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Ionograph or Omegameter



Ionograph or Omegameter | 1 November, 2004

Hi Guys,

Maybe you could help me with the above. We are doing IPC Class 3 products and would like to know more about the difference between the 2. We have an Omegameter, do we need an Ionograph too? Which one between the 2 is effective in Ionic Contamination Testing?

Thanks and regards,

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Ionograph or Omegameter | 1 November, 2004

Ionograph measures conductivity while the Omegameter measures resistivity. They both accomplish the same task in terms of ionic contamintation detection, but go about it a different way. One is really no more accurate than another. For more information, please go to:

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Ionograph or Omegameter | 1 November, 2004

Both are equally efficient process control tools. Neither is particularly effective in testing ionic contamination.

The best way to sell your customer on allowing you to do this is to show them that you understand the WHOLE process and are able to control it. And the best way to do this is to use an analytical method such as ion chromatography. Compared to a resistivity of solvent extract [ROSE] tester [eg, Ionograph, Omegameter, Zero-Ion, etc], the ion chromatograph (IC) is much more accurate, repetitive, not influenced by process conditions [operator skill], and best of all it is ion specific so it will tell you what kinds of ionic materials are being left on the assembly. These systems are rather expensive and not easy to operate. So maybe you should work with a lab that has this capability to optimize your process, rather than buying one of these to control your process.

Once you have optimized your process (including incoming inspection, quality control, storage, handling, etc.), send samples to the lab, while at the same time running duplicates on your ROSE tester. When the IC shows that everything is clean except for the weak organic acid from the low residue flux, correlate those results with the ROSE tester and use that as your process control tool. If at a future date, the numbers from your ROSE tester jump, you know something happened with your process that is contributing additional contamination.

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Ionograph or Omegameter | 1 November, 2004

Hi davef,

Will the ion chromatography be able to quantify then identify where and what the contaminant is? Is this a destructive type of testing or the PCB will remain intact right after the test?

thanks for the inputs.


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Ionograph or Omegameter | 1 November, 2004

Q1: Will the ion chromatography be able to identify and quantify the contaminant? A1: Yes, it will identify and quantify the amount of contaminant. Obviously this is very useful in troubleshooting the source of the contaminant. [The only problem for the cynics is: "So, how does this IC reading correlate with the reliability of the product?" IC doesn't. But then, again neither does the 10.07 �gm/sg in NaCl equivalent of J-STD-001.]

Q2: Will the ion chromatography be able to identify the location of the contaminant? A2: No. In that regard, IC is similar to ROSE.

Q3: Is this a destructive type of testing or the PCB will remain intact right after the test? Q3: Depends. On the other hand, odds are that you'll have some "special" test boards that you will use to calibrate your process when doing an IC run [and know what you're doing test-to-test that are years apart]. Doubtfully that you'll grab a random board from the line and run IC on it.

For more on contamination testing, look here:

We have no relationship, nor receive benefit from the company referenced above.

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Ionograph or Omegameter | 2 November, 2004

I agree with DaveF's recommendation to see Foresight's website ( They have excellent Case Studies on display (for free). There is a good case study which references the results you can expect using a ROSE tester vs other control methods.

Also, we've recently had some work peformed by Foresight and found them to be extremely helpful. Within a few days, we were able to pinpoint our issues to dirty bare boards.

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Ionograph or Omegameter | 6 November, 2004

Many Thanks Davef for your continuos great tech support.

From my side, I am still fighting against BIC coming with sockets ( still tons of Br-). Even the supllier is surprised about this pbm. But as we know no Standards available to control bulk ion contamination for each single part (BOM) of a PBA. Standard (like IPC-J-STD-001C) regarding TIC of PBA, does not help in this case. Any way we will see

Best Regards


This message was posted via the Electronics Forum @

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Ionograph or Omegameter | 8 November, 2004

The EMPF published a nice article, now old but relative, to Cleanliness. Under Technical Docs The listing is ...

RR0013 - An In-Depth Look at Ionic Cleanliness Testing - August 1993.


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