John
Yes have some knowledge, but from a long time ago (>15 years) so I expect
things have moved on considerably.
Back then we used CO2 lasers for ceramic cutting and scribing. Most of the
organic electronic substrates we did were emergency jobs (PCBs populated
before anyone noticed the scoring/break outs had not been done, v scoring
not deep enough. That sort of thing.)
CO2 worked well, you need quite a big poke to ensure the laminate is turned
directly to plasma and not charred, also plenty air to cool board. Pulse
rate is slowed compared to ceramic for same reason. The process window was
quite small and needed care to set and keep. Thinner FR4 was fine , over 60
thou/ 1.5mm was a challenge with our gear and we nearly always declined or
proceeded on best effort basis. Eximer or ablation laser would have been
better but back then was too slow to be economical. On all laminate types we
would not cut tracking.
Dimensionally we often found - certainly on larger boards and especially
polyimide and non-woven boards like Rogers, that the substrates were not to
drawing (Gerber) and had to be set by hand. For example, on shallow V
routing we nearly always asked "Do you want the scribe positioned at the
bottom of the V or to spec?" But really that was showing off.

Hope this helps a bit.

---


Regards


Mike Fenner
M: +44 [0] 7810 526 317

www.chrisfennerfund.org 
www.facebook.com/chrisfennerfund/ 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of John Burke
Sent: Monday, September 19, 2016 7:37 PM
To: [log in to unmask]
Subject: [TN] Routing

Hi guys,

Discussion came up on removal of routing dust particularly under BGA's what
is best practice?

Also does anyone have experience of laser de-paneling ??

Best regards,

John Burke