Howard,

The resistivity monitor on the cleaner is intended to be a process control, not a spec. qualifier, i.e., if you always run 20 boards (same P/N) to a specific resistivity in the cleaner rinse cycle, you could expect similar results on ROSE testing between batches. This doesn't tell you if you meet 10 ug NaCl/sq in or not, it can only tell you you've done the same as previously.

Ed Popielarski
Engineering Manager


                               970 NE 21st Ct.
                              Oak Harbor, Wa. 98277

                              Ph: 360-675-1322
                              Fx: 206-624-0965
                              Cl: 949-581-6601


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Watson, Howard A
Sent: Friday, February 01, 2013 1:47 PM
To: [log in to unmask]
Subject: [TN] Manncorp Trident Batch cleaner Onboard Cleanliness tester

Hi all,

My shop just bought a batch cleaner (dishwasher type); the manual says it is Aqueous Technologies, with an onboard cleanliness tester. This is a resistivity meter that measures the resistance of the rinse water, and I believe it has a range of 2k to 2000k ohm. This unit has both a closed-loop wash and  rinse, and we are using DI water. Does anyone have any experience with this type of cleaner with an "onboard cleanliness tester"?  Is this mostly for process control?  The manual is recommending a baseline cleanliness of 200-400 kOhm. I realize that this tester is not going to provide a level of cleanliness or contamination of each board processed, but I'm not sure what it is good for other than indicating the rinse water needs to be changed.

I was not involved in the selection of this system, but tasked with qualifying it.  My previous experience has been with no-clean processes, so cleaners are new to me!  I should add that currently we process a very small volume of PCBAs for space. All work is hand assembly and cleaning is by hand with Ensolv. The goal is to get away from Ensolv while still achieving clean boards. This shop has never done ionic contamination testing, ROSE, SIR, etc.  I believe some people were sold on the "onboard cleanliness tester" as a cure-all for aqueous cleaning validation, but I'm skeptical as to the benefits.  Any insight is appreciated.


Howard A. Watson


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