Homebrew PCBs

In a message dated 1/19/2003 4:29:47 PM Central Standard Time, 
twb8899@... writes:


> If you ever get the chance to watch one of these Excellon machines 
> run you will certainly be amazed. Try to watch even one hole being 
> drilled and ten more will be drilled before your eyes can focus on 
> one... these machines really scream.


Yes, Tom, I have SEEN a 4-quill drill stacks of 7-high blanks, and the "peck 
rate" was two to five holes per second (I am not an f-meter, myself, so I 
could not tell exactly how fast).  But I could have SWORN the quill-motors 
were air-driven.  Probably the operators had no clue, themselves!   
Definitely a mind-bending thing to watch!  $$$$!!!!!!!!!

High-F, huh?  Lessee, if 400 Hz. can make 24,000 RPM (woodworking machinery 
with which I had a tiny bit of hands-on), then 80,000 would require 1.33 kHz. 
"AC" 3-phase.  WOW!  Guess that's no big deal electronically, but the EMI 
must be SUMMIN to deal with!

Well, appreciate the info!             Jan Rowland


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