DFM – The Next Frontier

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Welcome to part two of this three-part series where we take you on a journey through the inner workings of the ACDi design team. In part one, “Beyond the Design Rule Check,” we took a deep dive into how we utilize and implement DRC best practices at ACDi, mitigate errors, and approach designs with the end game in mind to ensure an error-free design database at the conclusion of the project, which translates into better yield at the manufacturer and desired performance characteristics in end-use application. If you haven’t had a chance to read it, check it out now!

In this installment we will discuss how ACDi’s holistic approach to an integrated manufacturing package by way of concurrent design for manufacturing (DFM) analysis and cross-functional ownership of the final design outputs paves the way for success at subsequent phases of the product cycle – printed circuit board (PCB) fabrication and assembly.

Success starts from the initial data import, review and preparation from our resident expert Librarian who works extensively with the customer upon initial technical data package (TDP) upload to ensure the design intent and parameters are understood.

Dataprep is an all-encompassing term which includes the following; Mechanical verification of glued-part locations, part height and max height requirements, mounting/tooling-hole locations, board dimensions, component pin assignments/pin one indicators and keep out areas as well as customer bill of material) BOM, netlist and schematic verification.

When building new component footprints is a requirement, ACDi merges manufacturing experience with IPC specifications and manufacturers datasheet recommendations to create the necessary component footprints.

For all other components, we have found major success in leveraging ACDi’s tried-and-true component library which has been developed from over 25+ years in the design industry and 10,000+ completed designs.

At the conclusion of this stage of the process, we are in constant communication with the customer to ensure everything is acceptable before moving on to the next step. This includes a re-verification of the aforementioned activity by another member within the team to ensure the database is ready to be assigned to a designer. A second set of eyes never hurts!

Now that the database has been assigned, it is time to “kick-off” the design activity. This is where the designer becomes intimately familiar with the prepared database by way of analyzing all of the data presented. Customers statement of work (SOW) is the main driver for this discussion.

The assigned designer and the customer’s Electrical Engineer(s) have a call to discuss, understand and develop a board design strategy, with the big picture (final deliverables) top of mind. At the conclusion of this call, once a strategy has been derived, component placement begins.

Once placement has been approved by the customer, it is time to design the PCB stack up prior to any critical routing. This is a fundamental step of the design process. Selecting the correct dielectric material, dielectric thickness, copper weight and layers in the stack, to ensure the product is a) routable, b) impedance requirements met, c) manufacturable and d) product will perform as expected in the field.

This is where we kick DFM into high gear. We get in direct contact with ACDi/customers bare PCB manufacturing approved vendor list (AVL) for stack-up analysis and feedback. We look to the experts to tell us if what we have modeled meets the requirements for successful manufacturing and will meet all of the necessary parameters for a successful final data output.

Material availability is also taken into consideration as usually with a new product, customers want to get to market as fast as they can and designing in a long lead or volatile material is not advantageous to that mission. Although the topic of DFM discussions in early stages of the design has been written about ad nauseam, you would be surprised how often this stage is overlooked at the onset as an unnecessary or burdensome task, only to present data on the backend and have the manufacturer balk at the stack up and start requesting changes or exceptions.  At ACDi, however, we believe this to be paramount to the overall success of the customer engagement.

From here we proceed through the remaining “gates” of the design process. Critical routing referencing customer SOW, as well as component manufacturer design guidelines, seeking approval after critical routing is complete from the customer before proceeding into power and ground plane design and subsequent approval. Next, we move into the final stages of documentation, internal review and post-processing.

Internal and external verification/approval at each “gate” in the process makes for cross-functional ownership of the final manufacturing output from dataprep all the way through to the final manufacturing package. A very important part of ACDi’s design process is our peer review. A minimum of three different sets of eyes dive into the database, documentation and gerber plots, to re-verify original design intent and to ensure nothing was missed or overlooked along the way that would prohibit success in fabrication and assembly.

Finally, we’ve made it! It is time to generate the deliverables and provide the final manufacturing package to the customer.

This approach outlined above has many benefits that are not only gained internally but also passed along to our customers. Reduce re-spin risk, elimination of manufacturing defects and faster time-to-market for our customers are some of the primary benefits. Internally we create a positive feedback system (mind-sharing) for design staff so they can grow along multiple design disciplines, i.e. RF, digital, high speed, etc., thereby instituting a “best practices” mindset which is constantly evolving!

In closing part two, we appreciate your interest in ACDi and look forward to discussing your requirements in greater detail. Please visit our website at www.acdi.com for more information, or feel free to reach out directly to me to schedule a no-obligation consultation via video conference at your convenience.

Jesse Vaughan

Manager Design Services

jvaughan@acdi.com  301-624-1642

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