1. IPC-A-610E
SOLDERING

2. MODULE OVERVIEW Soldering Acceptability Requirements
Soldering Anomalies
High Voltage

3. Module Objective
Upon completion of this session, the participant will be able to identify the acceptability requirements for soldered assemblies and high voltage

4. Soldering
Nature of the soldering process may dictate that an acceptable condition may have the same characteristics for all three classes
Where appropriate, the type of soldering process used is addressed
The connection criteria apply regardless of which methods
• Resistance soldering apparatus.
• Induction wave, or drag soldering.
• Reflow soldering.
• Intrusive soldering.

5. Exception :
Some specialized soldering finishes require special acceptance
criteria, not found in the IPC-A-610E
Immersion Tin
Palladium
Gold
Criteria should be based on design, process capability and performance requirements

6. Figure 5-1
Figure5-1 (A, B). As an exception, the solder connection to a termination may exhibit a wetting angle exceeding 90°
Figure 5-1(C, D), when it is created by the solder contour extending over the edge of the solderable termination area or solder resist.

7. The primary difference between the solder connections created with processes using tin-lead alloys and processes using lead-free alloys
visual appearance of the solder
This standard provides visual criteria for inspections of both
Figures specific to lead-free connections will be identified with the symbol shown in Figure5-3.

8. Soldering Acceptability Requirements
Typical tin-lead connections
- Shiny to a satin luster
- Smooth appearance
- Exhibit wetting as - concave meniscus between the objects being
soldered.
- High temperature solders - may have a dull appearance
- Touch-up (rework) - Use discretion to avoid causing additional
problems

9. Soldering Acceptability Requirements
Target - Class 1,2,3
• Solder fillet appears generally smooth and exhibits good wetting of the
solder to the parts being joined.
• Outline of the lead is easily determined.
• Solder at the part being joined creates a feathered edge.
• Fillet is concave in shape.
Acceptable - Class 1,2,3
• There are materials and processes, e.g., lead free alloys and slow cooling with large mass PCBs, that may produce dull matte, gray, or grainy appearing solders that are normal for the material or process involved. These solder connections are acceptable.
• The solder connection wetting angle (solder to component and solder toPCB termination) do not exceed 90°, Figure 5-1 (A, B).
– As an exception, the solder connection to a termination may exhibit a
wetting angle exceeding 90°, Figure 5-1 (C, D), when it is created by the
solder contour extending over the edge of the solderable termination area or solder resist.  

10. Soldering Anomalies – Exposed Basis Metal
Acceptable - Class 1,2,3
• Exposed basis metal on:
– Vertical conductor edges.
– Cut ends of component leads or wires.
– Organic Solderability Preservative (OSP) coated lands.
• Exposed surface finishes that are not part of the required
solder fillet area.

11. Soldering Anomalies – Exposed Basis Metal
Acceptable - Class 1
Process Indicator - Class 2,3
• Exposed basis metal on component leads, conductors or
land surfaces from nicks or scratches provided conditions
do not exceed the requirements of for leads and
for conductors and lands.
Defect - Class 1,2,3
land surfaces from nicks, scratches or other conditions
exceed the requirements of and

12. Soldering Anomalies – Pin Holes/Blow Holes
Acceptable - Class 1
Process Indicator - Class 2,3
• Blowholes, Figures 8 and 9, pinholes, Figure 10, voids, Figures
11 and 12, etc., providing the solder connection meets all
other requirements.
Defect - Class 1,2,3
• Solder connections where pin holes, blow holes, voids, etc.,
reduce the connections below minimum requirements (not
shown).

13. Soldering Anomalies – Reflow of Solder Paste
Defect - Class 1,2,3
• Incomplete reflow of solder paste.

14. Soldering Anomalies – Nonwetting
Defect - Class 1,2,3
• Solder has not wetted to the land or termination where solder is required. (Figures 17,18,19, component terminations, Figure 20, shield termination, Figure 21, wire termination.)
• Solder coverage does not meet requirements for the termination type.

15. Soldering Anomalies – Cold/Rosin Connection
Defect - Class 1,2,3
• The solder connection exhibits poor wetting
and may show evidence of entrapped rosin
separating the surfaces to be joined.

16. Soldering Anomalies – Dewetting
Defect - Class 1,2,3
• Evidence of dewetting that causes the solder
connection to not meet the SMT or through-hole
solder fillet requirements.

17. Soldering Anomalies – Excess Solder
Metal Lidded Components
Solder splashes or tinning on a metalized package body, see Figure 27, should be evaluated for impact upon hermetic and radiation hardening performance of the component considering the intended performance environment. Solder splashes on the metalized surfaces may be acceptable if the extended electrical performance is not required or
compromised.

18. Soldering Anomalies – Excess Solder – Solder Balls/Solder Fines
Target - Class 1,2,3
• No evidence of solder balls on the printed wiring assembly.

19. Soldering Anomalies – Excess Solder – Solder Balls/Solder Fines
Acceptable - Class 1,2,3
• Solder balls are entrapped, encapsulated or attached (e.g., in no-clean residue, with conformal coating, soldered to a metal surface, embedded in the solder resist or under a component).
• Solder balls do not violate minimum electrical clearance.

20. Soldering Anomalies – Excess Solder – Solder Balls/Solder Fines
Defect - Class 1,2,3
• Solder balls are not entrapped, encapsulated or attached or
can become dislodged in the normal service environment.
• Solder balls violate minimum electrical clearance.

21. Soldering Anomalies – Excess Solder – Bridging
Defect - Class 1,2,3
• A solder connection across conductors that should not be
joined.
• Solder has bridged to adjacent noncommon conductor or
component.

22. Soldering Anomalies – Excess Solder – Solder Webbing/Splashes
Target - Class 1,2,3
• No solder splashes or webbing.
Acceptable - Class 1,2,3
• Solder splashes or metallic particles meet the
following criteria:
– Attached/entrapped/encapsulated on the PCA
surface or solder mask, or soldered to metallic
surface.
– Do not violate minimum electrical clearance.

23. Soldering Anomalies – Excess Solder – Solder Webbing/Splashes
Defect - Class 1,2,3
• Solder webbing.
• Solder splashes that are not attached,
entrapped, encapsulated.
• Solder splashes on metal component
surfaces impact form, fit or function, e.g.,
damages lid seal on hermetic
components.
• Violate minimum electrical clearance.

24. Soldering Anomalies – Disturbed Solder
Acceptable - Class 1,2,3
• Lead free and tin-lead solder
connections exhibit:
– Cooling lines, Figure 40.
– Secondary reflow, Figure 41.
Defect - Class 1,2,3
• Disturbed solder joint characterized by uneven surface from
movement in the solder connection during cooling.

25. Soldering Anomalies – Fractured Solder
Defect - Class 1,2,3
• Fractured or cracked solder.

26. Soldering Anomalies – Solder Projections
Defect - Class 1,2,3
• Solder projection, Figure 47, violates assembly
maximum height requirements or lead protrusion
requirements.
• Projection, Figure 48, violates minimum electrical
clearance.