IPC-A-610 Chapter 8 Flashcards

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Questions and Answers

What does acceptable staking adhesive look like for Class 1 components?

Adhesive material is visible in the termination area, but joint width meets minimum requirements (correct)

Adhesive is completely cured and homogemous

Adhesive extends from under the component in all areas

Adhesive material is not visible in the termination area

Adhesive materials extending from under the component are visible in the termination area for a Class 3 defect.

True

What is the minimum percentage of component height that adhesive must adhere to for round components in Class 1, 2, and 3?

25%

What is considered a defect for staking adhesive on round components?

Less than three beads of staking material Signup and view all the answers

What happens when solder touches a plastic component body during SMT?

It is not allowed unless a copper lead causes it. Signup and view all the answers

A lead that is damaged more than 10% of its diameter is categorized as a Class 1 defect.

True Signup and view all the answers

What is the acceptable thickness of a flattened lead for Class 1 and 2 components?

Less than 40% of the original diameter. Signup and view all the answers

What is the minimum end joint width required for Class 3 components?

75% of the component termination width Signup and view all the answers

What is the acceptable side joint length for rectangular or square end chip components?

Not required, but a wetted fillet is evident. Signup and view all the answers

What is the acceptable maximum fillet height (E) for Rectangular or Square End Chip Components?

Both A and B Signup and view all the answers

What does minimum fillet height (F) exhibit on the vertical surface(s) of the component termination?

Wetting Signup and view all the answers

What does minimum fillet height (F) consist of for Class 3?

Solder thickness (G) plus 25% termination height (H), or 0.5mm, whichever is less. Signup and view all the answers

What is the requirement for wetted fillet in terms of solder thickness?

It must be visible Signup and view all the answers

End overlap (J) must always be 25% or more between the component termination and the land.

False Signup and view all the answers

What should the width (W) to height (H) ratio not exceed for mounting on the side?

2:1 Signup and view all the answers

For components larger than size 1206, how many termination faces should they have?

Five Signup and view all the answers

Center terminations must have a minimum side termination width of 50% of the component termination width.

True Signup and view all the answers

What is the acceptable value for side overhang (A) of cylindrical end cap terminations?

25% or less of the diameter Signup and view all the answers

What is the defect related to the end overhang (B) in cylindrical end cap terminations?

Any end overhang is unacceptable Signup and view all the answers

What should be evident for the minimum heel fillet height (E) in case of a toe-down configuration?

At least to the mid-point of the outside lead bend Signup and view all the answers

Surface mount area array solder connections should not make contact with the land.

False Signup and view all the answers

What type of overhang is unacceptable for P-Style connections?

No side overhang Signup and view all the answers

What aspect of flat gull wing leads is considered a defect?

All of the above Signup and view all the answers

Study Notes

Staking Adhesive - Component Bonding

Acceptable (Class 1): Adhesive material visible in termination area, with end joint width meeting minimum requirements.
Defect (Class 3): Adhesive material visible in termination area, not meeting acceptable criteria.

Staking Adhesive - Mechanical Strength

Acceptable (Class 1, 2, 3): On round components, adhesive covers at least 25% of component height and requires a minimum of three beads evenly placed around the component.
Defect (Class 1, 2, 3): Fewer than three beads of staking material on round components.

SMT Leads - Plastic Components

Solder should not contact the package body or seal unless specific lead configurations cause contact with plastic components like SOIC family.

SMT Leads - Damage

Defect (Class 1, 2, 3): Damage or deformation to leads exceeding 10% of their diameter, width, or thickness.

SMT Connections

Components with non-wettable areas by design are exempt from solder wetting requirements in those regions.

Chip Components - Bottom Only Terminations

Side Overhang (Class 1, 2): Side overhang must be ≤ 50% of component termination or land width.
End Joint Width (Class 1, 2): Minimum width must be ≥ 50% of component termination or land width.

Rectangular or Square End Chip Components

Acceptable Side Overhang (Class 1, 2): ≤ 50% of termination or land width.
End Joint Width (Class 3): Minimum end joint width must be ≥ 75% of termination or land width.

Cylindrical End Cap Terminations

Referred to as MELF (Metal Electrode Leadless Face).
Acceptable Side Overhang (Class 1, 2, 3): Must be ≤ 25% of component width or land width.

Castellated Terminations

Acceptable Side Overhang (Class 1, 2): Maximum ≤ 50% castellation width.
Minimum End Joint Width (Class 3): Should be ≥ 75% of castellation width.

Flat Gull Wing Leads

Side Overhang (Class 1, 2): Maximum overhang should not exceed 50% of lead width or 0.5 mm.
Minimum End Joint Width (Class 3): Minimum end joint width should be ≥ 75% lead width.

J-Leads

Toe Overhang (Class 1, 2, 3): This parameter is unspecified, offering flexibility in design.

Surface Mount Area Array

Process guidance provided in IPC-7095 with a focus on addressing process development issues.
Solder Connections (Class 1, 2, 3): BGA solder balls must contact and wet the land to form a complete connection.

Additional Notes on Fillets and Joints

Minimum Heel Fillet Height (Flat Gull Wing): In toe-down configurations, minimum height should extend to at least the midpoint of outside lead bends.
End Overlap (Cylindrical Terminations): Must be ≥ 50% the length of component termination for acceptable standards.

Familiarize with the criteria detailed above for various components to ensure compliance with IPC-A-610 standards across different classes.### Components with Bottom Thermal Plane Terminations

Thermal plate terminations are characterized by their end joint width.
Acceptable standards include Class 1, 2, and 3.

Flattened Post Connections

Connections should comply with dimensional and solder fillet standards as per specific tables.
Maximum termination overhang differs based on solder land shape and class.

Maximum Termination Overhang - Square Solder Land

Class 1: Overhang must be less than 75%.
Class 2: Overhang must be less than 50%.

Maximum Termination Overhang - Round Solder Land

Class 1 defect: Overhang exceeds 50%.
Class 2 defect: Overhang exceeds 25%.

Maximum Fillet Height

Defect classifications for Class 1 and 2 occur when solder touches the package body.

P-Style Connections - Maximum Side Overhang

Class 1: Acceptable overhang is equal to or less than 50% of the termination width.
Class 2: Acceptable overhang is equal to or less than 25% of the termination width.
Class 3 requires no side overhang.

P-Style Connections - Minimum Side Overhang

Acceptable classifications for minimum side overhang are unspecified and marked as Class.

Surface Mount Connections

Defects in Classes 1, 2, and 3 must meet form, fit, and function requirements, often necessitating trial mating for acceptance.

Jumper Wires

Refer to IPC-7711/7721 for guidelines on rework and repair.
Criteria for wire includes selection, routing, and adhesive staking relevant to SMT jumper wires.

General Conditions for Lap Solder Connections

Key conditions include insulation clearance, no fractures, and specific wire contour standards, including wire overhang regulations.

Jump Wires - SMT - Chip and Cylindrical End Cap

Acceptable in Classes 1, 2, and 3 if properly adhered.
A defect occurs when the wire is soldered on top of the chip component termination.

Gull Wing Configuration

Jump wires in this configuration are acceptable across all classes ensuring proper wire extends past the knee of the bend.

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Test your knowledge on IPC-A-610 Chapter 8 with these flashcards. This quiz covers key concepts related to staking adhesive component bonding and acceptable quality levels. Perfect for anyone studying electronic assembly standards.