Figure 10-33 is an example of bow.
Acceptable – Class 1,2,3 • Bow and twist does not cause damage during post solder
assembly operations or end use. Consider ‘‘Form, Fit and Function’’ and product reliability.
Defect – Class 1,2,3 • Bow and twists causes damage during post solder assem-
bly operations or end use or affects form, fit or function.
Note: Bow and twist after solder should not exceed 1.5 for through-hole and 0.75 for surface mount printed board
applications. IPC-TM-650 has Test Method 2.4.22 but this is specifically for bare boards. Component size and placement
on assemblies often precludes use of that test method for populated assemblies. It may be necessary to confirm through
testing that bow and twist has not created stress that will result in solder connection fracture, component damage or
will otherwise cause damage during post solder assembly operations or use.
Figure 10-33
2 1
1 2
3
A B
C
Figure 10-34
1. Bow 2. Points A, B and C are touching base
3. Twist
10.2.7 Laminate Conditions – Bow and Twist
10-15 IPC-A-610F
July 2014
These criteria are applicable to PCAs with or without breakaway tabs. IPC-A-600 provides additional criteria for depanelization of bare boards.
Target – Class 1,2,3 • Edges are smooth with no burrs, nicks or haloing.
Acceptable – Class 1,2,3 • Edges are rough but not frayed.
• Nicks or routing do not exceed 50 of the distance from the board edge to the nearest conductor or 2.5 mm [0.1 in],
whichever is less. See 10.2.4 for haloing and 10.2.1 for crazing.
• Loose burrs do not affect fit, form or function.
Figure 10-35
Figure 10-36
Figure 10-37
Figure 10-38
Figure 10-39
10.2.8 Laminate Conditions – Depanelization
10-16 IPC-A-610F
July 2014
Defect – Class 1,2,3 • Edges are frayed.
• Nicks or routing exceed 50 of the distance from the board edge to the nearest conductor or 2.5 mm [0.1 in], whichever
is less. See 10.2.4 for haloing and 10.2.1 for crazing. • Loose burrs affect fit, form or function.
Figure 10-40
Figure 10-41
Figure 10-42
10.2.8 Laminate Conditions – Depanelization cont.
10-17 IPC-A-610F
July 2014
These criteria are applicable to conductors and lands on rigid, flex and rigid-flex circuitry. IPC-6010 Series provides the requirements for conductor width and thickness reduction.
Conductor – The physical geometry of a conductor is defined by its width x thickness x length.
Conductor Width Reduction – Reduction of the conductor width specified or derived due to individual defects i.e., edge
roughness, nicks, pinholes and scratches.
Defect – Class 1 • Reduction in width of printed conductors by more than
30. • Reduction in width or length of lands by more than 30.
Defect – Class 2,3 • Reduction in width of printed conductors by more than
20. • Reduction in width or length of lands by more than 20.
Note: Even small changes in cross-sectional area can have a large impact on impedance of RF circuitry. Alternate criteria
may need to be developed. 1
1 DIV. = 10 1
Figure 10-43
1. Minimum conductor width
