ESD Control Process
- a tutorial or summary about how to develop an ESD control programme or ESD process to ensure that ESD is addressed in a structured way.
ESD, Electrostatic Discharge is a fact of life that needs to be accounted for in any environment in which electronics equipment or assemblies are manufactured, repaired or serviced. While it is possible to put many measures in place to combat ESD, this can only be successful if a complete ESD control process or programme is put in place. An ESD control programme will address all the areas of ESD relevant to the particular area, and in this way the ESD control process will address all the relevant problems.
In view of the importance of ESD in today's electronics arena, it is imperative that organisations dealing with electronics equipment develop an ESD programme or ESD process to address all the issues in a structured manner. Additionally it is possible to release the ESD control process in such a way that all people in the relevant areas adhere to the standards and procedures. Only in this way will the ESD control mechanisms work effectively.
When considering setting up an ESD control process or ESD program, it is essential to consult the ANSI/ESD "20.20 standard. This standard is internationally recognised and has been developed by ANSI (American National Standards Institute) and the ESD Association.
The ANSI S20.20 standard covers the requirements necessary to design, establish implement and maintain an ESD control program. It is aimed at organisations that manufacture, process, test, repair or carry out any activity with electronics equipment.
Having been prepared by the industry experts, it provides the authoritative view on setting up and maintaining an ESD control program.
Management backing for an ESD control process
In order to put the ESD control process in place there are a few fundamental steps that must be taken. By ensuring that the proper foundations are in place, the ESD control process itself will be able to be rolled out more smoothly and effectively.
The first key step is to ensure that senior management are behind the ESD control programme. Without senior management backing any initiative of this nature is bound to founder. The implementation of the ESD control process will result in costs, and it is necessary that management are aware of these from the outset. Preparing them from the beginning will enable them to be prepared. With their backing it will be possible to have authorisation for the spend in terms of capital outlay, as well as other ongoing costs including training.
Fortunately the case for installing and ESD control process is well proven. Any electronics manufacturing or service organisation will need to employ ESD control precautions. Without them quality will be poor, and in addition to this many customers will not want to deal with a company that does not have a good ESD process in place. These facts are well documented and can easily be presented to management if any problems occur.
With the backing of management in place, it is then necessary to secure the cooperation of any associated departments who may be directly or in-directly involved in the set-up, use and maintenance of the ESD control programme.
ESD control process fundamentals
In order to be able to set an ESD control programme in place, it is necessary to start with the fundamental requirements. These have to be identified as the fundamental requirements, but in addition to this, the ESD control process needs to be tailored to suit the individual area in which it will be implemented. However the following form key elements in any ESD control process:
- ESD protected area: One of the key elements is to create an EPA, ESD protected area. This has already been covered in another page in this tutorial, and reference can be made to that page.
- Signs and notices: The EPA should be well highlighted with signs to let people know they are entering an ESD protected area. It also acts as a constant reminder about conforming to the ESD protective measures.
- ESD process: Creating the physical area in which the static sensitive devices are to be handled needs to be supplemented by a written process detailing how the EPA will be used and run. This is just as essential as the EPA itself.
- ESD training: ESD training is a further key point. All staff must be trained to inform they what ESD is, its importance, how ESD can be combated and how the equipment in the EPA will be used. All staff who are likely to use the EPA must be completely trained and have "bought into" the process.
Writing an ESD control process
An ESD control process defines how the EPA is set up, run on a day to day basis, and its maintenance. It should contain the "do's and don'ts and inform all who use it how it is to be used and what they should do.
An ESD control programme or ESD control process should define many elements. It can be split into two main elements:
- Definition of the physical elements within the EPA
- Definition of the way the EPA is used and the processes or actions required
In this way the ESD control process defines the equipment and the way it is sued. By keeping them all in one document together, and any changes that might be required can be reflected in both plant and process at the same time.
In terms of the plant or equipment that is required the items that might be covered will essentially form the EPA and should include the following: ESD workbenches, ESD wrist straps, ESD clothing, ESD shoes, ESD flooring, ESD chairs, ESD storage and packaging, ESD signs, humidifiers and anything else required for the EPA. It should also define the overall specifications required for any items within the EPA. Products should be defined so that the same products are usd throughout and they are to the required standard.
The ESD control process document should detail how people should work within the EPA and any other actions that must be undertaken.
- Basic instructions on using the system: The control process must define how the EPA will be used by those in it, detailing items such as the wearing of ESD clothing, ESD footstraps, or ESD shoes, etc. It should also include a mention of the fact that unwanted insulating materials should not be brought into the EPA. This should include personal belongings such as bags, etc. as these are likely to contain static carrying insulators.
- Training: The ESD control process should define who should be trained, to what level and how often. For an effective ESD process, all staff should be trained to a certain level to make them aware of the reasons for the EPA, how the EPA works, and how they should use items within the EPA and any special precautions to be taken.
- Testing and maintenance: With constant use, items within the EPA will fail. In particular items that are flexed such as the leads for ESD wrist straps may break and so forth. Often ESD workbenches have monitors fitted that continuously monitor the connectivity. Also other facets such as cleaning are important. Dirt build up on workbenches will cause the conductivity to fall and the static dissipative surface will become less effective. Flooring must also be cleaned. Any cleaning methods will need to be carefully specified so that the basic static dissipative properties of any surface that is cleaned are not impaired. Care should be taken when selecting any cleaning agents. They should not be abrasive so they damage any static dissipative surfaces, and some solvents may attack the surfaces and should not be used.
Any testing to be undertaken should be defined. Test equipment and the test method should be accurately defined. In addition to this routine audits should be included in the maintenance schedule so that standards are maintained.
The ESD control process should also include a regular audit capability. This should comprise formal audits to ensure that the process is being adhered to and that short-cuts are not being taken. It may also highlight new ideas that could be adopted into the process to bring about improvement. In addition to the formal audits, reviews should be scheduled periodically to look at process improvements. In this way, the ESD control process can be updated to reflect both changes in the environment or work being undertaken and also changes in ESD control technology. This will ensure that the ESD control process is always relevant and up to date.
A further element of any ESD programme is to ensure the safety of the people working in the area. There are possible safety implications of the use of some items such as ESD overshoes, ESD footstraps. Also electrical safety must be considered.
As a result, safety should be considered within the ESD control process. It may be necessary to carry out a risk analyses, assessing what risks there may be and how each risk may be reduced to an acceptable level.
By considering safety and risk at the conceptual stages of the ESD process, risks can be reduced or overcome and a safe operating environment can be assured.
The development of an ESD control process may seem like another excuse to generate paperwork. However by developing a document to define the ESD control process, it is possible to define all the elements that are needed. Using the ANSI/ESD S20.20 standard, it is possible to gain guidance on all aspects of developing the ESD control programme. A further requirement is the support of management and other related departments. With all these elements in place and then constant monitoring a development of the programme, it is possible to set in place a very successful ESD control process.
By Ian Poole
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