Jul 26, 2011 It’s well-known that residues on printed board assemblies can lead to serious reliability problems. Over the past several years the migration from the use of lead-bearing materials to lead-free materials has resulted in many changes in electronics manufacturing operations. Some of the residual materials that remain on the circuit card assembly are becoming increasingly more problematic to clean. Component densities and component under-clearances are creating new cleaning challenges. To help the process engineering community deal with these difficulties, IPC has released the B revision of IPC-CH-65, Guidelines for Cleaning of Printed Boards & Assemblies.
With guidance from industry experts, the cleaning guidelines have been completely rewritten and address all facets of cleaning, including material selection, process considerations, equipment selection as well as the environmental impact of cleaning. The 200-page document not only brings cleaning requirements up to date, it also combines multiple documents into a single, comprehensive guideline. IPC-CH-65B explains the interactions between materials and processes and outlines the sources and types of contamination found on today’s circuit card assemblies.
The cleaning of printed boards and assemblies has undergone a significant transformation in two decades, due in large part to environmental regulations which are cross-referenced in the document. No-clean fluxes and lead-free solder are among the technical mainstays. “Years ago a large portion of the electronics industry moved from solvent-based cleaning to water-based cleaning. Over the past few years we have seen another shift to the use of lead-free materials and processes. The combination of these events led to the development of the new guideline,” explains Dave Torp, vice president of standards and technology at IPC. He adds that, with the shift to lead-free solder, “reflow temperatures increased, which has impacted the character of residues that remain on the assemblies.”
“The update of IPC-CH-65B was a huge undertaking that could not have been done without the help and expertise from a great many volunteers,” says Torp. Not losing momentum, IPC-CH-65B’s developers are continuing their work to expand the document’s focus to address cleaning for rework and repair.
In the coming months, IPC will host two educational sessions covering IPC-CH-65B. On August 17, IPC will host a 30-minute webinar, “How Clean is Clean Enough? Overview of the IPC-CH-65B Cleaning Handbook,” at 10:00 am Central time. To register, visit www.IPC.org/cleaning-webinar-registration. In addition, a three-hour course, “PD-01 Cleaning Guidelines for Boards and Assemblies: Developing a Successful Process with the NEW IPC-CH-65B,” will be held on September 22 at 1:30 pm, in conjunction with IPC Midwest Conference & Exhibition, Renaissance Schaumburg Hotel & Convention Center, Schaumburg, Ill. For more information and to register, visit www.IPCMidwestShow.org.
IPC members may request a free single-user download of IPC-CH-65B, Guidelines for Cleaning of Printed Boards & Assemblies, by sending an e-mail to MemberTechRequests@ipc.org within 90 days of the document’s publication date. After that date, IPC members may purchase the standard for $50. The nonmember price is $100. For more information or to purchase IPC-CH-65, visit www.ipc.org/CH-65.
IPC (www.IPC.org) is a global trade association based in Bannockburn, Ill., dedicated to the competitive excellence and financial success of its 2,900 member companies which represent all facets of the electronics industry, including design, printed board manufacturing, electronics assembly and test. As a member-driven organization and leading source for industry standards, training, market research and public policy advocacy, IPC supports programs to meet the needs of an estimated $1.85 trillion global electronics industry. IPC maintains additional offices in Taos, N.M.; Arlington, Va.; Stockholm, Sweden; Moscow, Russia; Bangalore, India; and Shanghai, Shenzhen and Beijing, China.
»
