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What's The Dealy-O With Smocks?

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Why does everyone tell me smocks will prevent ESD. They're ... - Dec 16, 2005 by URL  


URL

#38526

What's The Dealy-O With Smocks? | 16 December, 2005

Why does everyone tell me smocks will prevent ESD. They're not grounded, so how can they bleed or prevent ESD? They may not cause any ESD, but they sure don't come close to a heel strap or ESD shoes. OK, maybe from a "management" standpoint it makes sense, but anyone with common sense or knowledge of basic electronics will know you can't bleed off ESD effectively without using a ground.

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Burgandy

#38527

What's The Dealy-O With Smocks? | 16 December, 2005

I think the whole point with smocks Peter is that they are ANTI static......and they must be used in conjunction with heal straps.....but IMO......heal straps or ESD shoes are all you need.

Now, I would recommend finger cotts to keep contamination out of your process though!

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Steve

#38528

What's The Dealy-O With Smocks? | 16 December, 2005

As you move, your clothing is rubbing against your body causing static to build up in the material. Since the material is a poor conductor, not all of the charge gets conducted through your skin to the heel straps. The smock is designed to prevent the build up and to help conduct the charge to your skin.

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URL

#38532

What's The Dealy-O With Smocks? | 16 December, 2005

OK, this is what I'm talking about. If static is building up between the skin and clothing, how will wrapping it in a smock prevent it? The static is still there, the same charge, except know has a smock is covering it. Unless the smock is grounded, how does it bleed this charge off?

It's like putting a static sensitive device in a static bag along with a static gun aimed at it. Close the bag around the device and static gun to create the Faraday cage. Now the trigger the static gun. It still operates the same and zaps the static sensitive device.

If people believe smocks prevent, they should buy my wireless wrist straps! They have and L.E.D. display and everything!

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Arnatt Thomovophoung Klinsong

#38534

What's The Dealy-O With Smocks? | 16 December, 2005

we use smock im our factory to pervent static charge from employee clothing, customer from oversea like to see this.

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#38537

What's The Dealy-O With Smocks? | 16 December, 2005

Does this bring back some awful memories! Back in the mid-80's I worked for a little company called Solectron (yes they were small back then). They wanted everyone to wear smocks and I fought that one come hell and high water. It was all for show as they didn't even have heel straps then. As someone who never handled the product I just couldn't justify it. Man did I get in some battles over that. Even now when I visit a facility and am forced to put one on just to go on the floor I cringe.

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Rob

#38538

What's The Dealy-O With Smocks? | 16 December, 2005

We did some research a few years back, but you do have to test them regularly and replace them.

http://www.twclean.com/debugging.html

Here's Topline's justification (but then again they do sell them):

ESD coats are required primarily for 3 reasons:

Shielding PEQ coats and smocks act as a shield, covering the operator's street clothes and preventing uncontrolled discharge.

Grounding To drain all charges from the operator to ground while sitting on ESD grounded chairs.

No tribo charge PEQ coats and smocks do not generate static charges. It's non-synethtic fiber does not cause tribo charging.

Hope that helps everyone sleep better tonight!

Rob.

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#38543

What's The Dealy-O With Smocks? | 16 December, 2005

And if you check the tags you will find over half are not even ESD smocks. Companies like everyone to look the same but they don't like the price tag on the real ESD smocks so the buy normal smocks and make everyone wear them.

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Thong Chai Jaidee

#38544

What's The Dealy-O With Smocks? | 16 December, 2005

will use the finger cot in process keep contamnant from PCB?

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URL

#38547

What's The Dealy-O With Smocks? | 16 December, 2005

Good article from Top Line. That does bring up a good point: how do you test that your smocks are working? Anyone? Almost as bad a a fat guy wearing a bunny suit - just looks like a dirty snowball!

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Ola

#38556

What's The Dealy-O With Smocks? | 16 December, 2005

Are You sure that You are working f0r a electronic/oil/fire works industry and Don't know what a ESD-coat is used for????!!! Or how it is build up with a lot of thin metal threads inside, so it will become someting like Faraday cage!!? Or how Electric static even with low voltages can damage PCB, PCBA:s, components etc. several meters away witouth touching it even if there is No visible "so called sparks"??!

This is the basic of ESD:s protection and the ESD-floor combined with proper ESD-shoes is cruical! http://en.wikipedia.org/wiki/Faraday_cage

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Ogie Alcasid

#38557

What's The Dealy-O With Smocks? | 17 December, 2005

At the s#$t-hole Contract Manufacturer where I work (name with-held), the motherf&ckers told us to wash them useless pieces of sh&% once a week, and "don't use fabric softener" otherwise you ruin the integrity of the faraday cage. Then they got on the Technician's case for having "dirty smock" even wben us poor souls were underneath equipment alot gettng dirty!

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Ola

#38564

What's The Dealy-O With Smocks? | 17 December, 2005

Washing the clothes is just for removing dust & dirt outside the coat that eventually can tamper with the ESD. The metal threads in a matrix grid inside the coat, will always work! You don't need to wash them more often than You normally do with Your own clothes. However, the washing process is special. As for the manufacturer You used to work for; they obviously didn't know what they are doing! There are so many examples out there of how company management introduce local regulations without knowing what's going on, just because they have attended "some fancy seminar" which they not fully understood the context of.

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URL

#38594

What's The Dealy-O With Smocks? | 19 December, 2005

NO, I'm pretty sure I work for an electronics manufacturer, since we place electrical components onto blank PC Boards. I guess it could be considered "fire" if one of the units starts to smoke.... As for "oil", no my pockets are too poor to be in the oil business. YES, I know about ESD coats and the Faraday cage model. Maybe my example was extreme, but my point was to say an ESD coat, or smock is useless unless it's grounded. Someone can generate ESD and zap parts if they just wear a smock. Wearing an ESD coat or smock is not the same as a Faraday cage.

I don't believe I ever said anything about sparks, but then you may be in management since you put words in mouth, believe I didn't know what I did for living, or couldn't deduct simple ESD reasoning.

Reminds me of a story: A man in a hot air balloon realized he was lost. He reduced altitude and spotted a woman below. He descended a bit more and shouted, "Excuse me, can you help me? I promised a friend I would meet him an hour ago, but I don't know where I am."

The woman below replied, "You are in a hot air balloon hovering approximately 30 feet above the ground. You are between 40 and 41 degrees north latitude and between 59 and 60 degrees west longitude."

"You must be an engineer!", said the balloonist.

"I am", replied the woman. "How did you know?"

"Well," answered the balloonist, "everything you told me is technically correct, but I have no idea what to make of your information, and the fact is I am still lost. Frankly, you've not been much help so far." The woman below responded, "You must be in management."

"I am," replied the balloonist, "but how did you know?" "Well," said the woman, "you don't know where you are or where you are going. You have risen to where you are due to a large quantity of hot air. You made a promise, which you have no idea how to keep, and you expect people beneath you to solve your problems. The fact is, you are in exactly the same position you were in before we met, but now, somehow, it's my fault."

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Brick

#38595

What's The Dealy-O With Smocks? | 19 December, 2005

I have an idea/invention to put this whole "ESD/floating potention/to-smock-or-not-to-smock" idea to rest!

Complete nudity underneath the SKIN-TIGHT-FULL-BODY-SUIT, anti-static, ESD smock, and all smocks must be "tethered" to the building's power ground. Kinda like a ESD body condom!

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URL

#38596

What's The Dealy-O With Smocks? | 19 December, 2005

Do you work for the Fire Department?

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#38598

What's The Dealy-O With Smocks? | 19 December, 2005

"Complete nudity underneath the SKIN-TIGHT-FULL-BODY-SUIT, ..."

Not in the plants I'VE worked in.

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rsmith

#38608

What's The Dealy-O With Smocks? | 20 December, 2005

I manufacture ESD supplies such as smocks and conduct ESD audits from time to time. With that said, here is my deal on smocks...ESD smocks work well to shield harmful static charges on clothing such as wool, silk, and synthetic fabrics. It is like wearing a static shielding bag for your body. Most ESD garments are not conductive enough to provide personnel grounding so do not get rid of your heel straps and wrist straps. According to ANSI20.20, ESD garments are considered an optional implementing method to control ESD. So bottom line is that they are helpful but are more of a marketing tool. If you chose to purchase ESD garments please make sure that you are provided with smocks that do not lose electrical integrity after at least 50 industrial washings. If you do use ESD smocks then you must test them and verify they work as intended.

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URL

#38614

What's The Dealy-O With Smocks? | 21 December, 2005

Hi rsmith,

How do you test them?

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rsmith

#38620

What's The Dealy-O With Smocks? | 21 December, 2005

The garment test standard is ESD STM 2.1. It states that point to point and sleeve to sleeve resistance tests should be made. The electrical integrity of the seams is critical and will be verified by these tests. When you conduct a sleeve to sleeve test you want to hang the garment on a plastic hanger and connect a clamp to each sleeve. The point to point test will utilize the same 5 lb weights that you use when you test mats. This will verify the that the panels are properly connected. You can order a copy of this standard at http://www.eosesd.org. The two main concerns that I look for when I test smocks are 1) Is the material permanently conductive, 2) Are the seams properly connected? Once you verify this ISO guys and customers should be happy!

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Loco

#38627

What's The Dealy-O With Smocks? | 21 December, 2005

We have used real ESD smocks in the past, we did do those correct test, turned out after washing them 3x at 30�C, they were useless, can you image the cost involed with suppling staff with new clothing every 3 weeks? Well we did anyways and just changed to regular non conductive ones which can be washed at 100�C for years. It does keep our custumers happy and that is what the smock thing is most about in most companies i think. We do still use straps that are being checked every day. But on a more serious matter, you wont be denying your collegues of 2 D's by wearing an ESD smock will you? I'ld go with the full body tight kit.

(i'm an engineer btw)

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rsmith

#38634

What's The Dealy-O With Smocks? | 21 December, 2005

Loco, I like your textile design talent but if we make those smocks too trendy people will steal them and start wearing them in the malls. There are ESD smocks on the market that have temporary electrical integrity. One such style is called Nylostat. The electricals will degrade over time. Some materials utilize a treated thread. A smock with permanently conductive threads costs no more money. I would ask your vendor to provide a warranty so you don`t get burned!

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Cmiller

#38635

What's The Dealy-O With Smocks? | 21 December, 2005

To try to address the original question, the smocks we use have a pretty healthy wrist band on them that grounds them to your skin. You still need to wear heel straps to ground your body to the floor. Some smocks do not have the wrist bands and those are usually designed to be connected to a ground strap or they dont do much. The wrist bands on the smock do take some getting used to and can really irritate some peoples skin. I have seen some companies use "summer" smocks in warm weather with short sleaves, these dont do much it not teatherd to a ground. If the humidity is reasonable in your plant, cotton shirts are probably an acceptabe alternative to smocks, but good luck convincing your customers of that.

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#38645

What's The Dealy-O With Smocks? | 22 December, 2005

They just make it look good, that's all. ESD flooring, heals straps and wrist bands have function, smocks do not.

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Ola

#38679

What's The Dealy-O With Smocks? | 25 December, 2005

I am truly sorry. It was Not my intention to let You the impression of that we do a better job than You do. Perhaps we could see this in an brighter light and then move forward? Best Regards, Ola

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