For all those folks who were interested :
Motorola patent number : 5818005
According to my (sadly neglected) notes, this patent is for making
electrodes through isostatic pressing of graphite.
I'll add a caveat from personal experience: its harder than it looks and
getting the right binders is a pain(conductivity, viscosity.... its a
minefield). Also, you'll have issues with modeling geometry.
Before my research group dissolved, we were doing some wear analysis on
these tools as well as on electrodes produced from electroplated copper
shells. The copper shells behave far more predictably than compacted
graphite. I could send along my research notes and comparisons for those
who would like to continue down that path.
I would consider Dr. Brent Stucker of the University of Rhode Island to be
an authority on the subject of graphite-based EDM tooling. He has authored
some fascinating work, including a study of relative tool wear ratios for
different materials. Their "Zrykon" based solution looks most promising,
although it is really not the "mouldable" solution that Rick was looking
for when he started this thread.
Adios!
Peter
Phil Dickens
<pdickens@dmu To: proy@chennai.tcs.co.in, rp-ml@rapid.lpt.fi
.ac.uk> cc:
Subject: RE: Graphite powder
09/12/01
02:39 PM
Rick,
Sorry for late reply. I did get some verbal information on a mouldable
electrode material around 1991. I eventually tracked it down to a company
called Erodex here in the UK. http://www.erodex.com/main.htm
However, by the time I had contacted them around 1994 they said that they
no
longer did the material and it was very difficult to get hard information.
I
believe the guy that used to run the company was most knowledgeable. If you
have any luck I would be very interested.
Regards
Phill
Prof. P. M. Dickens
Dept. of Engineering & Technology
De Montfort University
The Gateway
Leicester
England LE1 9BH
Tel: +44 (0)116 257 7689
Fax: +44 (0)116 257 7025
Mobile: +44 (0)7768 827039
Email: pdickens@dmu.ac.uk
www.rmg.dmu.ac.uk
-----Original Message-----
From: proy@chennai.tcs.co.in [mailto:proy@chennai.tcs.co.in]
Sent: 12 September 2001 04:44
To: rp-ml@rapid.lpt.fi
Subject: Re: Graphite powder
Rick,
My research team worked on rapid tooling EDM electrodes for over a year.
We tried compaction methods for creating EDM tools from graphite powder,
with a little bit of polyvinyl alcohol thrown in as binder. Motorola does
hold a patent for a similar process (I'll send you the patent number if I
can lay my hands on it...).
Adios!
Peter
<snip>
Dear List,
Is it possible to mix graphite powder with any electric
conductive bonding material ? So that we can cast any shape out of this
powder and use it as an EDM electrode just an idea to get your views.
Regards,
Rick
<snip>
For more information about the rp-ml, see http://rapid.lpt.fi/rp-ml/
For more information about the rp-ml, see http://rapid.lpt.fi/rp-ml/
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