There is a lot of confusion in the electronics manufacturing industry regarding packaging safety and ESD. There is an unfortunate tendency among manufacturers to call pink polymer bags “ESD bags,” which is incorrect. As a result, many circuit boards (and even some energetic materials, such as flammable materials) have been incorrectly packaged.
Pink Anti-Static Bags can dissipate a static charge to ground preventing static charge building up on the package or device within the bags. The material is also antistatic and will not charge up when rubbed against other materials and these bags can be used to safely package/transport your non-ESD sensitive devices within your ESD protected area. However, it does NOT shield against electrostatic discharge events. There are bags that are designed to be used for ESD shielding, which are metalized shielded bags or ESD shielded bags. These are specially designed multilayered bags engineered to prevent a discharge from releasing too much energy into the contents inside the bag.
As an analogy, imagine that packaging a sensitive object in pink poly antistatic bags is like packaging an egg in a pillow and packaging sensitive objects in a shielded bag is like taking that pillow packaged egg and placing it in a steel box. A firm punch could crush the egg in the pillow But when placed in a steel box it will remain unharmed. Likewise, a sensitive object is less likely to experience damage from discharge in a shielded bag than pink polymer packaging.
However, pink polymer material has it’s place for preventing static charge buildup. From a cost perspective, it is usually less expensive than shielded bags, which is part of the reason why so many organizations prefer it. Some organizations have determined through cost-benefit analysis that the risk of using a pink polymer Anti-static bag is achieving their desired goal of risk reduction without the added cost that comes with using shielded bags. While this serves a purpose, it should always come with an awareness that these bags are NOT shielding items from a discharge and are serving no risk mitigation if discharges are causing damage on a regular basis.
To make matters worse, it is quite easy to add pink coloring to a polymer film without adding any anti-static elements to the material. A host of companies around the world have arisen which make counterfeit or low-quality material. At Electro-Tech Systems, we regularly encounter customers who find that the packaging material they purchased is CAUSING problems rather than reducing the risk of static charge buildup. This may be due to a bad batch of pink anti-static polymer, or it may be an outright counterfeit material with fraudulent claims. Customers will ask ETS to test this material to see as a part of root cause or to qualify a supplier in the first place.
Furthermore, some anti-static additives are known to have a short shelf-life. A bag which is tested to be anti-static may lose the anti-static characteristics after a few months. This obviously poses problems for long term usage. To complicate matters even further, some companies re-use packaging material several times to reduce cost.
Be aware that a bag with an ESD symbol or logo does not necessarily mean that it is legitimately an anti-static bag. A good test is to use a wide-range resistance meter and resistance probe, such as the ETS model 871 and ETS model 803B to check if the material is in the dissipative range.
The best risk mitigation efforts should involve the knowledge that:
- Pink Polymer Antistatic bags are NOT ESD shielded bags.
- Just because a bag is pink does not mean that it is ESD safe material.
- Evaluating a supplier of such material should involve determining the resistance or surface resistivity of the material itself, often by using a third-party test lab, such as Electro-Tech Systems for validation.
– Shane Burns, Test Lab Manager at Electro Tech Systems