The Superconductive Circuit Board

    Understanding PCB Manufacturing: Avoiding File Errors

    At Omni not all PCB files we receive are from seasoned PCB design professionals.

    Designs also come to us from enterprising individuals who can credit their body of knowledge to the results of internet searches. The inspiration for this article came from one such individual.

    The Hiring Process - Conducting Interviews

    Interviewing provides the opportunity to learn about the applicants skills, abilities and how well they respond under pressure.

    < Short Listing the Candidates  Group Decision Making >

    Set the rules for the interview team

    Before the interview, sit with the team and review the rules of engagement. Basic rules include no questions regarding religion, ethnicity, family, sexual orientation or any topic which would make a reasonable person uncomfortable. If someone on the team doesn’t grasp the limits, replace them now.

    The Hiring Process – A practical guide

    With over thirty years experience culminating in my most recent adventure, PCB manufacturing at Omni Circuit Boards, I have had my share of successes and failures when it comes to hiring.

    Short Range Searches >

    Understanding PCB Manufacturing: Working with Duroid laminates

    If you have ever driven in the winter and suddenly lost control for no reason, you probably experienced black ice.

    Understanding PCB Manufacturing: Odd Layer PCB Boards

    Our cookbook of PCB recipes includes an assortment of odd layer PCBs.

    About 8% of PCB boards we are asked to produce are comprised of an odd number of layers. But unless you have a specific requirement, it is usually best to design a multilayer board with an even number of layers. Reducing an even layered board by one layer may seem like a cost-saving move, but from a PCB perspective it is not. It may actually increase the cost as well as lead-time and leave you with a warped PCB board which may not meet your expectations. Let's look at the issues in detail.

    How to Avoid PCB Board Delays in CAM

    CAM (computer-aided manufacturing) is the art of translating a PCB board designer’s creative CAD (computer-aided design) output into information required in our manufacturing processes.

    Our processes require your computer generated files to be converted into phototooling films and drill/router files which will allow us, the printed circuit board manufacturing facility, to produce a custom PCB to your specifications.

    Understanding PCB Manufacturing: Impedance Control

    Printed circuit boards with impedance requirements demand a high level of precision.

    Image courtesy of Zmetrix

    For standard circuit boards, a PCB manufacturer is given a set of patterns - copper patterns, hole patterns, ink patterns, which are combined into a single circuit board with all the pattern sizes and positions within certain tolerances. Failure to meet a certain size or position with the specified tolerance can be cause for the circuit board to be rejected. If a trace has been defined as an impedance control trace, it is not the trace size which is strictly defined, but rather the impedance. While a nominal trace size will be provided in the Gerber layer, it is understood the circuit board manufacturer can vary trace width, height, and dielectric thickness as long as the final impedance is within tolerance.

    Understanding PCB Manufacturing: Hard Gold Plating

    Plating Hard Gold onto printed circuit boards is typically done to provide contact points and PCB edge connectors.

    Gold contact surfaces are often used on circuit boards with membrane switches which are a technology of choice for industrial, commercial and consumer products. When PCBs will be repeatedly installed and removed electroplated gold is used for edge-connector contacts or as they are more commonly known: Gold fingers. It is difficult to hear the term Gold finger without remembering the villain Auric Goldfinger from the James Bond film of 1964. However, the gold fingers (gold-plated contact pins) found on PCBs are quite unlike Auric’s stubby, fat digits. To begin with, the plating thickness of a PCB gold finger is typically a mere 300 micro-inch. At this thickness the hard gold is expected to survive 1,000 cycles before wear through.

    Developments in Aluminum Trace Circuit Boards

    As you might expect, no two applications for aluminum trace circuit boards are the same and most often they are not even similar.

    While some customers are investigating frontiers in MEMS (Microelectromechanical systems), others are delving into the inherent superconductive properties at milliKelvin temperatures, while still others are exploiting the radiation response characteristics of aluminum. For the R&D personnel at Omni Circuit Boards, the requests have presented some interesting challenges.

    How Copper Weight Impacts PCB Board Manufacturing

    One of the critical steps when ordering a printed circuit board is specifying the copper weight.

    The default, should you choose not to specify a weight, is 1.2 oz of copper. This is because customers routinely specify a minimum 1 oz copper thickness and 1 mil of copper in plated through holes. To achieve this, we routinely plate up .5 oz base material with .7 oz of additional copper which provides the requested thickness in the hole. Often our PCB board quotes will reflect this specifying .5 + .7 oz Cu/sq ft where the .5 is the base copper and the 0.7 is the plated copper.