Guest Blog – MEMS New Product Development, The Technology Development Process and Design Review Checklist (Part 3)

Guest Blog – MEMS New Product Development, The Technology Development Process and Design Review Checklist
Written by: David DiPaola, DiPaola Consulting, LLC, www.dceams.com

After a functional A-sample prototype is built, it doesn’t take long for a project to gain traction that has market pull.  This is usually the point that a project becomes highly visible within a company and it enters the Technology Development Process (TDP).   The TDP is made up of multiple phases including concept, prototype, pilot and production with gates at the end of each phase.  Design and process reviews are required at each gate but may also occur within a phase.  These reviews are an open forum for communication of project progress and gaps towards technological, business and schedule milestones.  Furthermore the product is constantly evaluated against the market need and potential changes in market that may have occurred.  The audience for the reviews at a gate include peers and management who provide feedback on the project to date and collectively decide whether additional work is needed to complete the current phase or the completed work is sufficient to allow the project to proceed to the next phase with additional funding.  In certain instances, a project that has not met all of the deliverables may be allowed to proceed to the next phase but under strict conditions that must be fulfilled within a given timeline.  The goal of the TDP is to focus the team on high quality execution, effectively screen projects allowing only the best to proceed and hence accelerate successful innovation and profitability.

The MEMS Industry Group (MIG) Technology Development Process Template is an excellent tool for companies to use to implement the TDP within their organization (Marty et al. 2013).  The goal of the TDP was to create a simplified frame work that could be easily customized to fit a company’s needs.  The TDP structure shown below is a slightly modified version of the TDP developed by MIG.  In this version there are four major phases including concept, prototype, pilot and production with three major gates.

figure 1

The concept phase is where ideas are generated and the initial A-samples are developed.  It is also where the business case is first generated and the market need is defined.  It is highly desirable to have market pull at this point.  The prototype phase is where the design is developed in detail and B-samples are fabricated to support various levels of validation.  The outcome of the prototype phase is to have design that can be manufactured in volume production.  Towards the end of the prototype phase, production tooling is often released.  The pilot phase is where production tooling is built and qualified.  In addition, the product is made on production tooling (C-samples) and revalidated.  It is important to note that there should be no change in the product design between the last revision in prototype and the first samples off the production tooling.  The production phase is low to high volume production ramp.   Often customers will require revalidation of products in production once a year for the life of the product.

At each gate, there is a design and process review for the project.  In order for the team to be focused and efficient, there needs to be a clear set of deliverables defined for completion of each phase.  These deliverables range from business and market definition to project technical details to production launch.  The following checklist provides an in-depth set of deliverables for the design reviews at each gate that can be tailored to the specific needs of an organization.  It is noted that a fourth gate is common 3-6 months after production launch to review project status but is not depicted in Figure 1.


Figure 2

Design Review Checklist

figure 2
This table can be downloaded from the following link in PDF format.  Many of the items listed above are self explanatory.  Others are explained in more detail in previous blogs posts such as DFMEA and tolerance stacks.

The Technology Development Process is an essential element of successful MEMS new product launches.  The Design Review Checklist can also provide a frame work for discussion between management and engineers on required deliverables to pass a particle gate.  With improved communication and efficient execution of technology development, the TDP is a great tool for accelerating innovation and profitable MEMS products.  In next month’s blog, the necessary attributes of a MEMS engineer for new product development will be discussed.

Works Cited:

Marty, Valerie, Dirk Ortloff, and David DiPaola. “The MIG Technology Development Process Template.” MEMS Industry Group, Mar. 2013. Web. 28 Apr. 2013.

Updated Bio:

BioDavid DiPaola is Managing Director for DiPaola Consulting a company focused on engineering and management solutions for electromechanical systems, sensors and MEMS products.  A 17 year veteran of the field, he has brought many products from concept to production in high volume with outstanding quality.  His work in design and process development spans multiple industries including automotive, medical, industrial and consumer electronics.  He employs a problem solving based approach working side by side with customers from startups to multi-billion dollar companies.  David also serves as Senior Technical Staff to The Richard Desich SMART Commercialization Center for Microsystems, is an authorized external researcher at The Center for Nanoscale Science and Technology at NIST and is a Senior Member of IEEE. Previously he has held engineering management and technical staff positions at Texas Instruments and Sensata Technologies, authored numerous technical papers, is a respected lecturer and holds 5 patents.  To learn more, please visit www.dceams.com.

In Search of the Energy-Efficient Family Car

Written by: Karen Lightman, Executive Director, MEMS Industry Group
(as published in Design News on 09/06/2013)

Buying a car just isn’t as easy as it used to be, especially when you know just enough about alternative-fuel-source vehicles to make that decision very difficult. As my husband and I debate the merits and faults of energy-efficient cars (as the end date of his leased Prius looms in the background), I feel as though we must make a smart choice that is right for us and right for the planet. Perhaps you relate to such a quest for the perfect car that balances safety, comfort, fuel efficiency, and style.

When I entered this decision tree of what fuel-efficient car to buy, I initially thought that an electric vehicle (EV) would be the simple solution. EVs, which run on chargeable batteries, seem to make sense for our family. We live in an urban area and rarely take long trips requiring a long charge. We’ll just plug the car in at night and stop using petroleum that pollutes the air. Right?

Not quite. As I started discussing the decision with my MEMS colleagues (all with their EEs and MEs), I quickly learned that it’s not that simple. First, the biggest limitation is the battery itself. The energy-to-weight ratio for EVs is quite abysmal compared with gasoline. Up to one-third of an EV’s total weight can be attributed to the battery pack alone, and most of the batteries hold a charge for a few hundred miles at best. That’s a deal breaker for many.

Tesla appears to be the only EV company that is seriously attacking the battery issue. Its CTO has said battery energy density is improving about 7 percent a year. This clearly shows that his company understands one of the biggest roadblocks to EV adoption. Tesla has designed a beauty of a lightweight car that is chock full of MEMS/sensors and showcases an iPad-like dash between the passenger and driver. Plus it has two trunks; that is just so cool. (It’s the reason my 12-year-old daughter insists we buy a Tesla.)

Until we have cars that run on solar panels, energy is never free. Even if you decide to buy a Tesla, you have to think about where the energy is generated to recharge the battery every night. For me in Pittsburgh (and for most of the Northeast), the source is typically coal. Uh, oh. That means I would deplete more fossil fuels and release more greenhouse gases if I bought an EV. Another important issue is the disposal of heavy-lead lithium batteries. Some EVs need to replace their batteries after three years. So if you are the average American who holds on to a car for five years, you’ll need to dispose of (and pay for) two batteries and consider the environmental impact of that decision.

Let’s face it — the batteries for EVs (and for most consumer electronics) are still inefficient. Here’s where my MEMS brain starts to activate and I start thinking about energy harvesting. Can’t we find ways through MEMS to harvest the car’s vibrations at least to power its electronics?

I bet the folks at MicroGen Systems are already looking into this. I actually know of a few more companies (big and small) that are looking into ways to make vehicles smarter and energy efficient from the get go through a combination of MEMS and sensors. Examples include energy harvesters in the tire that capture the vibrations and power the tire-pressure monitoring system, as well as sensors embedded into an engine to maximize fuel efficiency. Take it one step further, and HVAC monitoring systems managed by an in-car sensor network could keep passengers comfortable as the vehicle passes through varying daylight and temperature conditions. MEMS will make this happen.

I guess I will have to wait until there’s smarter battery technology that recharges an EV by green energy. In the meantime, I’ll be asking my local car dealer how many MEMS and sensors are inside the vehicle. The car with the most MEMS wins.

MIG Visits the AUVSI Unmanned Systemss Conference

Written by: Monica Takacs, Membership Director, MEMS Industry Group

From robotic ground vehicles that enter areas too dangerous for humans, to maritime vehicles that explore and map underwater caves, and drones used for agricultural and environmental applications, the unmanned vehicle systems appears to be a growth industry for MEMS.

MIG attended the AUVSI (Association for Unmanned Vehicle Systems International) conference in Washington, DC, August 13-14 to check out all of the MEMS devices found in these unmanned vehicle systems. Inertial MEMS sensors were featured throughout the show and many of the exhibitors demonstrated the cost, size, and power consumption advantages that MEMS has over traditional inertial measurement systems (IMU) like fiber optic gyros.

Several MIG members were at the conference showcasing their technologies.

Analog Devices featured their signal processing technologies for advanced unmanned systems for defense & civilian applications, including their MEMS based inertial sensor technology.

Epson introduced their M-V340 IMU for unmanned vehicles and other space- and weight-sensitive applications.  They claim it’s smallest IMU among high-performance IMUs having gyro bias instability of 10 dph or less (as of the beginning of August 2013, according to Epson’s research.)

Honeywell presented their HG1930 IMU for flight control, navigation of UAVs, missiles, projectiles, and munitions that include inertial MEMS sensors designed, developed, and manufactured in-house.

Meggitt showcased their thermal management solutions for unmanned platforms, and projectile tracking technology that track bullets to large missile and can provide weapon performance data from a target platform or threat notification on a tactical platform.

PNI Sensor Corporation displayed their 9-axis sensor fusion pinpoint heading and orientation technology and algorithms for the consumer, military, and scientific markets.

Sensonor showcased their tactical grade STIM300 IMU, a non-GPS aided IMU, containing 3 MEMS gyros, that is suitable for various commercial and defense guidance and navigation applications.

Xsens demonstrated their MTi 100-series, their high performance product line that features vibration-rejecting gyroscopes and a sensor fusion algorithm that overcomes limitations in Kalman Filtering.

VetorNav Technologies displayed their VN-200 GPS-Aided Inertial Navigation System (GPS/INS) which incorporates a suite of MEMS-based 3-axis accelerometers, gyroscopes, and magnetometers, along with a barometric pressure sensor and a high-sensitivity GPS module in a surface mount package.

Guest Blog – MEMS New Product Development, Critical Design and Process Steps for Successful Prototypes (Part 2)

David DiPaola, DiPaola Consulting, LLC, www.dceams.com

The fourth article of the MEMS new product development blog is Part 2 of the critical design and process steps that lead to successful prototypes.  In the last article, the discussion focused on definition of the customer specification, product research, a solid model and engineering analysis to validate the design direction.  The continuation of this article reviews tolerance stacks, DFMEA, manufacturing assessment and process mapping.

A tolerance stack is the process of evaluating potential interferences based on the interaction of components’ tolerances.  On a basic level, a cylinder may not fit in a round hole under all circumstances if the cylinder’s outside diameter is on the high size and the inside diameter of the hole is on the lower size causing an interference when there is an overlap of their tolerances.  This situation can become complex when multiple components are involved because it results in the number of variables reaching double digits.  A simple approach to tolerance stacks is using a purely linear or worst case approach where full tolerances are added to determine potential for interference.  However, experience from producing millions of sensors shows this approach is overly conservative and a non optimal design practice.  If tolerances of the assembly follow a normal distribution, are statistically independent, are bilateral and are small relative to the dimension, a more realistic approach is a modified root sum of the squares (MRSS) tolerance stack technique.  In this approach the root sum of the squares of the tolerances are multiplied by a safety factor to determine the maximum or minimum geometry for a set of interrelated components.  The safety factor accounts for cases where RSS assumptions are not fully true.  This approach is only recommended when 4 or more tolerances are at play.  If only 2 tolerances are present as in the first example above, it is recommended to perform a linear tolerance stack.  In some cases, linear tolerances need to be added to a MRSS calculation (MRSS calculation + linear tolerances = result).  Pin position inside a clearance slot for anti-rotation is linear tolerance that is added to a MRSS calculation.  Reasoning for this is the pin can be any location in the slot at any given time and does not follow a normal statistical distribution.

An example of a MRSS tolerance stack is provided below to review this concept in more detail.    Let’s determine if the wirebond coming off of the sense element will interfere with the metal housing.  A modified RSS tolerance stack shows line to line contact and only a small adjustment in the design is needed to resolve the issue.  The linear tolerance stack shows a significant interference what requires a larger adjustment.  Dimensions and tolerances are illustrative only.

Figure 1

MEMS Sensor Package (mm)

Fig 1


Figure 2

Modified Root Sum Square Versus Linear Tolerance Stack Approaches

0.17 > SF*(((T1^2) + (T2^2) + (T3^2) + (T4^2) + (T5^2))^(0.5))        MRSS Approach

0.17 > 1.2*((0.01^2 + 0.05^2 + 0.025^2 + 0.10^2 + 0.08^2)^0.5) = 0.17

0.17 > T1 + T2 + T3 + T4 + T5        Linear Approach

0.17 > 0.01 + 0.05 + 0.025 + 0.1 + 0.08 = 0.27

An excellent text on this subject is Dimensioning and Tolerancing Handbook, by Paul J. Drake, Jr. and published by McGraw-Hill.

DFMEA, design failure mode and effects analysis. is another tool that is extremely effective to identify troublesome areas of the design that need to be addressed to prevent failures in validation and the field.  Simply put this is a systematic approach to identify potential failure modes and their effects and finding solutions to mitigate the risk of a potential failure.  A Risk Priority Number (RPN) is then established based on rating and multiplying severity, occurrence and detection of the failure mode (severity*occurrence*detection = RPN).  The input to the tool is the design feature’s function, the reverse of the design function, the effect of the desired function not being achieved, and the cause of the desired function not being achieved.  There is also an opportunity to add design controls prevention and detection.  The outputs are the corrective actions taken to mitigate risk of a potential failure. Figure 3 shows an brief example of this approach for a MEMS microphone.

Figure 3

Design Failure Mode and Effects Analysis (click to view full size)

Fig 3

Further information on DFMEA can be found at Six Sigma Academy or AIAG.  Corrective action section left out of illustration for clarity.

It is also extremely important that the manufacturing process be considered from the first day of the design process.  Complete overlap of design and process development are the true embodiment of concurrent design.  The following illustration depicts this well:

Figure 4

Concurrent Design

Fig 4

Hence before a MEMS design is started, discussions should be initiated with the foundry, component fabrication suppliers and the process engineers responsible for the package assembly.  These meetings are excellent times to review new capabilities, initial ideas and explore new concepts.   Considering the design from a process perspective simultaneously with other design requirements leads to highly manufacturable products that are often lowest cost.    In essence, the design engineer is performing a constant manufacturing assessment with each step in the design phase.  This methodology also encourages process short loops in the design phase to develop new manufacturing steps.  This expedites the prototype process with upfront learning and provides feedback to the design team for necessary changes.  The additional benefit of this approach is the boarder team is on board when prototyping begins as they had a say in shaping the design.

Another tool to thoroughly understand the process in the design phase is process mapping.  Using this methodology, process inputs, outputs, flow, steps, variables, boundaries, relationships and decision points are identified and documented.  The level of detail is adjustable and to start there can be a broad overview with more detailed added as the design progresses.  This quickly provides a pictorial view of the process complexity, the variables effecting the design function, gaps, unintended relationships and non value added steps.  It can also be used as a starting point for setting up the sample line in a logical order to assemble prototypes, estimating cycle time and establishing rework loops.  To further clarify this method, a partial process map for a deep reactive ion etch process is provided:

Figure 5

Partial Process Map of Deep Reactive Ion Etch Process

Fig 5

This process map is not all inclusive but illustrative of the process flow, critical parameters, inputs and a decision point.  The personal protection equipment, tools used and relationships in the process are omitted for brevity.  With this level of process detail available to the design team, the complexity of feature fabrication can be evaluated, anticipated variation from process parameters can be analyzed and much more possibly prompting design changes.
Knowledge of and attention to detail in these eight critical, yet often overlooked steps are essential in the design of highly manufacturable, low cost and robust products.  These methodologies create a strong foundation upon which additional skills are built to provide a balanced design approach.  In next month’s blog, the design review process and a checklist will be discussed to help engineers prepare for this important peer review process.

Updated Bio:

Bio

David DiPaola is Managing Director for DiPaola Consulting a company focused on engineering and management solutions for electromechanical systems, sensors and MEMS products.  A 17 year veteran of the field, he has brought many products from concept to production in high volume with outstanding quality.  His work in design and process development spans multiple industries including automotive, medical, industrial and consumer electronics.  He employs a problem solving based approach working side by side with customers from startups to multi-billion dollar companies.  David also serves as Senior Technical Staff to The Richard Desich SMART Commercialization Center for Microsystems, is an authorized external researcher at The Center for Nanoscale Science and Technology at NIST and is a Senior Member of IEEE. Previously he has held engineering management and technical staff positions at Texas Instruments and Sensata Technologies, authored numerous technical papers, is a respected lecturer and holds 5 patents.  To learn more, please visit http://www.dceams.com.

Thinking Outside the Mobile ‘Box’

Written by: Karen Lightman, Executive Director, MEMS Industry Group
(as published in Design News, August 1, 2013)

By now you’ve probably figured out that there are a bunch of micro-electromechanical systems (MEMS) devices inside smartphones and myriad other mobile consumer devices. But did you know that MEMS is also revolutionizing how dairy cows are managed and that it’s a potentially $40 billion business?

I learned this recently from Dr. Alissa Fitzgerald’s presentation at Sensors Expo 2013, “Thinking outside the (mobile) box: Other important high-value applications for sensor fusion.”

The cows wear MooMonitor, a collar outfitted with a motion sensor (MEMS accelerometer) and a temperature sensor that indicates when the mama cow is hitting peak fertility and is ready for reproduction. It’s called a “bovine estrus cycle detection” app, and you can get updates from the cows via iPhone right there on the dairy farm. There are a staggering 265 million dairy cows in the world that could wear these collars, and whose farmers can benefit from this application. This is a fine example of someone figuring out a way to make a ton of money in MEMS with a non-consumer mobile device.

 144549_679865

The MooMonitor collar.
(Source: Dairymaster)

Fitzgerald identified several other MEMS-based applications in markets that some might call “unsexy” but that actually have big potential. In home maintenance equipment, we have robotic vacuum cleaners (Roomba), gutter cleaners (Looj), and even pool cleaners (Mirra) — all made by iRobot. Even the big home appliance makers like Whirlpool and LG are getting into the action with “smart-home” goods such as clothes dryers embedded with humidity sensors.

While the thermostats that control HVAC might not seem like a huge market opportunity, Fitzgerald encouraged us to think again about this humble piece of electronics. There are 10 million thermostats purchased in the US each year, and 250 million already installed in homes and light commercial buildings. That’s a market ripe for smart MEMS-enabled systems that can intelligently sense a home’s/office’s heating/cooling needs.

Enter the Nest Learning Thermostat that has multiple MEMS temperature sensors, IR motion detectors, and behavior analysis and prediction, and voila! You finally have a thermostat that can save you money on your HVAC. And the best news yet? Nest is intuitive, so you don’t have to read a huge manual on how to program it. Fitzgerald estimated that based on the annual sale unit numbers, and estimating the cost of a thermostat at $50 to $250, the total available market for thermostats to control household HVAC would be at least $0.5 billion and possibly as high as $2.5 billion annually in the US. It’s looking a lot sexier now, right?

The success of MEMS beyond the mobile-consumer space is still a well-kept secret. While health/fitness and medical devices are gaining some ground, Fitzgerald reminded us that there are many other huge industries that are often overlooked by MEMS product companies and market analysts. These include oil and gas, steel, agriculture, textiles, and mining, for starters. Fitzgerald believes that billion-dollar business opportunities are out there for companies that can think outside the box, instead of just providing more cool stuff for urban gadget hounds.

So let’s hear it for MEMS-enabled products that help people in other large industries to get their work done in the oil fields of Texas and on the dairy farms of Wisconsin.