Are the tools and accessories on your workbench ESD safe? - Part 2
Last week we talked about why insulators in your ESD Protected Area (EPA) can cause problems and started creating a list of the most commonly used insulative items that you should replace with ESD safe alternatives. Missed the post? Catch-up here.
So let's continue with our list:
If you work with solder irons or perform various cleaning tasks at your ESD workstation, you will likely be using water or some sort of cleaning agent. Where do you store those liquids? Plastic cups? If so, that’s a BIG no-no and if you’re truly committed to your ESD Control Programme, you should be switching to ESD protective bottles immediately. ESD dispensing bottles come in all sorts of sizes, colours and with different pumps or spouts. Whatever type you need for your application, you will generally be able to find an ESD alternative.
Examples of ESD safe dispensing bottles - more information
ESD dispensing bottles are dissipative and high-quality types will have no migratory additives which reduces the chance for contamination from the bottle.
When a regular brush is being held by an operator and they wipe it upon a product or assembly, tribocharging occurs due to the contact and separation of the brush bristles on the product. Per the ESD Handbook ESD TR20.20 section 2.4 Sources of Static Electricity includes “Brushes (camel/pig hair and synthetic bristles).” “Even if the operator is grounded, the electrostatic charge will remain on the brush fibres and/or handle. It is therefore a threat to discharge possibly damaging ESD sensitive products. All portions of the ESD brush are to be conductive or dissipative.”
Examples of dissipative and conductive brushes - more information
Summing-up the most important points in regards to using brushes in your ESD protected area (EPA):
- Use dissipative or conductive brushes in an EPA.
- All portions of the brush (handle and bristles) need to be conductive/dissipative.
- Operators need to be grounded during use.
- Choose dissipative bristles if your product/assembly may be holding a charge and Charged Device Model (CDM) failures are a concern.
Probes are ideal for opening plastic cases such as MP3 players, cell phones, laptops, etc. and for popping out batteries. They are also used for holding, probing, and manipulating wires and components during assembly and soldering. ESD safe versions are made of nylon, wood or stainless steel.
Examples of ESD safe probes - more information
The hygroscopic (readily accepts moisture) properties of Nylon will make this tool suitable for use around ESD sensitive components after a few minutes of handling the tool with bare hands. If used with gloves in a clean environment the tools must be dipped in a topical antistatic solution before use in sensitive areas. Topical treatment should be repeated at six month intervals. Without exposure to moisture or antistatic treatment, Nylon is in the insulative resistance range and charges will not be removed to ground. Wood is considered a safe material for use in ESD sensitive areas. It is hygroscopic and has a low propensity for triboelectric charge generation under most conditions. Any charge on a stainless steel probe can be grounded when it is placed on an ESD protected work surface.
Waste bins and bin liners
ESD safe waste bins are generally conductive and are useful in ESD Protected Areas where waste accumulates and cannot be conveniently removed except in bulk. By placing them on a grounded floor, electrostatic charges are removed to ground. They do not require separate grounding when placed on a grounded surface.
Examples of waste bins and bind liners
If you’re currently using standard bin liners, replace those with non-tribocharging ESD versions. Even at low humidity they do not become charged with static electricity and are designed for use in ESD protected areas where electrostatic sensitive devices are present.
And there you have it - a list of of tools and accessories that you should be replacing with ESD protective alternatives. Can you think of any others? Let us know in the comments!