Dear All of You
I thank you for the answers I got from you last time I wrote a questian
about electrosetting. I tried to get Ronald Reitz E-mail adress from
David-Taylor Research center, but I recieved no answer. Since then I
haven´t spent so much time wondering about the secrets of electrosetting,
but today I was looking through my papers to get a picture about how the
process is working (...I was going to write about electrosetting and was
realizing that I still hadn´t a clue of how it worked). Beneth I have
attached the two sourches I have about the process.
Unfortunately they don´t give me a very clear picture of how the system is
(will be continued after the sources)
"As in commercial rapid prototyping systems, the technique divides parts to
be fabricated into numerous thin cross sections. A desktop computer uses a
laser printer to print out electrodes in the shape of each cross section.
These electrodes are stacked in an array with eighth-inch spaces between.
The stacked array is then immersed in a bath of electroset resin. On
application of electric power, electroset fluid within the electric field
solidifies. Fluid outside the field remains fluid. As the electrode array
is pulled from the bath, the electrically solidified portion of resin stays
within the array while the nonelectrified portion pours off.
The electric field is maintained until the resin hardens permanently,
usually within about an hour. Then the field goes off and the water-soluble
paper electrodes are removed in a water bath.
One strength of the process is that it can produce thick layers of material
fast. But the Navy, which holds the patents for the technique, never took
the idea much beyond a feasibility study. Right now, electrodes are printed
out and stacked by hand rather than automatically by computer. And you
wouldn't want to use this method if you needed tolerances within about 5
mils, says Reitz. There is no problem controlling tolerances to within a
few mils in the plane of the electrodes. But edge effects associated with
the electric fields cause variations in the plane perpendicular to the
plane of the electrodes."
"This system consists of a personal computer, an electrode printer, and a
high-voltage power supply. All of this equipment is readily available. The
personal computer must have a graphics system. "The electrode printer may
be a plotter that has specially adapted pens and ink for making the
electrode design, or it may be a laser jet printer or even a copier
machine. The high-voltage power supply preferably should be capable of
delivering up to 5 kilovolts and 50 milliamps of DC power."
This process takes several steps. First, a cross section of the object is
generated on the computer. The computer then sends the image to the printer
where the electrodes are formed into the shape of the image and attached to
a frame (the frame is a sheet of conductive material such as aluminum
foil). When all frames are complete, they are sandwiched into a mold, which
is connected to a power supply. The mold is immersed into a bath of
Electroset fluid and energized. Upon energizing, the fluid between the
electrodes solidifies. The mold is withdrawn from the bath and excess fluid
drains from the object. After trimming off the mold framing, the part is
The things I dont´t get are:
* How do one print electrodes on paper?
* How is the layerarray arranged?
* How and where is the power applied?
* How can you dissolve the papers? -shouldn´t they get trapped in the object?
If you understand this better than I, please let me know
431 67 Mölndal
tel 031-16 04 87 el. 070-602 60 58
This archive was generated by hypermail 2.1.2 : Tue Jun 05 2001 - 22:40:47 EEST