Bob, One other thing. A good ESD program and a good 5S program go hand-in-hand. A 5S program supports the ESD program in keeping items not necessary to perform the job out of the factory. Such non-essential static generators include the Mylar balloons celebrating someone's birthday, the packing materials such as vinyl wraps, plastic bags, styrofoam padding or packing peanuts, etc. In general, I try to keep work desks outside of the ESD zone, even if this means setting up a "cubicle farm" near the assembly area to do so. The "cubicle farm" is a good way of keeping personal items that clutter the common desktop from coming into contact with ESD hardware. No matter how careful a person is, simply having ungrounded desks in the production area leads to ESD hardware finding its way to the top of the desk. The floor taping (boundary marking) for the 5S program includes tape marking the ESD zone boundary to prevent inadvertent entry of personnel or visitors not wearing smocks and protective footwear. It brings more attention to the ESD and cleanliness requirements within the zone. Nothing looks cheesier than a factory floor with uncontrolled scrap hardware, components, expired materials such as epoxy, conformal coating, solder paste, and coats, hats, pictures, food such as potato chips, pop, cake, etc. on desks that are inside the production area. I have had a couple of questions that I received offline regarding the verification of the machine model. Here is some clarification. Many companies buy equipment for processing circuit card assemblies with little or no consideration to ESD protection. Conveyors, board loaders, pick and place equipment, reflow ovens, stencil printers, routers, etc. are quite often purchased and thrown on the production floor without any type of qualification. Granted, some companies do this and struggle with problems later because they to not have a good baseline for machine performance. They never establish process controls, and neither do they check to verify that the machine is properly grounded with dissipative or conductive materials between the assembly and electrical ground, as appropriate. Part of a comprehensive machine qualification procedure is to verify the ESD protection on a given machine or process is in place. Why would anyone verify all of the machine's operating parameters and ignore the ESD aspect? If you know that every single one of your assemblies is going to come into direct unprotected contact with a given machine, wouldn't you want to make sure it does not have the capability to zap every single board? -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D. Sent: Monday, September 18, 2006 4:00 PM To: [log in to unmask] Subject: Re: [TN] ESD protection Hi, Bob. I assume you mean a factory, not just the floor itself. There are at least 5 components to a good ESD control program. In order for the program to work, all 5 cylinders must be firing. The 5 main control factors are: 1. A good conductive ESD floor. Even a bare concrete floor with the proper floor treatments can effectively provide a non-tribocharging surface and drain potential ESD charges to the building ground. But if you are serious about this then get a good ESD tile floor installed. Note! The conductive epoxy/tile flooring can be disastrous if not properly applied, even by qualified installers. If you choose this type of flooring make sure that the company that you buy the tile from approves the installer. Should the installer put the epoxy down incorrectly, the floor will not meet the measurement specs, and the tile company will not warrant the installation as a result. Temporary ESD floors are available with all of the ESD performance and durability and none of the permanency issues. These can be installed in a working factory a section at a time to avoid impacting production, unlike epoxy/tile in which the entire area must be cleared of all equipment and the whole floor done at once. See an example of this removable conductive grid and the ESD tiles that go with them at http://www.tekstilconcepts.com/products/adhesives/adh-electronic.shtml. In past lives I have used their flooring for two large EMS corporations after I reviewed several other installations at major OEMs. I fully checked this out with these people and they were very happy with the performance and the appearance of the floors, and so was I after I had the Sigaway/Tekstil installed. With this system the tiles can be removed from the conductive Sigaway backing and re-used with a new application of the backing should you need to move the flooring from one area (or building) to another. 2. The assembly protection system. This would include proper grounding of all of the benches and shelves, with no daisychained workstations or shelving units (each connected to ground separately). There are sometimes situations where it is sometimes impractical to do this, but individual grounding should be the target. Daisychains can be broken at a single point, causing an entire line or area to become ungrounded. Assemblies should be kept in Faraday boxes or bags if they are not being worked on. Ionizers should be considered if class 0 assemblies are going to be worked on. This includes a Machine Model ESD analysis of each machine the assembly will come in contact with. Note! Most ESD damage is from the Machine Model, not the Human Body model. 3. Environmental control, monitoring and controlling the humidity between 20% and 60% RH (ideally) and with warning steps that kick in automatically should the humidity go above or below those levels. 4. Properly grounded operators, including ESD-safe shoes or heel straps, proper smocks with either ESD elastic wrist cuffs or smock ground connections to pass the charges accumulated on the smock to the operator's skin or to electrical ground, where it is dissipated through the ESD footwear or wrist strap or ground connection. There should be either a daily check of the footwear and wrist straps to verify they are working, or use a constant-monitor ESD system. 5. An ESD-Training program with a certified instructor, whether it is to EOS/ESD STD 20.20-1999 or MIL-STD-1686C or other standard. Training and certification is required, along with a good auditing program to show compliance. The quality records must be kept up. Get a copy of either ESD standard and read it through. Note that there is no actual requirement in 20.20, but you need to perform an assessment to determine just what your ESD program should include and you should have a written justification for the level of controls you feel you require. Please note that if you have all 5 components fully functioning, you will have less to worry about should any one of the components fall out. For example, if an operator fails to plug in their wrist strap or the cord opens up, the humidity controls, the conductive footwear, the flesh-grounded smock, the conductive floor, and the grounded benchtop/matting/fixtures are all working together to continue to protect that assembly. If you delete any of the systems, you incrementally increase your risk of ESD damage. As a minimum, I would ground the benches with dissipative mats, ground the shelves if there is any chance that unprotected ESD assemblies will be laid on them outside of their Faraday containers, and require the operators to wear wrist straps whenever handling unprotected assemblies. I would also require all equipment and fixtures to be grounded. This makes the flooring and humidity controls optional, but you have little or no comprehensive protection. ESD compliant floors covering the entire production area are not always necessary if good controls can be put in place to protect the hardware while moving from point A to point B. If that is the case then smaller ESD floor mats can be put down rather than tile. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Bob Wilson Sent: Friday, September 15, 2006 12:06 PM To: [log in to unmask] Subject: [TN] ESD protection Hey everyone, Happy Friday! Can anyone point me to the best way to set up a shop floor for ESD protection? Thanks a bunch. Regards, Bob Wilson Electro-Mechanical Designer, CID SpectraSensors, Inc. 972 N. Amelia Ave. San Dimas, CA 91773 800-619-2861 x239 www.spectrasensors.com --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------