[Robotgroup] Ferrocement Plotters (Was Menage a Tux)

[brooksdesign]

   Eggggselent...most of my tests with cement were done with all cement deposited in layers with water deposited in lines and dots just to see how it spread....Answer: too much. I made some small test walls (1ft X 1ft with 1inch lines) but quickly changed to using cedar sawdust (which I had about 2 dumptruck loads of from my column and balostrate milling operations)and made some only slightly better tests with the renewed idea of making furniture and sculpture with layers of sawdust patterned with glue.The glue would form pathways down thru the sawdust and collect on the bottom without bonding to much. No failures, just successfully finding ways that don't work :(
  Your seperate dry powders with wet cure sounds much better.Have you developed any test nossels for laying down the seperate matireals? If not I would like to help in the mechanicles as that is my main focus in roboland. I do alot of pnumatic actuation creations and have thought about a system that uses air power to move the dry cement thru a tube to the robot but uses a seperation chamber over a vibrating hopper/siv to apply it so as not to blow the other matireals out of place. Maybe even a wire feed with a chopper on the same bot that inserts them at the same time.That way you never have to stop the bot to reload.
-brooks  

-----Original Message-----
>From: Bruce Waters <biwaters at austin.rr.com>
>Sent: Feb 6, 2008 10:51 PM
>To: robotgroup at puremagic.com
>Subject: [Robotgroup] Ferrocement Plotters (Was Menage a Tux)
>
>brooks,
>http://createthefuturecontest.com/pages/view/entriesdetail.html?entryID=977
>has some additional info on my intentions to create a crew of ferrocement
>plotters as a Rapid Manufacturing (RM like rapid prototyping but full scale)
>technique for architectural objects such as single family dwellings and
>other
>low profile structures.
>
>A crew of plotter vehicles of different sizes and resolution capabilities
>would
>lay down layer upon layer of dry mortar mix (no aggregate) where there
>should
>be structure and dry sand where there will eventually be voids.   These
>mobile
>bots will travel directly on the surface of the previously plotted layers on
>low
>disruption (perhaps large rubber tires with no tread)  plotting subsequent
>layers.
>Every layer plotted will completely tile the plane (no voids remaining.)
>Automatic wire feed-and-cut bots will insert short, fine wires into the dry
>mortar mix to create the steel mesh within the ferrocement.   Each inserted
>wire segment would be injected into previously plotted layers with no part
>sticking out of those layers.   There is no need to interconnect these wire
>segments.
>
>After all patterened layers are completed, additional sand will be piled-on
>to the mound to compact the dry materials.   Soaker hoses or fine misters
>would wet down the entire mound to cure the ferrocement within the mound
>of sand.   The mound will be kept wet for a month or two to allow curing
>of the cement.   Front end loader bots, air blower bots, and power washer
>bots will remove the sand at the end of the curing period.
>
>This technique does not involve gantries so there is not a fixed limit to
>the area covered by the structure.   The vertical dimension is limited by
>the huge volume of dry sand required for structures of significant height
>since the mound should taper to the ground surface unless a wall is used
>to restrain the dry materal from collapsing on the periphery.   Tall objects
>might be manufactured horizontally and raised after cured.
>
>One type of plotter bot could fit in a cube four feet on a side.   It might
>have  a beer keg sized cement mixer style dry material feed drum with
>a small internal spiral to feed material in a controlled manner down chutes
>to the plotting area.  A vertically mounted laser rangefinder might measure
>the material deposited.   Two laser rangefinders pointing forward from
>either side of the vehicle and another pointing to one side could easily
>keep the vehicle travelling in a straight line indexed precisely to each
>subsequent stripe of material deposited.    Two sides of the work area
>would have a reflector surface for precise distance measurement with
>the laser rangefinders.
>
>All plotterbots would have wifi communication with the command
>and control server.   Some bots might be as large as a real cement
>mixer for depositing huge amounts of plain dry sand in large areas
>which have very coarse resolution.  Some bots might carry expensive
>laser rangefinder(s) and be capable of very high resolution plotting.
>Other bots might have simple, cheap sensors to track breadcrumbs
>(figurative) left by the more capable bots.   One extreme might be
>a line follower bot with wheel encoders laying down the next stripe
>of material just behind a high dollar sensor bot.
>
>One mental model of a crew in action might be a lidar bot followed
>by a number of same sized line-follower bots each laying down the
>next stripe.  The bots would travel in a moving oval over the work
>site depositing material one after another until a layer is complete.
>More practical crews might have a spectrum of sizes, resolutions,
>sensor capabilities with more complicated paths based on the
>variation of the data across the active area.   Other models might
>have the same appearance as diagonal lines of agricultural harvest
>machines in action.
>
>The active area must be protected from moisture and wind during
>plotting so a fan-inflated plastic film tent could be used to provide
>this protection.   These techniques should radically reduce the labor
>required to build a residence and greatly increase the flexibility of
>design by going directly from a CAD description of the structure
>to the actual item.   Pick and place robots should also be employed
>to embed items of small vertical extent (horizontal pipes, wires,
>anchor bolts, ....) as construction proceeds.
>
>Bruce Waters
>
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