Pictures and Video from the production
The production took place on 28th, 29th and 30th of April 2003 at a contractor of individual Computers. Since the pictures and especially the video take up quite a bit of webspace, we might
remove them shortly. If you like them, please download and keep them on your harddrive. Use by the press is explicitly allowed if you mention the source.
Jeri is a little camera shy :-)
before we even started, I took a close look at the circuit boards to check
if they have been properly tested. I've had problems before with boards
that came as "electrically tested", but still with a 4-6% failure rate,
which is typical for untested boards. Since there's a lot of valuable parts
on the C-One, I did not want to take any risk, and searched for the needle
prints of the electrical test adapter with a microscope. The picture shows
a section of the FPGA pads, which have a distance of 0.5mm (about 1/50th of
an inch). The needle prints are easy to see.
Prior to SMD placement, the SMD solderpaste is "printed" on the board.
Think of the solderpaste as viscous solder. It stays in shape after the
mask is removed, and it's (of course) only on the SMD pads. The mask is
0.15mm thin sheet metal, and the holes are lasered into it, which is
currently the most precise method of making such a mask. Many people still
think that etching the mask is state-of-the-art, but laser is a lot more
precise, faster, and about the same price.
The non-vision machine places all 0805 parts (ferrites and capacitors),
Tantalums, PLCC sockets and SO-ICs. This is a view from the back with all
the part feeders. Precision of this machine is about 0.25mm (1/100th of an
inch) due to possible shifts of the baord itself, which cannot be
recognized without a vision system. It would be possible to place 0603
parts with this thing, but the robot head is equipped with a nozzle that
can also carry heavy parts like PLCC chips and big tantlums. This nozzle
would swallow the small 0603 parts with the vacuum.
This is the robot arm of the vision machine. The arm uses a nozzle that can
be exchanged automatically, without manual interaction. This way, 0603
parts and the heavy FPGAs can be placed without interruptions. The camera
module, pickup-nozzle and centering/checking clamps are easy to see. The
centering clamps are also used for an identificatrion of the part:
Resistors and capacitors are checked for the right value "on the fly", and
if the part has the wrong value, it's dropped in the "bad ID" box. About
one out of 1000 resistors has the wrong value, so this ensures production
The "critical parts" like QFP208 and TQFP100 are aligned with the fixed
vision camera. This is a picture of the monitor that watches the part from
the bottom and recognizes it's shift/rotate alignment before it is placed
on the board. The board shift itself has been measured before with the
flying vision camera on the robot arm. Precision of the vision machine is
better than 0.05mm.
after the "small machine" has placed the "uncritical" parts, the
half-assembled board is placed in the vision machine. The picture shows the
machine near the end of the program, where the second FPGA is about to be
After SMD placement, the board is run through the "pizza street", the
reflow-oven. Hot air is used to solder all parts at the same time. The
temperature curve can be adjusted precisely in five zones, as the last
After manual placement of the through-hole parts (connectors, slots and pin
headers), the whole board is run over the wave solder. Liquid solder is
pumped from the bottom against the board. The soldering process itself only
takes a few seconds, but the board must run over the flux foam and the
pre-heat area of the machine, which takes about a minute. Still a very good
time, given the fact that it's a few hundred solder points on the C-One!
To all of you who are worried about the space for the second PCI: The
drills have been protected against soldering before the board has been run
through the machine, so a second PCI can be added without special equipment
- if this will ever be necessary :-)
Before the board is fired up the first time, all critical solderjoints are
inspected under a microscope. The picture shows the side of the most
critical parts, the FPGAs in QFP208 package. You see a perfect placement
and errorfree soldering. This is not always the case, sometimes
solderbridges have to be removed manually.
This picture shows the board and the two spots that require manual SMD
rework. The additional 10K resistor near the FPGA ensures safe startup of
the EP1K100, and the additional 3k3 resistor above the CPU is responsible
for startup of the whole computer (ATX power-on circuit).
final_board.jpg (caution: 436K!)
Same picture as above, but without the microscope add-ins and the whole
board. Found all the easter eggs ;-)?
vision_working.mpg (caution: 3.9M video!)
This is a small video of the vision machine working. After I push the
"start" button, the machine starts looking for three vision points on the
board to determine it's position and rotation (You can see the end of this
step when the light on the flying camera goes off). The video is about
three minute long, and does NOT show the full run of the program (that was
nearly 5 minutes). To be honest, it's quite boring to see the machine run
at it's 50-parts-per-minute beat, especially when you've heard the noises
of two machines in the same room continuously for three days in a row.