Do you have something on your board like pin-in-paste forcing you to a 6 mil stencil?  If not, just use a straight 5 mil.  The 0.69 area ratio will work with 6 mil but I'd personally want more margin.  I use step downs as a last resort and it may not even be an option for you if your board wasn't designed with enough clearance from where the step wall will fall.  If you have to use a 6 mil and can't afford an electroform stencil then find a stencil supplier with a newer fiber laser.  You'll struggle to get consistent release through 11x34 mil apertures with a 6 mil cut from an old YAG laser.

Scott Post
Staff Manufacturing Engineer
P.O.U. 0000-001E-0CTC
2151 E. Lincoln Road
Kokomo, Indiana    46904-9005
765-451-2983 (Phone)
765-451-0287 (FAX)


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jean-Francois Bissonnette
Sent: Tuesday, April 19, 2011 8:55 AM
To: [log in to unmask]
Subject: [TN] Stencil Thickness

Hello Technetters,



We have to order a stencil and I'm not too sure what to do in this
situation.  I use IPC-7525A for selecting the stencil thickness.  While 99%+
of the components are way within the Laser Range, 6mil thickness, there is a
component which leads are 11mil x 34mil.  In the 6mil thickness chart, this
falls in the electroform range.  What I'm a risking if I still select laser
cut, 6 mil thickness?  What would you guys suggest?



Thanks to all!



JF



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