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Join Date: Jun 2015
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Dust Sensor Calculation

06/15/2015 5:15 AM

I want to measure the dust in the soldering area and want to justify whether the levels are good or not. I am using the Amphenol Dust sensor SM-PWM-01A. And I am not sure about the dust particle size and confused about the calculation of the dust there in the atmosphere. So please help me in finding the relation between the sensor output and dust concentration so that I can conclude my dust levels in the soldering area. I am measuring it in the soldering area where basic soldering activity done is soldering the PCB. Lead used is 60/40.

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#1

Re: Dust sensor calculation

06/15/2015 5:25 AM

RTFM.

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Active Contributor

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#2
In reply to #1

Re: Dust sensor calculation

06/15/2015 5:29 AM

Sorry sir. I didn't get what you are saying.

Thanks

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#3
In reply to #2

Re: Dust sensor calculation

06/15/2015 5:37 AM

RoHS.

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Active Contributor

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#4
In reply to #3

Re: Dust sensor calculation

06/15/2015 5:43 AM

Hi Lyn

Thanks for your reply. The sensor is RoHS complaint and the sensor is giving the output in particles count and I want to convert it into mg for that I require the weight of the particles. So please tell if you know the particles size.

Thanks.

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#5
In reply to #4

Re: Dust sensor calculation

06/15/2015 6:40 AM

Really!

How is he going to know ANYTHING about YOUR dust?

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#6
In reply to #5

Re: Dust sensor calculation

06/15/2015 6:56 AM

hi

the mechanism of measuring dust is optical sensing.

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Guru

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#10
In reply to #6

Re: Dust sensor calculation

06/15/2015 10:39 AM

just read the manuals. instruction of how to tell should be there or call or contact the manufacturer and request tutorial.

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#7

Re: Dust Sensor Calculation

06/15/2015 9:10 AM
  • Lead soldering around 500°C is NOT a significant source of lead poisoning.
  • Rosin core solder's fumes are asthmagenic, paradoxically MUCH worse with "clean solder" due to higher temperatures, thus greater decomposition gases.
  • Your sensor cannot do quantitative measures of dust particles, you should try a different approach, perhaps extraction devices.
  • Read all CLAW and RoHs documentation pertaining to lead soldering; if you comply with all norms but still an inspector is giving you a hard time, sue the son of a gun !.

By the way, RTFM stands for Read The Furnished Manuals, and is very advise-able.

If still in doubt check this link.

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#8

Re: Dust Sensor Calculation

06/15/2015 9:57 AM

One of your first problems is that the smallest particle your instrument will measure is 1 µm in diameter whereas the smallest fumes emitted by soldering are 0.3 µm diameter.

What made you think that a dust sensor would be suitable for measurement of fumes?

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#9

Re: Dust Sensor Calculation

06/15/2015 10:02 AM

You're getting to be a pain.

Trap the particles in a filter. Weigh it before and after use to determine the weight of trapped particles.

Really, do some research before coming here and asking us to do it for you!

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#11

Re: Dust Sensor Calculation

06/15/2015 9:48 PM

This is ludicrous.

What possible reason would the total weight of particles matter in a soldering operation? I challenge you to produce ANY logical reason.

Particle SIZE, that's particle SIZE, matters in clean rooms and soldering operations.

And numbers size distribution and matters.

There's a reason why the size/concentration of the dust particles matters.

Do you understand what that is?

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#12

Re: Dust Sensor Calculation

06/16/2015 9:52 AM

In a sealed environment "clean" room where the technicians are wearing smocks?

Or in a room open to the atmosphere?

It does make a significant difference.

I would take several separate samples of the generated dust then have them analyzed for content and size by a reputable laboratory so that I could determine which type of monitoring is required.

There are portable analyzers available on the market that can be installed in the work area(s) which are capable of monitoring the environment for periods of time to determine the concentration (PPM) of a wide range of contaminants such as dust, gasses, chemicals, etc.

Most particulate analyzers provide the concentration readout in Parts Per Million (PPM) values because the Permissible Exposure Limit (PEM) of employees is spelled out as such.

Unless dealing with gases to my knowledge there is not any device that will distinguish between the type of solid particles in dust with any real accuracy and render an immediate display.

Most of the areas such as welding and soldering that we monitor are sampled at irregular intervals using portable sample gathering devices that are sent out to a laboratory for analysis once the sampling period is complete.

There are several reputable companies that provide environmental sampling equipment and certified analysis.

Attempting to do this in-house would be costly, the results suspect to say the least, and the risk/liability is huge.

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#13
In reply to #12

Re: Dust Sensor Calculation

06/16/2015 10:09 AM

But, if we're talking about a clean room, it's size and number of particles per a given volume of air. Class 1, 10, 100 etc. per ISO 14644-1.

I don't believe that the OP has knowledge of what they really want.

It sounds like he's trying to find the weight of all the particles in a given room??????

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#14
In reply to #13

Re: Dust Sensor Calculation

06/16/2015 10:19 AM

Yep, me too.

I am guessing that whatever dust they are dealing with is either negatively affecting their process QC or has been deemed as a possible risk to employees.

I would be very surprised if this is not a case of budget restrictions preventing proper monitoring of a work area environment where someone in management has come up with the idea that; "We can do this in-house a lot cheaper than what we can pay someone else to do it. Assign it to an engineer and let them be responsible so we aren't."

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#15
In reply to #14

Re: Dust Sensor Calculation

06/16/2015 10:29 AM

" Assign it to an engineer"?

I think it was assigned to NPD instead.

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#16

Re: Dust Sensor Calculation

06/16/2015 3:35 PM

You don't mention if the soldering is being done in a clean room environment.

What does the soldering specification require?

If this is a Class 100 clean room, then the filter requirement is for a 100 micron filter. Placing a Manometer in the Air Flow will determine if the filter is clogged (usually required in clean room specification(s))

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