We have the same clearance standards here.  I don't know why, but it's required by our manufacturing engineers to keep 15 mils away from NPT holes.

-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]]On Behalf Of ert
ert
Sent: Thursday, February 22, 2007 5:02 AM
To: [log in to unmask]
Subject: [DC] NPTH to copper/trace clearance


I got a mail from my FAB house to increase the NPTH - copper/t
Hi All,

I got a mail from my FAB house to increase the NPTH - copper/trace clearance from 0.010 inch to 0.015 inch for a NPTH hole with drill size 0.150".When my drill hole is 0.150 inch with offset tolerance of +/- 0.003, i still have 0.004 inch safer value when i use 0.010 inch clearance value. When I questioned the FAB house i got feedback that its their DFM rule for maximizing the production yield. 

I am not satisfied with the answer, Can anyone help me understand why NPTH to copper/trace clearance should be much higher? 

thanks,
Raj.






		
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