Issue link: https://iconnect007.uberflip.com/i/869081
12 SMT Magazine • September 2017 by Stephen Las Marias I-Connect007 Despite the many technology advances in the SMT process, there will always be a need for rework and repair of PCB assemblies. Most espe- cially as the industry trend continues towards finer pitch and spacing, smaller and smaller components, and increasing high-reliability re- quirements from customers. Not to mention that fact that the rework and repair processes are already challenging. You have to deal with already-finished boards, wherein improper soldering may cause collater- al damage to around the area that needs rework. So, for this month's issue of SMT Magazine, we interviewed Dan Patten, general manager, and Laura Ripoli, customer service manager for rework/repair, from BEST Inc.; Gary Freedman, president of Colab Engineering; and Andy Price, sales manager of Circuit Technology Center, to know more about the rework and repair of PCB assemblies, the critical challenges, and strate- gies to improve the process moving forward. The Challenges "We're always making more densely pop- ulated boards and we're making things small- er and packing more into it and so forth," says Patten. Price notes, "From our perspective, some of the most challenging issues that we confront daily tie in with the circuit board design. The spacing is tighter, the boards are thicker and contain heavy copper planes. Those factors along with the RoHS requirements help create many of the challenging issues that we face in trying to rework components. It also increases the challenge in getting complete solder fill in plated holes. Much of it is directly related to the circuit board design. Some of the other factors include rework and repair on boards that have gone through final processing. They may be field returns or failures that are found after con- formal coating application, or through the un- der-fill process at BGA component sites. There's are many problems that can arise when rework- ing boards with conformal coating. Often col- lateral issues to adjacent components can oc- FEATURE