Printed Circuit Boards - Design Mistakes to Avoid

Printed circuit boards (PCBs) are needed for most electronic devices and applications and the fabrication process is important for creating a PCB that will work best in the specific application.  But how should you approach PCB design to lower the cost of production and make for an easier assembly process?  The best way is through design for manufacturability, or DFM.  Designing a PCB according to DFM guidelines takes the processes and capabilities of PCB manufacturing into account to ensure that you create the most efficient PCBs for your application at a lower cost.

PCB Design Mistakes to Avoid

Submitting a Design Without Discussing your Application with the Manufacturer

A variety of materials are used to manufacture PCBs and the different materials can better suit specific needs.  It is beneficial to discuss the application you have in mind with your PCB manufacturer to determine which materials will be the most effective.  Different materials can be used for flex, high speed, RF, high temp, and RoHS circuit boards and certain materials may have a lead time of a couple weeks.  Talking to your manufacturer will help you determine which materials are the most available.

 Submitting a Design Without Knowing the Impedance Information from the Manufacturer

Every PCB fabricator builds PCBs at different tolerances which will affect the target impedance or stack-up in different ways.  It is important to establish your impedance requirements with the manufacturer before the fabrication because if the PCB is not built to your requirements, it may require adjustments before it can be used.  Making sure the manufacturer knows your impedance requirements before fabrication will help you avoid the need to make further adjustments which will save you lead time and money.

PCB Design with EI Connect

Regardless of the application, communication with your PCB fabricator before your PCBs are built will help you create and submit a PCB design that will best suit your needs.   Making sure the PCB design follows DFM guidelines will help ensure that your PCB is built to handle your specific application without the need for further adjustments.  If you have PCB designs to submit for fabrication, contact Electronic Interconnect.  We provide instant quotes for a variety of PCB types including zoom, multi-part, metal core, and bare bones PCBs.

Electrical Testing Options for Bare Printed Circuit Boards

There are 2 types of PCB bare board testing options available at most PCB manufacturing shops: Flying-Probe Testing & Fixture Testing. There are advantages in each type depending on board quantity, lead-time, and accuracy.

Flying Probe testing is usually used for low quantity printed circuit boards and always uses the Netlist extracted from the supplied Gerbers. Fixture Testing on the other hand has 2 options. 1st is the Golden-board testing which extracts the Netlist from an existing PCB. 2nd is Netlist based testing which uses the Netlist from the Gerbers.

If youd like a specific type of electrical testing done on your PCBs, please contact your PCB supplier for more information and pricing options.

Slow Growth for the North American PCB Industry

IPC - Association Connecting Electronics Industries announced the April findings from its monthly North American Printed Circuit Board (PCB) Statistical Program.

Sales and Orders Slow but Improving

Total North American PCB shipments increased 1.6 percent in April 2014 from April 2013, which moved year-to-date shipment growth to -0.2 percent. Compared to the previous month, PCB shipments declined 12.0 percent.

PCB bookings strengthened but continued negative at -1.5 percent year over year. Year-to-date order growth, while still negative, improved to -5.6 percent. Order growth fell 8.1 percent from the previous month.

The North American PCB book-to-bill ratio held steady in April at 1.01.

Read the article at http://www.ipc.org/ContentPage.aspx?Pageid=IPC-Releases-PCB-Industry-Results-for-April-2014

From PCB Design to PCB Fabrication

Too often the information en-route from PCB Design to PCB Fabrication is not conveyed properly, resulting in poor boards, higher costs, design re-spins, and ultimately slower product time-to-market. However, these problems can be avoided through careful planning, thorough communication, and proper documentation from the design-end.

A simple view of a typical product cycle from PCB Design to PCB Fabrication is shown below.

At Electronic Interconnect, at the Prototype Fabrication stage, we have seen a plethora of issues which could have been avoided if the Design Engineer had only provided the correct documentation and data for manufacturing the PCB. Some of the main issues are highlighted in the red box above. Overall, going back to the Design Engineer for documents, such as a dimensional drawing of the PCB, result in loss of time and money for all parties involved. Major issues which cause slowdown at the Prototype stage occur after a design-for-manufacturing check finds errors which will impede moving forward due to technology constraints; this is to say when no such constraints were intentionally added by the Design Engineer. For example, small annular rings around Vias, exceptionally thin trace widths and spacings, or antennas and electrical shorts, missing layers, missing drawings and notes; these issues will halt all operations in the engineering department before going to the plant floor. This will, in-turn, mean that the Design Engineer will have to go through each of these issues and either provide waivers to continue as-is, or a new set of fixed data.

In conclusion, valuable time can be saved with a concentrated effort at the design stage to provide proper documentation and cleaner data for efficient PCB fabrication!

For any questions, including DRC/DFM reviews, visit www.eiconnect.com