Process Monitoring and Electrostatic Risk Assessment
Measurements of electrostatic voltage on isolated conductors and electrostatic fields from insulators allow a prediction of isolated conductor and Charged Device Model (CDM) types of risk to sensitive items within any process. Measurement of the resistance to ground from all the conductors in a process, including personnel, helps to determine Human Body Model (HBM) risks. Process monitoring requires advanced knowledge of electrostatic principles in order to understand what needs to be measured and which tools to use in any given circumstance.
Affinity Static Control Consulting, LLC (Affinity) has process monitoring experience that is well beyond that of most consulting companies. Process monitoring experiences include all phases of electronics manufacturing as well as investigations in nearly any other imaginable industry. Understanding electrostatic phenomenon within process equipment helps establish process capability. Equating process capability to the measured component sensitivity as determined by HBM, isolated conductor and CDM test methods is a current goal. Electrostatic risk assessment is based on a comparison of the collected data from the process capability evaluation to the measured sensitivity of components. The acceptable risk level is set for all points within the process using statistical analysis techniques. Process monitoring and electrostatic risk can be established within most activities including, but not limited to, the following:
ANSI/ESD S 20.20 Certification Process FlowGeneral Guidelines
1.Prepare an ESD Control Program following the intent of S20.20
- Control of Measuring and monitoring devices (calibration)
- Control of nonconforming product
- Corrective and Preventative Action
- Process Audit type and frequency
- Technical element verification schedule
- Test methods and limits
2.Make sure all process areas follow the pre-set requirements of the Plan
3.Contact an Official ISO Certification Body that has trained S20.20 Auditors on staff. For a list of trained Certification Bodies inquire at ESD Association Headquarters in Rome, NY – www. esda.org
4.Arrange for a Pre-Assessment Audit either through the ISO Certification Body or a Consultant.
5.Schedule Formal ANSI/ESD S 20.20 Audit
Audit & Certification Follow Up
An internal audit, second party audit or a customer audit may find flaws or faults in your ESD Control Program. As the recipient of the audit, you may not agree to some of the “flaws and faults” found by the auditor. Obtaining Certification to ANSI/ESD S20.20 should reduce the number and severity of disagreement between parties. However, prior to receiving Certification, facilities may experience difficult audit situations.
Affinity can help you develop a corrective action plan to fix any and all ESD Control Program Plan deficiencies after an unsuccessful customer or second party audit. In addition, Affinity can provide expert third-party consultation and arbitration in the event of disagreement over implementation of ESD control technical elements or interpretation of administrative requirements.
A poor audit report need not ruin your reputation. It can actually help to make your operations better if you are open to improvement. Affinity can help you make productive improvements to your ESD Control Program.