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The benefits and implementation process of screw standardization for manufacturing industry
The Importance of Screw Standardization and the Purpose of this Article
In the manufacturing industry, the complexity of component management, ordering, and inventory control for a wide variety of screw parts has become a major issue. Screw standardization is a method of streamlining material procurement, improving production line efficiency, and stabilizing quality by adopting common standards such as JIS and ISO to narrow down the parts used. This provides a wide range of practical benefits, including reducing parts inventory, cutting down on ordering mistakes, and lowering the risk of fastening defects.
This article provides a detailed explanation of the basic concepts and practical processes of “screw standardization” for technical staff, production control, quality assurance, and procurement personnel in manufacturing. By presenting key points for implementation, step-by-step procedures, and case studies of cost optimization using procurement in Vietnam, we aim to support your company’s productivity improvement and cost reduction.
Specific Benefits of Screw Standardization
Cost Reduction and Inventory Optimization
By narrowing down the parts used through screw standardization, it becomes possible to optimize order lots. This not only reduces purchasing costs but also significantly cuts down on warehouse space and management man-hours by decreasing the variety of inventory. It mitigates the risk of excess inventory, which is common in high-mix, low-volume production, and leads to improved cash flow.
Quality Stabilization and Prevention of Fastening Defects
By standardizing torque control and tolerances based on common standards (JIS/ISO), the fastening strength of screws can be consistently maintained at a certain level. Establishing work procedure manuals with unified torque values helps prevent fastening defects and rework, reducing the burden on the quality assurance department.
Lead Time Reduction and Procurement Efficiency
Standardized parts can be arranged immediately by suppliers, significantly shortening procurement lead times. Furthermore, sharing common standard specifications among suppliers reduces communication costs in ordering operations and cuts down on man-hours for order mistakes and specification confirmation tasks.
Explanation of Key Points in Screw Standards and Technical Elements
Main Standards (JIS B 0209 / ISO 68-1)
Metric screws are the most commonly used standard in the manufacturing industry, with JIS B 0209 (Japanese Industrial Standards) and ISO 68-1 (International Organization for Standardization) being representative. There are two types: coarse thread (larger pitch) and fine thread (smaller pitch). Coarse thread screws are highly versatile, while fine thread screws are suitable for preventing vibration and loosening.
Key checkpoints when selecting standards:
- Outer Diameter and Pitch Suitability: Consider strength and loosening prevention effects according to the usage environment.
- Material & Surface Treatment: Requirements for corrosion resistance (stainless steel/plating, etc.) and load-bearing capacity.
- Compatibility Check: Affinity with existing tools and on-site processes.
- Cost Comparison: Balance between unit price for bulk procurement and storage costs for small-lot procurement.
Torque Control and Tolerance (Precision Class)
To stabilize fastening quality, proper torque control and screw tolerance management are essential. The torque value can be calculated using the following basic formula:
T = K × D × P
- T (Fastening Torque): N·m
- K (Friction Coefficient): Friction coefficient of the thread and seating surface (generally 0.15 to 0.20)
- D (Nominal Diameter): mm
- P (Clamping Force/Preload): N
The friction coefficient varies depending on the presence of lubricants and surface treatment, so it is important to set the K value based on actual measurement data from the field.
Additionally, by utilizing ISO precision classes (e.g., 6H/6g), the tolerance of screw and nut components can be managed. Generally, “6H/6g” indicates a medium level of precision and is optimal for mass-produced items, but for high-precision applications, selecting “4H/4g” can minimize clearance and improve fastening rigidity.
Implementation Steps and Practical Process for Screw Standardization
Visualize Usage Frequency and Defect Data through Current State Analysis
- Extract screw usage data from ERP or production management systems to visualize the usage amount for each type.
- Identify locations prone to fastening trouble based on defect analysis reports.
Select Optimal Standards to Balance In-house Products and Customer Requirements
- Evaluate the suitability of JIS/ISO standards and finalize requirements for outer diameter, pitch, and material.
- Collaborate with the design department to conduct fastening tests on prototypes and verify the suitability of the standards.
Establish an Internal System by Defining Responsibilities and Creating Workflows
- Clarify the scope of responsibility for purchasing, design, production, and quality departments using a RACI chart.
- Establish a standardization project team and set up regular review meetings.
Develop Training Programs and Standard Work Manuals
- Create torque control procedure manuals and tolerance management checklists.
- Conduct workshops for operators to check their understanding of the standardization procedures.
Evaluate KPIs through Pilot Line Operation
- Set KPIs such as lead time reduction rate, defect rate improvement, and inventory turnover rate.
- Quantitatively evaluate the results of the pilot implementation and identify areas for improvement.
Continuous Improvement and Review through the PDCA Cycle
- Share improvement progress in monthly reviews and devise solutions for issues.
- Reflect improvements in OJT and manual updates, and continue training.
Cost Optimization by Utilizing Procurement in Vietnam
With the local procurement service provided by Ohta Vietnam, it is possible to directly source standardized screws compliant with JIS/ISO standards from within Vietnam. This helps to control transportation costs and customs duties, optimizing total procurement costs. Additionally, by leveraging Vietnam’s manufacturing network, our system for handling high-mix, low-volume production allows for flexible and rapid procurement of various standard parts in small lots.
- Transportation Cost Reduction: Minimize sea and air transport costs through direct transactions with local suppliers.
- Lead Time Reduction: Same-day arrangement and delivery management through local inventory coordination.
- Quality Traceability: Consistent quality assurance through manufacturing lot control and pre-shipment inspections.
- High-Mix, Low-Volume Efficiency: Improve inventory turnover with a distributed inventory model utilizing our Vietnam logistics hub.
Through these measures, we streamline the screw procurement process in the manufacturing industry and enhance cost competitiveness.
Summary and Next Steps
By implementing screw standardization, the following benefits can be achieved:
- Cost Reduction: Improved cash flow through reduced purchasing costs and inventory compression.
- Quality Stabilization: Significantly reduce fastening issues with unified torque control and tolerance standardization.
- Lead Time Reduction: Shorten procurement lead times with standardized parts available for immediate arrangement.
- Operational Efficiency: Reduce man-hours for ordering and inventory management, and facilitate smoother supply chain communication.
We recommend starting with a small-scale pilot implementation on-site, measuring KPIs, and making improvements through the PDCA cycle. Afterward, expand the knowledge gained company-wide and build a global standardization system, including your Vietnam base, to further strengthen competitiveness.
Conclusion
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