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Praise, questions, complaints, etc. go here. Want to change our policy? This is where we calmly and thoughtfully discuss these matters at length.
Re: Live internet RepRap / Webcam? - 15 years ago
Hi Jim, ... it'll take some time, until reprapped cyborgs or such stuff would strife through your nightmares The main idea of the reprap is to make the fabbers cheap and common enough, so every interested could start with his or her own ... Until you can receive the kit from your friend, or give him one, the main goal should be to seed some 'competence-centers' at some locations, so it can spby VDX - Reprappers
Re: stepper motor bulk purchase - 15 years ago
Hi Zach, ... then it's a good one With 8 wires it's your deal to drive it as uni- or bipolar, so the 'unipolar' was a bit misleading ... Viktorby VDX - Mechanics
Re: Servo motor VS Stepper motor - 15 years ago
Hi Blerik, ... microstepping does add presision! If you drive your 200-steps-motor with half-steps, you receive 400 (nearly) accurate steps with positions inbetween the 'normal' 200-step-matrix - with 1/4 and 1/8 then ever more (Some companies sell 1/128-drivers too), so an 1/8-microstep-driver turns your stepper with 1600 discrete steps per turn! The absolute position isn't so absolutelly naby VDX - Mechanics
Re: interchangeable pressure nozzles - 15 years ago
Hi BDolge, ... i already milled in plastic, aluminium and brass with a 0,3mm-diameter milling head, so for milling freefrom-holes in thin plates or aluminium/brass-heads it should be no problem too ... For the orientation: - think on 'tangential'-cutter-plotters, here the cutting knife is turned with a motor in the driving direction, so you have a clean cut exactly in the moving line, not a bitby VDX - General
Re: Fibre powder - 15 years ago
... first experiments with waterglass showed, that it's a perfect soluble/fixing for glass- and ceramic-dust, as it dries on air in minutes to a solid matrix, stiff enough to support aditional layers and could act as ready-to-use moulding-form without further curing or heating ... Baking in an oven cure the body to maximal stability - i didn't try with melting of soldering glass at higher temperby VDX - Polymer Working Group
Re: Large Scale RepRap - 15 years ago
Hi Sebastien, ... look on the figures 4 and 5 in the paper Here is shown, how much preciser a parallelised scara-robot is, in respect to the serial setup ... Viktorby VDX - Reprappers
Re: Live internet RepRap / Webcam? - 15 years ago
Hi Demented, ... ah, clear - this is main the background of my faible for parallel-kinematics and 'bionic' or flexible/morphing actuators - here it's hard to bring the simulation to proper action, but relatively easy to build moving setups with bending and expanding arms activated by syringes or pressurised/expanded elastic hoses and bellows ... Viktorby VDX - Reprappers
Re: stepper motor bulk purchase - 15 years ago
Hi Zach, ... there are two types of unipolar motors: the simpler ones have only 5-wires, where the coils are in the middle connected - here you can't wire as bipolar. The better ones have 6 wires (coil-middles separated) or even 8 wires (every coil separate) - here you can wire as uni- or bipolar. So when you have 6 wires, its OK; with 5 wires it shouldn't work really as bipolar setup, or youby VDX - Mechanics
Re: Large Scale RepRap - 15 years ago
... you must think of the fabbing-time too ... If a decimeter-cubicle needs half'n hour (or even longer with better accuracy) to build, then a very big object with the same precision can eat weeks or months of time fabbing! And look on the material-amount and possible malfuctions in the support. For seriously speeding up the fabbing proces without losses in accuracy i hope to manage foil-latheby VDX - Reprappers
Re: Live internet RepRap / Webcam? - 15 years ago
Hi Demented, ... why? It's the way, i received most of my RP-models: - i constructed the parts in Lightwave or 3D-Studio and posted the STL-files to a comercial RP-company. Some days later i received the parts and send the bill to my boss I think it's a good idea to install some local reprap-copy-shops in towns, as many peoples, interested in the reprap-idea, aren't skilled or motivated enougby VDX - Reprappers
Re: stepper motor bulk purchase - 15 years ago
Hi Zach, ... an unipolar motor isn't so easy used for microstepping, as most discrete drivers are designed for bipolar ones. So if you want to rise the accuracy in future designs, a bipolar motor should be better - look, if you can get the kelig motor in bipolar too ... Viktorby VDX - Mechanics
Re: Servo motor VS Stepper motor - 15 years ago
Hi Jared, ... obviously the servo can do the same (and faster too!), but the driving of two steppers is simply clocking with a constant waiting time between steps or output single step-pulses until you reach the target-position, when a timer counts down. Servos needs much more software, as you have to control the moving-speed very accurate in respect to the actual position and the way the speciby VDX - Mechanics
Re: Live internet RepRap / Webcam? - 15 years ago
... hmmm, sound like waste of energy and potential ... Maybe some of you remember the Golem-project, where your computer was embedded in a internet-grid to evolve robots, build from sticks, joints and rod-actuators. There was the possibility too to RP your favorite bot and apply some linear actuators, so he could act in real as in the simulation. Maybe this is a more fascinating way: you buildby VDX - Reprappers
Re: Live internet RepRap / Webcam? - 15 years ago
Hi Zach, ... it seems, that i have to work a bit harder to bring my PC in the status to run the host-software The [email protected] is running and shows simulated building too, but the reprap-host didn't start ... Viktorby VDX - Reprappers
Re: Fibre powder - 15 years ago
Hi Fernando, ... i actually 'played' a bit with Natronwaterglass (water-soluble Alkali-silicate) and glass-dust. It seems to work as hoped - in the bottle/syringe it stays stable, on air it will dry in some minutes to nearly solid and with a H2O2-microflame i melted it without problems to solid glass - and there will only water fume out. At home i'll try with some other dusts and powders if itby VDX - Polymer Working Group
Re: RepRap can help end slave labor! - 15 years ago
Hi Demented, ... it's more a pressure-chamber, then an oven - i call it in german "Dampf-Kochtopf" or pressure-cooker, which is heated on an oven-plate ... With the right chemistry behind you can make all sorts of polymers from the right fractions. I think, with a more sophisticated physical infrastructure there would be simple carbon as building-material in future - think carbon-nanotubes, grby VDX - General
Re: Furfuryl Alcohol and blocked catalyzers (formerly delivery woes...) - 15 years ago
... i have a ceramic-paste called "Karger keramische Vegussmasse", which dries at room-temp to a hard to remove but brittle solid and can be cured in the oven to behold a bit better, but stays brittle too. I think, it's simply ceramic-dust wuth waterglass too! We used this paste for embedding and covering high-temp-sensors for 500by VDX - Paste Extrusion Working Group
Re: Live internet RepRap / Webcam? - 15 years ago
... so why not a VR-RepRap as Simulator for training mode? In my CAD/CAM-software i have an option to run a virtual milling-task in a simple coloured ISO-hidden-line-view, what's impressive enough. With a more sophisticated 3D-world, containing a virtual RepRap and a free moveable camera-actor there could be tested and visualized, how the (virtual) trays and slices would form a 3D-object. Butby VDX - Reprappers
Re: RepRap can help end slave labor! - 15 years ago
Hi Demented, ... a guy at Fraunhofer found a way: he encapsuled vegetables (grass, leaves, wood or some organic garbagge) and water with citric acid as catalysator in an autoclav and heated it some days at 120by VDX - General
Re: Servo motor VS Stepper motor - 15 years ago
Hi Jared, ... a better example: - say the extruder have to draw a straight line from 0,0 to 80,5 Then i simple divide 80:5=16 - so i know exactly how to move: every 16 steps in Y comes 1 step in X, until i count 80 steps in Y - and i can calculate the right faktor for the speed (idle-time between the steps) before i start ... With a servo i have to control the motion over the full path with enby VDX - Mechanics
Re: Furfuryl Alcohol and blocked catalyzers (formerly delivery woes...) - 15 years ago
... this is maybe usefull for other pastes too: I found that dexpanthenol is reacting with my soldering glass-powder, so it can't stay longer time or it changes chemically, in consistency and in end-colour. For this i searched for another solvent and found waterglass (water-soluble Alkali-Silicate). It seems to be a perfect solvent for ceramic and some powders, it's used in paper-industry as gby VDX - Paste Extrusion Working Group
Re: RepRap can help end slave labor! - 15 years ago
Hi mimarob, ... it's no real need to use plastic or expensive and/or proprietary stuff - i heard from experiments in africa, to make house-building-blocks from local ressources as grasshoppers/locust (as in locust-plague), sand and water - seems to be a good basis for a reprapper-paste too I have some samples of moulded 'wood-plastic' - wood-powder with water, extruded at high pressure and temby VDX - General
Re: New plastic is strong as steel, transparent - 15 years ago
... what's tis with 'steelwire'? It's the same behaviour, as a (clever) spam-bot! Viktorby VDX - Polymer Working Group
Re: Servo motor VS Stepper motor - 15 years ago
Hi Jared, ... one big point for steppers is the ability to 'synchronize stepwise', when moving 2- and 3-dimensional lines or interpolating 3D-curves. It's the same, as with the Bresenham-algorhytm, where you count the pixels of the longer side and synchrone insert the steps for the shorter side, so the line runs straight from X1/Y1 to X2/Y2 (or {X1,Y1,Z1} to {X2,Y2,Z2} for 3D) So for exact feeby VDX - Mechanics
Re: Fibre powder - 15 years ago
Hi Fernando, ... try coffee-powder - it's common and you can define the granulity by the time it's milled. When it's not enough interconnecting, then you can use all kinds of fibre-holding vegetables smashed to powder in a coffee-mill Viktorby VDX - Polymer Working Group
Re: RepRap can help end slave labor! - 15 years ago
Hi Colin, ... i didn't think the troubling would start and impact mostly in China or 3-rd-world-countries ... The most instabilities would be adressed in the most developed markets, as here is the 'just-in-time-fabbing' and 'time-is-money' comes together with an extremely complex infrastructure and mainly developed logistics. The Chinese or african workers could adapt reprapping easily in theiby VDX - General
Re: McWire RepStrap Z-Stage System - 15 years ago
Hi Demented, ... as you know, i'm a big fan of magnets as assisting elements It's dependant of the involved forces, what you can make with them - for a leightweight extruder- or a laser-head it's no problem, when i have more or heavier toolheads, then the magnets and bearings have to be bigger or in another arrangement. When you manage to balance the masses, so the feeding is vertically symmeby VDX - Mechanics
Re: Reprapping Engines - 15 years ago
... i used the Piezomotor-drives ( ) and developed 1- to 3-Axis-Micropositioning Stages at Gerwah Mikrotechnik (see MPL-3 ). The motor have an accuracy of nearly 150 nanometers per step, but it's depending on the load, vertical orientation an friction, so you hev to implement a precise encoder for error-correction. The travel-lenght is 25 millimeters, the maximal payload/stall-force lays betwby VDX - General
Re: Delayed feedback on the RepRap merchandise - 15 years ago
Hi Steve, ... i want to have one - as i didn't manage it until now, to bring the system to live on my Notebook with WindowsXP or my DualCore-Desktop with preinstalled Vista, i want to try with a Live-CD with Debian on an old 486-PC ... Viktorby VDX - General
Re: Servo motor VS Stepper motor - 15 years ago
Hi Jared, ... i'm working with steppers since over 30 years ... When i started with my first plotter-design, i had to build a driver-pcb with discrete transistors, later with single-ic 3479P, last with the IMT901 microstep-driver. Main advantage is the ability to 'clock and forget' - when the motor doesn't skip steps, he is exactly at the position, i counted as steps - with a 200-step-motor anby VDX - Mechanics