Column
media
column
How to Choose the Right Screws for Your Production Line: How to Achieve Efficiency and Quality at the Same Time
Introduction: Just a screw, but still a screw The importance of selection that affects the production line
“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.
Why is screw selection important? Understanding the impact on the production line
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.
Direct impact on production efficiency
- 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.
Serious impact on product quality
- 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.
Dramatically improve production efficiency! Key points for screw selection
So, how can we improve production efficiency? Here are some specific points for improvement when selecting screws.
Shapes and features of screws that reduce work time
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.
Don’t stop the automated line! Conditions for screws for automated machines
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 supply method: Choose a supply method suitable for your company’s automated machine, such as a parts feeder or tape reel.
- Surface condition: It is also important that the surface is smooth and suitable for the suction method.
The key is to decide the specifications in cooperation with the automated machine manufacturer.
How to proceed with efficiency through standardization and commonization
Narrowing down the types of screws used is the basis of efficiency.
- Benefits: You can expect simplified inventory management, cost reduction (bulk purchases), and consolidation of tools and equipment.
- How to proceed: Consciously unify the types of screws from the design stage and work with related departments to standardize. Cooperation with suppliers is also essential.
Utilizing special screws to reduce processes
There are also screws that can reduce the assembly process itself.
- Types that do not require pilot holes or nuts: By using tapping screws, drill screws, self-forming screws, etc., you can eliminate the trouble of pilot hole processing and nut tightening.
- Reduced part count type: By using SEMS screws with integrated washers or screws with anti-loosening functions, the number of parts and assembly man-hours can be reduced.
Using these screws in the right places with the right materials makes the production line simpler.
Building unwavering quality! Key points for screw selection
It is extremely important to select screws not only for efficiency but also to ensure product reliability. Let’s look at some key points for improving quality.
To achieve stable torque management
Proper torque management is the basis for obtaining stable fastening force.
- Key elements: Material and strength classification that meet the required strength, surface treatment with a stable friction coefficient, and high dimensional accuracy. These stabilize the relationship between torque and axial force (actual pressing force).
- Key points: The quality of the screw itself determines the accuracy of torque management. Choose screws of reliable quality.
Technology and selection to prevent the biggest enemy, “loosening”
Loosening of screws caused by vibration, temperature changes, etc. can cause serious problems.
- Main countermeasures:
- Physical lock: Spring washers, toothed washers, nylon nuts, double nuts, Hardlock Nuts®, etc.
- Increased friction: Anti-loosening adhesives, screws with nylon patches, etc.
- Special shapes: Special thread shapes (such as Thread Lock®), ribbed flanges, etc.
- Selection: Consider the usage environment, cost, workability, and maintainability, and choose the most suitable method to prevent loosening.
Preventing tightening problems (cam-out, thread stripping, etc.)
Problems during work also affect quality.
- Countermeasures: Use a recess shape that is less likely to cam-out, select an appropriate strength category, and tighten with the appropriate torque.
- Tool management: Use a high-quality driver bit that matches the screw, and replace it when it wears out. Periodic calibration of torque management tools is also important.
Precautions and countermeasures for fastening dissimilar materials
Caution is required when combining different materials.
- Prevention of electrolytic corrosion: Select metals with small potential differences, use insulating washers, and select appropriate surface treatments.
- Countermeasures for thermal expansion differences: Use tapping screws for resin, provide clearance, and other designs that relieve stress.
Poka-yoke (error prevention) ideas to prevent human error
Mechanisms to reduce human error are also important. They are called poka-yoke.
- Visual identification: By changing the color of the screw or marking it, mistakes are made easier to see.
- Identification by shape: By using screws and tools of different shapes, misuse is prevented physically.
- Systematic measures: There is also a method to manage the tightening history using RFID tags, etc.
Balancing efficiency and quality: Practical approach and collaboration
How can we balance efficiency and quality? A practical approach and organizational efforts are required.
A way of overcoming trade-offs
- Goal setting: Clarify the priority of screw selection based on the required quality and cost target of the product.
- VAVE approach: Review the type of screw and fastening method to see if we can reduce costs and labor while maintaining and improving function and value.
- Standardization and automation: By combining these, we aim to reduce variation and achieve both efficiency and quality.
Recommendation for interdepartmental collaboration: From design to procurement
The optimal selection and introduction of screws cannot be achieved without cooperation between departments.
- Information sharing: It is important to have a system in place to share design intent, production requirements, quality standards, cost targets, etc. with related departments (design, production engineering, manufacturing, quality, procurement).
- Concurrent engineering: Each department is involved from the early stages of development to discover and solve problems early.
Procurement strategies support the line
Reliable parts procurement is essential for stable production.
- Supplier management: We comprehensively evaluate quality, cost, delivery time, technical capabilities, etc. and select reliable suppliers.
- Inventory management: We maintain appropriate inventory levels based on demand forecasts. JIT (just-in-time) delivery and VMI (supplier inventory management) are also effective.
- Reducing lead time: Strengthening cooperation with suppliers and considering domestic or neighboring countries (e.g., Vietnam) procurement are also important.
Handling small-lot, multi-product production
For multi-product production, ingenuity in screw management is required.
- Standardization and modularization: Standardize screw types as much as possible across product groups.
- Flexible equipment: Introduce automated equipment that can handle a wide variety of products and easily change setups.
- Worker skills: Promote multi-skilling and thoroughly implement standard work.
Examples of improvement in Vietnam’s manufacturing industry (overview)
Here in Vietnam, improvements are being made by reviewing screws. There are factories that have increased efficiency by reducing processes through the use of tapping screws and reducing the number of parts by using SEMS screws. There are also cases of high-quality screws being introduced in conjunction with automation, mainly among Japanese companies. (As of April 2025)
Summary: Improve your production line by choosing the best screw
Screw selection is a critical factor that directly influences the efficiency and quality of a production line. Choosing the right screws is not only about cost reduction—it can also be considered an investment in strengthening competitiveness.
The key points for achieving both efficiency and quality are as follows.
- Fitness of purpose: Clarify specifications that meet product requirements and production conditions.
- Standardization: Consolidate screw types to optimize management and costs.
- Automation: Select screws suitable for automation for efficiency and stabilization.
- Quality assurance: Address quality issues such as loosening, torque, and defect prevention.
- Collaboration: Build a cooperative system between departments and with suppliers.
We encourage you to review the screws currently used in your production line and explore opportunities for improvement.
With optimal screw selection, your production line can evolve to the next level.
Conclusion
For inquiries regarding samples or materials, please respond to this email or contact our sales representative!
At Ohta Vietnam, we not only provide ready-made products such as screws and bolts, but also support activities in the manufacturing field such as cutting, inspection, assembly, packaging…
Our equipment list is here
As a “specialized support” for the manufacturing industry in Asia. If you have any related questions, feel free to contact Ohta Vietnam for detailed support!
URL: https://ohtavn.com/en/contact/