The Superconductive Circuit Board

    Can FR-4 Printed Circuit Boards operate in very low temperatures?

     

    The quick short answer is "Yes...,"

    One clarification is needed before addressing this question, though. 

    Originally "FR-#" was only meant as a NEMA designation for base epoxy material that was " F lame  R etardant". Unfortunately, it has become industry standard to call the most common used laminate (woven fibreglass-reinforced epoxy) merely by the name of "FR-4", and in this sense, the designation lost its significance and is now widely understood as a laminate name.

    With that clarification out of the way, we can share with you that our customers have been successfully using "FR-4" (woven fibreglass-reinforced epoxy) at cryogenic temperatures for years and counting.

     

    Understanding Printed Circuit Board Manufacturing: 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 signal routing requirement or need for a greater dielectric space, 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 Printed Circuit Board perspective it is not. It may actually increase the cost as well as lead-time and leave you with a warped PCB which may not meet your expectations. Let's look at the issues in detail.

    Understanding Printed Circuit Board 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.

    How to Avoid Printed Circuit Board Delays in the Quoting Process

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

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

    Understanding Printed Circuit Board 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. 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.

    Printed Circuit Board Design Techniques and Best Practices for Cheaper Quotes

    Using a few simple techniques can help ensure a more robust printed circuit board design which can also help you save money.

    Printed circuit board design is a balance between functionality, longevity, aesthetics and board costs, time to design and the PCB fabricators capabilities. Listed below are eleven of the most common best practices we recommend to our customers.

    Understanding Printed Circuit Board Manufacturing: Impedance Control

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

    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.

    How Copper Weight Impacts Printed Circuit Board Manufacturing - Copper Thickness Calculator

    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 0.5 oz base material with 0.7 oz of additional copper which provides the requested thickness in the hole. Often our PCB board quotes will reflect this specifying 0.5 + 0.7 oz Cu/sq ft where the 0.5 is the base copper and the 0.7 is the plated copper.

    Custom Printed Circuit Board Shapes

    In business as in life, we learn more from listening than talking.

    The other day we received a fairly odd question from an electrical engineer with a product development company we have worked with for many years.

    “Can you do round circuit boards?” he asked.
    “Yes…” we replied tentatively, thinking there must be so much more to the question.
    “So a board that’s three inches round… no problem?” he inquired.
    “Absolutely,” we confirmed.

    But then we began to think. If a long-time customer doesn’t know we have the capability to produce boards which aren’t just rectangular, how would a new customer know?

    4 Common Printed Circuit Board Design Mistakes to Avoid

    Avoid these four circuit board design mistakes:

     

    1.  Stipulating a "minus" tolerance on small micro via holes

    2.  Having Non-functional pads on inner layers

    3.  Not defining nor considering edge tolerances

    4.  Stipulating wrong copper thicknesses