Our AC/DC Power Adapter Quality Control System

This page provides a detailed explanation of the quality control system for AC/DC Power Adapter and switching power supplies. As a manufacturer of AC/DC Power Adapter and switching power supplies, we implement rigorous quality control at our own factory.

Definition of Quality Management and Our Approach

JIS Z 8101 is a collection of definitions for quality management terminology established by the Japanese Industrial Standards (JIS). It standardizes the fundamental concepts and terminology of quality management in the manufacturing industry and serves as the foundation for quality management systems in Japanese manufacturing.

Our approach is based on the quality management principles defined in JIS Z 8101. The standard defines quality management as follows.

Quality Control (QC): A system of methods for economically producing goods or services that meet buyers' quality requirements. Because modern quality control employs statistical methods, it may also be referred to specifically as statistical quality control or statistical process control.

Effective quality management requires the participation and cooperation of everyone at every level of corporate activity, including executives, managers, supervisors, and operators. Based on this concept of total quality control (TQC), we have established the following three elements as the pillars of our quality management system.

No.	Three Pillars of Quality Management
1	Fully understand the quality requirements of customers and society
2	Economically produce and market Products of a quality that meets these requirements
3	Ensure that all corporate departments efficiently improve and maintain quality to achieve customer and societal satisfaction

The following sections explain the specific quality management measures we implement in accordance with these three pillars.

[1] Understanding the Quality Requirements of Customers and Society

Our locations in Japan and other countries, together with our factory in China, hold technical specification meetings with customers and proceed to mass production after completing the verification process below. In addition to the design department, the Quality Assurance (QA) department conducts design verification from an independent perspective to prevent quality risks during the design phase.

No.	Verification Process
1	Conduct technical specification meetings with customers (Japan and China factory)
2	Drafting Product Specifications
3	Evaluation and identification of issues using engineering samples (ES)
4	Reliability evaluation and identification of issues using customer samples (CS)
5	The Quality Assurance (QA) department, as well as the design department, conducts design verification from an independent perspective
6	Conduct a design review
7	Submit CS to the customer and obtain approval
8	Approval of Product Specifications -> Transition to mass production

[2] Economical Production and Market Supply of Products of Conforming Quality

The following control systems are implemented at each stage, from incoming inspection through manufacturing process control and shipment inspection.

Incoming Inspection

All purchased components undergo incoming inspection in accordance with ANSI/ASQC Standard Z1.4. The following individual inspections are also conducted for key components that directly affect quality.

Inspection Target	Inspection Details
All Purchased Components	Inspection of RoHS-restricted substance content using an X-ray fluorescence analyzer
Solder in the Wave Soldering Bath	Daily inspection of lead content using an X-ray fluorescence analyzer
Transformer	Disassembly inspection: Inspection of the number of magnet wire turns, winding method (loose or tight winding), insulation tape wrapping method, number of tape layers, etc.
DC cord (Plug, USB, and Core)	Disassembly inspection: Inspection of soldering quality

Manufacturing Process Control (FMEA and SOP)

Based on process FMEA, we create QC process charts and Standard Operating Procedures (SOPs) to establish production lines.

When a defect is detected on a production line, the operator at the relevant process presses the alarm button to trigger an alarm and summon the production line supervisor. Defect information is promptly fed back to the preceding process to prevent recurrence and proliferation of the same defect.

In addition, before work begins, after breaks, and every two hours, the supervisor of each production line ensures that all operators are thoroughly informed of the latest defect information and work-related precautions.

IPQC (In-Process Quality Control) Patrol Inspections

The QA department's IPQC (In-line Process QC) personnel regularly patrol the production lines and check the following items.

IPQC Patrol Inspection Items
Whether operators are performing their work in accordance with the SOP
Verification of the specifications of input components against the BOM (Bill of Materials)
Soldering iron temperature control
Torque value control for torque drivers
Verification of settings for various jigs and tools

Shipping Inspection

During shipping inspections, shipping lots are divided by pallet, and sampling inspections are conducted in accordance with ANSI/ASQC Standard Z1.4.

[3] Quality Improvement and Maintenance Across All Departments

We conduct quality improvement activities involving all departments, from management to production sites.

Management Reviews

At the beginning of each year, all departments establish quality objectives, and management reviews progress and identifies areas requiring improvement at monthly management review meetings.

Daily Quality Improvement Activities

Every day after regular working hours, meetings are held with the supervisors of each production line and QA personnel to share nonconformity information and discuss measures to prevent recurrence.

Handling Market Complaints

When a market complaint occurs, the QA department conducts an analysis and implements corrective actions based on the classification of the cause to prevent recurrence.

Classification of Defect Causes	Corrective Actions
Work-Related Causes	Incorporation into SOPs and improvement of jigs and tools
Component-Related Causes	Feedback to component manufacturers (including process audits)
Design-Related Causes	Incorporation into design standards

For more information about our quality management, please also visit the following pages.

Quality Initiatives:
Quality Initiatives / Component Supplier Selection Process / RoHS2 Compliance / Measures for Red Phosphorus (Ion Migration) / Traceability / Reliability Testing / Management of the Ultrasonic Welding Process for Enclosures