Hi Samuel, ... i used the syringes only to apply pressure for demostration - in a 'real' setup there should be much more 'muscles' (with attached magnetic/solenoid valves each), and the syringe would be driven oszillating as central pump by a motor with excenter ... For solenoids you can salvage old solenoid-relays (?) or electromechanic switches, the use often 12 or 24 Volts and can perform hiby VDX - General
Hi zzorn, ... a better way for precise switching and applying short pressure-pulses of air or liquid could be a solenoid-valve with a trapped steel-sphere, which is through the solenoid moved in the way and settled on the tube to stop flow and pulled away, to give the way free ... Viktorby VDX - Mechanics
Hi zzorn, ... you can reprap hoses with inserted strings, when you manually inlay the strings during the fabbing process ... Another pneumatic muscle without strings is like a bicycle-hose - without pressure you can stretch it to full length, but when you apply pressure, it morphs to the ring-form (or other endforms with more displacement) and contracts with some force ... But this muscles areby VDX - General
Hi Samuel, ... 'soft' mean, that the ferrofluid in the magnetic field can perform only weak pressure forces - dependant of the size and strength of the magnets, the amount of feerofluid and the gap-width i achieved some Newtons as pressure on the complete surface, what mean, that the compressing force on the tube is a bit lower. Normally a wall of ferrofluid can withstand a pressue of 0,3 to 0,by VDX - Mechanics
Hi zzorn, ... the idea with the latex-'fingers' is good - as samuel mentioned, you should glue 4 to 8 strings along the sides of the finger, best with gummi-arabicum-glue or with the solvent-glue, you use for bicycle-repairs, because the glue should be elastic too ... It's the best, you wet the strings with the glue and press them onto the latex, so it could make a firm contact over the completby VDX - General
Hi Samuel, ... i like the tripods, because of the much simpler assembly and the simpler and easier reprapable parts. Compare the amount of the darwin-parts to the green coloured parts in my second post. I'll have 12 parts, which i can reprap easily (6 rods, 3 columns, 3 plates), three linear motors and three linear bearings (or complete, but expensiver linear stages, where the bearings and theby VDX - Mechanics
Hi Samuel, ... the pump in the second image should be filled with ferrofluid, which forms fluid threads on the spiral-magnets and on the linear magnets inside the tube. When i insert the spiral in the tube, both ff-thread-setups overcross and form cavities, which are surrounded by ferrofluid-walls. When turning the spiral, the cavities moves in the corresponding direction (as in a archimedic-pby VDX - Mechanics
Hi Samuel, ... it's half-on-half - sometimes i'm employeed (as now) for starting a microtech-branch in a company, sometimes it runs at home ... The parts i made on my own are mostly milled from aluminium or Delrin/POM on a ISEL-3D-mill. The fabbed parts from UV-epoxy, inkjetted plaster or stark i've got from 3D-printing companies - sometimes in tech-cooperation for free, sometimes with customby VDX - Mechanics
... i've found some stuff from my experiments with ferrofluids some years ago ... In the first image you can see an (UV-epoxy-fabbed) electro-magnetic nanopositioner with ferrofluidic-bearings and two prototypes of peristaltic pumps (without the normally inserted soft air-feeding tubes) - you can see the ferrofluid inside the nanopositioner or on the teeth of the pump-magnet-gears. The second iby VDX - Mechanics
... 'back to the roots' and to real life Here i assembled the linear axes and temporarily atached the magnetic joints and rods - i have to mill the 45by VDX - Mechanics
... it seems, we've lost the connection to the basic reprap a bit It's obvious, that simplifying the reprap-setup would be good for spreading the ideas and fabbing possibilities for selfmade home-manufacturing worldwide - and here is my aim, to initiate faster progress ... It's obvious too, that noncartesic systems need a more sophisticated software, to control them, but if the controls are prby VDX - Mechanics
Hi fernando, ... the gold is for a special problem: - we assemble a sensor, which is made from ceramic with gold-pads, on which we fix thin platinum-wires (10 microns and 1 micron diameter) as temp-sensing elements. Until now the wires were fixed with a conducting silver-filled polyimid paste, which will be heat-cured at 175by VDX - Paste Extrusion Working Group
Hi Demented, ... very interesting! The 90% volume-change in 50 seconds isn't so clear for me - 90% change would be exorbitant, but the reacting time is a bit longlasting ... Another interesting concept: - i experimented sometimes with ferrofluids and magnetorheological fluids (in special: carbonyl-iron-microspheres in different solvents) and found some methods for pumping volumes and apply preby VDX - Mechanics
Hi Fernando, ... thanks! Sounds to be a very interesting material, when dispensed and tracted with the laser With a heating spot of 50 microns i think the activation-zone should be around 80 microns, if the reaction doesn't expand on self? If you find a mixture, which will stay stable and fluid at room-temp and harden in seconds when lasercured, then there should be some testing with partialby VDX - Paste Extrusion Working Group
Hi Demented, ... my approach is a low-viscose paste, which i can dispense in diametres under 100 microns or single droplets down to 10 microns, which i heat-cure with the laser to harden directly after releasing ... A second setup is to output a complete layer and bake the layer completely - then a big IR-heater, which activates the complete surface is better and faster, then a laser-spot ...by VDX - Paste Extrusion Working Group
Hi Samuel, ... it's only theoretical In practical issues the one-motor-per-axis-approach ist the best start. It's not so essential, if the setup is cartesic, polar, polypod or other - in the cartesic systems is the software easier to create, some others (like my tripods) are very easy to assemble, but the controling is a mess ... When i'll have a fabber capable of making elastic resins, thenby VDX - Mechanics
Hi Fernando, ... can you give me the formula and tech-specs of your polymers please? I'm playing around with a 1Watt-Diodelaser with 60micron-fiber at home and in my job i today finished the drivers and optics of a 9-Watts-Diodelaser with 100micron-fiber, so i can make a focus down to 50 microns and tests with sintering or heat-curing of different material. Some years ago i had 3Watt- and 5Watby VDX - Paste Extrusion Working Group
Hi Steve, ... in the past (2002 or so) i had good experiences with and with a company called '4D-concepts', which i didn't find online anymore ... I send STL-data per email and received the finished epoxy-parts 3 days later. My last try this year was with , here i received FDM-test-parts for free, so i didn't know, what's cheaper, epoxy or FDM ... Viktorby VDX - Reprappers
Hi zzorn, ... you're right, but this would extend the building time per slice (in a 2D-Peano-curve with rounded edges) from minutes to days or weeks, if you want an usable accuracy I had some ideas for reducing the amount of motors too - if i use two rotating axes, where an arm moves horizontally (like the arm of a phono) and the other turns a threaded rod, where i can change with clamps the mby VDX - Mechanics
Hi Samuel, ... i'm working now at - a small company with 4 employees, where i have to develop and realize all kinds of micro-stuff (sometimes nano- too) ... From 2000 to 2006 i made the same thing for GERWAH - here i invented and built some micropositioning systems ( ), microgrippres and special video-microscopes (with the tenfold field-of-view then normal), to realize stereo-vision in the miby VDX - Mechanics
Hi Samuel, ... in this sample-setup i have only linear bearings with 40mm free run, so the maximal displacement in XY would be at 30 millimeters with a 'safe' heighth-zone of 10 millimeters over the whole working area (in the centre then more, so at 30 millimetres too). I designed this 'micro-fabber' for a special problem, where we have to fab mikrosensors from a ceramic-paste with gold-inlaysby VDX - Mechanics
... most liquid-curing RP-systems activate the surface of the liquid epoxy through an UV-laser or LCD-beamer-focus, so you build slices on slices as normal - but you have to build supports too, or your hardening parts would crumble, if you move the basis-platform in the bath and move the washer to make the surface plain after overfilling ... I had similar thoughts - when the curing area would beby VDX - General
... it's not so hard to make a hydraulic reprap - for my tripod-setup i can replace the three linear stages through three big syringes and activate them through three thinner but much longer sysringes, which i'll push with weak linear motors (here: TylerM tried a similar approach for a Stewart-platform or hexapod in Nov. 2006 ) ... If, for example, the inner size of the small syringes is a tentby VDX - General
Hi zzorn, ... hydraulic structures are much better for reprapping, because fluids are not compressible, and you can activate expanding silicone-tubes with a simple syringe full of water ... Try to twist some elastic tubes to a kind of helix and fix them with radial orineted strings - if you arrange it feasible and expand the right tubes, the structure can rotate, expand and bend. With thinningby VDX - General
Hi zzorn, ... i'm playing around with different concepts - look at the 'bionicle'-robots at my c't-bot-gallery: In the past i experimented with many other active structures and methods too, as pzt-actors and -resonance-drives, shape-memory-alloys (e.g. nitinol-bug-bot 'boris'), magnetorheological- and ferrofluids, magnetic-shape-memory-alloys (active NiMnGa-crystals) and other stuff like thatby VDX - General
Hi Sean and nophead, ... i knew, that elastic tubes will shorten a bit, when twisted. For this reason i searched a bit, until i found the perfect material: It's a merely stiff pneumatic tube - you can have them in different shore-values, my type is so stiff, that i can't sense any distortion, when twisting the rod against the motor-shaft (i had to apply a lot of force to screw the rod into theby VDX - Mechanics
Hi zzorn, ... i would prefer a single oszillating pump and fast switching micro-valves for the capillaries. When the pump is oszillating, then you have a sinusoidal pressure-curve between max, zero and min. For rising the pressure in a single capillare the corresponding valve should only open, when the pressure is on max, then it adds pressure in every half period, until max -- for reducing thby VDX - General
Hi Demented, look on the linked images and files in - here i described the tripod-system and linked some infos in my answer to Zach, where you have some background ... In my concept the three linear stages aren't in a plane as usual, but parallel, so i have a more cylindrical defined working area - here i can perform a straight Z-movement with moving all three axis synchrone. The thin rods bby VDX - Mechanics
Hi zzorn, ... the simplest moving structure, which can be build by 3D-fabbing, is a pneumatic or hydraulic setup from a highly elastic resin. Image a 'finger' from elastic silicone with some capilaries in the outer area: - if i apply pressure to a capilary on one side (and mabe vacuum to the corresponding one on the other side), then the finger would bend away from the pressurized side. Combinby VDX - General
... here is my idea for a tripod-setup with the 'Easy to build linear stages' and the self-assembling magnetic joints from . The green parts could be entirely made from plastics (reprapped, molded or milled) or from aluminium, the spheres are my joint-magnets and the linear stages from the previous post ... The transparent insert is a displacement-sample of the toolhead, to demonstarte the plaby VDX - Mechanics