Proper protection of circuits and electronic components against electrostatic discharges is important not only during their production but also at the stages of storage, dispatch, and transport. ESD bags are the primary protective measure here.
From TME warehouses, you can purchase various types of ESD bags. They come from recognized and specialized manufacturers such as: Antistat, Desco Europe, Eurostat Group or StaticTec. Since this is a diverse assortment, below we present an overview combined with an explanation of the technologies most commonly used for protecting electronics from electrostatic charges. It should also be emphasized that most of the presented solutions can be purchased in packages (often 100 pcs.) and directly from TME, which minimizes shipping time.
Types of ESD Packaging
Below are presented the two most important features of ESD bags (material of construction and closure method), highlighting the most common solutions. Of course, when choosing a product, the size of the packaging will also play a key role. From the TME catalog, bags are available with widths from 50mm to 610mm and lengths from 76mm to 772mm, as well as sleeves for sealing (100…250m). This allows for the protection of both small components and circuits with a significant surface area (e.g., computer motherboards, machine modules, etc.).
Closure Methods
First of all, it should be noted that there are three typical ways to close ESD bags: ziplock, heat-sealed, adhesive. The first is the simplest and known from ordinary packaging. Its biggest advantage is the possibility of multiple use of the lock. This solution is most often used for manual packaging of goods and requires some skill. A faster method is offered by bags with a self-adhesive strip – however, these can be used a limited number of times before the adhesive becomes contaminated and degrades.
In conditions of mass production or dispatch, where machine packaging is required, heat-sealed bags or sleeves are most commonly used. In addition to speeding up the process, they offer another significant advantage: the closure is hermetic, i.e., it prevents contamination of the interior, penetration of moisture, etc. Moreover, this way it is possible to create vacuum packaging (using products designed for this purpose).
Material of Construction
The diversity of materials from which ESD bags are made is easiest to explain by focusing on the principle of operation and properties of packaging for electronics. Their primary task is to neutralize electrostatic charges.
Pink Polyethylene
When making bags from polyethylene, substances are added to them, which cause the material to achieve a medium level of electrical conductivity. This chemical composition ensures that charges appearing on the surface are gradually dissipated. This helps to neutralize the potential difference between the packaged component and the environment.
With Metallic Layer
A higher level of protection is offered by solutions made from metallized film. The outer layer of plastic reduces charge accumulation and mechanically protects the interior. The metallic layer (most often made using aluminum, i.e., a material with very low resistance) creates a kind of Faraday cage around the contents, additionally neutralizing charges. In the case of some ESD bags, the metal layer is thick enough (or multiple) that they achieve shielding properties – in this way items are protected that could be damaged not only by electrostatic discharges but also by electromagnetic radiation.
Additionally, TME offers bags made from polyethylene and carbon fiber additives. Such material not only dissipates electrostatic charges – it also has increased resistance to UV radiation (including sunlight) and protects the contents from exposure.
Mechanical Protection
In some cases, especially when securing printed circuits covered with delicate components, in addition to the issue of electrostatic discharges, mechanical protection is also important. Here, the best solution is bags whose walls are covered with bubbles, i.e., made from so-called bubble wrap. Such film can also be one of the layers forming the packaging, thus securing the goods in many aspects.
