As the name suggests, micro fasteners or nano screws are significantly smaller and lighter than conventionally sized fasteners. They have finer threads and smaller heads compared to regular screws, making them suitable for delicate and compact devices. They’re designed for applications where conventional fasteners would be too large or heavy, and space and weight constraints must be considered.
Despite their smaller size, micro screws serve the same purpose as typical screws: to join or secure two or more objects together. These small screws are only one type of micro fasteners. There are also micro nuts, bolts, washers, rivets, pins, springs, and other micro-sized joining devices.
Micro fasteners are usually measured in fractions of an inch or in millimeters, with thread sizes and lengths ranging from as small as M1 (1mm diameter) — or smaller. Typically, for a fastener to be considered micro, it will have an outer diameter (thread size) of M1.6 or below.
They’re often used in delicate electronic devices like smartphones, laptops, medical devices, and laboratory equipment, where their small size and lightweight nature are essential.
Micro fasteners also find use in the aerospace and automotive sectors. In avionic systems, they’re used to secure aircraft components such as navigation systems, communication devices, and control panels. In vehicles, they’re used to join interior components, securing items like entertainment systems, control panels, and dashboard displays. They’re also used to ensure the secure attachment of sensors and cameras for advanced driver-assistance systems (ADAS).
These tiny fasteners play a crucial role in holding the intricate components of devices together, ensuring they function safely and reliably. Their minuscule size means most micro fasteners require specialized tools and precision during installation, which often requires precision and patience. Sometimes, a micro screwdriver is used with the appropriate tip (Phillips, Torx, slotted, etc.) that securely fits the fastener’s head.
There are also automatic mini and precision screw feeders, typically allowing greater speed and accuracy. The ideal technology can mitigate issues more common in micro installations, such as static charges. This can cause micro fasteners to cling to the surface of a feeder.
When looking for micro fasteners for electronics applications, there are several factors to consider:
Size and shape: like most fasteners, micros are available in various sizes, shapes, and head types — including pan, flat, and round. The size, shape, and head type should be chosen based on the application requirements. The same consideration should be given to the thread type, whether coarse, fine, or metric.
Material: should be selected based on the application requirements, such as conductivity, corrosion resistance, and strength. For instance, it’s crucial to consider the material’s conductivity in electronic applications, particularly for applications involving electrical connections. Common materials for micro fasteners include stainless steel, brass, and titanium.
Drive type: Micro fasteners can come with different drive types, including slotted, Phillips, and Torx. The drive type should be chosen based on the application requirements and the tooling available for installation.
Strength: Consider the tensile strength of the fastener to ensure it can withstand the expected load conditions of the assembly without breaking. Also, choose micro fasteners with the appropriate hardness to resist wear and deformation, especially if they will be subjected to repeated assembly and disassembly.
Quality: It’s always important to choose high-quality micro fasteners to ensure they can withstand the stresses and forces of the application without breaking or stripping. Look for fasteners that meet industry standards and are certified for quality.
Although micro fasteners are more common than ever given the increase in electronics, it can be more challenging to source large qualities. Be sure to purchase these fasteners from reputable suppliers with a history of providing high-quality, reliable products. If necessary, work with suppliers who can provide customized micro fasteners tailored to your specific application requirements.