From shott at stanford.edu  Wed Mar 10 19:10:43 2010
From: shott at stanford.edu (John Shott)
Date: Wed, 10 Mar 2010 19:10:43 -0800
Subject: Probe station status ...
Message-ID: <4B985F33.9020504@stanford.edu>

EE410 and other Micromanipulator 6000 users:

It was brought to my attention that the Z-axis (up/down motion of the 
stage) had "gotten frozen".  I was able to salvage our one 
quasi-functional brass threaded piece that controls this motion.  
Micromanipulator has not had these in stock for 25 years.  The last 3 
that we had were custom machined for us.  In fact, since the last new 
one that I had was put into service just before EE 410 started, I 
haven't even been able to get over to the Physics Machine Shop to get 
them to make a half-dozen more of them for us.

Here are a couple reminders:

If turning the Up/Down knob seems hard, quit turning it!   Someone 
really was forcing this thing to damage the brass piece this badly.  In 
the 35 years that we've had this tool, I've never seen both the internal 
AND the external brass threads damaged. (I can usually rebuild the 
Z-motion in about 2 hours ... this time it was so badly jammed that it 
took me 4 hours.)

The stage height when the lever is down should always be well within the 
upper and lower range marked with tape near the lever and should never 
be far from the optimum height.

I also put four brand new probe tips and adjusted them for proper 
height. I think that four new ones may have been put on yesterday ... 
and somebody had already bent them so that they had a 30 degree kink in 
the shaft.  The height of the probe can always be adjusted with a 0.035" 
hex key ... there is never a valid reason to bend the probes.

As of this moment, the probe station is behaving very nicely.  Please be 
gentle with it ... there are still a few days of around-the-clock 
testing before EE 410 is complete.  Lots of folks will be inconvenienced 
if this is mangled again between now and then.

Thank you for your continued support,

John



From shott at stanford.edu  Fri Mar 12 08:41:58 2010
From: shott at stanford.edu (John Shott)
Date: Fri, 12 Mar 2010 08:41:58 -0800
Subject: Move the up/down knob slowly ...
Message-ID: <4B9A6ED6.1030004@stanford.edu>

Micromanipulator 6000 Community:

Because of heavy damage on the threaded brass piece, when we re-assembled 
the system up/down system, we lowered part of the assembly to take advantage of a region 
of less-damaged threads.  This, however, slightly misaligns the nylon 
belts that connect the up/down knob to the actual part that controls the 
motion.

Please turn this knob slowly when moving the stage up/down.  If you turn 
it quickly, the nylon belt will be thrown off of the drive pulleys and 
will no longer control the up/down motion of the stage.

Thanks for your continued support,

John

p.s. We are having 5 new brass pieces machined for us at the Physics 
Machine Shop.  Those will not be available until late next week.  Until 
they are available, we have no alternative to trying to treat this 
system gently.



From shott at stanford.edu  Wed Mar 31 16:25:24 2010
From: shott at stanford.edu (John Shott)
Date: Wed, 31 Mar 2010 16:25:24 -0700
Subject: Smooth Z-axis motion ....
Message-ID: <4BB3D9E4.4020505@stanford.edu>

Probing community:

I've replaced the damaged brass threaded piece that controls the vertical position of the stage with a newly machined piece.  The vertical axis now works very nicely and the probes have been adjusted so that the probe stage can be in the middle of the "sweet spot" as indicated by the tape on the left near the left lever.

If you think you need to move the chuck height beyond this range ... DON'T!  If you think that you need to bend a probe tip .... DON'T!  If you think that you need to do either of these things, you may  not fully understand the full range of adjustment on this probe station.  Ask me and I'll gladly refresh your memory.

Thanks,
John