Introduction

Vietnam, with its robust economic growth and abundant workforce, has become a crucial hub for global manufacturing. Over the past five years, the manufacturing GDP growth rate has averaged over 6% annually. More than 2,000 Japanese manufacturing companies have established operations here, driven by objectives such as relocating production bases and diversifying supply chains, and this number continues to rise.

However, amidst this growth, quality assurance for component procurement, especially for fastening parts like screws, presents an urgent challenge for Japanese companies. Screws are critical components directly impacting product safety, durability, and functionality, ultimately determining the quality of the final product. It is estimated that a 1% defect rate in screws can account for 3% of total production costs, indicating that quality issues can lead to increased costs and brand damage risks.

This article clarifies the quality challenges in screw procurement in Vietnam and explains concrete methods for establishing a quality assurance system to overcome them. Ensuring a rigorous inspection system, reliable quality certificates, and robust traceability (manufacturing history tracking) are key to stable screw procurement.

Current State and Quality Challenges of Screw Procurement in Vietnam

While Vietnam’s manufacturing industry is developing rapidly, the supplier market for basic components like screws is diverse, with varying quality levels. There are an estimated 200+ screw suppliers domestically, but many are small and medium-sized enterprises (SMEs) with often underdeveloped manufacturing facilities and quality control systems. In fact, SMEs account for approximately 97% of Vietnam’s manufacturing sector, making the selection of high-quality suppliers challenging.

The main quality challenges for Japanese companies procuring screws in Vietnam are as follows:

• Gap with Japanese Standards: The quality consciousness, stringent inspection systems, and high technical levels demanded by Japanese companies can be a significant hurdle for many local Vietnamese suppliers. Discrepancies between Japanese and local standards are particularly common in dimensional accuracy, material uniformity, and surface treatment quality.
• Risk of Counterfeit and Substandard Products: In a market with strong cost-reduction pressures, there is a risk of inexpensive counterfeit or substandard products circulating. These can be difficult to distinguish visually and may compromise product reliability due to insufficient material strength or improper surface treatment. Recall costs due to quality issues have been reported to range from several hundred million to several billion JPY on average, depending on the industry and product.
• Balance Between Cost Reduction Pressure and Quality Maintenance: One of the biggest attractions of procurement in Vietnam is cost reduction. However, excessive cost-cutting pressure carries the risk of quality degradation. It is necessary to consider the possibility that suppliers might use cheaper raw materials or omit inspection processes to reduce costs.

To overcome these challenges, it is essential to establish strict criteria from the supplier selection stage and build a continuous quality management system.

Establishing and Implementing a Rigorous Inspection System

To ensure stable quality in screw procurement in Vietnam, it is crucial not to solely rely on suppliers but to establish and implement a rigorous in-house inspection system. We will explain how to build an effective inspection system.

Introduction of a Three-Stage Inspection Process

• Incoming Inspection: The initial inspection conducted for each lot of delivered screws. This verifies dimensions, appearance, quantity, etc., preventing defective products from entering the production process.
• In-Process Inspection: Performed at each stage of the screw manufacturing process. This helps detect problems early, preventing rework and mass production of defective items.
• Final Inspection: The ultimate inspection conducted before finished screws are shipped. This confirms that the quality of the final product is assured.

Key Inspection Items

To evaluate screw quality, the following items should be inspected with particular focus. A minimum of 10 inspection items is recommended.

• Dimensional Accuracy: Screw diameter, length, pitch, head shape, etc., are measured using micrometers, calipers, thread gauges, and image measuring instruments. Strict dimensional tolerances, such as within ±0.1mm based on JIS B 1002, are common.
• Material Composition: Verify that the correct material is used. Elemental composition is analyzed using X-ray fluorescence (XRF) analyzers or spectroscopic analyzers, and consistency with the mill sheet (material certificate) is confirmed.
• Surface Treatment: Check the film thickness, uniformity, and adhesion of plating or coating. This is evaluated using X-ray film thickness gauges and salt spray tests.
• Strength: Tensile strength, torque strength (breaking strength during tightening), and shear strength are measured using tensile testing machines and torque testing machines. The introduction cost for a tensile testing machine ranges from approximately 1 million to 5 million JPY.
• Hardness: Material hardness is measured using hardness testers (e.g., Rockwell hardness tester, Vickers hardness tester). Introduction costs range from approximately 300,000 to 1.5 million JPY.
• Appearance: Visually inspect or use a magnifying glass to check for scratches, dents, burrs, rust, or foreign matter adhesion.

Selection and Utilization of Inspection Equipment

To address the aforementioned inspection items, the introduction of appropriate inspection equipment is essential. It is advisable to check the supplier’s equipment status and, if necessary, consider in-house procurement or utilizing reliable third-party inspection agencies.

Clarification of Inspection Standards and Training of Inspectors

Inspections should be conducted based on international standards such as JIS (Japanese Industrial Standards), ISO (International Organization for Standardization), ASTM (American Society for Testing and Materials), and internal company standards tailored to specific product characteristics. It is crucial to clearly document these standards and share them with suppliers.

The skills of inspectors are paramount for quality assurance. Regular specialized education and training on inspection techniques, standard knowledge, and defect judgment criteria should be provided. Establishing a certification system will help standardize and improve inspection quality. A typical training period includes approximately one month for basic training and three to six months for On-the-Job Training (OJT).

Ensuring Quality Certificates and Traceability

To make a quality assurance system effective, objective documentation of inspection results and a traceability system capable of quickly identifying the root cause in case of issues are indispensable.

Essential Quality Certificates

When procuring screws in Vietnam, the main quality certificates that should be obtained from suppliers are as follows:

• Mill Sheet (Material Certificate): A document detailing the chemical composition and mechanical properties of the raw materials used. It certifies that the material quality meets design requirements.
• Inspection Report: A document listing the inspection items and their results for the delivered product lot. It is crucial that specific inspection data is provided.
• RoHS Compliance Certificate: A document proving conformity to the EU Directive on the Restriction of Hazardous Substances (RoHS), which limits the use of certain hazardous substances (e.g., lead, cadmium, mercury). This is essential, especially for screws used in electronic and electrical products.
• ISO 9001 Certification: Obtaining ISO 9001 certification, an international standard for quality management systems, is important for assessing the maturity of a supplier’s quality management system. Approximately 30% of manufacturing companies in Vietnam are ISO 9001 certified, making it a significant factor in supplier selection.

These certificates are typically issued within 1 to 3 business days, but it is advisable to confirm their availability and lead time in advance.

Tracking Manufacturing History through Lot Management (Traceability)

In the event that defective products are discovered, thorough lot management and the establishment of a traceability system are indispensable for quickly identifying the cause and limiting the scope of impact.

• Assignment of Lot Numbers: A unique lot number is assigned to each manufacturing lot of screws, linking all manufacturing-related information such as manufacturing date, production line, raw material lot number, heat treatment conditions, and surface treatment conditions.
• Information Sharing Across the Entire Supply Chain: Establish a mechanism to link lot information across the entire supply chain, from material manufacturers to screw manufacturers and final product manufacturers. This allows for rapid identification of the process and material that caused a problem when it arises.
• Promotion of Digitalization: By introducing information management systems such as Manufacturing Execution Systems (MES) and Enterprise Resource Planning (ERP) to centrally manage lot information digitally, the accuracy and efficiency of traceability can be significantly improved. For SMEs, ERP/MES implementation costs range from several hundred thousand to several million JPY, and the reduction rate in defect response time due to traceability system implementation is said to average 20% to 40%.

These initiatives minimize the scope of recalls in the event of defective products and help maintain customer trust.

Quality Assurance Support Provided by Ohta Vietnam

Establishing a quality assurance system for screw procurement in Vietnam is a complex process that requires specialized knowledge and local execution capabilities. Ohta Vietnam leverages its extensive experience in Vietnamese manufacturing and robust local network to strongly support Japanese companies in resolving their screw procurement quality challenges.

• Local Supplier Selection & Evaluation Support and Quality Audit Representation: Selecting reliable screw suppliers is the first step in quality assurance. Ohta Vietnam has partnered with and audited over 50 factories, assisting in selecting suppliers that meet Japanese quality standards. We represent clients in conducting quality audits at local factories, thoroughly evaluating manufacturing equipment, quality control systems, and technical levels.
• Inspection Representation and Technical Guidance Based on Japanese Quality Standards: We formulate inspection standards tailored to your required quality and conduct incoming, in-process, and final inspections on-site. When necessary, we also provide technical guidance to supplier inspectors, contributing to the improvement of local inspection capabilities. Based on over 100 quality audit achievements annually, we propose optimal inspection processes.
• Prompt Local Response and Root Cause Analysis Support for Defective Products: In the unlikely event of defective products, Ohta Vietnam’s local staff promptly liaises with suppliers to support initial response, root cause identification, and the formulation of recurrence prevention measures. In past support cases, we have achieved a 30% reduction in defective products.
• Quality Standard Formulation Support and Supplier Engagement Activities: We assist in formulating realistic and effective quality standards, considering your product characteristics and Vietnam’s manufacturing realities. We conduct regular visits and training to ensure these standards are thoroughly understood and implemented by suppliers.
• Proposal of Procurement Strategies Balancing Stable Quality and Supply: We develop optimal screw procurement strategies for our clients, considering the balance of cost, quality, delivery time, and risk. We support the construction of sustainable supply chains, including multi-sourcing from multiple suppliers and optimizing inventory management.

Ohta Vietnam is committed to providing comprehensive support, enabling our clients to conduct screw procurement in Vietnam without quality concerns.

Conclusion

Vietnam is gaining increasing importance in the global manufacturing supply chain. However, for critical component procurement like screws, quality assurance remains a significant challenge for Japanese companies. To ensure product safety and reliability and maintain corporate competitiveness, establishing a rigorous inspection system, obtaining reliable quality certificates, and implementing a robust traceability system are indispensable. This three-pronged quality assurance system serves as the foundation for reducing the risk of defective products and responding quickly and effectively when issues arise.

By understanding the unique quality challenges of the Vietnamese market and implementing appropriate measures, companies can stably procure high-quality screws that meet Japanese standards while enjoying cost benefits. In this complex process, Ohta Vietnam leverages its extensive experience and local network to strongly support clients in establishing their quality assurance systems. Through continuous improvement and partnership, we aim to minimize quality risks in screw procurement in Vietnam and contribute to our clients’ business success.

Conclusion

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