Target – Class 1,2,3 • There is 1.2 mm [0.05 in] separation between the coating
meniscus and the solder fillet.
Acceptable – Class 1 • Components with a coating meniscus can be mounted with
the meniscus into the solder provided: – 360° wetting lead to land on the solder source side.
– Lead coating meniscus is not discernible within the con- nection on the secondary side.
Acceptable – Class 2,3 • Coating meniscus is not in the plated-through hole and
there is discernible clearance between the meniscus and the solder fillet.
Process Indicator – Class 2 • Coating meniscus is in the plated-through hole but solder
joint meets the requirements of Table 7-4. Defect – Class 3
• Coating meniscus is in the plated-through hole. • Coating meniscus is embedded in the solder connection.
Figure 7-103
1 2
Figure 7-104
1. Class 1 2. Class 2,3
7.3.5.8 Supported Holes – Solder Conditions – Meniscus in Solder
7-50 IPC-A-610F
July 2014
Defect – Class 1,2 • The meniscus is discernible in the solder on the solder
source side. Defect – Class 1,2,3
• Does not exhibit 360° wetting on solder source side. • Does not meet requirements of Table 7-4.
Note: When required for certain applications, meniscus on the components are to be controlled to ensure that, with compo-
nents fully seated, the meniscus on the leads does not enter the plated-through holes of the assembly. Example: high fre-
quency applications, very thin PCBs.
Figure 7-105
7.3.5.8 Supported Holes – Solder Conditions – Meniscus in Solder cont.
7-51 IPC-A-610F
July 2014
The following criteria apply to printed board assemblies where the connections have been trimmed after soldering. Leads may be trimmed after soldering provided the cutters do not damage the component or solder connection due to physical shock. For
Classes 2 and 3, when lead cutting is performed after soldering, the solder terminations
shall be visually inspected at 10X to
ensure that the original solder connection has not been damaged, i.e., fractured or deformed. As an alternative to visual inspec- tion, the solder connections may be reflowed. If the solder connection is reflowed this is considered part of the soldering process
and is not to be considered rework. This requirement is not intended to apply to components that are designed such that a por- tion of the lead is intended to be removed after soldering, i.e., break away tie bars.
Acceptable – Class 1,2,3 • No fractures between lead and solder.
• Lead protrusion within specification, see 7.3.3.
Defect – Class 1,2,3 • Evidence of fracture between lead and solder fillet.
Defect – Class 3 • Lead trimming that cuts into the solder fillet and is not
reflowed.
Figure 7-107
1
Figure 7-106
1. Lead protrusion
7.3.5.9 Lead Cutting after Soldering
7-52 IPC-A-610F
July 2014
These requirements apply when the solder connection meets the minimum requirements of Table 7-4. See 6.2.3 for extruded insulation clearance requirements.
This section applies to coatings that may extend into the connection during soldering operations, provided the material is not corrosive.
Target – Class 1,2,3 • Clearance of 1 wire diameter between solder fillet and
insulation.
Acceptable – Class 1,2,3 • Coating is entering solder connection on primary side and
meets minimum requirements of Table 7-4.
Defect – Class 1,2,3 • Solder connection exhibits poor wetting and does not meet
the minimum requirements of Table 7-4. • Coating is discernible on secondary side.
Figure 7-108
Figure 7-109
Figure 7-110
7.3.5.10 Supported Holes – Coated Wire Insulation in Solder
7-53 IPC-A-610F
July 2014
Supported holes used for interfacial connection not exposed to solder because of permanent or temporary masks need not be filled with solder. Supported holes or vias without leads, after exposure to wave, dip or drag soldering equipment are to meet these
acceptability requirements.
Target – Class 1,2,3 • Holes are completely filled with solder.
• The tops of lands show good wetting.
Acceptable – Class 1,2,3 • Sides of holes are wetted with solder.
Acceptable – Class 1 Process Indicator – Class 2,3
• Solder has not wetted side of holes.
Note: There is no defect condition for this. Note: Solder capped PTHs have the possibility of entrapping
contaminants that are difficult to remove if cleaning is required.
Figure 7-111
Figure 7-112
Figure 7-113
7.3.5.11 Supported Holes – Interfacial Connection without Lead – Vias
7-54 IPC-A-610F
July 2014
No board in board criteria have been established for Class 3 assemblies. From IPC-T-50: ‘‘Daughter Board - A printed board that is fastened to a mother board and electrically connected.’’
When required, attachment will include additional mechanical support aids, e.g., adhesives or hardware, to ensure the connec- tions will not be damaged in the intended service environment.
Table 7-5 Board in Board – Minimum Acceptable Solder Conditions
1
Criteria Class 1
Class 2
Vertical fill of solder, Note 2 75
Wetting on primary side solder destination side daughter board land to PCA solder connection width
50 75
Percentage of land area on PCA mother board covered with wetted solder on primary side solder destination side
Fillet and wetting solder connection width on secondary side solder source side of PCA mother board to lands on both sides of daughter board
50 75
Percentage of land area on PCA mother board covered with wetted solder on secondary side solder source side
75
Note 1. Wetted solder refers to solder applied by the solder process. Note 2. The 25 unfilled height includes both source and destination side depressions.
Acceptable – Class 1,2 • Daughter board is mounted perpendicular to PCA.
• Daughter board is flush to PCA. • Mechanical constraints, if required, are properly attached.
• Vertical fill of solder is 75.
Figure 7-114
Figure 7-115
7.3.5.12 Supported Holes – Board in Board
7-55 IPC-A-610F
July 2014
Acceptable – Class 1 • Solder is wetted a minimum of 50 width X of each of the
sides of the daughter board lands L to PCA on secondary side solder source side.
• Solder is wetted a minimum of 50 width X of each of the sides of the daughter board land L to PCA on primary side
solder destination side.
Acceptable – Class 2 • Solder is wetted a minimum of 75 width X of each of the
sides of the daughter board land L to PCA on secondary side solder source side.
• Solder is wetted a minimum of 75 width X of each of the sides of the daughter board land L to PCA on primary side
solder destination side.
Figure 7-116
Figure 7-117
Figure 7-118
7.3.5.12 Supported Holes – Board in Board cont.
7-56 IPC-A-610F
July 2014
Defect – Class 1,2 • Daughter board angle stresses mounting through-hole tabs.
• Required mechanical constraints not present or not properly attached.
• Vertical fill of solder is less than 75. • Solder not wetted to each of the sides of daughter board
lands or PCA land. Defect – Class 1
• Solder is wetted less than 50 width X of both sides of the daughter board land L to PCA on secondary side solder
source side. • Solder is wetted less than 50 width X of each of the sides
of the daughter board land L to PCA on primary side sol- der destination side.
Defect – Class 2 • Solder is wetted less than 75 width X of each of the sides
of the daughter board land L to PCA on secondary side solder source side.
• Solder is wetted less than 75 width X of each of the sides of the daughter board land L to PCA on primary side sol-
der destination side.
Figure 7-119
Figure 7-120
7.3.5.12 Supported Holes – Board in Board cont.
7-57 IPC-A-610F
July 2014
Target – Class 1,2,3 • The entire body length of the component is in contact with
the board surface. • Components required to be mounted off the board are at
minimum 1.5 mm [0.06 in] from the board surface; e.g., high heat dissipating.
• Components required to be mounted off the board are pro- vided with lead forms at the board surface or other
mechanical support to prevent lifting of solder land.
Defect – Class 1,2,3 • Components required to be mounted off the board are not
provided with lead forms at the board surface or other mechanical support to prevent lifting of solder land.
• Components required to be mounted above the board sur- face are less than 1.5 mm [0.06 in].
• Component height exceeds user-determined dimension. 1
2
Figure 7-121
1. No plating in barrel 2. Clinch required for Class 3, see 7.4.4
