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 thorough management at our own factory.

Definition of Quality Control and Our Approach

JIS Z 8101 is a glossary of terms related to quality control established by the Japanese Industrial Standards (JIS). It standardizes the fundamental concepts and terminology of quality control in the manufacturing industry and serves as the foundation of quality control systems in Japanese manufacturing.

Our company bases its practices on the quality control concepts defined in JIS Z 8101. The standard defines quality control as follows.

Quality Control (QC): A system of methods for economically producing goods or services of a quality that meets buyer requirements. Modern quality control adopts statistical methods and is therefore sometimes referred to as statistical quality control or statistical process control.

To implement quality control effectively, participation and cooperation are required from everyone at every stage of business activities, including top management, managers, supervisors, and workers. Based on this concept of company-wide quality control (TQC), our company has established the following three elements as the pillars of our quality control system.

No.	Three Pillars of Quality Control
1	Fully understand the quality required by customers and society
2	Economically produce Products that conform to these requirements and bring them to market
3	Ensure that all departments efficiently maintain and improve quality to achieve customer and societal satisfaction

Below, we introduce the specific quality control measures we implement in accordance with these three pillars.

[1] Understanding the Quality Required by Customers and Society

Our bases in Japan and other countries, together with our factory in China, hold technical specification meetings with customers and proceed to mass production through the following verification processes. In addition to the design department, the Quality Assurance (QA) department conducts design verification from an independent standpoint, thereby preventing quality risks at the design stage.

No.	Verification Process
1	Conduct technical specification meetings with customers (Japan and China factory)
2	Products specification drafting
3	Evaluation and issue identification using engineering samples (ES)
4	Reliability evaluation and issue identification using customer samples (CS)
5	Design verification conducted not only by the design department but also by the Quality Assurance (QA) department from a third-party perspective
6	Conduct design review
7	Submit CS to the customer and obtain approval
8	Products specification approval obtained → Transition to mass production

[2] Economical Production and Market Supply of Products that Meet Quality Standards

From incoming inspection to manufacturing process control and final shipment inspection, the following management systems are implemented at each stage.

Incoming Inspection

All purchased components are subject to incoming inspection based on ANSI/ASQC Standard Z1.4. For key components directly related to quality, the following individual inspections are conducted.

Inspection Item	Inspection Details
All Purchased Components	RoHS specified hazardous substance content analysis using an X-ray fluorescence analyzer
Solder in Jet Soldering Bath	Daily inspection of lead content using an X-ray fluorescence analyzer
Transformer	Disassembly inspection: number of magnet wire turns and winding method (loose winding/tight winding), insulation tape winding method and number of turns, etc.
DC Cable (Plug/USB/Core)	Disassembly inspection: inspection of soldering quality

Manufacturing Process Control (FMEA・SOP)

Based on process FMEA, we create QC process charts and work instructions (SOP: Standard Operating Procedure) to build our production lines.

If a defect is detected on the production line, the operator at the relevant process presses the alarm button to issue an alert and call the production line supervisor. Defect information is promptly fed back to the previous process to prevent the recurrence of the same defect.

In addition, not only before starting work but also every 2 hours after breaks, the supervisor of each production line thoroughly communicates the latest defect information and work precautions to the operators.

IPQC (In-Process Quality Control) Patrol Inspection

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

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

Shipping Inspection

In the shipping inspection, shipment lots are classified by pallet units, and sampling inspections are conducted based on ANSI/ASQC Standard Z1.4.

[3] Quality Improvement and Maintenance by All Departments

Our company implements quality improvement activities involving all departments, from management to production sites.

Management Review

At the beginning of each year, all departments set quality objectives, and management reviews progress and areas requiring improvement at the 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 of Market Complaints

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

Classification of Defect Causes	Corrective Actions
Work-related Cause	Reflection in SOPs and improvement of jigs and tools
Component-related Cause	Feedback to component manufacturers (including process audits)
Design-related Cause	Reflection in design standards

For more details about our quality control, please also see the following pages.

Our Quality Initiatives:
Our Quality Initiatives / Component Supplier Selection Method / RoHS2 Compliance / Response to Red Phosphorus (Ion Migration) / Traceability / About Reliability Testing / Management Method for Ultrasonic Welding Process of Housings