IPC Standards

Classification

IPC Product Classes

The IPC divides electronic products into three classes based on required functionality, reliability, and consequences of failure. It is up to the customer to determine which class is appropriate for their product.

1

General Electronics

Consumer products where cosmetic imperfections are acceptable. Lowest reliability requirements.

2

Dedicated Service

Industrial controls, computers, telecom. Extended life and reliable performance expected.

3

High Reliability

Defense, aerospace, medical. Continuous performance essential. Failure cannot be tolerated.

Core Requirements

Circuit Board Fundamentals

Every circuit board must meet three fundamental requirements throughout its expected life:

Requirement	Description
Physical Form	Dimensions and interconnect points must match intended design and facilitate component attachment
Interconnection	Must provide proper electrical connection between all components that should be connected
Insulation	Must provide adequate insulation between points that should not be connected

Class 3 Thresholds

IPC-6012 Class 3 Requirements

Class 3 builds on Class 2 but tightens almost every parameter for extreme reliability in defense, aerospace, and medical applications.

Parameter	Class 2	Class 3
Copper Plating (Avg)	≥20 μm	≥25 μm
Annular Ring (External)	90° Breakout OK	≥50 μm (No breakout)
Annular Ring (Internal)	90° Breakout OK	≥25 μm
Copper Wrap	≥5 μm	≥12 μm
Plating Voids	<5% circumference	Near-zero tolerance
Barrel/Corner Cracks	Minor allowed	None allowed
Delamination	Limited allowed	None allowed

Qualification Standards

PCB Performance Specifications

IPC-6012

Rigid Printed Boards

Primary specification for rigid PCB fabrication. Class 1/2/3 requirements. Addendums: ES (Space/Military), EM (Medical), EA (Automotive).

IPC-6013

Flexible/Rigid-Flex Boards

Performance specification for flexible and rigid-flex printed circuits used in dynamic and space-constrained applications.

IPC-6017

Microvia HDI Boards

High-density interconnect specifications for microvia and fine-line printed boards.

IPC-6018

High Frequency Boards

Performance specification for high-speed and microwave printed boards.

Test Methods

IPC-TM-650 Procedures

TM-650 2.1.1

Microsection Preparation

Manual and semi-automatic microsectioning. Cutting, mounting, grinding, polishing, and optical inspection procedures.

TM-650 2.6.8

Thermal Stress Testing

Solder float test for evaluating resistance to thermal shock. Pre-microsection stress testing.

TM-650 2.6.27

Reflow Simulation

Thermal cycling simulation for lead-free assembly process evaluation.

IPC-9252

Electrical Testing

Requirements for electrical testing of unpopulated printed boards.

Acceptability Standards

Visual Inspection Criteria

IPC-A-600

Acceptability of Printed Boards

Visual guide for bare board inspection. Target, Acceptable, and Non-conforming conditions for each characteristic.

IPC-A-610

Acceptability of Electronic Assemblies

Soldering, component placement, cleanliness, and workmanship standards for assembled boards.

J-STD-001

Soldered Electrical Assemblies

Requirements for soldered electrical and electronic assemblies. Process and workmanship specifications.

IPC-9241

Microsection Evaluation Guide

Companion guide for IPC-TM-650 microsection analysis interpretation and artifact recognition.

Materials & Finishes

Base Materials & Surface Finishes

IPC-4101

Base Materials for Rigid Boards

Specification for base materials including FR-4, high-Tg, and specialty laminates.

IPC-4552/53/54/56

Surface Finishes

ENIG, immersion silver, immersion tin, and ENEPIG surface finish specifications.

IPC-SM-840

Solder Mask

Qualification and performance of permanent solder mask for printed boards.

IPC-4562

Copper Foils

Metal foil specification for printed board applications including ED and RA copper.

Microsection Analysis

Automated Cross-Section Inspection

IPC-TM-650 Method 2.1.1 defines the standard microsection procedure: sample selection, precision cutting (200-300 RPM), acrylic mounting, grinding (120-1200 grit), diamond polishing (6.0-1.0 μm), micro-etching, and optical evaluation.

Manual analysis requires 45+ minutes per section. Viafense automates the optical evaluation phase in under 3 seconds, applying 42-class CNN defect detection trained on 50,000+ microsection images with 99.2% accuracy.

Automated measurements: PTH copper plating thickness, annular ring width, dielectric spacing, copper wrap, plating integrity, barrel/corner cracks, interlayer separation, laminate voids, and delamination detection.

Independence Statement

Standards Compliance

Viafense automates microsection measurements in accordance with IPC-6012, IPC-A-600, and IPC-TM-650 test methodology, providing decision support for Class 2 and Class 3 acceptability evaluation.

Viafense is an independent inspection and analytics platform. It is not affiliated with, endorsed by, or sponsored by IPC. IPC standards remain the governing authority for acceptability criteria. Viafense assists users in interpreting and applying those standards through automated measurement and analysis.

Results are provided as decision support and do not replace the customer's quality system or contractual standards. Final acceptability remains subject to customer-specific requirements and quality system authority.