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Building a SplineScanner or BookScanner? Using one, made it better? Your RepRap is a scanner? You just use a (video)camera to scan things? You make your own telescopes? Talk about it here.
Re: Bipolar Stepper driver with just 2 DACs and 2+1 mosfets - possible? - 13 years ago
patbob Wrote: ------------------------------------------------------- > If I understand you right, the answer is yes, but > why bother? You're halving the applied voltage to > the windings that way and thereby limiting the > possible torque. The microstepping controller > chips (such as the AllegroMicro's 3967) already do > an H-bridge with regulated directional current > tby ElectricMucus - Stepper Motors, Servo Motors, DC Motors
Re: Heated bed & Glass - 13 years ago
Would it be possible to put a glass sheet on a Aluminum bed? What would be the best way to attach it? Should I use heat contact paste?by ElectricMucus - General
Re: Practical uses for a reprap in the home. - 13 years ago
Things you can mount to the wall, like hooks, holders for toilet paper, cups, soap, and so on. not only can you decide exactly how it is going to look you can use existing holes in the wall without the need for drilling. Certainly nothing so that "it is worth it" but something which cannot be accomplished otherwise. you might also wanna check out the " better living with makerbot" series, also sby ElectricMucus - General
Re: Why are filament spools so expensive compared to pellets? - 13 years ago
zekebird3 Wrote: ------------------------------------------------------- > I like that idea. Have you made any attempts to > make a working prototype? Not yet, but which idea are we talking about?by ElectricMucus - General
Re: What would be the ideal (theoretical) hotend/extruder combo? - 13 years ago
There seems to be not much left except testing it From how I understand it polymer degradation occurs by the formation of free radicals which react with air over time. In this case the time in which this can happen is minimal and we do not have any air in the extruder. So this could even be beneficial if re-polymerization occurs in the molten material. My assumption that a uvc lamp is the onlyby ElectricMucus - Plastic Extruder Working Group
Re: What would be the ideal (theoretical) hotend/extruder combo? - 13 years ago
I have now found a source for the absorbance spectrum of PLA. As it turns out the only part which shows significant absorption is in the UVC spectrum... so that rules out pretty much any other source except a circular UVC disinfection lamp. At 253nm this graph would be around 0.75-1 so we would have between 82% and 90% of energy going into the pla. Well enough. The good part is there are plenby ElectricMucus - Plastic Extruder Working Group
Re: 500mm cube build area Reprap in planning - 13 years ago
Keep in mind that you are having a ~16 times larger build volume (in comparison to a 200mm cube) with this printer. You would need a insanely fast built speed, again this depends on the objects you are planning to build but I suggest you look into making a ultimaker style gantry with a bowden extruder and mount the extruder on top to minimize the length of the cable.by ElectricMucus - General
Re: Hot end & cold end of extruder separate,.. disadvantages? - 13 years ago
Njones Wrote: ------------------------------------------------------- > I assume this problem would be minimised by using > the shortest run possible, by using 3mm filament > and by using a tight fitting sheath? To some extent maybe. The problem is: Thicker filament requires more pressure at the nozzle and the less play is between the bowden cable and the filament the more friction andby ElectricMucus - General
Re: Hot end & cold end of extruder separate,.. disadvantages? - 13 years ago
The disadvantage is the springiness of the filament. Each movement of the extruder side leads to a delayed reaction at the nozzle. At different rates in either direction. This is difficult to compensate.by ElectricMucus - General
Re: What would be the ideal (theoretical) hotend/extruder combo? - 13 years ago
Problem with germanium & silicon is that their transmission spectrum isn't as wide, which is fine if you want to focus a laser. And they transmit only the long wavelengths which would give a very poor efficiency overall. Well there is always table salt. (home grown crystals) or rock salt. Too bad it would probably be too soft for our uses, and it's hygroscopic. Otherwise it would be nearlyby ElectricMucus - Plastic Extruder Working Group
Re: What would be the ideal (theoretical) hotend/extruder combo? - 13 years ago
According to this graphic there are several ir transparent materials, mostly salts (maybe we could machine a nozzle out of a solid salt crystal) What would have to be done is checking the availability of these materials and whatever temperature (black body radiation) would be required to get the best transmission for each material.by ElectricMucus - Plastic Extruder Working Group
Re: What would be the ideal (theoretical) hotend/extruder combo? - 13 years ago
I had another Idea of how heating of the filament could be done in a more efficient fashion. The idea is to use a infrared transparent glass for the nozzle. There have already been successful experiments with glass hotends, but no good method of heating. Using a red-hot heating filament around the hot-end and a aluminum reflector could provide heat where we need it. We could use a steel springby ElectricMucus - Plastic Extruder Working Group
Re: Nozzle Limbo - How Low Can You Go? - 13 years ago
If you look at it this way... of course. But isn't the movement of the axis more of an issue? Nice photos, that looks fine enough to be indistinguishable by the plain eye! So did you finish both objects in the same amount of time if you get a higher feedrate? Funny thing is: The smallest widely available drill is ΓΈ 0.2mm so any smaller than that would be difficult to make. There should be a 0.by ElectricMucus - General
Re: Nozzle Limbo - How Low Can You Go? - 13 years ago
How does the smaller nozzle result in a higher feedrate? You need less energy to heat the same length, of course, but shouldn't that be no issue if you simply increase the temperature of the nozzle a little to compensate for the heat loss?by ElectricMucus - General
Re: Polycarbonate cap, is possible with RepRap to print it? - 13 years ago
PVC and plexiglass generally fit well together, and there exist welding rods for it. (You can even weld PVC and Plexiglass together) You can probably print with PVC but there would be a major effort in tweaking the extruder, it requires high temperature to melt and is very viscous. There is "transparent pvc" but it could just be a special kind of plexi glass.by ElectricMucus - General
Re: What can a reprap print? - 13 years ago
Well polystyrene is available as welding rods as far I know. And it is really easy to work with, it has a very sharp glass transition and doesn't require a lot of heat to melt. In fact is is the easiest material to weld from my experience. Welding rods should also be very common and should be cheap, lets go for it. Also there is quite a large potential to recycle Styrofoam, there a masses of thiby ElectricMucus - General
Re: Alum Pulleys - 13 years ago
Couldn't such pulleys be made using a standard 2.5D CNC Mill? This way the parts still stay replicateable and cheap. Prices aren't that big of a deal, but if you live in Europe you'd pay duties & extra shipping which makes this thing a whole less economic.by ElectricMucus - General
Re: What can a reprap print? - 13 years ago
What does Stratasys use for support material anyway? I know they use ABS as main material, and the support is able to be broken away...by ElectricMucus - General
Re: Isn't the speed limit of the Axis rather an acceleration limit? - 13 years ago
Yes but isn't that where microstepping comes into play? In your example (47 deg movement) we shouldn't have points where we the movement of the axis completly stops but rather points where we only advance by a few microsteps. But I guess that depends more on the implementation. When I find the time I will try to create a proof of concept for my sine wave movement idea using plain gcode. Just a sby ElectricMucus - General
Re: Isn't the speed limit of the Axis rather an acceleration limit? - 13 years ago
jcabrer Wrote: ------------------------------------------------------- > There is more to consider. A stepper motor pair > can only approximate a sine wave. This is done by > meshing pulses using the micro-controller and > drivers, so the CPU speed is part of the > equation. Of course, but we could store a lookup table in flash and use linear interpolation. This way it shouldn'tby ElectricMucus - General
Isn't the speed limit of the Axis rather an acceleration limit? - 13 years ago
I have been thinking about speed and the way acceleration works in current firmwares which support it... Right now we move the axis in a triangle wave that is without acceleration, once we change direction we do it instantly, and at the same speed. As for acceleration we simply do the same but increase the speed during travel. This has some serious disadvantages: The torque requirements still sby ElectricMucus - General
Re: Openscad thing I made - 13 years ago
I don't exactly get the purpose of this. Couldn't the thing you see in the picture be constructed with openscad itself? As for 'missing' language features in openscad... do you need recursion? what are real variables? If you want a certain feature why not patch openscad itself? And not that openscad is a standalone system or something it basically just is a user fronted for OpenCSG.by ElectricMucus - General
Re: Complex part, G-code memory limit? - 13 years ago
Thinking about what might come, is gcode still practical? As far I know it was created as direct user language for the terminals of a dedicated cnc machine, not as intermittent data format as we are using it now. Especially using a (!) string representation of floating point numbers is particularity ineffective. Even more so g-code isn't exactly portable the way we are using it, we are using vaby ElectricMucus - General
Re: 3D printers in the developing world - 13 years ago
Voronoi Wrote: ------------------------------------------------------- > That couldn't be farther from the truth. But > perhaps we're talking about different sorts of > developing countries - not all countries are made > the same. Yes. > For Bolivia, a lot of people here are fairly well > educated - they just dont have the sort of means > of production that allow them to kby ElectricMucus - General
Re: Plastic recycler - 13 years ago
Yes PET is quit viscous, similar to ABS but even more so. We would need a sharper temperature gradient so it would work. But it is possible - I did some hot-air welding of PET once. The thing with PET is: It stick only to itself and only if both sides are sufficiently hot, so we would have to print at a certain speed in order for it to work. The advantage is that PET has enough strength to suppoby ElectricMucus - General
Re: 16 micron resolution? What's the tech? - 13 years ago
I wonder if it were possible to print molten PLA in this "inkjet" manner. It's viscosity might be sufficiently low to do this. I am thinking of an "extruder" where the orifice is too small for the pressure built up from regular extrusion but wide enough to squirt out tiny droplets using a piezoelectric element or a heater to create a gas bubble. This way we might get a similar resolution but wouby ElectricMucus - General
Re: Microprocessors manufactured locally - is it possible? - 13 years ago
I wouldn't be concerned about the amount of energy too much since everything would have to be done in vacuum anyway. The major power drain would be the pump. For cooling we could either try sandwiching peltier elements or cryogenics. The latter would be more complicated, especially if we have to do this in a vacuum. But as far I know the above configuration is a fairly standard sem configurationby ElectricMucus - Controllers
Re: 3D printers in the developing world - 13 years ago
3D Printers - in their current form cannot make a difference for third world countries. They cannot be used to provide these 3 basic things: water, food and shelter. Once these are abundant everything else automatically follows. So if there is a printer which can be used for that purpose it would make sense, otherwise it is just another useless tiny possession. In order to do that you have toby ElectricMucus - General
Re: 16 micron resolution? What's the tech? - 13 years ago
While this fellows printer is slow the process itself could certainly be accelerated. From how I understand it the only limit is the power output of the projector and (very much later) the reactivity of the air and the viscosity of the resin. There are few techniques which could one day compete with traditional mass manufacturing and imo this kind of stereo-lithography is one of them. I doubt thby ElectricMucus - General
Re: 16 micron resolution? What's the tech? - 13 years ago
These presentations are also a little deceptive. From the animations you might think that this machine builds things one layer each pass and the process would be very fast. In fact they use only a few jets and interlace them to build one layer. So these machines are actually pretty slow. There is different approach though by curing the resin selectively at the surface using a projector which thiby ElectricMucus - General