From ESD User guide CLC/TR 61340-5-2:2008 clause 4.1:
This clause outlines a step-by-step approach that can be used to establish an ESD control program.
4.1 Developing an ESD control program plan
4.1.1 Assignment of an ESD coordinator
In order to have a well thought out and implemented ESD program an ESD coordinator must be assigned. The ESD coordinator is responsible for all aspects of ESD in the facility. In order to be effective the ESD coordinator needs:
- the full support of management
- a good understanding of electrostatics and how ESD sensitive devices can be damaged. The ESD coordinator will often need to attend educational classes or seminars related to ESD in order to maintain or update their knowledge
- a thorough understanding of IEC 61340-5-1 and all of the organization’s processes related to the handling of ESD sensitive devices
- access to measuring equipment for the purposes of performing compliance verification audits as well as testing new ESD products and materials for use in the ESD program
- depending on the size of the facility, the ESD coordinator might also need to have auditors assigned to conduct the ESD audits
Finally, management must provide the ESD coordinator with the authority and funding necessary to ensure that the ESD control program is maintained and enforced.
4.1.2 Determination of part ESD sensitivity
The next step in developing an ESD control program plan is to determine the part, assembly or equipment sensitivity level under which the plan is to be developed. Although the requirements outlined in IEC 61340-5-1 are effective for handling parts sensitive to 100 V HBM or higher, the organization may choose to develop an ESD program based on ESD sensitivities that are greater or less than 100 V HBM. In this situation, the organization must develop an ESD control program plan that clearly states the ESD sensitivity that the program is based on. The organization can use various methods to determine the ESD sensitivity of the products that are to be handled. Some of the methods include: assumption that all ESD products have an HBM sensitivity of 100 V; actual testing of ESD sensitive devices to establish the ESD sensitivity thresholds using IEC 60749-26; referencing ESD sensitivity data in published documents such as manufacturer’s published data sheets.
4.1.3 Initial process and organizational assessment
Before the ESD control program plan can be developed, an initial assessment of the processes and organizations impacted by an ESD control program should be conducted. Organizations and processes that might be affected include:
- design engineering
- receiving inspection
- quality assurance
- packaging and shipping
- field service
- failure analysis
- repair services
- spare parts storage
- material handling and parts conveyance
An assessment of each area where ESDS parts are handled should be conducted in order to determine ESD hazards and possible ESD process procedures. The information accumulated throughout these steps forms the basis for developing the ESD control program plan.
4.1.4 Documentation of ESD control program plan
After gathering the above information, the organization is in a position to begin documenting the program plan. The plan should state the scope of the program which includes the tasks, activities and procedures necessary to protect the ESD sensitive items at or above the ESD sensitivity level chosen for the plan. Although the primary focus of the plan is to outline strategies for meeting the administrative and technical elements of IEC 61340-5-1, other items may be beneficial to incorporate as well. These additional items might include:
- organizational responsibilities
- defined roles and responsibilities between the organization and subcontractors and suppliers
- strategies for monitoring product yields and processes that might be important in determining the effectiveness of ESD control measures currently in place or in assessing whether additional measures should be taken
- approaches for ensuring continual improvement of the ESD program
- a list of approved ESD control products and materials.
The administrative and technical elements of IEC 61340-5-1 that need to be addressed in the plan (unless tailored) include:
- training plan
- compliance verification plan
- technical requirements
- grounding bonding systems
- personnel grounding
- protected areas
Charleswater – your ESD Control Experts. Contact Customer Service for help with your ESD Control Programme.
Our thanks to Conformity Magazine Published in December 2004 issue
Accurate process evaluation provides real answers
Provided by the ESD Association
by Stephen Halperin, in collaboration with Ron Gibson
“We need to spend HOW MUCH?”
Recently, a company experienced several large losses due to electrostatic discharge (ESD) and had a very unhappy customer on their hands. The manufacturing vice president now faced a substantial expenditure for new ESD loss prevention equipment. The company’s first step had been to hire an ESD consultant who recommended the purchase of several thousands of dollars in ionization equipment and monitoring instruments for several of the company’s facilities.
The troubled VP read the report several times looking for justification of the expense. However, the report did not define how the recommended equipment would meet the VP’s specific needs. Other than describing how ionization reduced electrostatic charge after it is generated and that the instruments could confirm that a discharge occurred, the report did not identify the actual cause of the process problem. No ESD measurements were described. There were no details related to cause of product loss, device sensitivity concerns, value issues, process and handling details, examination and description of existing controls, or rationale for how the recommended tools would solve the problem in question. The report was clearly based on the consultant observing the process of a single manufacturing environment. In effect, the report made a purchasing recommendation based on a “blanket” opinion, not on facts specific to the needs of the company or their customer. Such an approach typically makes a bad situation worse. While the recommended tools may have been very useful for investigating a process or for solving defined problems, they are expensive Band Aids“ when used in undefined problem situations.
Today’s electronic manufacturing environment demands that minimal ESD controls be in place to provide fundamental protection for electrostatic discharge sensitive (ESDS) devices. When basic ESD controls are employed and losses still occur, manufacturing and quality managers face more difficult problems., In assessing the problem, companies struggle with a variety of major questions concerning a specialized technology, while having minimal information and available skills. To avoid the risk of making the wrong investment decision without solving the initial problem, management needs a way to select and implement the most effective ESD controls that fit their financial situation, solve their specific problems, and provide a respectable return on their investment.
To continue reading Enhancing Profits with Effective ESD Control Click Here
ANSI/ESD S20.20 Foreword states:
- “This standard covers … electrical or electronic parts, assemblies and equipment susceptible to damage by electrostatic discharges greater than or equal to 100 volts Human Body Model (HBM).”
- “When handling devices susceptible to less than 100 volts HBM, more stringent ESD Control
Program Technical Requirements may be required, including adjustment of program Technical
Element Recommended Ranges.”
HMB Classification Class 0 is:
Per ESD-STM5.1 Human Body Model (HBM) Table 1 Class 0 has ESD Voltage Range < 250 Volts
Basically, to control the environment to decrease the probability of ESD damage in “Class Zero”
situations, involves increasing ESD protective redundancies and periodic verifications to those ESD
Control technical elements.
- Personnel: Decrease Wrist Strap and ESD Footwear upper limit permitted (The ESD Association has test data showing charge on a person is less as the path-to-ground resistance is less) The use of continuous monitors, smocks, use / increased use of ESD flooring, sole or full coverage foot grounders (HBM & CDM)
- Worksurfaces: Dissipative (CDM) i.e. change < 10^9 to a requirement of 10^6 to 10^8 ohms
- Bonded grounds – Carts, shelves, equipment
- Conductors: Minimizing isolated conductors like devices on PC Boards (CDM)
To see examples of Wrist Straps capable of dealing with class zero environments Click Here
To see examples of Grounding Cords capable of dealing with class zero environments Click Here
Minimize Charge Generation
The best form of control is to minimize charge generation. Grounding and ionization eliminate charges once generated. Shielding protects from generated charges.
- Personnel – Low Charging floor finish
- Surfaces – Use of low charging (anti-static) topical treatments
- Eliminate as best as possible all non-process necessary insulators
- Topically treat where ever possible insulators that cannot be removed
- Consider use of ESD Chairs or treat to reduce charge generation
- Shield charges on clothing by using ESD Smocks
To continue reading ESD Control Program Considerations when Dealing with
Class Zero Items Click Here
by Rick Cardinale, Bird Electronic
Bird Electronic, founded in 1942 by J. Raymond Bird, soon became a leader in radio frequency instrumentation. Today, Bird also has moved into digital instrumentation test equipment.
With the development of digital instrumentation came the increased need for controls to prevent ESD events. Improving ESD protection has been an ongoing process since the late 1980s. In 1997, the company determined that an automated PCB production line would be installed and that the entire manufacturing area should be protected against ESD.
This decision led to an evaluation of ESD protective flooring. In 1998, 20,000 square feet of conductive floor tile were installed in the main production area. To help brighten the area, white tile was selected. The floor resistance measured less than 1.0 × 10^6 ohms.
A bright, high-gloss appearance was part of the selection criterion for the floor. While the electrical properties were unchanging, by 1999, the floor was starting to dull. It was being maintained like a regular tile floor. No waxes or finishes were used; however, the tile manufacturer did recommend using buffing pads.
After consulting with the tile manufacturer and the installer, maintenance was increased to sweeping clean and damp mopping two times per week and buffing once per month. Monthly floor maintenance was $1,700 per month, a $20,400 annual expenditure.
In late 1999, the maintenance schedule was modified to add more buffing since this was the only way to keep the floor shiny. The floor now was swept and damp mopped weekly and buffed twice per month. The floor was clean and shiny, but the cost went up 41% to $2,400 per month, a $28,800 annual expenditure.
Click Here to continue reading Reducing Floor Maintenance Costs while Improving ESD Performance