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July 18th, 2025

Key Points for Selecting Fastening Tools to Improve Efficiency on the Manufacturing Floor: Securely and quickly fastening bolts and screws on the production floor is a crucial element that affects both product quality and line efficiency. Particularly at manufacturing bases in Vietnam, where high-mix, low-volume production and a shortage of skilled workers are advancing, the selection of appropriate fastening tools directly impacts yield and operating rates. This article will systematically explain the approach to tool selection and present a decision-making framework that can be immediately utilized in practice. Purpose of this article To systematically explain the “method for selecting fastening tools,” which is essential for increasing the operating rate of production lines, and to support on-site personnel in confidently choosing the optimal tools. Target Audience Engineers from Japanese companies working at or collaborating with factories in Vietnam who are in charge of production technology, maintenance, or equipment design, or local staff tasked with improving the fastening process. What you will gain after reading Decision-making criteria for selecting fastening tools based on bolt specifications, site conditions, and management accuracy. A checklist for comparing tools tailored to on-site conditions. Information on the support menu offered by Ohta Vietnam and the contact point for inquiries. If there is a large variation in torque values, rework such as re-tightening and quality inspection occurs, prolonging the cycle time. According to test data from the Tohnichi Torque Handbook, it takes an average of 9.6 seconds to tighten one M8 bolt with a manual torque wrench (direct reading type), whereas a fully automatic nutrunner can shorten this to 3.2 seconds, about one-third of the time. Furthermore, because powered tools have a constant rotation speed, the torque curve is stable, and there are reports of cases where the variation in tightening force (Cpk) improved from 0.6 to 1.4. In this way, tools with higher repeatability can significantly shorten work time, making them an essential condition for home appliance and motorcycle parts lines with short line tact times. A shortage of skilled mechanics has become chronic in ASEAN countries, including Vietnam, requiring the creation of systems that maintain quality while reducing the number of workers per line. Hydraulic torque wrenches and bolt tensioners allow even a single person to safely reproduce high torque through “reaction force assurance” and “simultaneous tightening,” realizing minimization of personnel and reduction of physical burden. In addition, preset-type torque wrenches and digital nutrunners are valued for their ability to provide OK/NG feedback with sound or light, allowing even new workers to become ...

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July 16th, 2025

Ohta’s Flexible Procurement Service Provides a Competitive Edge for Manufacturing Businesses: The Vietnamese manufacturing industry has expanded rapidly in recent years, with an increase in new investments from companies, including foreign-affiliated ones. The entry of Japanese companies has been particularly active, with some data reporting that approximately 80% of these companies are in the manufacturing sector. Amidst this growth, procurement challenges have become apparent, such as “difficulty in predicting the quality and delivery times of local suppliers” and “inability to place bulk orders for high-mix, low-volume parts.” Source: JETRO “Excellent Vietnamese Supporting Industry Companies” Ohta Vietnam offers flexible procurement services to solve these practical challenges. By utilizing partner factories selected from JETRO’s list of excellent companies and our proprietary database, we provide one-stop support in Japanese, English, and Vietnamese, quality control compliant with ISO/JIS standards, and total cost optimization. For companies looking to diversify their procurement sources under a “China +1” strategy, we have established a system that allows them to safely and efficiently take the first step into procurement in Vietnam. This article will explain the latest trends in the procurement environment in Vietnam and how to utilize Ohta Vietnam’s services, with concrete examples for purchasing and materials managers in the manufacturing industry. The purpose of this article is to provide hints for updating your company’s procurement strategy after reading it. In recent years, Vietnam has been in the spotlight as the top candidate for the “China +1” strategy. As of 2024, the average manufacturing wage is equivalent to 304-340 USD per month, which is less than half of that in coastal China (hourly wage is 3 USD in Vietnam compared to 6.5 USD in China). Furthermore, tariff benefits can be enjoyed due to the effectuation of large-scale FTAs such as the CPTPP and RCEP. It is not uncommon for cases to see procurement cost reductions of up to 30% due to these factors. Against the backdrop of US-China friction and rising geopolitical risks, the demand for multinational diversification of parts supply chains is growing year by year. FDI into Vietnam in the first half of 2025 is at a record high of 11.7 billion USD, an 8.1% increase from the same period last year. Source: VietnamNet “Vietnamese workforce sees more money in their wallets for 2024”, Vietnam News “Foreign investment inflows rise to $21.5 billion in the first half of 2025” On the other hand, in high-value-added fields such as electronics and medical equipment, the ability to handle “high-mix, low-volume” and “short delivery ...

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July 10th, 2025

The Proper Use of “Custom Screws” and “Standard Products”: The Key to Optimizing Cost Performance: In the world of manufacturing, a single screw, just a few millimeters in size, can have a significant impact on the overall quality, cost, and even the delivery time of a product. A screw is not merely a fastening component; it is a “linchpin of machinery” that is involved in all processes of design, procurement, production, and maintenance. Especially in recent years, with the diversification of products, shorter delivery times, and the advancement of overseas procurement, the optimal use of “standard screws” and “custom screws” has become more important than ever. Standard screws offer low cost and stable supply, but they also carry the risk of significantly compromising performance if they do not match the product or structure. On the other hand, custom screws can be optimized for required performance, but cost and lead time often become issues. This article provides practical judgment criteria and optimization perspectives that designers, procurement managers, and manufacturing engineers can implement on-site to address this “screw selection dilemma.” We will organize the differences between custom and standard screws, their manufacturing processes, and cost-performance considerations, and provide a practical explanation that includes a perspective rooted in the field, particularly in procurement and manufacturing in Vietnam. We hope that this article will provide you with practical hints on how reviewing your screw selection can achieve both improved product reliability and cost reduction. Screws, often used inside products, are not visually prominent. However, in reality, they are a crucial element that influences the assembly precision, performance, and safety of a product. It is not uncommon for the choice of a single screw to significantly alter performance aspects such as durability and vibration resistance. The selection of a screw is not simply a task of applying a standard; it affects the overall cost structure, delivery time management, and quality assurance of the product. For example, choosing an unnecessarily high-performance custom screw can lead to over-engineering, while a standard product that fails to meet the required performance can lead to product trouble. Judgment at the design stage is particularly important for screw selection. By quickly identifying “whether a standard product can be used” or “which parts should be custom-made,” it is possible to prevent rework and cost increases in later processes. This is an area where collaboration between design and procurement is required. For purchasing departments and maintenance sites, screw selection is a critical issue related to operational costs and ...

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July 03rd, 2025

Prevent Fastening Failures in Manufacturing! Summary of Case Studies and Countermeasures: In manufacturing sites, fastening with screws and bolts is a crucial process that supports the reliability of all machinery and equipment. However, if proper tightening is not performed, “fastening failures” such as loosening or breakage can occur, leading to quality defects and serious accidents. Such failures often arise from mistakes in the design phase, problems with tools or the working environment, or external factors like material properties, corrosion, or temperature, requiring constant attention on site. This article will clarify the basic mechanisms and main causes of fastening failures, while also providing easy-to-understand examples of actual troubles and their countermeasures. In manufacturing sites, fastening failures involving screws and bolts are frequently reported, and many of them lead to serious consequences such as the detachment of structural components or machine stoppage. Below are some representative issues along with their summaries. Case of Nut Detachment Due to Creep of Resin Parts In a certain device, a nut securing a resin part detached during operation. The cause was the creep of the resin due to axial force during fastening, and further deformation progressing due to external forces during use. As a result, the tightening force of the nut was lost, and the machine stopped. Fatigue Fracture of Rail Fixing Bolt (Poor Heat Treatment, Insufficient Torque) An SCM435 bolt used for rail fixing in railway vehicles experienced fatigue fracture due to repeated loads. The cause was coarse metal microstructure due to poor heat treatment, in addition to improper management of the tightening torque. Ultimately, fatigue fracture was confirmed through fracture surface observation. Defect Outflow Due to Misaligned Tightening and Double Tightening of Small Screws In the assembly process of electronic devices requiring minute torque tightening, misaligned tightening and double tightening that could not be visually confirmed occurred. The outflow of defective products was a challenge, but by introducing an error detection device that can precisely manage torque and angle, the outflow was completely prevented. Trouble and Undetected Issues Due to Appearance Defects (Burrs, Cracks) On a mass production line, burrs generated during the rolling process and minute cracks caused by forging were overlooked during inspection, leading to insufficient strength and fastening failures after assembly. This case highlighted the limitations of manual inspection. A common lesson learned from these cases is the importance of a three-pronged approach “design, process, and inspection” to ensure fastening reliability. Importance of Strength Confirmation and Material Selection at the Design Stage ...

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June 27th, 2025

Procurement strategies in the era of small quantities and a wide variety of products: the latest methods that manufacturing companies should know about: In the manufacturing industry, there is a shift towards “high-mix, low-volume” production to meet diversifying consumer needs and rapid market changes. Against this backdrop, challenges that traditional procurement strategies cannot address are becoming apparent. Examples include increased procurement costs, complicated parts inventory, and cumbersome supplier management. This article introduces procurement methods suitable for the high-mix, low-volume era from a professional and practical perspective, including examples from Vietnamese manufacturing industries and GIS OTA Vietnam’s support cases. “High-mix, low-volume” production is a manufacturing method where a rich variety of products are available, but the production volume per item is small. This style enhances responsiveness to diverse consumer needs while also contributing to reducing the risk of excess inventory. However, it also creates significant changes and challenges in procurement operations. In contrast to conventional “low-mix, high-volume production,” where a fixed set of items could be procured and stored stably, high-mix, low-volume production necessitates procuring more parts in smaller lots and with shorter lead times. This leads to issues such as rising procurement costs, an increase in the number of suppliers, and increasingly complex inventory management. In such a situation, “strategic procurement,” which combines procurement classification according to order patterns, utilization of cloud-based procurement systems, and flexibility in local procurement, is gaining attention. This makes it possible to achieve both overall procurement efficiency and flexibility, thereby realizing competitive manufacturing. Procurement in high-mix, low-volume production presents multifaceted challenges different from traditional mass procurement. Below, we will specifically explain the main challenges and methods for solving them. When sourcing a wide variety of parts in small quantities, unit costs tend to be higher. Additionally, each part may come with different delivery times and ordering conditions, which increases the workload for ordering and inspection. These inefficiencies ultimately drive up overall procurement costs. Solution: Clarifying procurement policies according to order patterns (e.g., high-frequency/small-lot vs. low-frequency/large-lot) is effective. For example, by switching frequently used standard parts to forecast orders while ordering custom parts as needed, inventory and costs can be optimized. An increase in product types directly leads to an increase in the number of suppliers. If suppliers are dispersed, managing quality and delivery times becomes difficult, potentially destabilizing overall manufacturing. Solution: It is necessary to consolidate suppliers and strengthen relationships with those capable of handling multiple items. Real-time information sharing through EDI (Electronic Data Interchange) and ERP integration also contributes to the efficiency of procurement operations. Due to ...

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June 19th, 2025

How to Choose the Right Screws for Your Production Line: How to Achieve Efficiency and Quality at the Same Time: “Screws” are used daily on production lines. However, did you know that the selection of this small part greatly affects the efficiency of the line and the quality of the product? Inappropriate screws can lead to work delays and poor quality, which can lead to increased costs and loss of credibility. It is important not to underestimate “just a screw” and choose strategically. In this article, we will explain to those at manufacturing sites a practical method for selecting screws to balance the “efficiency” and “quality” of the production line. Please use this as a hint for daily improvement activities. A mistake in screw selection can cause problems that cannot be overlooked. Let’s look at the impact from both the perspectives of efficiency and quality. Loss of work time: Difficulty in screwing and slippage of the driver bit (cam out) worsen the takt time. Hinderance to automated lines: Dimensional variations in screws and poor supply can cause automatic machine stoppages (short stoppages). Shortened tool life: Inappropriate screws can accelerate tool wear, increasing replacement costs and time. Increased management effort: Having a large number of screw types can make inventory management and ordering tasks more complicated. Failed fastening: Insufficient torque management can lead to loose or damaged screws, reducing product reliability. Problems with the screws themselves: Insufficient strength or poor quality of the screws can cause product damage or malfunction. Problems when fastening dissimilar materials: Problems can occur due to electrolytic corrosion (galvanic corrosion) or differences in thermal expansion. Recall risk: Screw defects can cause serious product accidents and lead to recalls in many cases. In this way, screw selection is an important factor that is fundamental to productivity and product reliability. So, how can we improve production efficiency? Here are some specific points for improvement when selecting screws. This is a design that makes tightening by hand or with tools smoother. Easy to screw in: The tapered shape and guide shape of the tip make it easy to insert into the hole. Reliable torque transmission: Recess shapes such as hexagonal holes and Torx® prevent cam-out and transmit force reliably. Improved workability: Low head shapes and flanged shapes prevent interference with parts and help with positioning. For automated machines to operate stably, the screws themselves must also be of high quality. High precision and high quality: High dimensional accuracy and the absence of burrs and foreign matter are essential. Compatibility with ...

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June 12th, 2025

Prevent Over-Tightening! What Is the Proper Torque for Fastening Screws?: Are you thinking, “It’s just a screw”? In the world of manufacturing, how you tighten this small component can significantly affect the quality and safety of a product. One of the most important factors is “torque management”—in simple terms, how much force is applied when tightening a screw. If you apply too much force, the screw or parts may break. On the other hand, if the force is too weak, the screw may loosen over time, potentially leading to unexpected problems or accidents. So, what’s the right way to do it? This article will answer that question. We’ll clearly explain everything you need to know about the “proper tightening torque”—from the basics to practical applications on the production floor. This is a must-read for anyone involved with screws: manufacturing engineers, quality control personnel, designers, and on-site workers alike. Let’s dive in! Let’s start with the basics—what “tightening torque” actually means. Tightening torque refers to the rotational force applied when tightening a screw or bolt with a wrench or similar tool. It’s calculated by multiplying force (N) by the distance from the center of rotation (m), and it is expressed in units of N·m (Newton meters). So why do we tighten screws? The purpose is to generate axial force that firmly holds the parts together. When you tighten a screw, it slightly stretches. The force trying to return it to its original length is the axial force. Think of it as an invisible, powerful spring clamping the parts together. Thanks to the friction from this axial force, the components stay fixed and don’t slip or loosen. In other words, tightening with the right torque = getting the right axial force. That’s the essence of screw tightening. Have you ever thought, “I better tighten this really well!” and used too much force? That mindset can actually backfire. Both over-tightening and under-tightening can cause various problems. Over-tightening (over-torque) can cause “damage” The screw or part may break!: The screw may stretch too far or even snap. If the part being screwed into is soft, it may become dented or cracked. More likely to loosen instead?: If the screw thread is damaged by over-tightening, friction changes can cause unexpected loosening. Under-tightening (under-torque) can lead to “loosening or detachment” It’s loose before you know it!: Vibrations and temperature changes can gradually loosen the screw. This is a very common issue. Looseness and malfunction: If parts are not securely fixed, ...

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June 05th, 2025

Commonly Used Screw Sizes in Manufacturing: Quick Reference Chart by Standard: In manufacturing sites, screws are truly unsung heroes. While they may not be prominent, they are indispensable and crucial components for assembling machinery and products. Without screws, everything around us, such as cars, home appliances, and furniture, would fall apart. The role of screws is not merely to fix parts. By selecting the appropriate screw and tightening it correctly, the safety and durability of the product can be ensured. Conversely, using an inappropriate screw or insufficient tightening can lead to product failure or accidents. The basics of screw selection involve considering three elements: size, standard, and material. Size: Choose according to the thickness of the part to be attached and the size of the screw hole. Standard: Choose according to the place of use and parts, such as metric threads or inch threads. Material: Choose according to the operating environment and required strength, such as iron, stainless steel, or titanium. It can be said that comprehensively judging these elements and selecting the optimal screw is the first step in quality control at manufacturing sites. This article comprehensively provides necessary information about screws commonly used in manufacturing sites, focusing on a quick reference table by standard, including their types, applications, tightening torque, materials, and strength. We hope this deepens your knowledge of screws and helps you in your daily work. Screw sizes and standards vary widely depending on the place of use and application. Here, we introduce representative screw standards commonly used in manufacturing sites in a quick reference table format. Metric threads are screws measured in millimeters and are widely used in Japan and Europe. They are based on JIS B 0205 standard. Quick Reference Table: Typical M-Thread Sizes Nominal Diameter (M) Pitch (mm) Typical Tool Size (mm) M3 0.5 5.5 M4 0.7 7.0 M5 0.8 8.0 M6 1.0 10.0 M8 1.25 13.0 M10 1.5 17.0 M12 1.75 19.0 Inch threads are screws measured in inches and are mainly used in the United States and the United Kingdom. Standards include Unified Thread (UNC/UNF) and Whitworth Thread (BSW). Quick Reference Table: Typical Inch Thread Sizes Nominal Diameter (inch) Pitch (threads/inch) 1/4 20 (UNC) 1/4 28 (UNF) 3/8 16 (UNC) 3/8 24 (UNF) 1/2 13 (UNC) 1/2 20 (UNF) Pipe threads are used to seal pipes and fluids. There are two types: tapered threads (R/PT) and parallel threads (G/PF). Quick Reference Table: Typical Pipe Thread Sizes Nominal Diameter Pitch ...

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May 22nd, 2025

What Are Heat-Resistant and Corrosion-Resistant Screws? Characteristics of Products Suitable for Harsh Environments: In the manufacturing industry, screws used in harsh environments exposed to high temperatures and corrosive substances are indispensable. In such environments, ordinary screws cannot maintain their performance, which may lead to serious accidents or deterioration in product quality. Therefore, special screws with excellent heat and corrosion resistance are required. This article explains in detail the types, characteristics, and actual use cases of heat- and corrosion-resistant screws. It especially targets engineers and procurement personnel in the manufacturing industry, covering how to choose the right screws, important precautions, and the latest technology trends. This will provide readers with the knowledge needed to use products safely and efficiently even in harsh environments. Heat-resistant screws are intended for use in high-temperature environments and are made from special materials. The main ones include stainless steel, heat-resistant alloys, and ceramics. Stainless Steel: Ferritic and austenitic stainless steels are highly resistant to high-temperature oxidation and are relatively inexpensive. Ferritic types in particular are excellent at maintaining strength at high temperatures. Heat-Resistant Alloys: Heat-resistant alloys such as nickel-based alloys can be used at even higher temperatures and are widely used in the aerospace and power generation industries. Ceramics: Ceramics like alumina and zirconia have extremely high heat resistance but are brittle, which limits their application environments. These materials are selected according to the usage temperature and environment to produce screws with appropriate characteristics. There are standards for heat-resistant screws to ensure their performance in high-temperature environments. Representative standards include JIS G 3411 (stainless steel bars for high temperature) and JIS G 4901 (heat-resistant alloy bars). These standards specify the chemical composition, mechanical properties, and high-temperature performance of materials, making it essential to select screws that meet the appropriate standards for the application environment. Heat-resistant screws are used in various fields exposed to high temperatures, such as semiconductor manufacturing equipment, the aerospace industry, and automotive components. Semiconductor Manufacturing Equipment: Used to fix parts of equipment used in high-temperature processes. Aerospace Industry: Screws that can withstand high temperatures are essential for joining jet engine parts and airframe structures. Automotive Components: Used in high-temperature areas such as around engines and exhaust systems. In these cases, the screws must also resist vibration and corrosion, so appropriate materials and standards must be selected. Corrosion-resistant screws are used in environments exposed to corrosive substances such as moisture, chemicals, and saltwater. Therefore, materials with excellent corrosion resistance are selected. Stainless Steel (Austenitic, SUS316L): Contains chromium ...

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May 16th, 2025

Difference Between Bolts and Nuts: Essential Knowledge for Manufacturing Personnel: In the manufacturing field, bolts and nuts are critical fastening components that influence product quality and safety. However, due to the wide variety of types and standards, many people may feel uncertain about their selection and use. This article provides a clear explanation of the basics of bolts and nuts for those working in manufacturing. From the differences between bolts and nuts, to types, standards, fastening techniques, and procurement strategies, it comprehensively covers practical information. By reading this article, you will be able to choose the right bolts and nuts, ensuring a safe and efficient manufacturing environment. A bolt is a male-threaded fastener used to securely join two components. The threads are cut on the outside and are used in combination with a nut. Hex bolts are commonly used in construction and machinery assembly, while socket head bolts are useful for working in tight spaces. Eye bolts are used for lifting objects, and wing bolts can be tightened by hand, making them suitable for frequent removal. When selecting a bolt, consider strength, size, material, and surface treatments to prevent rust. A nut is a female-threaded component that is used in combination with a bolt to fasten parts. Threads are cut on the inside. Hex nuts are the most common, while cap nuts cover the end of a bolt to improve safety. Wing nuts are easy to tighten by hand, and spring nuts are excellent for preventing loosening. When selecting a nut, be sure to check compatibility with the bolt, fastening strength, and anti-loosening features. Proper bolt and nut combinations are essential to ensure fastening strength, safety, and durability. If the thread diameter, pitch, or material do not match, it can lead to loosening or breakage. Especially in environments with vibration or heavy loads, proper matching and fastening control are critical. JIS standards are national standards aimed at improving the quality and standardization of industrial products in Japan. In the case of bolts and nuts, detailed specifications exist for dimensions, materials, and strength, and they are widely used within Japan. Representative examples include JIS B 1180 for hex bolts and JIS B 1181 for hex nuts. In recent years, new JIS standards conforming to ISO have also been introduced to align with international standards. ISO standards are international standards defined by the International Organization for Standardization and are widely adopted in global trade. The primary difference from JIS standards lies in ...