The terminologies “Design for Manufacturing “and “Design for Assembly” cover a very broad spectrum of
operations that are intended to integrate the various elements of
manufacturing into a cohesive system. Any DFMA system will account for different product manufacturing paths, which
include alternate design, materials, process, and their respective impacts on production costs and product quality. Fundamentally, the premise for DFMA is to define the parameters at a very early stage, consider the advantages and disadvantages of pursuing a particular set of design rules, account for the various cost alternatives and assess the metrics used to deliver the final product. 

There is no one unifying approach that is an unyielding tenant of DFMA. Reducing cost and cycle time, while maintaining or improving the quality and serviceability of a product, remains a central theme in the execution of a DFMA system. Ideally, the use of COTS materials would be preferred for reducing lead time, cost and  maintenance as well as having an increased availability of components.  In some cases where changes in the market have driven manufacturers toward a rapid assimilation of new technologies, the implementation of a DFMA program is vital to avoid the potential roadblocks that can impede rapid progress.

A prime example of where DFMA is now being employed is in lead-free manufacturing.  The use of a suitable DFMA method can be instrumental for the transitional phases of package
assembly, where the introduction of a lead-free solder can have a
significant impact on the subsequent manufacturing processes.  For instance, some of the factors to be considered in a lead-free package design, which can potentially cause risk, are:

1. Circuit design- What are the proximity and the locations of the active and passive circuits?
   
   
2. Component geometry – Are BGA’s, QFP’s or other devices going to be warranted, and how will they impact soldering operations?
   
   
3. Substrate materials Are the substrate properties chosen for the design suitable for the higher assembly temperatures?
   
   
4. What specific alloys will be utilized as the replacement for SnPb? Will the alloy replacements cause issues for productivity and quality down the line?
   
   
5. Will there be additional environmental testing needed for the qualification of a lead-free process?
   
   
6. What additional equipment costs will be incurred by changes in process?

In answering some of these questions pertaining to lead-free manufacturing, a projected critical path is created. In doing so, DFMA allows for the identification of potential risks and benefits for each respective assembly process, while employing the design guidelines necessary to meet the performance metrics. A proper approach combines experience and prior knowledge, along with new research studies and tools, to bring the DFMA process beyond the abstract and into a working manufacturing model.

There are a variety of vendors and software configurations used to monitor and sustain the DFMA efforts, most  of which organize and integrate all the various inputs from the contributing manufacturing sectors.  In some cases, the resulting output is a theoretical index designed to gage the efficiency of the specific process as defined by the user. Some software is simply designed as itemized checklists or flow charts to ensure that the proper process parameters are entered. Others rely on internal design rules that integrate a good cross section of pertinent manufacturing and assembly information to deliver an effective system.  In either case, whatever DFMA system is chosen, there is a need to guarantee that the proper inputs have been
considered for the critical path chosen. The success of optimizing any manufacturing process is only as good as the information that is gathered through contributions from each individual, section, or department involved in producing the product.

At the EMPF, we are often engaged in the development of new electronic packaging technology. One of our goals is to keep re-educating ourselves on the importance of maintaining flexibility, quality, and cost for our valued customers. DFMA is another tool in the tool box that helps us achieve those goals through both our learning center and our manufacturing facility.   For more information on the courses offered, please visit the EMPF website at www.empf.org and click on training.

Next Month - We will breakdown a DFMA case study.