.....and some micro-soldering kit to attach the plated unit to the lead
frame. Our factory used homemade hot air jets, I have no idea what the
solder was prob LMP.
Lapping a single blank is difficult, one tends to get rounded edges(even
with the best machine) which affect the activity. See the video, they are
lapping several at the same time. The unplated blanks are put into a skelton
holder and measured and the most promising one proceded with. First an
evaporated contact to fix the blank to the lead frame. Then electrode
evaporation which brings the frequency down, so the final stage evaporates
electrode while measuring the mounted crystal frequency. Allowances need to
be made for the can.
I doubt most small modern firms would have a X-ray goniometer (?) The one I
saw in the 60s would never pass H&S criteria now. They probably buy cut
blanks in bulk, I think they are relatively cheap this way. My supplier in
the 90s did this.
The whole job is quite labour intensive, making a single crystal might
easily eat $1000 worth of manhours for an amateur, not even allowing for the
occasional "oops".
:-))
Alan
G3NYK
----- Original Message -----
From: "Attila Kinali" <[email protected]>
To: "Discussion of precise time and frequency measurement"
<[email protected]>
Sent: Monday, March 13, 2017 7:56 PM
Subject: Re: [time-nuts] Bye-Bye Crystals
On Mon, 13 Mar 2017 15:01:39 +0000
Adrian Godwin <[email protected]> wrote:
What minimal equipment would you need to make your own crystals ?
The equipment is quite minimal:
* A diamond precision saw to cut the crystals
* Some tool to check the accuracy of the cut (orientation and thicknes)
* a lapping/grinding machine
* an electroplating machine (usually sputtering) for the electrodes.
* either some machine to produce the crystal holder yourself or buy them
* vacuum system to evacuate the crystal holder and to bake everything
* something to (cold) weld the case close
All of this can be put in a (relatively) small workshop.
The difficulty is also not producing quartz crystals
in holders. The difficulty controlling the whole process
to such an degree that you get high quality crystals
at the frequency you want.
If you managed to do that, you can further improve
your system by using a BVA[1,2] like geometry, where
the electrodes are not on the resonator itself but
on the surrounding crystal, which acts at the same
time as holder.
But be warned, many attempted to re-create the BVAs
but few succeeded... and none but Oscilloquartz ever
managed to produce a economically viable product.
Attila Kinali
[1] http://www.nature.com/articles/srep02132/figures/1
[2] http://www.nature.com/articles/srep02132/figures/2
--
It is upon moral qualities that a society is ultimately founded. All
the prosperity and technological sophistication in the world is of no
use without that foundation.
-- Miss Matheson, The Diamond Age, Neil Stephenson
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