... some years ago i developed a mikrodispenser capable of placing single droplets of high viscous fluids (e.g. toothpaste - look here: ) down to sizes/diametres of 5 microns (i printed with 10 microns, but it's working down to submicrons). It's not a really fast process, as you only have repetition-rates of max. 5 Hz for small droplets or 1-2 Hz for bigger ones. With conductive fluids and paby VDX - Plastic Extruder Working Group
... when you've separated the motor-current with discrete drivers, it's only some Milliamperes at 5 Volts what's needed for activating the stepper-driver input pins ... Viktorby VDX - General
... but again, until now the researchers can print only very simple and nearly homogenous structures as bladders, blood vessels and shapes from bone or cartolage. Even printing a complete heart isn't doable at the moment - only specific parts as heart valves or muscle-pieces - most successfull samples weren't complete repelacements, but 'only' repairs of damaged valves, vessels, or such. When fby VDX - Tissue Engineering
... it's questionable, if the cost for one or more additive 'small' controllers, compared to the costs of the multiple stepper-drivers and wiring, is it worth. I bought an Arduino Mega with more than 50 I/Os for 50 Euros here in Germany and the 'small' Arduinos are around 20 ...by VDX - General
Hi Forrest, ... i know this clip and some earlier too ... it's not only the price what renders common "organ-printing on demand" useless. This is not real shape-printing, but more flood specific areas with supporting fluids embedding some floating cells and hope they will settle in the right positions and start growing and spreading. Some ten years ago i had some crosstalks with scientists froby VDX - Tissue Engineering
... it's an issue with other programs too - i design a box with e.g. dimension of 10x10x10, export as STL, import in the fabber-host and measure there ... Viktorby VDX - 3D Design tools
... life could be so simple Viktorby VDX - Tissue Engineering
... there are some experiments with ink-jet printing live tissues - extreme complex, as you can't simply print the shape of the organ and "have it running" You have to embed some specialized functions too: - supporting blood vessels, glands, aditional stem-cells for automatic reshaping/reparing when activated, and some others too ... And then you have to connect the organ wihle 'fabbing' to aby VDX - Tissue Engineering
... it's a bit from all My basic idea was a sort of an optional 'video card' for the arduino capable of generating video-content for an embedded display and/or some other benefits too when needing much more processing power, than the Atmega core has. The Arduino is much easier to handle, so for the everyday-user it should be the basic Arduino with some aditional libs and options, advanced progby VDX - Controllers
... i remember some talks about this last year - but AFAIK until now nobody has received reprapped organs or such Viktorby VDX - Tissue Engineering
Hi Larry, ... its an Isel C-142 controller which is capable of 6A@70V and 10 kHz maximum steprate. Additionally i have three IMS-1/256-microstepping-drivers with 3A@30V, and max. 10 kHz too, which i can exchange with the Isel drivers for higher accuracy. In my 'scrapery' there are some IMT901-drivers and a SMC11 from nanotec - all 2A@30V and 1/8 microstepping with more than 10 kHz. My controlby VDX - General
... maybe it's all based on the same cause? My first thoughts when diving into Transputer-specs and Occam were about overrunning some serious performance-problems i had with other computers and OSes ... maybe it was simply so good, that the other vendors tooks all neccessary steps to stop them from penetrating the market In the last 30 years there were some similar occasions, where superior soby VDX - Controllers
aka47 Wrote: ------------------------------------------------------- > ... > I must confess to being a bit of a parallel junkie > having done some professional work with Inmos > Transputers some years ago. > ... ... me too - in my diploma-thesis (around 1988) i had to research the possibilities of massive parallel networks for numberchrunching and simulation of physical problemsby VDX - Controllers
... the propeller ( ) is a multicore-chip with 8 32-bit RISC-CPU's inside capable of realtime-video-generation and much much more In fact it's much more cpable than the arduino but it's harder to code too and lacks enough IO's. In the propellurino it's an interfacing part for realtime video and audio and could be much more in respect of numberchrunching or higher level logics. Maybe this wilby VDX - Controllers
... i think you can't compare a constructed/fabbed apparatus with a biological system as the actual mechanics aren't capable of 'growing up'. Whereas some of the behaviour of the development process could be comparable to evolution, the fabbing process is complete different. Why shouldn't a smaller reprap build stackable elements which assembled represent a much bigger part than the fabbing areby VDX - General
Hi Grogyan, there are some methods and materials for building really stiff and big frames - e.g. big and high precise CNC-mills are built from stone, not from steel or aluminium. Similar DIY-frames are made from hollow structures out of steel or aluminium and filled with sand-epoxy-mixtures, what's a really rigid compound sometimes even better than real stone and much cheaper and easier in handby VDX - General
... for 'really big' repstraps you'll use much sturdier/stiffer materials (there are big cartesian 'bots' for handling ship-containers with some ten meters dimensions) or you'll try with parallel kinematics and lightweight rods made from carbon. I made a tripod setup with hinges made from magnetic orbs ( ), that could easily be scaled up or down (here i scaled down ), but the controlling softwaby VDX - General
Hi all, here: you can find a 'Propeller'-shield for the arduino with the capabilities of video- and audio-interfacing and some more capacity - maybe it's interesting for the Arduino-RepRap too? Viktorby VDX - Controllers
... my 1.8°-steppers with 2Amps (@60V-f/h, @30V-microstepping) can drive safe until 2kHz with fullstep, 5kHz with halfstep and until 10kHz with microstepping (max. steprate of my controller/drivers ). So with direct driving and a 5mm/rev-spindle i have 50mm/s @full-, 62.5mm/s @half- and the same speed at 1/4- and every slower (but more accurate) at higher microstepping-ratio ... Viktorby VDX - General
... i've found small chainwheels and chains in different sizes and lengths (smaller formfactor than bike-chains) in old copiers - there are many other usefull parts for repstrapping too ... Viktorby VDX - Mechanics
Hi Walter, ... i use hollow glass-spheres (=eccospheres from Trelleborg) around 50 microns in size until 400 centigrades, solid glass-spheres around 100 microns (until 1000 centigrades) or molten rock-spheres around 200 microns (until 1500 centigrades) from Sil-trade mixed with waterglass. There are some comercial mixtures based on waterglass with talkum and different additives for temperature-by VDX - Paste Extrusion Working Group
... the hard and abrasive particles in most ceramic slips would damage the pump, so you need another design (e.g. a peristaltic one) or you mix with microspheres which are round and smaller in diameter than the gaps. Viktorby VDX - Paste Extrusion Working Group
Hi Kerstin, Kerba Wrote: ------------------------------------------------------- > up to now I have exactly one response for RepRap > ;-) > But I only started contacting RepRap folks today, > so I assume you found my survey somewhere else. ... ooopps, this one should be mine - i stumbled in your call at fab@home ... I hope there will be some more activity here Viktorby VDX - General
Hi Kerstin, i've run through the survey some days ago - have you already collect some representative data? Viktorby VDX - General
... it's my aim too to cocreate a "technological environment" where everyone is able to produce all he need either on his own or he can find it in the local sphere - from food over clothes to sophisticated hardware. But in this world most of the common markets and commercial structures aren't stable or needed any more, so it could be a very hard/dangerous way there ... Viktorby VDX - General
... a good reprappable redesign of the extruder ... Viktorby VDX - General
... we had last year some talk about measuring the extruding-speed. One possibility is marking the filament with colour-dots for visual sensing, another is embedding some magnetic microparticles and magnetize single segments and measuring with a highres Hall-sensor. AFAIK sensing without marking was not possible as the extruded filament is very homogene in colour and occasional air-bubbles wereby VDX - Mechanics
... the lower border is dependant of the accuracy/resolution of the positioning system and smallest diameter of the extruded tray or dispensed droplets. Actually i'll guess the best achievable accuracy is around 10 microns (RepRap is designed/specified for 100 microns accuracy) - i have mechanics, electronics and reference-switches that are capable of 0.1 microns accuracy, but the mechanical setby VDX - General
Hi Sven, Willkommen Ich bin im Rhein-Main-/Main-Kinzig-Gebiet Daheim - wie's aussieht, sind die RepRapper in D noch ein recht selten anzutreffendes und ziemlich verstreutes Völkchen, so daß nur selten lokale Gruppen zusammenfinden Ich hoffe doch, daß sich das in der näheren Zeit ändert! Ciao, Viktorby VDX - Schwarzes Brett