What works the best is to use commonly accepted Best Manufacturing Processes. In this case, on the process detail sheets you call out the specific solder, flux, solder tools, tips, and temperatures to be used for that particular process on that particular product. Not a general Standard Operating Procedure that is particular to a process only, but on the particular detail for the specific product to be soldered. You don't do that, you depend on the operator's expertise, you say? Sorry, your process is then out of control. General 5S procedures should be used to keep solder, solder tools, tips, fluxes, etc. in visible control on the benches, including signage to control the benches themselves. Color coding no-clean, water-soluble, and lead-free fluxes and solders for visible management is the first step. Training and certification of the assembler so he/she knows what each is used for (and not used for) is another step. Once the operator is trained and certified, you shouldn't have to worry about improper use of the wrong tools or materials. It is always the manufacturing engineer's responsibility to keep the process in control, and proper documentation of tools, methods, and materials used is part of that. Keeping lead-free tips and soldering systems in a separate bench to avoid cross-contamination of alloys left on the tips is a commonly used practice, and a good approach. Segregation without training does not work, as it is too easy for an uneducated operator to "borrow" the wrong materials for the product. Training without segregation can be done, but it is much more difficult to prevent the wrong tips and tools from being used. The workbench or station that the process should be done at should also be called out on the process detail, just like any other tool or material. It is not always economically feasible to segregate an entire SMT line for Pb-free products. In that scenario only the printer needs tight controls over the solder paste to be used. The workstations for solder rework (touchup rework) and post-SMT assembly and soldering should be segregated into Pb-free and non-Pb-free. Although economically prohibitive for some, the wave solder machine should never be used for both processes. Another area where segregation is not always possible is the Hot Gas Rework area. The operator(s) in that area need to be very knowledgable of the product they are working with in order to prevent the wrong materials from being used. While specific detail for reworking every possible component on a given product is not possible, a rework detail sheet can be provided in the product-specific instructions that calls out the appropriate process materials and methods to be used for reworking that particular product. Examples such as notations not to wash a no-clean board in the water-wash process, use only no-clean or lead-free solders when performing rework, etc., etc., can be documented as a reference for the rework operator. Some segregation is necessary, but proper documentation, training, and certification is more important. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of bob wettermann Sent: Wednesday, August 10, 2005 6:37 AM To: [log in to unmask] Subject: [TN] Hand Soldering-Mixing Sn63 and L-F Processes Ladies and Gents: There have been several ways discussed in the trade press and in papers re: how to separate/keep separate Sn63 and l-f hand soldering tools and materials. Some claim completely separate hand soldering tools are required while others claim that separate tips are sufficient in segregating the processes. Other larger companies have completely dedicated mfg lines dedicated to l-f mfg and hence the hand soldering tools are separated with respect to floor space. Does anyone have these or other practical experiences on what works the best? Bob Wettermann Bob Wettermann --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- PH 847-767-5745 --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------