Hi Lloyd,

That makes sense. One of my concerns is the repeatability of the onboard cleanliness tester. I have read that proper calibration of the resistivity probe would be very difficult, due to the turbulent nature of the flowing water, so I think it does make sense to use another tester like you say to validate the washing machine. If you don't mind, I might contact you offline with specific questions on the Trident.

Thanks! 

Howard A. Watson
Phone: 505-665-3402

-----Original Message-----
From: Lloyd Duso [mailto:[log in to unmask]] 
Sent: Friday, February 01, 2013 3:21 PM
To: 'TechNet E-Mail Forum'; Watson, Howard A
Subject: RE: [TN] Manncorp Trident Batch cleaner Onboard Cleanliness tester

We have the exact machine here and use it often. The cleanliness testing portion is useful to set a range and let it rinse until it reaches that point. It in no way replaces a task specific cleanliness tester like a Zero-Ion or an old school Omega. Since it is a batch machine, the cleanliness is just an average not a specific count for one board. The benefit is that if it reaches the cleanliness value programmed in on the first rinse it's done. If it hasn't reached that value it will keep rinsing until it hits the programmed Max Rinse number. We still use the cleanliness tester to validate the washing machine.

Lloyd E Duso
Plant Manager
(814) 535-3505
 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Watson, Howard A
Sent: Friday, February 01, 2013 4:47 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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