... another idea for a low-cost but high-accurate probe-head: Atach an ultrasonic resonator to a tool-tip and a microphone to the bed. When the tool-tip touches the surface of the object, the microphone senses the contact ... Viktorvon VDX - 3D Scanners, Book Scanners, and Optics
... in the last years there were several types of piezo-motors - different inchworm-types, piezo-legs and 'elliptec'-oszillators. I experimented with some inchworm-drives and built some micro-(and nano-)-positioning stages with 'piezolegs' and ferrofluidic actuators. The drives were capable of 20mm travel range, accuracies of 0,1 microns per single step or single nanometers in 'bending-mode', bvon VDX - General
... one of the biggest problem beside bending of the frames with steppers is blocking/stalling when the motor-frequency hits some resonance-points of the frame. This is the main source for limitating maximum frequencies ... This could be reduced by smaller steps (half-stepping with 0,9von VDX - Reprappers
... i think when the size of the nozzle-output is much smaller, than the slit(s) between the auger-blades and the enclosing tube, you can't extrude with a constant rate - the 'back-welling' should be bigger than the extruding. When used a mincer (meat-grinder) i notized a similar behaviour, when the holes were blocked ... Viktorvon VDX - Mechanics
... maybe noisy signal or missing ground/shielding? Somehow the input of the steppedriver receives 'signals'. Check the voltage-level at the pins - when the system didn't move, it should be near to zero, with running motors something above 2 volts (depends on the pulse- or PWM-rate). The "DIR"-pin should be either zero or 5volts ... Viktorvon VDX - Reprappers
... when finding some more time, i will test with wood-dust, talkum, and waterglass - this could be an interesting mix for fast hardening, light but very stiff material with low shrinkage. In particular you can use any powder or dust (or mixtures) you have at hand - the 'magic' lies in the fluid base: epoxy, dextrose/shugar, waterglass or others ... Viktorvon VDX - Plastic Extruder Working Group
... i didn't allow my sons (7 and 10) soldering, but they already have some experience with 'electronic-experimental'-kits from 'Kosmos' and 'Schuko'. Both managed to build some of the experiments on their own - the 7-year-old some blinking lights, the older (with the much complexer "Schuko"-set) some theft-alarms and TTL-amplifiers! For some more 'sophisticated' tasks the older reprogrammed avon VDX - General
Hi Fim, wie's momentan aussieht, bist du am Besten dran, wenn du dir den Extruder-kit und die Elektronik bei BitsfromBytes bestellst und versuchst, die Mechanik als RepStrap aufzubauen. Mit etwas Glvon VDX - Altes Forum
... an update ... My older son is celebrating his tenth birthday and i'm actually busy moulding "Han Solo in chocolate" for his friends - this time it's very tasty milk-chocolate The first three bars: Viktorvon VDX - Plastic Extruder Working Group
... i'm soldering SMD and/or 'conventional' occasionally, but for SMD you need serious training and reworking isn't so easy. So for the average reprapper SMD isn't optional - try to design for single-sided PCB's with conventional parts and through-holes without vias. But with time and reprap more matured this should change Viktorvon VDX - Controllers
... here: - - is a collection of different parallel-kinematics with movies showing them in action ... Viktorvon VDX - General
... hummm ... here in Germany would be fine One of the points for developing interests in micro- and nanotech was the hope, that all my tools, equipment and hardware-archives sometime would fit in a fly-case But in the meantime i have to deal with the remnants of the enroute ... ***Edit: @matt - you have to select the supporting materials carefully or your extruded trays wouldn't stick andvon VDX - Paste Extrusion Working Group
Hi all, ... yesterday i found in my basement some samples of injection-moulds made with 'fluid wood' from a project-development out of 1997 - the company started as spin-off from the project can be found here: The method used for the injection-mould isn't so easy adaptable for us, as they use very high pressures and temperatures. But this let me think about mixing wood-dust with some epoxy fovon VDX - Plastic Extruder Working Group
Hi Demented, ... it's only a little fraction - i have a big besement and nearly 20 years development for microtech leaves some bits Viktorvon VDX - Paste Extrusion Working Group
Hi Forrest, when using soldering paste i have the same when the metal-base isn't hot enough. You have to heat the metal around, and then dip the braising rod into the hot-spot, so the melting front wet the surface and didn't form a blob on the rod itself. A hint for aluminium: - there are some aluminium soldering pastes around, which can be used with a normal soldering bit ... Viktorvon VDX - Plastic Extruder Working Group
... here the promised images (some more detailed at the bottom) Two pneumatic paste-dispensers (the big one with a heater): Some tools for pick-n-place and micro-handling: Viktorvon VDX - Paste Extrusion Working Group
... there's a lot of possibilities with embedding prefabbed parts and/or changing materials 'on the fly' while fabbing the body/housing. When at home again, i'll post some photos of tweezers and vacuum-grippers, i designed for microassembly - with milling i can make any shape or type of pick-n-place toolheads or specialized tweezer-inserts. As mentioned before the only actual problem i see is tvon VDX - Paste Extrusion Working Group
Hi all, ... i had some ideas with embedding spacer-parts in the fabbing, so you could fab complex objects with overhangs without the 'teardrop-shape' in vertical bores and such ... It's the same idea as embedding sticks, rod, threads ant nuts in a mould, but here included in the fabbing process itself. When you want to build with the same material, then you can prefab the parts to embed in a pvon VDX - Paste Extrusion Working Group
... i was thinking about optimizing a glue-gun for using ABS-filament ... Viktorvon VDX - General
... nice tool-head for a repstrap Viktorvon VDX - General
... continuous lines, criss-crossed over the slices, are much, much faster ... One good point for circles are the complex arrangement of circular and triangular tubes (where three circles connects) and you can forget the outline, when the circles are small enough. Viktorvon VDX - Reprappers
Hi Forrest, ... replace the steel with other low-melting materials and you'll be on the way I'm on a similar route with my 'room-temp-paste-fabbing' and have some possibilities around for heating samples until 600von VDX - Casting and Moldmaking Working Group
... if the stepper hasn't to run very fast (e.g. <1kHz) and pulls only 0,7Amp per coil, then the single-chip-driver MC3479P is the simplest route - here some images of my first prototype (built around 1985): Viktorvon VDX - Controllers
... my primary idea was to use this sort of heating-sheets in the bed and around the inner housing for temp-stability until 200von VDX - General
... reading the specs of Kapton-insulated flexible heaters ( ) i found that this kind of heaters should be printable or made with etching. Maybe a good thing for heating the bed/housing or as tube around the extruder? Viktorvon VDX - General
... here: is an interesting paper about fabbing (with a f@h-printer) and sintering objects fromm steel-powder-slurry. It's very short, but touches some points we had discussions about - warping, shrinking, heated syringes, paste-extruding and such ... Viktorvon VDX - Casting and Moldmaking Working Group
Hi Richard, look at the spread of 3D-CNC-milling over the last 20 years - there are expensive comercial machines (>>50000$) with high accuracies and throughput, but now even more home-made or 'cheap' CNC-kits are around, so 3D-milling or engraving is a 'standardized' common methode every interested individual with 1000 to 2000$ (or even less, i reworked an old CNC-robot for ~500$) can buyvon VDX - General
Hi Matt, ... instead of cement you can use a mix with 6% to 10% epoxy with sand - it would better fill and grip and you can mostly adjust the settling-time by reducing the hardener-component from 30 minutes to some hours (or even days). Look here: Viktorvon VDX - Reprappers
Hi Richard, ... some comments ... 1. - sure ... 2. - look at and - it's dort of open-source too. And there are some other individuals and groups scattered worldwide, which are on the theme too ... 3. - maybe, time will show ... 4. - this will change with the evolution of home-brewed RP ... You have many parts around, made from resin, which can be replaced or optimized. I'm on experimentvon VDX - General