Posts Tagged ‘printed’

Etch Factor

Sunday, February 10th, 2013

An etch factor or etch compensation is a process modification made by the Printed Circuit Board (PCB) manufacturer to compensate for the chemical etching process. The chemical etching process is a subtractive operation that removes copper gradually when forming the circuit pattern. The size of the features at the end of the process are smaller than the size of the features at the beginning of the process. When a PCB design requires a track width of 0.005″ (0.127 mm) the PCB manufacturer has to start out with a wider track. The amount the track is increased by is referred to as an etch factor or etch compensation. The etch factor is also proportional to the thickness of the copper or copper weight weight being removed. The more copper being etched through the larger the etch factor.

Etch factor added with CAM tool.

Etch factor added with CAM tool.

The fact that the PCB manufacturer has to increase the feature size to compensate for their manufacturing process is critical for a PCB designer to understand. The designer must provide enough spacing in their design for the PCB manufacturer to process the design. In other words, the minimum spacing in the design must meet the manufacturer’s minimum space that they may consistently process. In PCB manufacturing there are three types of spacing that we consider. They are… (more…)

Simple Yield Improvement. (Part 1)

Monday, December 31st, 2012

Over the past 15 years we have seen some very amazing advancements in technology. Our electronic devices have become smaller, faster and more powerful. The capabilities of these new devices have brought science fiction to life for many of us. What the common consumer does not realize is that these advancements have occurred in a more destructive Lead-Free assembly process. Lead Free assembly methods consisting of higher assembly temperatures (around 260ºC) for longer dwell times at temperature along with a smaller processing window for success. The assembly methods today are challenged to not only maintain yields but to improve them. All the while cutting costs where ever possible. The desire to cut cost is where we see the result of unintended consequences.

I have been asked repeatedly by customers for my opinion on methods to improve yields. I evaluate designs and work with designers and assemblers on solutions to help them improve yields. This includes in process and post process yields. In other words build it right the first time and make sure it lasts in the field. A common question I am asked by customers is…

What is the one thing that we can do that can  improve our yields?

The answer is very simple… (more…)

Dry Film Lamination (history)

Sunday, September 23rd, 2012

Dry film is commonly used in the printed circuit board industry in the formation of circuitry on both inner layers and outer layers of a printed circuit board. Dry Film acts as a resist to either plating or etching chemistry. In order to understand and appreciate the current process (and how it came about) I’ll begin by explaining some of the history behind the process commonly used today. Many of the operations used by the printed circuit board industry originated (more…)

ITAR and Printed Circuit Boards (Part 1).

Saturday, July 21st, 2012

ITAR is an acronym for the International Traffic in Arms Regulations. The purpose of ITAR is to safeguard and control the export and import of defense related information and technology related to and that appear on the United States Munitions List (USML). ITAR is a set of regulations that came into being in order to implement provisions of the Arms Export Control Act of 1976 (AECA). The United States Department of State Directorate of Defense Trade Controls (DDTC) interprets and enforces ITAR. The mission statement of the DDTC is as follows…

The U.S. Government views the sale, export, and re-transfer of defense articles and defense services as an integral part of safeguarding U.S. national security and furthering U.S. foreign policy objectives. The Directorate of Defense Trade Controls (DDTC), in accordance with 22 U.S.C. 2778-2780 of the Arms Export Control Act (AECA) and the International Traffic in Arms Regulations (ITAR) (22 CFR Parts 120-130), is charged with controlling the export and temporary import of defense articles and defense services covered by the United States Munitions List (USML).

The USML in its entirety may be found here. The list is segregated into 21 categories. Most categories cover specific technologies, equipment or applications. The important classification that you need to be aware of is (more…)

The Bare Board Group Incorporated.

Sunday, June 24th, 2012

I joined the Bare Board Group (BBG) in March of 2012 as the Engineering Director of the organization. BBG began operations in 2002 in response to a growing need among smaller OEM and EMS companies for lower volumes of printed circuit boards at lower offshore prices. BBG became a US supplier of printed circuit boards built in the Far East. BBG set out to eliminate the fears and difficulties of offshore manufacturing by becoming an extension of its customers’ purchasing departments, handling all interactions with pre-qualified overseas vendors.

During my time at the company I have come to appreciate the differences that set BBG apart from their counter-parts sourcing boards from other parts of the Globe. The key differences are as follows… (more…)

Envision HDI

Sunday, May 22nd, 2011

Envision HDI is an alternative copper deposition process that just works. Deposition or metalization is the basic foundation of a plated through hole structure. The deposition material makes a drilled hole conductive enough to allow copper to be electroplated within the drilled hole. Without metalization there would be no plated through hole. Of course there are several different chemicals available to metalize a non-conductive surface.

Electroless copper deposition was the original chemical process employed by the pcb industry to form this conductive layer. There were many downsides to this process. Chemical cost, time of operation and waste treatment to name just a few. Some of the chemicals used in the overall process are highly toxic. The process has been improved over the years.

Copper deposition was the only option for a number of years until (more…)

What is a Fabrication Drawing?

Sunday, January 4th, 2009

Not clearly specifying information may result in errors along the manufacturing supply chain. For example, one of my customers had an old legacy design they needed to have built. The fabrication drawing called for FR4 as the material the board was to be built on. The original designer specified a high volume resistivity requirement in an email sent to the previous manufacturer. The requirement was never added to the the fabrication drawing. The company that used to build the pcb went out of business. The original designer retired. My company built the design. A contract manufacturer assembled the boards. The customer installed it into their rack. None of the assemblies worked.

To make a long story short, (more…)