keyblog - Our thoughts on Engineering, Design, and everything else
Abbie Shoemaker

Flexible PCB Design Considerations

05.22.2013 by Abbie Shoemaker

Flexible circuits are all around us – in cell phones, cameras, and laptops – and also in us – in pacemakers, cochlear implants, and defibrillators. Over the years, as devices have become smaller and wearable and implantable medical devices have become more prevalent, the flex circuit industry has boomed. Key Tech has also been involved in this trend. We’ve designed a number of flex and rigid-flex PCBs for various applications, and along the way we’ve picked up a few tips.

When compared to typical rigid PCBs (the green, stiff boards you see in most electronics), flex PCBs offer many other benefits in addition to being flexible. Flex circuits are made of layers of polyimide instead of FR-4 (fiberglass reinforced epoxy laminate), making the board much lighter. The polyimide layers are also thinner allowing the board size to be thinner than typical rigid PCBs. Flex PCBs can eliminate the need (and cost) for connectors and cables improving connection reliability and reducing assembly time, assembly cost, and overall size of the device. Additionally, when two rigid PCBs connected by a cable can be optimized to one Flex PCB, this simplifies the design to one Bill of Material, one set of design files to manage, and one PCB fabrication and assembly step.

If the benefits are so remarkable, why aren’t all PCBs of the flex variety? One little dirty secret of flex is that it’s not always that flexible. The bending portions become increasing less flexible as the number of copper layers increase. There are a number of good rules of thumb to estimate bend radius, one of the more conservative being the minimum bend radius should be greater than 10x the overall thickness for multilayer boards. From a design perspective, significantly more communication is required between the designer and board house to finalize materials stackup and address DFM considerations. Also, the manufacturing lead time is longer and more costly than that of rigid PCBs. Though flex PCB manufacturing has existed for a number of years, it is a newer art and therefore there are fewer manufacturers. And, unfortunately, snafus in manufacturing are more common for flex PCBs and do occur from time to time pushing back delivery lead times.

In summary, flexible PCBs have been opening the door to exciting new applications and devices that weren’t possible with rigid PCBs. However, in the early stages of product development the team must carefully consider the pros and cons of creating a flex vs. rigid PCB before jumping into a flex design.

See 1 comment and add your own.

Eric Schneider

Working with Complicated Disposable to Instrument Interfaces

04.25.2013 by Eric Schneider

Lab on a Chip, Microfluidics, and Sample to Answer are terms we hear a lot when designing medical devices.  For years the trend has been to integrate more and more laboratory functions into small disposable chips or cartridges with the ideal goal of being able to perform all the functions from sample preparation to detection in a single disposable on one instrument.  This has led the instrument to disposable interfaces to be increasingly complex.  Sometimes there are hundreds of electrical connections for internal sensors or actuators, multiple heaters for PCR amplification, magnets for magnetic bead capture, pressure connections for fluid control, actuators for dispensing stored fluids, and external sensors  just to name a few.  The complex interfaces required can cause many design challenges, but after working on several of these types of projects over the years we’ve learned there are some ways you can make your life easier, and end up with a better design.

Proper alignment between the instrument and disposable is key to making reliable connections.  Ensuring proper alignment with the large quantity of connections is often one of the most difficult challenges.  The size of the disposables makes it tough to fit all of the connections in the available space.  This drives the design towards smaller interface components that are less tolerant of misalignment.  Also, to provide an optimum user interface, usually the user inserts the disposable, and then the instrument must move the interface connections to engage with the disposable.  This usually results in a large tolerance stackup between the interface and the disposable.  Adding alignment features to the disposable and the moving interface portion of the instrument (e.g. two alignment pins on the instrument and a hole and slot in the disposable) can significantly reduce the stackup and improve alignment.  Adding compliance (e.g. spring loading the interface) in the direction of motion of the interface can eliminate the effects of the tolerance stackup in that direction.   In addition, assembly jigs can be beneficial in ensuring that the connections are positioned correctly relative to each other, especially when the components are mounted on something like a PCB where holding tight tolerances on placement might not be possible.

The large quantity of connections can also result in fairly large forces that the disposable and instrument need to withstand.  For instance you might be using a 50 gram spring loaded pogo pin to make electrical connections, which doesn’t seem high, but when you need to make 200 connections the forces add up quickly.  The wide variety of connections that need to be made can also cause problems, especially when they fight each other.  For example, you might need to press on the top of the disposable to dispense a stored fluid that takes 20 lbs to dispense, but that force might cause electrical connections on the bottom to disengage.  Keeping the forces in mind early in the design can help make things easier as the design progresses.  The correct amount of compliance can be added to the interface and the connections can be laid out so they work together as opposed to fighting each other.

Another challenge with these types of projects is that often different teams/departments/companies are designing the instrument and the disposable.  Dealing with communication between the teams and working to come up with a layout that meets everyone’s requirements exacerbates some of the challenges mentioned above.  Keeping as much inter-team communication as possible is crucial.  On time critical projects even having daily meetings between teams can be worth it.  In the early stages of these projects, requirements documents or specifications are often evolving and not finalized.  At least writing interface specifications to document connection locations and other information on how the disposable and instrument will interface can help significantly.  Even if they eventually get folded into larger instrument and disposable requirements documents/specifications, having an interface specification early helps facilitate communication between teams and makes sure that everyone is on the same page.

Every project with these types of interfaces will have its own set of unique challenges.  Keeping these general challenges and lessons learned in mind though has helped us be more efficient and produce better designs when working with these complicated disposable to instrument interfaces.

Add a comment.

Jessica Fisher

“KTIM”: Key Tech Inspiring Minds

04.10.2013 by Jessica Fisher

Key Tech was busy in March giving back to the local community through meeting with middle and high school students.  Opportunities like these are available everywhere and are helpful for students and engineers alike.  For the students, it opens their minds to how they can change the world as engineers; for engineers, it reminds us all of the great opportunity we have to transform the world around us and share that enthusiasm with young people.

Two events we participated in were hosted off-site (at BLSYW and NDP) and one event was hosted at Key Tech.  We had a blast being involved in these crucial opportunities to inspire students to think big and think TECH!

BLSYW:

On March 21st, Abbie Shoemaker attended the “Cool Women Hot Jobs” career fair at the Baltimore Leadership School for Young Women (BLSYW). BLSYW is an all-girls public charter school in Baltimore that focuses on college preparation and leadership development for girls in grades 6-12. Abbie introduced the girls to what engineering is and discussed the engineering process: from identifying a problem through designing, testing, and manufacturing a product. The girls were attentive and asked great questions and came away excited about engineering!

NDP:

Also, on March 21st, Danica Gordon and I visited Notre Dame Preparatory School (NDP) to talk to middle and high school girls about working as an engineer.  NDP is an all-girls catholic college prep school which has an awesome mission statement: “where girls become women who transform the world” and has been named a top-feeder school for the UMD engineering program.  The girls were excited to learn about the different opportunities available as an engineer and were very interested in the Key Tech products that we brought in to show off such as the UltraCrit and Flow Sensor.  They were engaged and very inquisitive, showing that even now they are putting their investigative minds to work!

GoodWill:

On March 15th, Andy Rogers from Key Tech hosted a workshop for a dozen Baltimore City students enrolled in the Goodwill Industries Job Placement Program.  The intent of the workshop was to present product development and engineering to the students to inspire them to consider careers in the technology industry.  The interactive workshop focused on how to fund product development endeavors and lessons learned from Key Tech experiences.  There was a special feature in the workshop discussing how mobile technologies, such as iPhones, are being used in the medical world and the product development challenges associated with them.  The attendees were incredibly interactive throughout the workshop and left with some basic knowledge of what it takes to get a product idea to market.

 

Add a comment.

Mariano Mumpower

Please Excuse the Growl

03.20.2013 by Mariano Mumpower

Over the past year I’ve gotten hooked on two-wheeled commuting. Not the human powered kind, the small two-stroke engine powered kind, a moped. My newly acquired love for this mode of transport actually took me a bit by surprise as I had never been a motorcycle or powersports type of guy before. I only picked up a used moped off of a craigslist ad out of frustration with my daily commute downtown in a giant gas guzzling Astro van.

If you’re not sure what exactly I mean by moped, and are thinking of the popular Vespa type of scooter with the floorboards you put your feet on, you are close (but oh so far). Think more like a beefed up bicycle frame with a motor bolted on it. The utilitarianism and simplicity of moped designs is something that gives these little bikes a unique style and makes them immediately approachable. Their small 50cc engines and two-speed automatic transmissions are designed to produce just enough power to get you up to 30-35mph, allowing you to keep up with traffic on most back roads without having to worry about clutches and shifting. This small engine category also means that you don’t need a motorcycle license, and insurance is cheap. Despite the small size, the pick up, handling, and throaty growl of a well tuned moped can really put a smile on your face.

Most of the advantages of moped commuting in the city are pretty obvious, great gas mileage, less waiting in traffic, easier parking etc, but the real reason I’ve fallen for mopeds is the culture of creativity and DIY tinkering that goes along with riding this little machine. Learning the basics of the two-stroke engine cycle and the quirks of tuning a carburetor has been just as enjoyable as twisting the throttle and leaning into turns. Not to mention the mechanical and visual design inspiration that has come from some seeing of the amazing work in the custom moped builder world.

So, what started out as an experiment in lowering my fuel consumption and time wasted in traffic has turned into a bit of an obsession, with lots more to learn and more fun to be had.

 

Some links if you’d like to explore the world of mopeds:

Custom Moped Builder Image Gallery

Moped Specialty Shop

Moped community forum / wiki

Moped Laws in Maryland

 

 

See 1 comment and add your own.

Brian Lipford

15 Years!

03.04.2013 by Brian Lipford

Alexis, our marketing coordinator, recently stopped by my office and asked me for two things: a blog celebrating  Key Tech’s 15th anniversary, and my personal interpretation of Key Tech’s brand.  Since I’m just a lowly engineer, I had to ask about that last part…our brand?  She told me that this concept is often misunderstood.  Most think a brand is like Coke, Apple or IBM that has a name or a symbol, or even a sound that is recognized by the outside world.  But that’s not what a brand means.  It’s  the outcome of a good brand, not the brand itself.  A brand is very much internal to a company; with little to do with outside forces or perceptions.  It’s what makes you get up every morning to go to work, what gives you passion to do what you do.  It’s  something steeped consistently through the company.  Ultimately, over time, this same brand is how others outside of the company might come to know you better, perhaps even on a more personal level.

I’ve often thought about Key Tech and what we do, but not exactly like that.  And so I did a little introspective searching to reflect on what is our brand.  I didn’t have to think long.  Not because it’s not important; it just wasn’t that hard.  There’s a certain DNA in all us at Key Tech.  We are passionate about three things:  learning, creating and helping others, both inside and outside the company.  We all love to learn, whether it’s about a new product, process or some new technology.  We regularly host events and weekly meetings just for learning.  It makes us feel good, and reaffirms our continued growth and self-worth.  Folks at Key Tech don’t just live with the ‘new and different’ – we embrace it.  It is a challenge, and we love challenges.  Another passion is creating; it’s what we do at Key Tech.  It was our founding premise, a consensus to focus on creation, to design and develop new devices and systems – to form ideas in our heads and transform them into a physical reality.  There is no better high than the power of creation, being a part of something bigger than oneself.  It inspires and excites the senses.  Lastly, there is helping.  Of all the things engineers could do, this is why we choose to develop complex electromechanical devices and systems.  It fits us.  What better way to help people than to create devices that improve their daily lives.  And our helping is not just limited to inside the company.  Regularly, we volunteer with the local Habitat for Humanity, visit local middle schools, and mentor FIRST robotic teams (For Inspiration and Recognition of Science and Technology).

So Alexis…the two items you requested:  a blog for our anniversary and my interpretation of our brand.  Here’s to Key Tech and 15 years of learning, creating and helping!  I’m looking forward to the next 15 and beyond.

Add a comment.

Jenny Regan

We Won!

02.20.2013 by Jenny Regan

For the second year in a row, Baltimore Magazine has selected Key Tech as one of Baltimore’s Best Places to Work!  We couldn’t be more ecstatic to hear this news.  There are many outstanding places to work in the Baltimore area, so we are honored to be recognized again!  This year also marks our 15th anniversary as a company, which is quite an achievement in its own right.  After all these years, we’ve been able to stay true to one of our basic principles: doing fun work with fun people.  We put a strong emphasis on this, and we wouldn’t have it any other way.  Fun work is what attracts and retains our great employees, but fun people form the fabric of our company.  Who wouldn’t want to ride in a Zorb ball with a client or dress up as a Groundhog for a random holiday card?  This jovial atmosphere naturally attracts fun clients as well, resulting in long-term, fruitful relationships (unless those clients aren’t Ravens fans!).  Thanks again Baltimore Magazine for this accolade, but look out…we’re just getting started!  To view the article click here.

See 1 comment and add your own.

Alexis McKenzie

Happy Thanksgiving!

11.21.2012 by Alexis McKenzie

Add a comment.

Andy Rogers

Habitat for Humanity

11.19.2012 by Andy Rogers

Most of us at Key Tech thoroughly enjoy renovating things…it’s just in our blood as designers and engineers to take something old and outdated, and transform it into something new and useful.   Whether it’s refurbishing an old bike, or renovating a run-down vaudeville theater into our office, Key Techer’s are innately passionate about applying their talents and resources to improve something. Thus, it’s no surprise that a handful of Key Tech volunteers spent a day recently in the South Baltimore neighborhood of Brooklyn volunteering for Habitat for Humanity of the Chesapeake.

Brooklyn, like many neighborhoods in the city unfortunately, suffers from dilapidated housing, neglect, and increased crime.  It wasn’t always this way however.  In fact, the community once flourished in the 1940’s, when the Bethlehem-Fairfield shipyard was packed with Liberty Ship workers.  As part of an emergency ship-building initiative announced by President Roosevelt, the Bethlehem-Fairfield shipyard cranked out a staggering 385 ships in a four year period to support the war.  To achieve such astonishing production numbers, an influx of workers was needed, and quick housing was erected in Brooklyn to accomodate them.

Bethlehem-Fairfield Women at Lunch

 

Bethlehem-Fairfield Workmen at Lunch

Photos courtesy of the Library of Congress

 

However, once production halted, the excess workers fled the area, and that housing was left to decay over time.  That, combined with urban flight in the 50’s and 60’s resulted in many row homes lying vacant or boarded up, which are a prime haven for squatters.  Enter Habitat.  Habitat started renovating the old shipyard worker properties starting in 2006, and since then has dedicated close to 50 homes to deserving families.

A typical renovation takes about a year’s time for Habitat, or roughly three times the duration of a typical professional team.  The added time is likely due to the thinly spread, virtually all-volunteer labor force.  It’s worth noting that Habitat does outsource the skilled portions to subcontractors, such as major structural work, HVAC, electrical, and plumbing to keep volunteers like us from royally screwing up the renovation!  That leaves volunteers the fun work like demolition, framing, painting, and landscaping to name a few. The following shots were taken from our volunteer day:

Frank and Josh prepping for dry-wall

Alexis painting ductwork seals

Brian cutting trim for a closet door

Habitat for Humanity also relies heavily on monetary donations to keep their operation running.  One recent house dedicated in Brooklyn was fully funded by the National Football League and Warrick Dunn Charities.  Here is a link to the video showing the family as they see the home for the first time.  While Key Tech didn’t work on this house directly (other than moving a port-a-john from the site!), the house is remarkable…a true testament to the Habitat for Humanity mission.  What a great story, and Key Tech was glad to contribute its small part in restoring Brooklyn.

Key Tech Habitat for Humanity Volunteers


 

Add a comment.

Keith Lipford

Re-Engineering Beer

10.31.2012 by Keith Lipford

On 7/15/2012, Dave Hershey did a wonderful job of summarizing the enjoyment most engineers would get from brewing beer (even though he omitted the part about designing, building and testing the brewing system – details about Key Tech’s custom brewing system coming in a future Blog). Dave also mentioned the Key Tech brewers won “Best of Show” in a local craft brew competition (Maryland Micro-Brew Festival) which entitled the Key Tech brewers to compete this year at a national level in a Pro-Am competition (GABF, in Denver, Colorado).

While we didn’t win any awards at the GABF, the event inspired us to take beer brewing to a new level and if successful, we hope to be eligible to compete at the GABF in 2013 – stay tuned!

 

Add a comment.

Abbie Shoemaker

Betascape 2012

10.03.2012 by Abbie Shoemaker

2012 marked the third year of Betascape, the annual weekend gathering of artists and technologists (some may say nerds) from the Baltimore area to explore the intersection of their disciplines.  This year, the event was held at the Maryland Institute College of Art (MICA) in downtown Baltimore, an apt location for delving into creative thought.

In the afternoon participants broke off into one of three “exploratoriums” (aka workshops) centered on the topics of physical computing, data visualization, and digital fabrication.  Each day began with interesting presentations from local and national speakers including Nathalie Miebach – a data visualization artist, Marco Perry – co-founder of PENSA and an inventor of the DI Wire Bender, Nervous System – a generative design studio inspired by science, art, and technology, and Hod Lipson – Associate professor and director of Cornell University’s Creative Machines Lab.

Due to my involvement in product development and electrical hardware design, I was most inspired by Dr. Hod Lipson’s presentation on the present and future of 3D printing.  Perhaps the most mind blowing concept presented was the idea of printing on the micro-scale level with a variety of multi material 3D pixels which Dr. Lipson referred to as “voxels”.  Voxels could be insulating plastics, conductive blocks, complex programmable or sensor based pieces, or even batteries.  The implementation of voxels could revolutionize the way product designers think about and create objects.  For example, the majority of PCBs I’ve designed are built on a rigid 2D surface.  Over the past few years, flexible PCBs have allowed designers to pack circuits into tinier packages.  However, these flex boards are limited to bending in a single plane and are further limited in bending by the number of metal layers in the stackup and the thickness of the materials.  Now imagine being able to print a circuit in a 3D grid structured like a micro Rubik’s cube!  Entire circuits, not just traces, could be designed to wind and weave around obstacles.

Voxels would also completely transform the manufacturing process.  Currently, a bare PCB is fabricated, populated with components, and then integrated into a device assembly.  Voxel printers could simplify human interactions in manufacturing to the press of a button that instructs the 3D voxel printer to assemble a multitude of prefabricated voxels into a final device.  And maybe at the end of printing that device will be able to walk off the printer…

Pretty rad.

Add a comment.