Looking at the picture, you may first want to do a soft clearance of mask a bit beyond the desired cut with milder parameters and then cut with higher laser parameters within the already cleared path. You will need to optimize your parameters for both passes. This is one possible solution. At our center, we have three lasers with different capabilities. We have been able to find adequate parameters for no-char clean patterning of soft (e.g., Mylar, polyimide) and hard materials (e.g., steel, diamond, sapphire) creating smooth edges.
Syed, NDSU/CNSE.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ed Popielarski
Sent: Tuesday, June 17, 2014 5:42 PM
To: [log in to unmask]
Subject: [TN] Laser depanelization

Hi all,

One of our aerospace customers is requesting boards depanelized from support frames.

I looked into router, but the conformal coating tends to smear and will be a significant FOD issue later.

We are willing to invest in laser, however, the result is a bit of charring on the edge, not much of a surprise. Unfortunately, this example http://stevezeva.homestead.com/Capture.JPG was rejected on IPC-A-610-Rev E Para. 10.7.4 "Solder Mask Coating-Discoloration" "Burned or charred solder mask material.

In my opinion, this is not within the "spirit of the law" since there are no specific provisions for laser depanelization, only marking.

Anyone know of some way around this?

Ed Popielarski
Engineering Manager

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