How to Choose the Right Fastener?
Choosing the right fastener for your application can be a difficult task. The basics of choosing the right fastener is to size to best fit the aesthetics of the application and to meet strength requirements. Engineers should use a fastener that is not too big or too small and will not fail during operation. Fastener installation methods include self-clinching for threaded nuts to clip-on or snap-in for receptacles. Studs, bolts, and screws can be attached to a panel by using a retainer.
Here are some other design considerations engineers should keep in mind when choosing the right fastener for their product.
Material
Engineers should carefully choose what material is ideal for their application. Steel, stainless steel, and thermoplastics are common fastener materials. Each of these materials have different cost and performance characteristics. Engineers have to consider static load force requirements in their application. Choosing a material that cannot withstand the forces during normal operation could lead to failure.
Steel and stainless steel provide high to medium load performance. Meanwhile, thermoplastic has a low rating when it comes to load performance. This material choice largely depends on the end application. For example, the access panel must hold firmly onto the frame of the car while experiencing all of the forces and vibrations that occur when a car drives down a road. An all metal system is typically used due to the high strength of the material.
Lifecycle
Engineers have to consider how long the fastener will last in operation. Cycle life performance is dependent on the number of expected times users will fasten and unfasten the device, plus the design and material of the fastener. The operating environment may also impact the cycle life of the fastener. Extreme high or low temperatures and salt corrosion may have detrimental effects on the cycle life expectancy.
For example, a car access panel will need to be removed to service the vehicle while performing routine maintenance. The fastener should be able to withstand the user unfastening and fastening the panel. Since the car will have regular maintenance throughout its lifetime, the fastener should be designed to have a cycle life equal to or greater than the expected service life of the vehicle. Southco offers fastener designs for high and moderate cycle lives.
Application Environment
One of the main factors in fastener choice will be the environment that the product will be operating in. Engineers should understand the vibration and shock that the fastener will be exposed to. Other moving parts, dropping the panel, and other operating conditions can vibrate and shock the fastener which can lead to unfastening. For example, a car access panel fastener will be constantly exposed to vibrations from the car operating.
Engineers should fully understand the temperature, chemical, and sunlight conditions that the fastener will be exposed to. Fasteners that are exposed to outdoor environments with sun and wind will likely degrade faster than if the product was only exposed to indoor environments. Chemical exposure from materials, such as oils and cleaning chemicals, could compromise the quality of the fastener. A car access panel is often made of plastic to resist outdoor exposure. The fastener will need to withstand the same conditions without corroding.
Security Requirements
Engineers may be designing products that have certain security requirements. Hand operable fasteners are used when there is no need for high security. Engineers can use wing, bail, and knob style fasteners for various low-security needs. These fasteners are designed for maximum ease of use.
To improve security some fasteners can only be operated with certain tools. This limits access to the enclosure to users who have the correct tool. Users can incorporate unique tools to increase security. There may be certain regulatory requirements that require products to be designed with this type of fastener. Phillips and Slotted stud recesses are examples of tool-operable fasteners.
Engineers should also consider possible criminal activity, where unauthorized users may attempt to damage the fastener to access the enclosure. Fasteners with vandal resistance can help protect enclosures from thieves. Bellcore Electronics Recess has a hex socket with a center pin is an example of a fastener that is resistant to causal opening.
Off-the-shelf fasteners may not fit into your application. You may need to design a unique fastener. The experts at Southco are more than happy to help you develop a customized fastener system to meet your application’s needs. Reach out to Southco today to learn more about all of the different types of fasteners available. Our team is more than happy to answer any questions you may have about fasteners and how they fit into your application.
This article was originally published by Southco.