to have a lot of slipping/stripping isby destroyer2012 - General
Drilling the nozzle hole has always been the hardest part for me. An alternative to doing it your way is to make the nozzle with a brass acorn nut. That way, you can drill the nozzle hole from the back side (where the acorn nut already has a cone-shaped indentation) and it is almost guaranteed to be centered. THE TRICK IS: you do that first, then you mount the acorn nut on a threaded rod or a boby destroyer2012 - General
Might want to check this out:by destroyer2012 - General
So you are going to make a cheaper printer with more expensive materials? How does that work? How do you hope to keep up with demand with your home mini machine shop? Will this machine be rigid enough to do CNC milling? If so, will you design its parts so the machine itself can make them? That would be a good step forward. Otherwise, I don't see why having metal parts made by a machine shop isby destroyer2012 - General
I've found that if you just clamp the hot end brass tube to the PTFE insulator with like a piece of sheet metal and a couple of screws holding it to the extruder mount, all issues with "PTFE being a poor material" are eliminated. This is because the sheet metal and screws bear the weight of extrusion, not the PTFE tube itself. Even if the threads in the PTFE tube are totally stripped this methodby destroyer2012 - Plastic Extruder Working Group
Before I got my HBP I have printed ABS on a platform of melted sugar. What i did was melt powdered sugar in a metal ladle over a stove and pour it onto an aluminum platform, squishing the molten sugar down from above with a sheet of stainless supported by a cutting board. coins in the four corners made the sugar platform level. It worked, except larger parts would warp and the melted sugar woulby destroyer2012 - Plastic Extruder Working Group
try turning on your fan all the time during the build. I build with ABS and this has worked wonders for me. I also have a duct on my fan so it's blowing only on the nozzle and not cooling down the entire bed.by destroyer2012 - Printing
I don't know how you hob your bolts but if you just put the tap into your drill press and spend a bit more time pressing the bolt into the spinning tap you will happily get that concave radius. It just requires a bit of patience and some oil to facilitate the cutting. Especially when you have teeth on the bolt already you should have no trouble getting the tap to catch and start the bolt rotatingby destroyer2012 - General