Magnetic joints and selfassembling ...

... hi folks,

i sort of invented a self-assembling-mechanism for macroscopic joint-structures and flexure hinges, as known in flex-joint parallel kinematics.

In the image below you can see a tripod-sample with this joints, i 'assembled on the fly' in two minutes - if i set it on three linear drives, then the fully functionable tripod-system for reprap-dispensing or micro-tooling is ready

The rods are magnets from a toy-mag-box of my children, but the balls are not from steel, but spherically shaped neodym-magnets ( [www.supermagnete.de] , ~50 cents).

With the stacking of mechanic-parts with spherical magnets or perpendicular magnetised rods i can easily build highly precise, stiff and stip'n-slick-free joints and flexure hinges, which are nearly fail-resistant (if they rip apart, i only have to reassemble them again ...)

My actual interest goes in parallel kinematics, but maybe this method is useful in joining and (self-) fixing of other structures too?

Bye, Viktor

Edited 1 time(s). Last edit at 09/22/2007 03:15PM by Viktor Dirks.

interesting... that looks like a pretty rad little setup there.

Hi Zach,

here [www.pp.bme.hu] you have an example of hexapods and tripods for CNC-systems with some basics and formula for converting ...

I think, with an easy to assemble (because of magnetic selfassembly) and reliable mechanic for a 3-axis-system we can go deeper in the development of the software, which is free of charge then.

With 3 linear stepper-drives and controller-modules from nanotec and all the parts for building a feasible tripod-reprap i estimate a price of 500 Euros for the complete kit - how much for the 'cartesian reprap' with the many parts for fixing and feeding?

If i get the software working, for converting STL-data into tripod-movement, then i have my nano-reprap ready to use in two or three weekend-sessions!

Then i can go in developing of the toolheads and image-recognition for some of my other problems ...

Maybe you are interested in stereoscopic systems, which are based on cheap web-cams, have an excellent depht-field (nearly ten times more then normal) and receive 3D-stereo with only one camera and vizualize it in a live-video-stream?

Here is a link to samples, which are made with my optics: [www.mikroskopkamera.de]

And here direct to the first image-gallery (all images are live-snapshots without optimisation or computational stacking!):
[www.mikroskopkamera.de]

Ciao, Viktor

...how much of it is self-replicateable? That's always been my problem with most designs, too much of the assembly can't be self replicated...

self replicating is what puts the 'rep' in 'reprap'!

Hi lordcat,

look at the image 'Tripod-2.jpg' ( [forums.reprap.org] ) at [forums.reprap.org]

Here you have a reprapable 'one-sheet' body, which contains all the mechanical stability, the flexure hinges and the feeding.

You need only the linear drives and the tool-head ...

Until the reprap is capable of printing the hinges (minimum 0,1 micron accuracy), i have to glue thin pieces of superelastic nitinol or springy steelfoil as hinges, or i apply the spherical magnets, what is much easier ...

I must buy the motors either, so why not 12$ more for the magnets?

The stiffnes of the tripod-rods i can guarantee with inserted and overmolded sticks, so the only actually not reprable parts are the motors, the electronic and the connectors ...

Ciao, Viktor

Edited 1 time(s). Last edit at 09/24/2007 01:18AM by Viktor Dirks.

For those of us who can barely follow... where is this research heading? Are you thinking of putting the extruder on this tripod assembly?

Just curious, as I saw your video on the blog...

Hi RoundSparrow,

... with the Tripod i'll try to develop a sort of easy to assemble 'micro-reprap' with much higher accuracy, as achievable with a FDM-extruder.

With the magnetic joints and the parallel kinematics i only need three linear drives as showed in my setup, six rods, two plates for fixing the drives and a third plate for the toolhead (plus some screws and glue for fixing)

As the size is scalable up and down freely, i can design a much smaller setup (and a very big one for buildung furniture or so too ), so it's possible too to make a sort of 'Tripod-toolhead', which sits as tool in my cartesian 3D-cnc-mill ...

My primary goal is to make very small and accurate parts from pastes i mix from glass- or ceramic-powder (and other materials too) with different fluids.

In my first experiments with glass- or gold-powder in dexpanthenol+water i extrude/dispense much smaller trays and dropplets as possible with the FDM-head - i achieved trays with 0,1 mm width and single droplets of maybe 50 microns with a syringe and nearly 20 microns with a dip-pen-dispenser.

By heating the paste with a diode-laser i dried the solvent away and then melted the powder to solid.

With the gold-paste i managed fixing and contacting of 1-micron-diameter platinum-wires on goldpads for a very precise gas-temp-sensor.

With the glass-paste (and later some ceramic-pastes) i want to fab the body of sensors - when i can in the same process (but with two syringes filled with ceramic- and gold-paste and a diode-laser-head for sintering) build the rigid sensor-body and interlayer gold-wires and vias, then it's running right

***
In another developing-path i'll insert only the diode-laser in the head and layer (or roll as in a lathe-setup) many plastic-sheets on the basis-plate (or -axis), where i cut sheetwise the contours and separating-lines - so with glue-stacking all the sheets to a solid block i'll have a LOM-body (LOM=Laminated Object Modelling/Manufacturing) with the inlaying 3D-object(s) - i only have to brake the outer volume off to 'free' the objects

The LOM-approach is very much faster then normal extruding, as i only have to process the outlines and some separating lines, not every point of the 3D-object ...

***
And a third possible path is the inserting of a normal ink-jet-printhead and either print with a glue-solvent on a powder-surface as in Z-corp 3D-printers, or only print the contours and separating lines (as in the LOM) with salt-water and heat the powder-surface until it melts, so i'll have a solidified and more rigid body, as in powder-glueing ...

Viktor

Edited 1 time(s). Last edit at 11/20/2007 01:39AM by Viktor Dirks.

... as I've stumbled over this Thread from 28 years ago, here some maybe interesting "update"

Some of the ideas and concepts, mentioned here, were developed for R&D-projects in/for my day-jobs.

Actually I'm starting another R&D for "laser-multimaterial-micro/nano-3D-pronting" with a sort of laser-thermotransfer approach, where I'm transferring super thin sheets of all sorts of materials (plastic, ceramic, metall, ...) on any sort of surface ... either "pure" or intermixed materials for more complex structures.

Her two smaple images - a test with copper with resultet sheet "thicknesses"from some nanometers to some microns ... or conducting traces on different surfaces (glass, plastic, paper):







Or black ceramic on a 20x20mm tile:








Or a demonstrator sample of a LOM-approach:

---

Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]