Washers are crucial components in mechanical fastening systems. They absorb vibrations, distribute loads and prevent fasteners from loosening. Their action in mechanical assemblies enhances performance, stability and durability. These devices come in different designs and types that meet the specific demands of modern manufacturing industries.
Before using washers for any application, you should understand the types available and their functions. This article will explain what washers are, the various types of washers, and how to select the right one for your project.
What are Washers and their Uses?
Washers are mechanical devices that are used in part assembly. You will most times find them in conjunction with different types of fasteners, including screws, bolts and nuts. They are disc-like with a hole in the centre where the fasteners stay. Washers come in various sizes and shapes to meet individual unique preferences and applications.
Furthermore, washers are used across manufacturing industries for many reasons, which include
- Washers ensure even load distribution and prevent damage to the assembly surface.
- They prevent premature loosening when components undergo excessive vibrations and dynamic forces.
- You can also use them in plumbing works for proper sealing to prevent leakage.
- Furthermore, washers offer surface protection to parts in contact with fasteners.
- They are used for alignment and spacing to maintain the appropriate distance between components.
Types of Mechanical Washers in Part Assembly
Washers can be categorised into three; plain, spring and specialised. Let’s discuss these categories in detail.
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Plain Washers
Plain washers are the most common type of washer. They are usually made from high-grade metals such as stainless steel, aluminium and brass. Plain washers do not come with special features and are affordable. The following are common types of plain washers.
Flat Washers
They are thick structures with disc-like holes. The primary function of flat washers is to ensure proper load distribution. Flat washers spread the load over a large surface area when used with fasteners. They prevent direct contact between the fasteners and the workpiece surface. Additionally, flat washers protect the part surface from damage during tightening.
Fender Washers
Fender washers are similar to flat washers. However, they have a larger outer diameter relative to the central hole. As a result, they distribute the load more evenly over a broader area. Fender washers are used with thin or soft materials. They prevent fasteners from pulling through this material type.
Torque Washers
Torque washers are slightly different from the washer types previously described. They have a central square hole that fits carriage bolts. Torque washers’ primary function is to prevent fasteners from turning during assembly. Some have extra teeth that provide better resistance against corrosion.
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Spring Washers
Spring washers are another category you can use in product development. They have unique shapes and designs which affect their applications. Let’s look at the three most common spring washers.
Split Lock Washers
You can also refer to it as helical spring washers because of its shape. Split lock washers are produced by bending a single metal coil into a helical shape. When installed, the sharp edges lock into the part surface to increase friction and prevent loosening.
Wave Washers
They are thin washers with a wave-like shape. The wavy profile of this washer type allows it to compress under stress. This action provides flexibility and tension. Furthermore, wave washers are ideal for noise-dampening applications because they minimise vibrations and rattling.
Belleville Washers
Another name for Belleville washers is conical spring washers. Their unique cone-shaped design allows them to handle high loads and stress. Belleville washers are thermally stable and will not expand or contract with temperature changes.
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Specialised Washers
This category of washers is designed for unique and specific applications. They do more than load distribution and ensure a tight connection. Specialised washers cater to particular challenges depending on the type.
Sealing Washers
This type of washer provides a watertight or airtight seal in fastening applications. A sealing washer is made up of a metal washer with an elastomeric ring. The ring compresses under pressure to create a tight seal. Sealing washers prevent leaks in fluid or gas systems.
Shoulder Washers
Shoulder washers thrive in electrical and electronic applications. They are made from insulating materials such as nylon and PVC to prevent electrical conductivity between fasteners and assembly components. Furthermore, shoulder washers protect against galvanic corrosion.
Tab Washers
These are simply lock washers with tabs. They have one of more tabs and notches and provide more secure connections. Tab washers are known for their anti-rotation capabilities. The tabs lock into a hole to prevent the fasteners from rotating.
Tips for Selecting the Right Washer for Your Project
Using the right washer will determine the success of your applications. With the different types available, choosing the best can be daunting. The following are factors you should consider during the selection process.
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Define the Washer’s Purpose
Determining the primary function of the washer will help you decide on the type to use. Evaluate the purpose and check for proper load distribution, vibration resistance, sealing fluids, and locking. Washers have their specific strong points and roles they play in part assembly.
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Match Material to Environment
The material makeup of the washer is key. It will help determine longevity and how well it can withstand environmental conditions. Common materials used for washers are metals, plastics, rubber and nylon. They have different properties and shortcomings. For instance, stainless steel is suitable for high-temperature environments, while Teflon washers are best for chemical resistance.
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Consider Load and Assembly Needs
You should also keep in mind the type and magnitude of the load. Flat and Belleville washers may be ideal for assemblies with unchanging loads. However, use a split lock or wave washers for those exposed to varying movement and vibration.
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Environmental Changes
It is crucial to account for environmental changes when choosing the best washer for your project. You should assess if the application will encounter serious temperature changes. Stainless steel washers are perfect in this instance. Additionally, evaluate exposure to moisture, corrosion, and chemicals.
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Proper Sizing and Fit
Choosing the right washer is not just about the material and environmental conditions. It also extends to prioritising proper sizing and fit. Make sure that the inner diameter matches the fastener and that the outer diameter is sufficient for adequate load distribution. Furthermore, the washer should be thick enough to ensure durability and load-bearing capacity.
Conclusion
Mechanical washers are indispensable during part assembly. They are used with fasteners for proper load distribution, vibration prevention and sealing joints. Furthermore, some specialised ones provide watertight seals and prevent electrical conductivity. However, you must use the correct washer type to make the most of it. When making your decision, consider your project requirements, washer material, and environmental conditions.
