Re: DRO - multiple items
Posted by
beer@s...
on 2000-04-07 10:57:00 UTC
Bertho Boman wrote:
output detectors. The more common detectors are digital output, and so
alignment is best determined with a storage scope, checking for state
changes 90 degrees out of phase channel to channel.
John Elson wrote:
but wanted forty bucks to do it. What I would get would be a sheet
12" x 18" that I could cut into smaller strips. This would be fine for
my little machine, but still more money than I wanted to spend on a
"maybe".
My idea was to build my own decoders and just space them accordingly,
using a fine thread to move just one of the decoders until it was in
position.
Another possibility for "films" are companies that make solder paste
masks. I don't know how fine a line they can laser etch, but it must
be pretty small.
In a recent conversation with some of the Boeing folks, they showed me
an IC manufactured by IBM (?). It LOOKED at first glance like an RF
amplifier, a little square thing with four flat leads out the side.
Closer observation showed some moire effect from the leads - like the
four leads were silvered mylar or something. CLOSE observation under
a microscope showed the thing was actually a quad flat pack, with
leads and spaces about .001" in width ! The comment was that the can
make it, they can place it, and they can even solder it.
That means that they must have paste masks pretty fine.
( Fine for production , but pity the poor rework guy ! )
Alan
--
Alan Rothenbush | The Spartans do not ask the number of the
Academic Computing Services | enemy, only where they are.
Simon Fraser University |
Burnaby, B.C., Canada | Agix of Sparta
> For the quadrature decoders, each should be adjusted for best alignment (largest analog signal swing on a scope) and then the 90I think that this alignment strategy would be most useful for analog
> degree phase adjusted while watching that the "lines" alignment is not lost.
output detectors. The more common detectors are digital output, and so
alignment is best determined with a storage scope, checking for state
changes 90 degrees out of phase channel to channel.
John Elson wrote:
>Really, if someone can come up with accurate grating patterns on film orMy local PCB manufacturer volunteered to print me some 500 line films,
>glass, it is fairly
>easy to make your own linear encoder. Does anyone have any ideas on
>where to get
>such grating patterns?
but wanted forty bucks to do it. What I would get would be a sheet
12" x 18" that I could cut into smaller strips. This would be fine for
my little machine, but still more money than I wanted to spend on a
"maybe".
My idea was to build my own decoders and just space them accordingly,
using a fine thread to move just one of the decoders until it was in
position.
Another possibility for "films" are companies that make solder paste
masks. I don't know how fine a line they can laser etch, but it must
be pretty small.
In a recent conversation with some of the Boeing folks, they showed me
an IC manufactured by IBM (?). It LOOKED at first glance like an RF
amplifier, a little square thing with four flat leads out the side.
Closer observation showed some moire effect from the leads - like the
four leads were silvered mylar or something. CLOSE observation under
a microscope showed the thing was actually a quad flat pack, with
leads and spaces about .001" in width ! The comment was that the can
make it, they can place it, and they can even solder it.
That means that they must have paste masks pretty fine.
( Fine for production , but pity the poor rework guy ! )
Alan
--
Alan Rothenbush | The Spartans do not ask the number of the
Academic Computing Services | enemy, only where they are.
Simon Fraser University |
Burnaby, B.C., Canada | Agix of Sparta