SEMS Services
A SEMS fastener is a pre-assembled screw and washer combination created during the thread rolling operation. In this process, one or more washers are placed onto the fastener blank before threads are rolled. Because the outside diameter of the rolled threads is larger than the washer bore, the washer becomes permanently captive on the fastener. This results in a single, ready-to-use component that cannot be separated during handling or assembly.
Benefits of SEMS Fasteners
- Reduced Assembly Time: With the washer permanently attached, operators no longer need to fumble with separate parts. This speeds up production lines and simplifies manual or automated assembly.
- Lower Total Cost: Eliminating the need to source, handle, and install washers separately reduces labor costs, inventory management, and part counts.
- Improved Reliability: The captive washer is always in place, ensuring consistent performance, preventing loss during assembly, and reducing the risk of field failures caused by missing washers.
- Versatility: SEMS fasteners can be configured with different washer types (tooth lock, flat, conical, etc.) to provide specific performance benefits such as vibration resistance, load distribution, or electrical grounding.
- Better Ergonomics and Safety: Operators handle fewer loose washers, reducing strain, improving efficiency, and minimizing dropped or misplaced parts.
Industries That Use SEMS Fasteners
SEMS fasteners are widely adopted in industries where efficiency, consistency, and vibration resistance are critical, including:
- Automotive: Used in both interior and under-hood assemblies where speed and reliability matter.
- Electronics & Electrical Equipment: For attaching panels, covers, and components where small, precise fastening is required.
- Appliances & Consumer Products: To streamline high-volume assembly lines.
- Industrial Equipment & Machinery: In assemblies that must resist vibration and heavy use.
- Defense: For lightweight, reliable fastening where captive components simplify assembly.
Common Applications
- Dashboard and interior trim panels
- Electrical connectors, panels, and enclosures
- Appliance housing and subassemblies
- Automotive underbody and engine components
- Small equipment and consumer products requiring efficient mass assembly
Why Choose SEMS Fasteners?
SEMS fasteners combine the function of a threaded fastener and washer into a single, efficient solution. By integrating the washer during thread rolling, they deliver faster assembly, reduced costs, and improved performance. Whether your need is vibration resistance, load spreading, or streamlined production, SEMS fasteners are a proven choice across multiple industries.
Why Valley Fastener?
We know that your reputation depends on the quality and tolerances of our products. We have nearly 50 years in business as a supplier for major OEMs across medical device manufacturers, automotive manufacturers, military & defense, the energy sector, and electrical component manufacturers. Valley Fastener is the largest fastener manufacturer in North America and has an international distribution network that allows us to control quality from design through shipping. Let our manufacturing experience guide your product design to ensure you’re getting the most cost-effective solution.
Contact one of our experts today to answer any questions or for a detailed quote.
