Quality printed circuit boards require more than quality manufacturers.
It never ceases to amaze me that OEMs and design bureaus deliver watered down and unintelligent data to their EMS vendors or manufacturing groups, yet keep their high expectations of high-quality products and consistent reliability.
One of our customers is a contract electronics manufacturer. He sent this actual example:
Table 1 is an excerpt from an actual customer’s BoM with incomplete data. These incomplete data cause significant time expenditures and delays. For example, on capacitor C101, what voltage rating and tolerance are needed? For the screw and nut, what material (steel, brass, nylon, etc.), and style (slotted, Philips, hex, etc.)?
A number of factors drive the necessity for high-quality data. Shorter product lifecycles coupled with higher reliability expectations and lower cost mean the data should be correct and complete when delivered for manufacturing. The result: a growing need for effective, efficient utilization of intelligent data, from design through manufacturing. It is critical not only that complete and intelligent data be provided to ensure products have the highest quality and reliability, but to meet cost targets and critical release dates.
Consider the importance of the manufacturing utilization of data. Manufacturing groups are highly dependent on product data received to provide outputs and information necessary for a manufacturing process to yield products of high quality and reliability. Manufacturers use these data for a large variety of things: BoM/MRP reports, defect statistics, and other manufacturability reports, DFx analyses (assembly, fabrication, and test), test programs, and other reports and programs. Without the intelligence embedded in good data formats, creation of these outputs is cumbersome, slow, or worse, exposed to error and data integrity issues.
These two examples underscore the importance of high-quality data. Each requires higher quality intelligent data to permit manufacturers to take advantage of advanced solutions for the benefit of their customers (i.e., you):
1. Machine programming process with validation. With data consisting of top/bottom copper layer, silkscreen with polarity, component reference designators, and a BoM with accurate component information, manufacturers can validate SMT machine programs offline for rotation and offset issues at an engineer’s desk ($40-$75/hr. burdened rate), instead of relying on a live pilot run, which ties up production line time ($2,000-$7,000+/hr. burdened rate).
2. Quality data system infrastructure. With data consisting of all board layers (internal and external) and the netlist, manufacturers have the baseline information necessary to streamline test and inspection loops on the shop floor. These data provide the means to quickly analyze and repair errors found through automatically collected test results of printed circuit assemblies using paperless visual aid tools and documentation.
Second, it is critical to understand the importance of the quality of data provided to the front-end process efficiency of your manufacturing group or third-party vendor. The type of data received can result in this process being measured in hours or days. Unintelligent data – single-layer Gerber files, DXF/HPGL files, PDF files (BOM or drawings), paper drawings – can add hours, if not days, to the processing time, just to get started on manufacturing, and significantly increase the cost. Using the same examples, this time with a focus on manufacturing process efficiency, it is easy to see the value of intelligent data.
1. Machine programming process with validation. The use of intelligent data (e.g., ODB++) to create and validate a complete machine program offline can be completed in less than 45 min., compared to 3 to 12 hr. with copper pad Gerber data only and standard BoM files, which lack CPL or IPC-D-356 netlist information.
2. Quality data system infrastructure. Without the use of intelligent data, such as netlist information, integrated into a quality data collection and analysis system, the ability to analyze and repair assemblies quickly and efficiently is a challenge. Using intelligent data can yield review processes that can take minutes, instead of hours spent searching for information on paper drawings and the tedious reviews that follow.
The data a designer provides directly affect downstream process efficiency and the ability to utilize the data effectively for manufacturing processes. The next time you prepare to send a data package to a manufacturer, consider the ramifications of providing insufficient or unintelligent data on the resulting product’s quality, reliability and delivery time.
Michael Dryer is account manager, manufacturing team, Mentor Graphics Valor division (valor.com); This email address is being protected from spambots. You need JavaScript enabled to view it..
