-
- News
- Books
Featured Books
- smt007 Magazine
Latest Issues
Current IssueBox Build
One trend is to add box build and final assembly to your product offering. In this issue, we explore the opportunities and risks of adding system assembly to your service portfolio.
IPC APEX EXPO 2024 Pre-show
This month’s issue devotes its pages to a comprehensive preview of the IPC APEX EXPO 2024 event. Whether your role is technical or business, if you're new-to-the-industry or seasoned veteran, you'll find value throughout this program.
Boost Your Sales
Every part of your business can be evaluated as a process, including your sales funnel. Optimizing your selling process requires a coordinated effort between marketing and sales. In this issue, industry experts in marketing and sales offer their best advice on how to boost your sales efforts.
- Articles
- Columns
Search Console
- Links
- Events
||| MENU - smt007 Magazine
To Bake or Not to Bake: Examining the Impact of Waiving PCB Pre-Baking Prior to Assembly
November 15, 2016 | Yash Sutariya, Saturn Electronics/Saturn Flex SystemsEstimated reading time: 1 minute
I’ll always remember the summer of 2004 as the “Summer of Lead-Free.” Finally, Pb-free circuit boards were going into standard production mode. Assemblers focused the majority of their efforts (often at my behest) on final finish and proper laminate selection. What none of us saw coming, however, was the rash of delamination that would burn the entire industry during that long, hot lead-free summer.
After a good amount of research, Isola came up with a Lead-Free PCB Fabrication and Assembly Guideline that outlined various steps in the PCB fabrication and assembly processes that are critical to successful lead-free PCB assemblies. The most prominent process step that was added in this guideline is baking—during fabrication and, most critically, just prior to assembly. The goal of baking is simply to drive moisture out of the PCB.
Moisture plays a critical role in lead-free PCB assembly. Therefore, it is important to discern the specifications of your base laminate. One knee-jerk reaction of North American PCB users was to specify what they believed to be the highest end laminates, those that qualify under IPC 4101/126 and /129 slash sheets. These are typically phenolic-cured materials, which have much higher thermal properties in terms of glass transition temperature (Tg) and decomposition temperature (Td) that are required to survive lead-free assembly without via failure.
Unfortunately, other properties of the laminate and assembly temperatures create a perfect storm for reliability failures. These include: moisture absorption, interlaminate adhesion strength, and water vapor pressure at lead-free assembly temperatures.
Moisture Absorption
Moisture absorption of phenolic materials is more than 2x as compared to traditional FR-4 materials that qualify under IPC 4101/21. In the early days, the technical data sheets used a 0.028" thickness core material for moisture absorption measurement. Based on this test vehicle, phenolic laminates showed moisture absorption of 0.45%; comparatively standard FR-4 laminates scored a 0.20% rate of moisture absorption. Over time, I think someone got wise and changed the test vehicle to a 0.059" thickness core, thereby increasing the denominator of the weight loss calculation. This resulted in a moisture absorption rate of 0.20%, matching the rate of standard FR-4 laminate.
To read this entire article, which appeared in the November 2016 issue of SMT Magazine, click here.
Suggested Items
The Knowledge Base: A CM’s Perspective on Box Build Practices
04/30/2024 | Mike Konrad -- Column: The Knowledge BaseIn the ever-evolving landscape of electronics manufacturing, the box-build process stands out as a critical phase that bridges the gap between individual component manufacturing and the delivery of a fully functional electronic system. This intricate procedure, encompassing the assembly of everything from PCBs to wire harnesses and mechanical enclosures, demands a high level of precision, efficiency, and innovation. As the electronics assembly industry expands and diversifies, understanding the best practices within box-build assembly has become paramount for manufacturers aiming to stay ahead in a competitive market.
Latest Test and Inspection Solutions from GOEPEL electronic at SMTconnect 2024
04/29/2024 | GOEPEL electronicGOEPEL electronic will be demonstrating automated test and inspection equipment at SMTconnect, taking place in Nuremberg from June 11 to 13, 2024.
Determining the Value-add of Box Build
04/24/2024 | Nolan Johnson, I-Connect007At a strategic level, adding box-building services makes sense for customer loyalty. But is it really that simple? Jon Schmitz, who manages customer engagement at RiverSide Integrated Solutions, talk about about what it really takes to be successful in offering EMS and final assembly services under the same company banner.
IMAPS & IPC to Host Onshoring Workshop
04/16/2024 | IPCThe International Microelectronics Assembly and Packaging Society (IMAPS) and IPC will host an Onshoring Workshop to discuss ongoing progress and forward-looking strategies to drive the Onshoring Advanced Packaging and Assembly, April 29 – May 1, 2024, in Arlington, Virginia.
IPC WinterCom 2024 Through the Eyes of One Dedicated Student
04/12/2024 | Sanjay Huprikar, IPCLauriane Testuz stands as a testament to the power of curiosity, perseverance, and the relentless pursuit of knowledge. Her story serves as a reminder that the path to success is often paved by an unwavering commitment to one's dreams.