How DFMA guides design and development cycles.
Practically reduce costs without affecting performance.
Common parts and features that can increase costs and turnaround time.
Electronic product design and development needs to adhere to machining capabilities and component availability.
Given that most consumer electronics tend towards disposability, most people are unlikely to consider the immense amount of work that goes into the board responsible for powering their devices. Designs and revisions can span months, sometimes years, and raw materials and components must go through a dizzying amount of processes to be shaped into the final product end users are familiar with. However, one curious peek reveals a highly-trafficked network of traces, vias, and the assembly of components that provide the overall functionality working tirelessly (and often thanklessly!) behind the scenes in the modern world.
Even those with some background in electronics may wonder about the market forces that also play a hand in refining designs. After all, every commercial board is produced with profitability in mind, and high-volume lots are especially vulnerable to individual costs multiplied thousands or millions of times over. Electronic product design and development looks at the processes and parts that inhibit high yield and can be distilled into a few simple guidelines as well as features to avoid if at all possible.
DFMA Encompasses Electronic Product Design and Development
Design for manufacture and assembly (DFMA) captures the core intent of electronic products intended for full production. Like prototyping, DFMA has to be built to the precision of tools and equipment, but there is an additional budgetary constraint to contend with. Whereas prototyping may be able to get away with manufacturing choices that are less cost-efficient, these choices won’t bear out financially when lot sizes swell to the 100s, 1000s, and beyond.
DMFA is a superset of two independent, yet closely related, design protocols that both stress producibility and low cost:
Design for manufacture (DFM) - Practices that help ease the construction of the board, encompassing the raw materials used in construction to the layout phase. Though this can include assembly, in context it may refer only to the fabrication of the bare board. Design rules need to accommodate, which usually stands in opposition to ease of placement and routing.
Design for assembly (DFA) - Application of design techniques that are best suited for mass assembly, including minimizing the bill of material items. Layout designers will want to minimize processes involved, such as multi-step soldering, whenever possible.
The first stage of any design intended for mass production quantities should be an initial consult between engineers, designers, and machine operators. Modern electronics, especially HDI designs, will be a contest between features/optimal performance and feasibility, resolution of tools, or cost. In this sense, the layout designer serves to balance the wishes of the engineering team against the realities of manufacturing. DFMA may need to sacrifice some level of quality to maintain high volume guidelines in a dense design, but this should not be performed haphazardly. Instead, engineers should inform designers of crucial circuits and nets within the design so that critical features such as data lines, differential pairs, length matching, and similar structures may be prioritized.
Providing an Action Plan for Design and Development Efficiency
Optimizing electronic product design and development cycles boils down to incorporating changes at the earliest point possible in the development cycle where savings are maximized and designs are most fluid. Due to the compounding costs of labor, processing, materials, and parts, modifications made to the board increase on the order of magnitudes as it passes through manufacturing benchmarks. A three-pronged approach may be utilized by design teams to optimize builds for cost efficiency:
- Part reduction - Though less rampant than software due to physical constraints, feature bloat can become an issue with electronic design. Engineers should keep core functionality and support at the focus and take note of any opportunity to whittle down the bill of materials without sacrificing any design intent. Alternatively, later product revisions of a successful design can leverage improvements in technology and reductions for better profit margins.
- Material cost - An added complication to sourcing materials for the board itself is that both electrical and mechanical properties contribute to the device’s operation. However, there may be opportunities for alternate materials in enclosures to reduce cost while still providing necessary rigidity, shock absorption, and heat dissipation.
- Supplier bulk negotiations - Though backlogs arising from global supply chain issues are still ongoing and affecting the purchasing power of assemblers, procurement teams can utilize information from early models and toolsets to more effectively price out parts for high-volume production far in advance of assembly.
Improve Board Feasibility by Avoiding Some Common Pitfalls
While PCBs represent a wide range of design opportunities, sometimes the easiest path to producibility is eliminating nonstandard features that introduce additional steps to manufacturing. The best manner to reduce cost, increase yield, and improve production speed is by minimizing (ideally, eliminating) manual processes. While design integrity should always trump manufacturability, engineers and designers should ensure as much as possible that boards avoid some key troublesome inclusions:
- Adhesives - Often dispensed automatically as part of the machine placement process, larger components may require manual applications for improved vibrational resilience, sealing pins to prevent dendrite growths, or other bonding/coating purposes. Depending on the bonded surfaces, additional cure times or conditions (e.g., anaerobic) can complicate and lengthen production.
- Components - For a variety of reasons, certain components may necessitate additional or alternate steps to accommodate manufacturing. Whether it’s a lack of compatibility with insertion machines, cleaning solutions, soldering temperatures, or other drawbacks, these parts need a manual assembler to complete. Further, hand soldering is much more prone to error than a wave or reflow oven.
- Miscellaneous parts - Washers, nuts, screws, spacers, jumpers – all introduce supplementary labor that serves as a bottleneck to production. Components with unusual elements such as sleeved leads can trap fluids like solder, flux, and cleaning solutions that contribute to immediate failure via shorts or corrosion and oxidation damage that imperil long-term reliability.
Cadence Software Empowers Users and Hones Designs
Electronic product design and development offers teams multiple avenues to improve their board, from procurement through the entire manufacturing stage. With it, teams can hone in on individual elements of their design and seek out the best resolution to balance cost-effectiveness and performance. In support of this endeavor, Cadence’s PCB Design and Analysis Software toolset provides a wealth of solutions at all steps of design for greater optimization. Combined with the speed, power, and ease of use found in OrCAD PCB Designer, teams can quickly update layouts to reflect changes best suited for manufacturing.
Leading electronics providers rely on Cadence products to optimize power, space, and energy needs for a wide variety of market applications. To learn more about our innovative solutions, talk to our team of experts or subscribe to our YouTube channel.