By Luke C. Kensen
 Interior shot of Express Mfg.'s PCB design and manufacturing facility. |
Realizing that top-tier companies in the contract manufacturing industry must be able to offer their original equipment manufacturer (OEM) customers a total supply chain solution that includes design, product/system assembly, manufacture and support services, many contact manufacturers (CMs) have added printed circuit board (PCB) layout and design to their overall capability. This development is fueled by the never-ending drive toward smaller, smarter electronic products.
Bringing PCB design in-house allows CMs to provide turnkey services and deliver products much faster, as well as pass along savings in redesign to their customers.
It also allows OEMs to take advantage of their CM's engineering and production expertise, get a firm hold on product cost drivers, speed up overall product development and shorten time-to-market.
Shift Toward Outsourcing
For many OEMs, the shift to outsourcing has become an essential part of their strategic business plan. Many CMs are taking the lead in developing turnkey manufacturing processes to support advances in component and process technology. However, industry-wide standardization and cooperation (such as acceptance of the 2.4 GHz universal telecommunications frequency) is essential in developing new platforms for emerging technologies, packages, substrates, components, attachments and test processes to meet future needs. That is why OEMs often make statements like, "We do not know what we will need six months or a year from now, but whatever it is, we are depending on our CM to be prepared with the right equipment, techniques and processes."
For OEMs or customers, the No. 1 rule is to always try to compress the package size of their product to lower cost and increase market share. This means that they must reduce the size of the overall unit, the board, the components and the component count. To achieve this, the designers or CMs will exercise the different alternatives:
- Sourcing components that are nonallocated; avoiding components that are hard to find
- Sourcing components of alternate package type; analyzing which component package type may reduce manufacturing cost
- Modifying the intensity of the mechanics; changing out labor-intense mechanical assembly components to something less time-consuming
Evolution of the PCB Design Process
So, how does this new, integrated PCB development work? OEMs come to CMs not only for product assembly, test and manufacture, but also for design ideas regarding PCB layout. PCB layout is, in one sense, a necessary evil in going from raw engineering design to final production. It has evolved from a non-computer-aided design (CAD), hand-layout and photonegative process into a fully computerized, e-mail and modem operation. Now, CMs e-mail out the schematic, get the optimized PCB design back within 5 to 7 days, then begin building it. So-called "breadboarding" (prototyping a product in the development cycle) is no longer a consideration.
Many factors are involved. Although there are CAD systems that can automatically analyze signals and lay out PCBs accordingly, they are not necessarily the final word in layout design. The human element is still important, especially considering that PCBs are now very dense, and guaranteed to become denser still. Some factors that may require human knowledge and intervention include use of smaller boards, more complex hookups, ultrafine-pitch circuitry, capacitance relationships, crosstalk between lines, desirability of multilayers, resolution of mechanical and electronic compatibility problems, and electromagnetic compatibility/electromagnetic interference (EMC/EMI), which must be considered in the initial design.
The desirability of flexible circuitry and any advantages that might be implicit in the design of a PCB with components on a flexible base should be appraised.
Multilayer boards and flexible print can be very appealing to a manufacturer faced with miniaturization problems in producing wireless telecommunications equipment. For example, a four-layer PCB can be up to 8 times smaller than the prototype, and flexible print, which contains no substrate, is an attractive technology in such products as cameras, pagers and hand-held phones.
In an environment of shrinking footprints, increased input/outputs (I/Os) per square inch and array package sizes that have gone to 0201 pitch, PCB design is not necessarily a slam-dunk, even with highly computerized design equipment. In light of all the interdependent processes and the possible pitfalls, there can be no question that a turnkey service that includes optimized PCB design is looked upon with great interest by most OEMs that employ an outsourcing manufacturing strategy.
What the Future Holds
What about the direction of growth? What are the trends? For starters, employing CAD systems in the design of PCBs will continue to reduce the turnaround time in the manufacturing cycle. With the fast turnaround, micro line widths and high frequencies involved, engineers can now bypass breadboarding altogether. And again, the trend toward multilayer board design has been advanced by the insatiable trend that includes smaller, more compact boards and the fact that they provide for better ground planes for reducing emissions (i.e., enhancing EMC/EMI control). Multilayer boards up to 18 layers are now regularly produced, with each layer being only 1.0 mil thick.
Every development, of course, is flavored by cost. Just about all PCB designs are now CAD, which tends to speed up everything in the development cycle. This, obviously, involves cost considerations. Despite cost, the continued growth in storage media and memory systems is bound to continue. The industry can also expect greater use of electronics in toys, with some of them containing very complex circuitry. Miniaturization and PCB density will continue as well. In fact, it will never stop. One thing is certain: as soon as it appears that limits have been reached, new technologies spring up to continue these trends.
LUKE C. KENSEN is director of Business Development, Express Mfg. Inc., 3115 West Warner Ave., Santa Ana, CA 92704; (714) 979-2228; Fax: (714) 556-0575; E-mail: LKensen @emine.com; Web site: www.eminc.com.
