From what I know, too major players are involved in hole counter mfg.
They come from Japan.  You'll find them in every large scale expo.
These tools are very reliable and can verify from 0.2 to 5.3 mm ( 8 mils
to 0,200" ).   They are typically precise at +/- 0.001".   However,
you'll have to deal with your absolute reference and  the hole condition
including the surface finishes.   The bright side of it...  it can
verify up to 40 000 holes per panel  in few seconds.

P.S.:  They can also check hole positioning in +/- 0.001"  but it take
more time.

How it works ?    It measures uninterrupted light qty, define a surface
and finally calculates the diameter based on a well known equation.

Regards,



Michel Poulin
Technical advisor / Conseiller Technique
Circo Craft Co. ( Division of Viasystems Group )
379 Brignon Granby,  Quebec  (Canada) J2G 8N5
Tel.: ( 514 )  378-0193,       FAX:  ( 514 ) 378-5110
E-m a i l :  M i c h e l . p o u l i n @ c i r c o . c o m

> ----------
> From:         drilbert[SMTP:[log in to unmask]]
> Reply To:     TechNet Mail Forum.;drilbert
> Sent:         Saturday, September 13, 1997 3:47 PM
> To:   [log in to unmask]
> Subject:      Re: [TECHNET] Hole counting equipment
>
> I am looking for information on equipment that can optically
> verify/count holes after drill.  Does reliable equipment exist?  How
> does it work?
>
> Drilbert
>
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