Thanks Inge
Yours is exactly the kind of thinking that is required to get us beyond the problems our poor beleaguered industry faces.
All of what you list are certainly candidates for inclusion in a future world of solderless assembly. I trust that you have sparked some new thinking here as well.
Best regards and wishes,
Joe
-----Original Message-----
From: Hfjord <[log in to unmask]>
To: 'TechNet E-Mail Forum' <[log in to unmask]>; [log in to unmask]
Sent: Tue, 26 Feb 2008 11:59 am
Subject: SV: [TN] Do it yourself Occam assembly
Joe, you should change name to Joy ! And found the company 'JoyToys', if not
lready established.
Right you are
anish will soldering
ome will else
Yoda)
But I don't think all soldering will be superseded by alternative methods.
Solderfree connecting has indeed existed for decades:
Thickfilm hybrids with conductive adhesives, as you pointed out.
Trillions of semi chips have been scrubbed to the header.
YAG laser spot welded components
Vacuum metal deposition
Plasma metallization
Plating technologies
Chemical metal joining
Electron beam spot welding
Beamlead welding
Amalgam technologies
Electric discharge welding
Friction welding
Wire bonding
Gold stud bumping
Ultrasonic technologies
Etc.
Who knows, maybe one of these technologies will be developed for mass
roduction of boards, or rather something that reminds of today's boards.
/Inge
-----Ursprungligt meddelande-----
rån: TechNet [mailto:[log in to unmask]] För Joe Fjelstad
kickat: den 26 februari 2008 18:49
ill: [log in to unmask]
mne: [TN] Do it yourself Occam assembly
Greetings folks,
have tried to sidestep most of the controversy associated with Occam and
solderless assembly as much as possible to focus on getting projects done.
However some controversy is, I suppose, good as it keeps interest alive. As
Yogi Berra might have noted: "If it wasn't controversial, everybody would
ot
top to avoid talking about it"... ;-)
o I thought it might be worth while to give everyone here a way to make
heir own Occam type assemblies using legacy through hole components at
heir
esk in a matter of minutes. This will allow folks to form their own
pinions
s to the fundamental viability of the concept for the future.
his is only for demonstration purposes but I trust it will open some
inds
o the possibilities that exist in the fundamental concept. The following
ill work for one or more metal layers but designs should be kept simple
or
ractical reasons.
) Obtain a piece of corregated cardboard box (Option: draw your
ircuit
ayout on the surface)
) Tape a piece of clear polyethylene (a half a common sandwich bag will
o) to the cardboard
) Place a second larger piece of card board underneath to keep the desk
or other surface clean
) Clip the leads down slightly (one can intuit for themselves how much
o clip off)
) Push the leads through the polyethylene into the card board at (the
olyethylene should seal the leads reasonably well but there might be some
mall leakage to the card board) Pin holes might be required as starters
or many
eaded devices. Shorter clipped leads will be easier.
) Cut a hole in another piece of cardboard that will encompass the
omponents and provide a resin dam wrap polyethylene around the exposed
dges
this step is optional depending on size of the assemlby)
) Mix up some 5 minute epoxy and pour over components (try not to get
oo many bubbles entrained)
) Remove the assembly and trim the leads as necessary
) Using a silver ink pen (available from some circuit equipment
roviders) draw your interconnections between contacts
0) If cross overs are required, use some nail polish at the
ntersection.
It can be used for cover coating if desired.
1) Attach battery and go have some fun. :-)
otes. 1) If you want to include connectors, have the mated portions in
hem in case some wicking occurs.
) Small batteries (or screw top battery holders) can be embedded if
esired.
) Dome switches are a low profile choice.
) A piece of 100 mil center "bread board" without plated through holes can
be used in place of the cardboard for greater placement accuracy if that is
of interest.
) The process will work for SMT devices as well but the devices need to be
kept flat and a sanding step will likely be required to clean off resin
rom
ontact surfaces.
) The conductivity of silver ink is about 10% of copper so stay away from
high power designs. (keep it simple)
his is obviously not a production technology but it does provide a simple
demonstration. I sent Steve Gregory a photo of a simple assembly for those
nterested to view what such a simple assembly looks like and he has kindly
consented to post it. Here is the link:
ttp://stevezeva.homestead.com/files/Through_hole_Occam_prototype.jpg .
t could also serve the needs of some hobbyists and could be a fun project
or anyone having children interested in electronics.
hile I appreciate the skepticism of those who question the potential of
olderless assembly, including many long time friends whom I respect and
old
ear. I trust that there will be some increase in acceptance of the concept
with the data that we are in the process of generating.
t may well be that the final versions of Occam assemblies will not look
ery much like today's assemblies. They could well appear to look more like
metal jacketed bricks with interconnections on the surfaces to which other
ssembly elements (keyboards, displays, etc.) can be joined using other
olderless
echniques such low profile connectors or conductive and/or anisotropic
onductive adhesives.
he brick like structure should also prove great for product design
ecurity. Remember when Apple announced the I-Phone last year? 3 days
ater there
as a public tear down of the product design an everyone could see what was
going on. It will be much more difficult with the solderless brick
pproach.
ortunately, wholesale change within the industry is not required for the
rocess as identified. The equipment, materials and chemistry exist for
very
rocess required. More importantly, there are some new materials and
rocesses on the horizon that appear extremely well suited to the
olderless
pproach.
nother point that needs to be addressed related to the process
nvironment.
number of folks have registered alarm or at least concern at the thought
f having plating equipment under the same roof as pick and place equipment
(or vise versa). To allay such concerns, one need only go to just about any
CB
hop in the world to see precision equipment (drills, lasers and imaging
quipment) under one roof with a plating shop. The process areas are
hysically
nd environmentally separated of course. The PCB industry has operated in
uch a fashion since the 1960s.
hanging topics, I found the following quote from a Test and Measurement
orld article from October of last year.
ttp://www.tmworld.com/article/CA6482921.html
In 1999, Stig Oresjo, then of Agilent Technologies, conducted a major
tudy
f solder-joint defects on printed-circuit boards (PCBs). The study, which
t the time provided the most definitive data on the subject, involved 15
ompanies and more than 1 billion solder joints. Oresjo concluded that
lthough
ompanies claimed defect levels in the range of 75 to 150 defects per
illion
pportunities (DPMO), the reality was 5 to 10 times that high."
n Oresjo's original study, he found the following defect distribution:
) 41% Solder Opens
) 20% Shorts
) 20% Solder Quality
) 8% Placement
) 8% Electrical
) 3% Other
t appears that almost 80% of the problems are related to soldering (90% if
the 8% for placement is included but I am sure it is much better these
ays.)
he 8% electrical problems cited are, I assume, parts related problems of
nspecified cause.
hile on the subject of electrical failures, does anyone here have any data
on how many components are damaged by the temperatures associated with the
soldering process? Also how many of the electrical failures might have been
caused by poor cleaning? I have heard a lot of anecdotal information but no
hard facts. I guess I am wondering, has there been an identified and
easured
ffect of the lead-free assembly on first pass product assembly yield
ompared
o tin-lead solder?
would prefer an open forum answer to these questions but I realize that
here might be some discomfort so if anyone prefers to respond off line,
hat
s fine. Thanks in advance for any input on the topic.
est wishes to all and have some fun with the table top solderless
ssembly...
oe
**************Ideas to please picky eaters. Watch video on AOL Living.
http://living.aol.com/video/how-to-please-your-picky-eater/rachel-campos-du
fy/
050827?NCID=aolcmp00300000002598)
---------------------------------------------------
echnet Mail List provided as a service by IPC using LISTSERV 15.0
o unsubscribe, send a message to [log in to unmask] with following text in
he BODY (NOT the subject field): SIGNOFF Technet
o temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
o receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
earch the archives of previous posts at: http://listserv.ipc.org/archives
lease visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
or additional information, or contact Keach Sasamori at [log in to unmask] or
47-615-7100 ext.2815
----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
|
