Hi Gary,
The present IPC-2222A states the following:
10.1.1 Edge Spacing Except for edge printed board contacts, the minimum distance between conductive surfaces and the edge
of the finished printed board, or a NPTH, shall not be less than the minimum spacing specified in Table 6-1 of IPC-2221 plus
0.4 mm [0.0157]. Printed boards that slide into guides shall have a minimum external conductor to guide distance of 1.25 mm
[0.0492 in] or minimum electrical clearance (see Table 6-1 of IPC-2221), whichever is greater. Special design applications in
areas such as high voltage, surface mount, and radio frequency (RF) technology may require variances to these requirements.
Ground and heat sink planes may extend to the edge when required by design.
The design should provide sufficient edge spacing to avoid unnecessary haloing and crazing rejections. Rejections can occur
when the edge defect is greater than 50% of the clearance to edge spacing. Brittle material or heavier glass weights increase this
risk.
The fabricator can do this, but from a design point of view we worry about edge defects the can impact the assembly performance.
Dieter
-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Gary Koven
Sent: Tuesday, February 26, 2013 9:10 AM
To: DesignerCouncil
Subject: [DC] Edge spacing
We design small form factor PCBs with board edge to copper spacing typically 0.25mm (0.010").
Thus far, no fabricator, whether our American prototype or our Asia Pacific production, has indicated this distance is a problem. Online prototype shops such as Advanced Circuits specify this distance as their minimum.
Which IPC document addresses minimum edge spacing? My copy of IPC-2222 is 15 years old,and I was not able to find this information in any other IPC specs on hand.
TIA and Best Regards,
Gary M. Koven, C.I.D.
InVue Security Products
Charlotte, NC, USA
Board Of Directors, RTP Chapter
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