Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

SMTnet
»
Electronics Forum
»
Dusted By Dross

Dusted By Dross

Subscribe to Thread

How do you control the "lost" of dross dust in you collecti... - May 16, 2000 by davef

Sounds 'on the money'. By gear up, I assume you use respir... - May 17, 2000 by Boca

Hey Dave: At our facility, we use those masks that filter ... - May 17, 2000 by C.K.

Hi Dave It sounds like you do pretty much what we do. A cou... - May 17, 2000 by John Thorup

I just wanted to add a comment to the newbies, that dross m... - May 17, 2000 by

Absolutely Mike Lets take that one step further and say tha... - May 17, 2000 by John Thorup

We don't do any of this. We had our operators tested by OS... - May 17, 2000 by ScottM

Scott: First, it's neat that you do cartridge monitoring o... - May 18, 2000 by davef

Dave - well said ScottM - I'm appalled - Your management s... - May 19, 2000 by John Thorup

Thank you much folks! I've printed out these messages and ... - May 22, 2000 by ScottM

davef

#4101

Dusted By Dross | 16 May, 2000

How do you control the "lost" of dross dust in you collection can?

When picking dross from our wave; we gear-up, hook-up an aux vent pipe, and use ss kitchen utensils to seperate the dross from the solder mass. We deposite the dross into a 5 gal container. When the contaner is full or 90 days from starting to fill the container, we seal the it for shipment to the recycler.

In the interim, between when we start and when stop filling, we don't do anything special to this material except cover the container when it is not being filled.

Should we cover the dross with something to prevent material from being moved into the air? What do yall do?

Dave F

reply »

Boca

#4102

Re: Dusted By Dross | 17 May, 2000

Sounds 'on the money'. By gear up, I assume you use respirators. Wipe up any dust deposited on surfaces and dispose of the wipes as lead waste. Keep the cover firmly on the dross can when not in use. You've got it covered (pardon the pun).

Do you think you are losing some of the dross dust after it is put in the collection can? It's probably just the dust settling out in the can.

Boca

reply »

C.K.

#4103

Re: Dusted By Dross | 17 May, 2000

Hey Dave:

At our facility, we use those masks that filter out particulates. Our safety department requires all wave operators, maintenance, and even wave process engr's (like me) to have these masks checked every 6 months for proper gasketing, filters, etc.

I know alot of places do use AUX vent pipes and some even use those external fume extractor units.

As far as the time between filling and covering the dross container, nobody is allowed within 10 feet of the area while de-drossing is taking place. I'm sure some dross dust gets into the air during this process, but I'd guess that it's minimal. Because you guys do have an aux vent, personally, I wouldn't cover the dross.

-CK

reply »

John Thorup

#4104

Re: Dusted By Dross | 17 May, 2000

Hi Dave It sounds like you do pretty much what we do. A couple of points: If your machine allows, open, fill and seal the dross container inside the machine. Otherwise, the auxillary exhaust as you describe is a must. Be gentle in your movements. Don't "slam" the spoon into the collection can. Never transfer or pour the dross from one container into another. If you must transfer, wet down the dross to control the dust. Keep your tools segrated and in a closed container when not in use. Avoid laying them about during use. Avoid local air movement like fans, HVAC, etc to avoid blowing the powder into other areas of your shop. The "gear" should not be hung with other shop wear or street clothes and should be regularly laundered. Of course, never at home. I'm assuming that the "gear" includes a filter mask and it is of a type that can handle the particle size of the dross and seals properly to the face. The ordinary paper dust masks are not enough. I find that most of the loose powdery dross occurs when cleaning the interior works of the wave outside of the machine. We do this in a segregated area and clean up with a vacuum equipped with a HEPA post filter. We use this vacuum inside the machine as well. It should be stated that a regular vacuum will just spread the contamination all over the shop. Good hygienics mandates no food, drink, smoking, etc, + removal of the gear and a good wash-up before leaving the area for lunch or whatever. Above all - TRAINING, TRAINING, TRAINING Anything else gang?

Someone, maybe Pace or Fancort, makes a cart mounted collection system that holds the container within a negative pressure area with HEPA filtration. Hope my babble is of some help. I've been thinking about our responsibilities to ourselves, our employees and their families a lot recently and the bottom line is that "we've always done it that way" just doesn't cut it anymore. John Thorup

reply »

Mike F

#4105

Re: Dusted By Dross | 17 May, 2000

I just wanted to add a comment to the newbies, that dross must be recycled or it is considered a hazardous waste by the EPA. If you recycle it you can avoid a lot of documentation requirements needed for hazardous wastes, but you still need to have documentation that shows you sent the dross to a company equiped to recycle it. I would also strongly urge you to keep the dross can covered at all times you are not actually adding more dross, and keep the can away from any aisle or traffic path.

reply »

John Thorup

#4106

Re: Dusted By Dross | 17 May, 2000

Absolutely Mike Lets take that one step further and say that almost anything that you use to clean up with will from then on be considered hazardous waste. Wiping rags/pads, the previously mentioned vacuum bags/filters, the piece of cardboard that you used under the guts of the wavesolder when you cleaned it, even the disposable mask you used. The mind boggles. All this applies to your SMT operation as well. Wipes, tissues, stencil wiper rolls, paste containers/cartridges, test prints, etc. Since the metal content of this stuff is so low it is technically hazardous waste rather than recycleable material and can be more difficult to legally dispose of. If your big enough (read: profitable)many recyclers will take it anyway. Be sure to drum it separately. Anyhoo...Bottom line is that you can't ethically or legally put any of this stuff in the trash or down the drain. All it takes is one disgruntled employee to make you wish you had done it right. Try explaining that to upstairs. John Thorup

reply »

ScottM

#4107

Re: Dusted By Dross -what a wake-up | 17 May, 2000

We don't do any of this. We had our operators tested by OSHA for lead inhalation using special sniffers during the wave solder process and passed by a magnatudes in limits while operating the machine and removing dross. Our recycling agency doesn't provide dross pails with lids so they're kept open...

Does anyone have any agency sponsored guidelines for handling dross? OSHA visited our shop and found no problems, am I'm missing something? Has the IPC generated any guidelines? If the special handling precautions you've outline is required, I'll need to documented proof in order to sell it to my management.

Cheers, Scott

reply »

davef

#4108

Re: Dusted By Dross -what a wake-up | 18 May, 2000

Scott: First, it's neat that you do cartridge monitoring on you staff. We do that once a year. We (and I assume others) are responding to OSHA requirements:

Lead CFR 1910.1025 permissible exposure limits for lead, provisions for medical examinations, and abatement procedures.

These rules are aimed at lead smeltering and battery assemblers. So, their limits are far more stringent than ours, as you say.

In line with this, we: * Encourage our wave solder operators and maintence types to take annual blood testing for lead. * Inform all of our staff once a year (during reviews) that they can elect to be tested for lead. * Upon notifying their supervisors, pregnant mothers have the option of working in areas without solder contact.

I hear you stating a need for regulations to force you to follow good practice and have to chuckle. The guidelines are fairly standard practice in electronic assembly. You are out-of-line. (The reason I asked the question was to assess if we should be limiting "secondary" dross dust loss and to see if people were providing disposable suits)

The things people responded with are low cost things to do, and you should want to do them to prevent the off-change that you may harm your workers and to limit the potental liability to your company. Those OSHA inspections will not shield you.

You want to hear a crazy one? One of our post wave assemblers got a troat x-ray (why? I can't remember). It showed that she had about 10 tick sized black spots half way from her mouth to her lung. Her doctor freaked and dug one out. (not a fun thing to have someone do to you, I might add) Turns-out she's indvertantly swallowing things (ie, leads, solder, what ever) that she's trimming from the boards.

Enough (for me) Dave F

reply »

John Thorup

#4109

Re: Dusted By Dross -what a wake-up | 19 May, 2000

Dave - well said

ScottM - I'm appalled - Your management sounds like a throwback to an early industrial age where the workers were treated as a commodity. It's not right to do only what you're forced to do when protecting human beings and the environment. It seemed like your OSHA airborne lead level sampling was done during process operation. Studies have shown that the typical mean airborn lead concentration from wave soldering is 0.01 mg/cubic meter. This is indeed well below OSHA 8 hour TWA PEL. Dross and sitting dust is not normally disturbed during normal operation but rather in service operations. This is where the main problems arise. As Dave says - it doesn't cost alot to do it right, or at least better. You say that your dross recycler does not provide lids. Are they nuts? Would you leave a 5 gallon pail of a pesticide sitting around your garage without a lid? Same thing. Actually, a better question is whether you and they are legal and in compliance with EPA regulations. There are specific rules for licencing, storage means and location, allowable accumulated quantities, accumulation time, labeling, manifesting, transportaion and re-smelting of this material. Some are your responsibility, some are theirs. Most of these are in CFR 40. Ultimately, as the generator, your company is responsible for everything, even after the material is out of your control. As an example of container policy, our recycler will not touch the stuff unless it is sealed in a "gasketed, steel, crimp top can or a steel drum with a bolt locking gasketed lid". I think you may have a problem with these people. If you thing the OSHA stick is big wait till you see EPA's stick. I suggest that you analyze your entire operation with regard to environmental and personal safety and bring your practices into line with industry practices and the law. In addition to this thread, your should search these archives and the IPC Technet archives on the subject. Also check EPA and Osha web sites (both federal and state). whew...can we put this one to bed? John Thorup

reply »

ScottM

#4110

Re: Dusted By Dross -what a wake-up | 22 May, 2000

Thank you much folks!

I've printed out these messages and will be acting on it with management.

Interesting that I don't get hazardous waste manifests from the dross recycler but I do with my CLS chemicals for the washers (hummm....). I might add that the numerous companies I've worked at here have never used these practices (scarry!). I also know that these same companies didn't concider their Mixed Beds, carbon, etc. on there CLS as hazardous waste!

What was MOST interesting was when I transferred dross today from one container to another -- the dust was something to behold!

I'm a stickler for complying with the EPA and keeping my employees safe (I refused to use a chemical cleaner an out of state customer sent me due to the MSDS requirements).

Thanks again, but I've got some work to do....

Cheers, Scott

reply »