... 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 ... Viktorby 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 ... Viktorby 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 ... Viktorby 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 aby 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 Glby 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: Viktorby 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 Viktorby VDX - Controllers
... here: - - is a collection of different parallel-kinematics with movies showing them in action ... Viktorby 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 andby 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 foby 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 Viktorby 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 ... Viktorby 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: Viktorby 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 tby 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 pby VDX - Paste Extrusion Working Group
... i was thinking about optimizing a glue-gun for using ABS-filament ... Viktorby VDX - General
... nice tool-head for a repstrap Viktorby 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. Viktorby 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 600by 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): Viktorby 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 200by 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? Viktorby 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 ... Viktorby 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 buyby 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: Viktorby 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 experimentby VDX - General
Hi Ru, ... look through the links in this post: ... especially the different kinematic-concepts here: [155.69.254.10] There are many different ways of enhancing the accuracy with parallel kinematics or special setups. My favorite is the bionic approach, where we print elastic morphing structures with embedded hydraulic structures - as discussed here: Viktorby VDX - General
Hi sid, ... same electronics, other software ... The main advantage of a BRR (read 'babyreprap') would be lesser friction and so smaller motors, shorter rods, belts, studdings ... and such. So it's something cheaper and more portable/shippable ... Viktorby VDX - General
... this lets me remember an old thread about fabbing objects out of uniform shapes - as lego does from bricks, here stacking small uniform spheres to a bigger object. So you haven't to remelt the balls, but simply heat a small zone on the base and pick-n-place the balls into the molten area. With smaller spheres (e.g. 1mm diameter or even smaller) you should have a finer granulity and with shoby VDX - Plastic Extruder Working Group