PNC’s step by step guide to PCB Design component placement

1. Accelerate Your New Product Development With Rapid PCB Assembly Prototyping The time from concept to prototype has accelerated remarkably in the past decade. 3D printed prototype components in a wide variety of materials are available in hours. Machined or sheet metal components are available from rapid prototype shops in only one or two days. Prototype Printed Circuit Board Fabrication and assembly companies like PNC have followed this trend towards faster prototypes and can now provide complete assemblies in less time than ever before. PNC can fabricate and deliver a bare 10-12-layer PCB in just three days, and a simple double-sided board in just 24 hours. However, even with the streamlining of PCB fabrication, the fully assembled PCBA is often the longest lead component in prototype designs primarily because of the sheer number and variety of passive and active components to be purchased and the demands of accurately placing and soldering those components. Sourcing the components on a typical PCBA BOM can take days in the best case and weeks in the worst case. Setting up and running the assembly job can add another few days, especially for double sided PCBs, and PCBs with a combination of surface mounted and through hole components. Fortunately, there are some things that a product development team can do to reduce PCB assembly lead time. First, do everything possible to reduce the impact of long component lead times. Plan to order the components as early as possible in the circuit design process. Deciding when to order components requires balancing the costs of scrapping some components as the design matures vs. the benefits of reducing the lead time for an assembled PCBA by days or weeks. Second, reduce the time required to set up and build the prototypes by working with a full-service company like PNC. PNC has the capability to both fabricate the bare PCB and assemble the components. This means that the PCB fabrication team and assembly team can save time by working in parallel. While the PCBS are being fabricated, PNC’s engineers can create pick and place data, solder paste stencils and program the assembly equipment. When the PCBs are finished and the components arrive, everything is ready to begin assembly immediately.

2. The third way to save time with PCB prototypes is to minimize the number of PCB prototype iterations. Saving a full printed circuit board assembly prototype cycle is the most effective way to reduce the time from concept to mature design. One way to reduce design iterations is by testing circuit designs as early in the design process as possible by building “Works Like” prototypes. “Works Like” prototypes are usually combinations of development kits, large one or two layer PCBs with larger SMT components that can be soldered by hand and various types of breadboards. In addition to testing the circuit, a “Works Like” prototype gives software developers an early platform to start developing code and debugging the circuit design. The result of testing early with rough prototypes is that you fix problems before you have invested the time in the full layout and prototyping process. In parallel, the mechanical engineers can optimize cable routing and connector placement by printing 3D models of the PCBs, then epoxying actual connectors to the board model. This is an effective way to quickly try different options for cable routing using actual cables and connectors, since it is difficult to simulate the way actual cables behave with CAD software. Experienced electrical engineers know that it is often poor connector access or cable interference that drive Printed Circuit Board layout redesigns as often as issues with actual circuit performance. Once the circuit has been tested with the “Works-Like” prototype, and the board layout has been tested with 3D printed models, the last way to save time is to work closely with the PCB manufacturer to make sure that the PCB fabrication files are clean and complete, and that the BOM is accurate and matched with the circuit and layout to avoid placement mistakes. This is another reason to select a full-service prototype pcb manufacturer like PNC. PNC can be a partner during the layout and design process, though fabrication and assembly ensuring the final design can be translated into a working prototype in the least possible time.