Thanks for comments. 
IPC-6012C 3.10.12  have defined that the unsupported component hole land shall withstand 2kg or 35 kg/cm2, whichever is less. I think it is too lower. 
What about SMT land? Normally, which value shall withstand if tested in accordance with IPC-TM-650 2.4.8?

 
RongJun Deng
Electronics Engineer
Design Link
BB Electronics (Suzhou) Co., Ltd., EMS - from idea to solution

Block E, No.58 Yangdong Road, Loufeng, Suzhou Industrial Park- 215122 Suzhou - P.R.China
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-----Original Message-----
From: Chris Mahanna [mailto:[log in to unmask]] 
Sent: Thursday, October 01, 2015 12:06 AM
To: TechNet E-Mail Forum <[log in to unmask]>; Deng RongJun <[log in to unmask]>
Subject: RE: Land bond strength on rigid board

The IPC SMT land bond strength test method was cancelled due to
1) uncertainty of the method
2) ultimate tensile strength doesn't model the actual failure mode risks very well

Note that:
2.4.1 has much lower uncertainty because it provides a circular land, with hole to build ideal attachment geometry.
Ultimate tensile is not useless data, but peel strength (IPC-TM-650 2.4.8) is generally considered a better model of foil adhesion to laminate.

Chris Mahanna
Robisan Laboratory Inc.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Deng RongJun
Sent: Monday, September 28, 2015 6:45 AM
To: [log in to unmask]
Subject: [TN] Land bond strength on rigid board

Hi Experts:

Is there have a standard for SMT Land bond strength test? What about the formula for force calculation?
Can I use “IPC-TM-650 2.4.21 Land Bond Strength, Unsupported Component Hole” for reference?




Best regards

RongJun Deng
Electronics Engineer
Design Link




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