“ROSE is a Cleanliness Test. It never was, nor ever could be, anything more than a Process Control tool.”
Absolutely correct! I couldn’t agree more.
dean
From: Graham Naisbitt [mailto:[log in to unmask]]
Sent: Monday, June 26, 2017 6:45 AM
To: IPC TechNet Forum
Cc: Stadem, Richard D.; [log in to unmask]; Doug Pauls
Subject: Re: [TN] PCBA Cleanliness
Good day to all fellow Techies,
Cleanliness assumes you have tested all possible contaminants on the board. You can’t do this!
Process control assumes you are removing the same contaminants every time. You can do this reliably and reproducibly.
I have drafted PICT: Process Ionic Contamination Testing into a new DRAFT International Standard: IEC 61189-5-504 that I hope will find its way into a similar IPC Test Method.
The test technique has already achieved 6-Sigma verification as presented by Robert Bosch at the IPC APEX event in February this year.
The biggest challenge I continue to face on this subject is the confusion that abounds throughout our industry that ROSE is a Cleanliness Test. It never was, nor ever could be, anything more than a Process Control tool.
If anyone wants more info, let me know?
Kindest regards
Graham Naisbitt
Managing Director
Gen3 Systems Limited
P: +44 (0)12 5252 1500
E: [log in to unmask]<mailto:[log in to unmask]>
W: gen3systems.com<http://gen3systems.com>
On 23 Jun 2017, at 13:35, Douglas Pauls <[log in to unmask]<mailto:[log in to unmask]>> wrote:
Good morning Steve,
Yes, It Depends. IPC sends people my way when they have questions in this
area.
What you want are two documents
IPC-948095 Cleanliness Requirements for Pretty Normal Processes
IPC-948096 Cleanliness Requirements for Weird Ass Processes.
Just kidding.
Over the last two years, I have been leading a small team of SMEs for the
J-STD-001 committee on what should replace ROSE testing for the next
generation of ionic residue testing. Although we missed the window for the
upcoming G revision, I believe that the committee will review our proposal
as an Amendment activity, though I have not yet discussed this with the
J-STD-001 leaders. The draft of our proposal and an associated white paper
explaining the proposal, was turned in to the committee earlier this
month. It should be circulated sometime this summer.
Doug Pauls
Principal Materials and Process Engineer
Rockwell Collins
On Fri, Jun 23, 2017 at 6:50 AM, Steve <[log in to unmask]<mailto:[log in to unmask]>> wrote:
I realize that this is an old and continuing subject of debate in the
industry, but I am interested in the current updated consensus on the
topic. Specifically, what kind of PCBA cleanliness level should be
reasonably expected to achieve?
Of course the answer is always "it depends," because that is the reality.
And the actual acceptance or control level needs to be set according to
product requirements. But what I am after is slightly different: What level
of cleanliness would you expect to be readily achieved by a good quality
manufacturing process under normal circumstances?
Some general parameters to narrow down the question:
- Measurement technique bulk solvent (ROSE per IPC TM-650 2.2.25)
- Pretty normal PCBA design - 0403 components, some through hole, nothing
really unusual
- Pretty normal process, RoHS, no-clean.
- Class 2 PCBA, but high impedance low current battery powered application
- High production volume (>1 million units annually)
I am not aware of anything that has replaced the 1.56/cm^2 "standard." but
this has been around forever, it seems. Common sense tells me that even if
a formal standard has not changed general performance might have improved,
on account of smaller components, tighter board spacing and general
technological improvements.
What has been your actual experience in this regard?
Thanks in advance,
Steve
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