Thanks folks , been bit vague, sorry,
standard (whatever that stands for)laminate FR4 4layer 1/16 ,
mainland china via HK,
Yes the cracks are on the barrel rings (not a pad/track separation)
That is why i wonder if anybody would have a set routine,
say 2000 and change (for a particular board configuration )?
Or how is the "due" determined ?
From the fab side , am i on the right wavelength assuming blunt drill>coarse
wall>uneven plate would be the most common cause of cracked barrels ?
No high resin content (can see some 7-8 layers of glass from routed edge);
overcured laminate ? = harder ? ; aggressive desmear ? (now 'm definitely in
deep end)
thanks again paul
-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Friday, 7 January 2000 21:36
To: [log in to unmask]; [log in to unmask]
Subject: Re: [TN] Standard No. of via drill cycles
Paul,
Depending on the number of layers and aspect ratio of the product you are
drilling, most folks are getting 3 to 7 repoints and 1000 to 3000 hits
per use with small drills (.0210" - .0120"). All of this depends on what
level of positional accuracy, hole quality, and breakage the quality
departments of PCB manufactures can tolerate. As for utilization habits,
the US tends to be more aggressive in tool utilization in the drill room
than most other countries, however, when competing with countries that
have much lower wage and salary structures you can understand why.
A question that I raise is what is the substrate material that is giving
you cracking? There are several resin systems with higher Tg's that when
drilled aggressively tend to crack easily. Also, you mention uneven
barrel plating (rough holes). This can be a sign of over-cured material,
an aggressive desmear process, or a board design with a high resin
content.
Regards,
Mark Ford
On Fri, 7 Jan 2000 16:00:53 +1100 Paul Klasek <[log in to unmask]>
writes:
>Dear fab folks ;
>could you give me indication of "standard" No. of cycles on small via
>holes
>drill sizes ,
>on carbide and steel bits please ,
>and would there be a difference of utilization habits between say US
>and
>SEA/CHINA/SOB regions ?
>
>Facing patches of cracked vias , suspecting blunt drills > uneven
>barrel
>plate .
>
>And class 3 , is there via fill (solder) mandatory ?
>
>Thanks a lot
>
>Paul Klasek
>ResMed
>
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