... last i followed a documentation about the "Dacota"-dino-mummy in tv, where they simulated the biped-walk of the hadrosaurs and T-rexes - it was funny to see, how the biped's in the simulation 'learned' to walk and run from scratch in a progressive learning curve. After some hundred thousands 'lessions' the programm managed to steer the simulated dinos in rough terrain and in virtual battlesby VDX - General
... ABS should work much better - AFAIK after solving in acetone and complete drying it's around 70% the strength of bulk (e.g. extruded) ABS. I used this sometimes to glue together or repair ABS-elements ... Viktorby VDX - Polymer Working Group
Hi Andy, ... i tested with heating for faster hardening, it's not essential when you wait between the slices until it's hard enough ... Today i tried the hardened polystyrene - it's complete hardened, but stays brittle, so i't not such a good material for fabbing. I think it's more suitable for sacrifice mold-forms or as support-material. Viktorby VDX - Polymer Working Group
Hi, ... i tried with polystyrene (styropor) solved in acetone: It's very easy to dissolve - simply put as many foam in the acetone as you want. When the foam dissolves it morphs to a paste with a fixed amount of acetone in it, the other acetone stays as separate fluid phase and didn't mix/solve, so you can extract the paste and let the not embedded acetone in the pot. Then i put some paste inby VDX - Polymer Working Group
... when heating the topmost layer to evaporate the solvent (IR-heater or hot air) then it should shrink mostly vertically, so you should calculate the layer-hight/slicing with this shrinking. Horizontal shrinkage should be in a very low percentage, when layered on a complete hardened surface. Another excelent point should be the good interlayer adhesion, as the acetone re-solve the surface ofby VDX - Polymer Working Group
Hi nophead, yes, i milled the "Han Solo in Carbon"-thingy out from black DELRIN/POM because it should be REAL BLACK ... It's my best material - stiff for construction, elastic when used for solid-state-hinges and very good and accurate milling without any coolant in any cutting speed (my millhead runs with 11000 until 25000 RPS and until 50mm per second travelling speed). The next selection isby VDX - Reprappers
... i want to try with all types at hand. The hint with polystyrene-foam (styropor) solved in acetone should be interesting too - maybe with a heating-break per slice to harden the surface ... Viktorby VDX - Plastic Extruder Working Group
Hi nophead, the Drader Injectiweld/Orbi-Tech-injection-press works with 1000 bar pressure! I think you need at least 5 to 10 bar for a coarse fitting, better some 100 bar, which could be made with a drill-press and metal forms. This high pressures are most made with small pistons pressed in the fluid plastic - you can calculate the end-pressure by the diameter of the piston and the force you aby VDX - Reprappers
Hi Forrest, ... got the point Maybe i'll try to make a molding form from aluminium with my CNC-mill and shoot some plastic-parts with the drill-press ... In the mean-time my older son ordered some StarWars-toys: Viktorby VDX - Reprappers
Hi Fernando, your stuff is ready to use, but i didn't find time until now (some trouble around), so the experiments delayed, maybe i'll find some time next week. The pneumatic dispenser i borrowed from a previous company wasn't usable (all tubes filled with hardened epoxy), so i have to build a new one from scratch - i think a mechanical dispenser with a motor-piston should work better ... Vikby VDX - Plastic Extruder Working Group
... wow, thats impressive - especially the 'dance' on ice and the single-step-walk over the stones ... When i heard 'dog' and 'robot', then i remembered another video - Let's fab some robots and artificial pets to play with next Viktorby VDX - General
... in the past i found a mini-injection-molding system from Drader Injectiweld at Orbi-Tech: The price is something around 3000 Euros, but with a CNC-mill you can easily make some molding forms for bigger series ... Viktorby VDX - Reprappers
... i used pneumatic hoses for coupling, they are stiff enough but have some inherent elasticity, so you can push them over thicker rods or threads: Here: we discussed some of the specs ... Viktorby VDX - Reprappers
... my CNC-controller has a RS232-port, what's more suitable for actual PC's which have a Serial port or over a USB-to-Serial-converter-cable. On the other side i have some discrete stepper-drivers with CLK/DIR-input, which i could wire to a parallel port, but it's much better to drive them with a microcontroller-board, which has an USB- or serial interface. So i want an open and freely reconfiby VDX - Controllers
... another idea: - instead of ultrasonic welding you could maybe try with inductive welding? When you have metallic/ferromagnetic particles in your FDM- or dispenser-paste or coat the topmost slice with a thin layer of iron-dust, then you can apply a high-frequent EM-field, so the embedded metallic particles start to rotate and vibrate. The vibration of the particles heats only the area aroundby VDX - Mechanics
... here: i started a discussion about 'mega-sized-repraps' and fabbing with construction-foam (or 2K-polyurethane-foam) which you can extrude in centimeter thick trays from pressurized bottles. With the possibility to print with trays of some centimeters diameter it's very interesting to design real big robots - for example for building furniture or architectural components ... Viktorby VDX - General
... yes, here: - and here: - are examples and some basics of a milling/fabbing combination. A very helpful aspect is the fact, that by milling/finishing the fabbed layers with a mill you only have to mill one sheet at once, but you can build very big objects by stacking many sheets. So you have the overall precision of a CNC-mill and could process any geometry and size your robot can handle,by VDX - Plastic Extruder Working Group
... here: - - i found some infos for galvanic art-work. And here the shop: In the past i ordered some components and experimented with micro-galvanic fixing of platinum micro-wires on gold-pads - worked fine, but i needed only thickness of some microns of the gold-coating/fixing. Cuprum-galvanic should be much easier ... Viktorby VDX - Plastic Extruder Working Group
... and a major point for additive fabrication is the ability to mix the materials in the fabbing process: So with a two- or three-head-reprap (extruder and paste-dispenser) you can start with plastic and build the bottom of a housing, then print some conductive trays and landing-pads, insert some IC's and discrete parts in the wet paste, cover with plastic, embed some elastic bulbs as buttons aby VDX - Plastic Extruder Working Group
Hi Steve, ... i had a similar talk with my older son (9 years) - he was fascinated of the promise to build more lego-bricks and some cool parts for his Playmobiles. I had a long dispute until he accepted, that i won't build lego so soon Now we're on CNC-milling of toys and 'usefull stuff' and he and the younger (7 years) are busy by re-arranging my spare time at the free weekends ... Viktorby VDX - Let's design something! (I've got an idea ...)
Hi idlewire, a pen-plotter is the perfect system for drawing, but today the ink-jets are much more capable, so pen-plotters aren't so common and distrubuted as some decades ago .. Instead of re-inventing the plotter you should look around, if you can find an outweared one or buy cheap in ebay. Viktorby VDX - Let's design something! (I've got an idea ...)
Hi Fernando, on monday i'll check some infos and sources. Normally you can use a common silver-conducting-paint (german 'Silber-Leitlack') or graphite-spray (german 'Graphit-Eisen-Spray'). With the galvanic felt-tip you can simply 'paint' pure gold on conducting surfaces or the conducting paint - here i'll post some links, but you can find some infos in wikipedia too ... Viktorby VDX - Plastic Extruder Working Group
Hi Fernando, i'll post, when it's there ... My easiest way to chemicals is my local apothecary shop - there i got my waterglass, wool-wax and some other stuff for the experiments with pastes. Ciao, Viktorby VDX - Plastic Extruder Working Group
... on my CNC-mill i have two methods of panic-brake: First - a hardware-stop-button on the housing of the CNC, which instantly power down the motors and the millhead (if controlled by the CNC) and send a 'panic-stop' condition to the PC. And second - when pushing the -button on the keyboard, the software stops the movement and the mill-spindle, but it opens a dialog box, where i can continue oby VDX - RepRap Host
... some days ago we had to cover a thin gold-surface of some hundred nanometers with 10 microns copper, what was made electrolytical with two electrodes - one connected to the gold-surface, the other free in the blue (cupric sulfate?) fluid ... I know too, that you can cover a surface with a conductive paint and then 'draw' pure gold-lines with a pen with a felttip, filled with the gold-electroby VDX - Plastic Extruder Working Group
Hi Fernando, ... good to have all infos on one place! I'll post the results here, when your stuff arrives and i can fiddle around a while ... Viktorby VDX - Plastic Extruder Working Group
... right, simply stack a 3-axis-nano-positioner, capable of some nanometers accuracy in the fine-range and 20mm in the step-range as tool on your reprap-bot and with the right controller/measurementsystem you have nanometer accuracy over the complete working-area of the reprap ... My goal aren't single atoms per second, but more the LOM-approach, where i put one after another thin sheets of matby VDX - General
Hi damonb, some years ago i got some of this (should be 60USD per single motor): and built a sort of a mobile, which glides with three motor-tips settled over the ground. Then i tested with this type (should be at 30by VDX - General
Hi Bob, actually we can move (relative) easily in the submicron-range with PZT-actuators. I have some single-axis devices with a 'propagating-wave-movement', which costs between 60USD and 300Euros and are capable of single-steps in the range of 100 nanometers over a traveling range of 30 millimeters. I normally combine three of them for an orthogonal 3-axis-nanorobot for my microassembly-systeby VDX - General
Hi Andy, fabbing any size should be done by assembling small printable parts, fitting together to form the next bigger hierarchy. Imagine ropes of some kilometer length, 'assembled' of short strings of some centimeters ... So why not going the 'lego'-way? I'll print small elements with fitting-details, which easily can be 'clicked' together. In particular the extruder does the same by addingby VDX - Casting and Moldmaking Working Group