Hi, Steve, I've limited RF experience here, but here goes as a mechanic. 1. Non-aqueous (solvent) cleaning may do the job of removing the residues, but there is a good chance of the stuff clinging to the corners and not coming out. You could avoid the bake-out process, but if the shield you mention has only small holes and is otherwise sealed, you may have to wait a while. 2. Can't comment of cold soak with Bioact. 3. Ultrasonics would be your best bet IMHO for loosening and removing the residues, though I'm still concerned about entrapment under that shield. I guess I would be concerned about that with any method though. If you don't have vapour degrease already, but do have ultrasonics, I would go with that. Just make sure the frequencies you use aren't around the natural frequency of the objects you're cleaning, or its harmonics, or you might jar something loose. Pete Steve Abrahamson To: [log in to unmask] <sabrahamson@ cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group) MCMS.COM> Subject: [TN] Unusual Cleaning Operation- Help! Sent by: TechNet <[log in to unmask] ORG> 05/03/01 07:01 AM Please respond to "TechNet E-Mail Forum."; Please respond to Steve Abrahamson Howdy, I have got a major mess on my hands. We may soon be running a double sided SMT product that needs to be fully cleaned due to a conformal coating process. Both sides of the assembly have two 2" x 1" x .3" RF Shields that are soldered to the PCA. There are SMT components under the shield, and the shields have two .040" holes on top- the rest of the shield is sealed. Just in case we cannot clean 100% of the residue out of these shields, the customer requires a no-clean chemistry solder paste. (They claim no clean residue has caused problems with past due to issues with the battery pack...I am not much of an electrical guy, and cannot refute them). They are pushing us towards a vapor degrease cleaning method, since they had used the process sucessfully during the design phase with good luck. Question 1: If we did use a non aqueous solvent for cleaning, especially one that has evaporative characteristics (any HCFC replacement), could we avoid the "bake out" process? Question 2: Would a cold soak process with somthing like Bioact be a viable alternative- and be performed without a bake out? Question 3: Would ultrasonics be valuable (if we had alternating frequency such as with the Smartsonic system), or could more damage be done. Steve Abrahamson 208-898-2695 [log in to unmask] --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 --------------------------------------------------------------------------------- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------