Background

    Most people only think of static electricity as the shock from touching a metal doorknob after walking across a carpet.  However, static discharge can be very dangerous in modern work environments.  Electronic devices have become more sensitive to static discharge as they've become faster and smaller.  ESD impacts productivity and product reliability in almost every aspect of today's electronics environment.  Electrostatic control also applies to other industries such as clean room applications and graphic arts.

    ESD affects manufacturing costs, product quality, production yields, product reliability, and profitability.  Experts have estimate the average product losses due to static to be from 8-33%.  This could quantify the amount lost due to ESD, or electro-static discharge, to be in the billions every year.  Whether it's the cost of a damaged diode which may only cost a few cents or a complex hybrids which could run a company several hundred dollars, the threat of ESD is a growing concern.  Other losses due to ESD could be costs of repair and rework, re-shipping, extra labor.

_{from Botron Co.}

Create an ESD Audit

It is important to create an ESD audit for each department where ESD control is required.  This should include a daily audit, performed by the operator at their workstation, to ensure equipment and materials are compliant.  You should also schedule a routine department audit every 2-4 months

Why audit, you ask...

This is how you ensure the quality and safe handlind of your product, justify your efforts to management and evaluate the equipment and products that you are using.

Continuing ESD events might require a change in packaging materials, worksurfaces or grounding devices.  be sure to check the contact between ground bolts and worksurface along with the connection to your grounding device.  Be aware of static generators like shoes, carpet, rolling chairs, carts and plastics used in the area.  Cleaners must be compliant; use only silicon-free, water based products to clean workstations and other surfaces.  Consistent performance means your ESD program is working.

For auditing tools and other testing equipment please check our catalog under test equipment.

For further information on ESD safety please contact Indoff.

Establish ESD Standards and Procedures

In order to evaluate and measure your ESD initiatives, you must have something to compare.  Documenting your minimum operating standards and handling procedures will solidify your program.  Determine the acceptable range.  Generally, ESD lamintate should measure 10⁶ to 10⁸ ohms for both resistance to ground (RTG) and point to point on the surface (RTT).

Identify Departments Where ESD Control is Required

Any department where sensitive components are assembled, tested, stored, packaged, repaired or handled requires static control.

Train Managers, Employees and Visitors about ESD

Educate individuals on the standards and procedures you have extablished.  Clearly communicating your standards and objectives will help eliminate misunderstandings. Provide certification upon sucessful completetion of your training.

For further information, please contact Indoff or check for future postings.

Introduction 

Controlling and eliminating static is essential to the quality of the product for manufacturers of electric components.  Even a small amount such as 1,000 volts can damage components that populate circuit boards.  In contrast, a person can feel staic discharge if it's greater than 3,500 volts.  Do you know what's happening with your circuit boards?

There are many elements that compromise a successful ESD program.  Indoff is happy to provide a basic outline to help you get started.

 The main steps are:

1. Establish ESD Standards and procedures
2. Identify departmets where ESD control is required.
3. Train managers, employees, and visitors about ESD.
4. Create an ESD audit.

For further detail on these steps please check back weekly, or give us a call and we would be happy to help you in whatever way possible.

As a continuation of last weeks post, I will continue on the different characteristics that you should look for in a mat for your ESD application to ensure that you are running workstation that is up to ESD standards.

Selection Guide:

You can use this chart to select the material(s) appropriate for your application(s)

by,

Brent Beamer-SCC

For further information on mat usage or any other information regarding this topic please check previous postings, or view the SCC's Technical Bulletin Posts.

As a continuation of last weeks post, I will continue on the different characteristics that you should look for in a mat for your ESD application to ensure that you are running workstation that is up to ESD standards.

Mat Usage

Mats are generally divided into table and floor usage categories. Some mats are advertised as useable in either place. 

However, these mats are a compromise and lack features of dedicated mats.

Table Mats:

• Use light colors to make finding small parts easier.
• Have smooth or lightly embossed surfaces.
• Are usually thinner then floor mats.
• Are suitable for special purposes.

 Floor Mats:

• Use dark colors to hide dirt.
• Have heavy embossing or grooves to improve traction.
• Are usually thicker then table mats to absorb more wear.
• Are available in anti-fatigue style to reduce stress.

For further information on mat usage or any other information regarding this topic please check back every week for further posts, or view the SCC's Technical Bulletin Posts.

Homogeneous (vinyl and rubber)
Homogeneous, or solid, mats consist of the same material throughout the entire mat. These mats usually provide good mechanical service. Electrical performance is usually limited because antistat can only provide aboout 10⁹ to 10¹⁰ R_TG.

Three Layer (vinyl)
Three layer mats sandwich a conductive metal or carbon layer (called a scrim) between a top surface of homogeneous vinyl and a layer of foamed vinyl on the back. The conductive scrim layer improves the electrical properties by acting as a fast track to move static charge to ground. Th foam back layer provides a cushion for operators and makes picking up parts easier.

Two Layer (vinyl)

Two Layer (rubber)
The Top layer of rubber is static dissipative and the back layer is conductive. This accomplishes the same electrical goals as the three layer vinyl mat. Combined with tolerance to heat and chemical, the rubber mat is an over achiever. However, these features come with a cost premium.

For further information on the construction of mats or any other information regarding this topic please check back every week for further posts, or view the SCC's Technical Bulletin Posts.

As a continuation of last weeks post, I will continue on the different characteristics that you should look for in a mat for your ESD application to ensure that you are running workstation that is up to ESD standards.

Mat Materials
A mat's performance is based on the material that is used to make it. Performance includes electrical values, tolerance to heat, chemicals,mechanical abrasion, and cost.

There are two materials that are used to make these mats, they are:

Vinyl
Vinyl is the plastic most widely used to make mats.  The material is cost effective, easy to render static dissipative, takes color well, and remains pliable and easy to cut and shape.

Rubber
Rubber is being used in situations that require high resistance to heat and chemicals.  Only recently has this material been available at a low enough cost to make it a consideration.