One of the most crucial aspects of the strength differentiation method employed by electronic product manufacturing service (EMS) providers, particularly in the PCBA foundry sector, is the assessment of product quality.

1. Electronic Manufacturing Service (EMS) and Development

In the realm of electronic manufacturing services (EMS—Electronic Manufacturing Service), ODM and OEM have emerged as the primary production models for PCBA foundries. Approximately 40% of global electronic products are manufactured through outsourcing, and this figure is expected to rise.

2. Customers’ Requirements for PCBA Quality

Clients are setting increasingly stringent quality standards for OEM PCBA assembly. This demand is primarily driven by the consumer market, which seeks high profitability, especially in the OEM sector, where profit margins are dwindling and quality expectations are on the rise. The assembly of PCBA forms the foundation of the complete electronic information product and is a critical element in ensuring the overall quality and reliability of the final product. Unlike general component manufacturing, this process necessitates stringent oversight when outsourced.

3. Understanding the Importance of the Three-Inspection System

The three-inspection system is a management-oriented inspection initiative. It serves to verify that each stage of the PCBA OEM production process adheres to established requirements.


1. Quality control records should serve as evidence. Their purpose is to manage defects in PCBA assembly and manufacturing processes, ensuring adherence to the principle that “products are manufactured” and focusing on establishing stable, repeatable, and monitorable process control objectives. This is not merely about mass inspection.

2. So, what is the first item? The first product refers to the initial (part one) product produced for each shift or model. First article inspection is conducted to verify and confirm the first product.

3. The three inspection system emphasizes the specific on-site quality performance and the management of key factors affecting manufacturing quality, known as 5M1E (Man, Machine, Material, Method, Environment, Measurement). This system assesses whether production conditions meet the final quality requirements of the product. Its goal is to prevent batch errors and minimize risks.

4. The foundation of the three inspection system is the first article, with its comparison standard being the agreement on the accuracy of the actual OEM product—the sample and the guiding documents between the customer and the PCBA foundry. Correctness encompasses not only material accuracy but also the correctness of assembly (mounting and insertion), soldering, and electrical performance. In cases of discrepancy, the guiding document takes precedence; if absent, the sample is authoritative. This principle must always be upheld. It protects PCBA foundries and is a responsibility for customers, aimed at ensuring and enhancing product quality while preventing quality losses stemming from errors by either party.

5. Fourth, how to implement the three inspection system? The first article management method stipulates that in each production section, the first 1 to 3 PCBAs of the production batch that have passed all processes must be confirmed for the accuracy of assembly materials, soldering integrity, and appearance completeness. The aim is to identify various process issues early in the production cycle to avoid batch failures. Typically, the first production parts include those from the placement section, assembly section, testing section, and finished product. Adjustments may be made based on the specific section of the PCBA foundry.

6. This system must be applied to every batch of production, especially for prototyping and the initial production runs of PCBAs, which require heightened attention. Quality line inspectors must conduct a special inspection based on the customer’s original BOM and unique processing requirements to ensure compliance of the PCBA. It is essential to move away from the practice in some foundries of converting customers’ original BOMs into assembly material cards for production, as this heavily relies on individual understanding and responsibility, lacking systematic oversight and making it difficult to ensure consistent quality across diverse customer needs.

7. So, what are the three inspections? They comprise self-inspection, mutual inspection, and special inspection. The first, self-inspection, involves production employees reviewing the products from their own workstations against work instructions, samples, etc., and promptly addressing any discrepancies with the production engineer. The second, mutual inspection, is where inspection personnel from each section confirm product compliance, also using work instructions and samples, resolving issues with the production engineer immediately. The third, special inspection, involves in-line inspection based on the customer’s original BOM, special processing requirements, and sample parts, confirming whether the first produced item meets customer standards and aligns with production technical documents. It also assesses whether production conditions and process parameters can yield qualified mass-produced products. PCBAs passing the “three inspections” will be retained until the end of batch production.

8. Control requirements for the first three inspections include: (1) Ensuring the harmonization and unity of technical documents such as product drawings, process documents, BOM, and special processing requirements. (2) Verifying that the parameters, positions, polarity, angles, etc., of mounted components meet technical document specifications. (3) Confirming the quality of raw materials is adequate (e.g., solder color, component appearance, correct polarity).

9. Identification and records: The first piece that has successfully passed the “three inspections” will be marked by the inspector and retained until the entire batch is processed and transitioned to the next step. This identification serves to trace whether any of the initial inspections were overlooked if quality issues arise within the batch. All personnel involved in the first “three inspections” must sign the “first inspection form,” ensuring signatures are neat and complete for product quality traceability.

10. PCBA inspection content includes: (1) Inspecting solder joint conditions to ensure reliable soldering that achieves good electrical performance. Common issues include wrong soldering, missing solder, cold solder, excessive or insufficient solder, voids, and thermal damage. (2) Assessing materials and parts to ensure accuracy and correct installation. Issues may include wrong parts, incorrect orientation, missing components, and improper installation. (3) Evaluating PCB condition to prevent defects and potential failures.

—

Let me know if you need further adjustments!