What ESD Bags Should I Buy?

by Andy on February 18, 2008

Anti-Static BagsThe options are almost endless when it comes to ESD bags on the market. Some of the more popular bags are anti-static bags, static shielding bags and moisture barrier bags. Many of the bags come in different variations and size; which bag you choose depends on your need.

Anti-Static bags are almost exactly like

poly bags.These bags are made with an additive in the material so the anti-static properties of the bag will never wear off. While anti-static bags will not protect what is inside the bag from an electronic charge, they will not build up a charge either.Because of this, an anti-static bag is generally used in a situation where the part being placed in the bag is not particularly ESD sensitive but some of the items it may come in contact with are ESD sensitive.

Static shielding bags are another common type of bags. These bags are made to hold items that are ESD sensitive. They are made up of a multi-layered material which includes a specialized layer to reduce static build-up. Part of the layer is made with aluminum which keeps the charges out of the bag and creates a Faraday cage. A Faraday cage is an enclosure made of a conductive material that blocks out electrical fields. An example of a common Faraday cage is an elevator. Depending on the material used to construct the elevator, cell phones may not work because the elevator is blocking out the signal needed to send or receive phone calls.

Both anti-static and static shielding bags have options for both open top and zip-top.The open top bags are sealed with a heat sealer or folded and secured with either tape or an ESD label.The zip-top bags cost more but have a closure of their own which is similar to a freezer or sandwich bag.

Moisture barrier bags, also known as Dri-Shield bags, are designed to keep items safe from not only ESD but also moisture, radio frequency interference (RFI) and electro magnetic interference (EMI).These bags are very similar to the static shielding bags with the exception of a thick single layer of  metalized material or multiple layers of the metalized material.This addition makes it more difficult for the bag material to “breathe,” which means moisture doesn’t transfer through the bag as easily. The added thickness is what shields magnetic and radio interference.

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