If you’ve had even the slightest inkling of initiative but have been stifled by fear or doubt or something else, I recommend reading Seth Godin’s new book, “Poke the Box“. It might give you the push off the branch you need to really fly. It’s well-written and a quick read. It’s really his manifesto calling people to action with the thesis that everyone can be innovative. Well, not everyone, but innovative people can exist anywhere, from those with authority over a Fortune 500 company to those with barely authority over the mail room. Your job description doesn’t matter. Initiative and the ability to overcome fear is what matters.

Poke The Box from Seth Godin on Vimeo.

Have you read the book, yet? What did you think?

When connected to two dissimilar metals (such as copper and zinc), the lemon transforms into a battery, producing a small voltage potential.  A new found use of lemons is discovered, much to the delight of kitchen scientists everywhere.  For us here at Key Tech, it illustrates the positive use of a usually avoided event: Galvanic corrosion.

The process: break it down

Galvanic corrosion occurs when dissimilar metals are in the presence of an electrolyte, such as salt water (or citric acid in the case of lemons).  One metal forms the anode and the other metal forms the cathode. The anode is more active (less corrosion resistant) and the cathode is less active (more corrosion resistant). When they are electrically connected, a current is produced which causes a change in the corrosion properties of the metals:

• The more active anode corrodes faster than it would by itself
• The less active cathode corrodes slower than it would by itself

These metals must be in electrical contact and they must be exposed to an electrolyte. This type of corrosion will not occur if the metals are completely dry or electrically insulated from each other. Galvanic corrosion is a common enemy of ship builders, but this destructive process is of interest to any designer where metals and alloys interface, such as at fastener locations.  Material choice as well as surfacing options become critical at these junctions for the life and structural integrity of the system.

Welcome to the Galvanic Series (in seawater)

For those of us who love tables, galvanic series were developed to list metals and alloys based on their corrosion potential in a specific electrolyte.  In seawater, these materials are listed from most cathodic (inactive/resistant to corrosion) to most anodic (active/ease of corrosion).  The further apart the metals/alloys are in a particular series (thus the most dissimilar they are), the higher the risk of galvanic corrosion.

Least Active (Cathodic)

• Platinum, Gold, Graphite, Titanium, Silver
• Stainless Steel (passive)
• Brass/Bronze
• Stainless Steel (active)
• Chrome
• Nickel
• Steel
• Aluminum
• Zinc
• Magnesium

Most Active (Anodic)

How to prevent or minimize galvanic corrosion

• Choose metals close together on the galvanic series for mating parts and fasteners.
• Never place a small area of active metal on a large area of inactive metal (e.g. a zinc-plated fastener on stainless steel part).
• Use coatings or other means to prevent electrical contact between parts:
  • Anodize
  • Chromate conversion (iridite)
  • Phosphate
  • Electroless nickel
  • Paint
  • Lubricants
  • Insulating tape
  • Non-absorbent washers
• Use a sacrificial anode (e.g. galvanized steel)

Rules of Thumb: Know Your Environment

Where the metallic components will reside should be considered when designing your overall system.  The Anodic Index can be found here.  These anodic index values provide the comparison needed when deciding what type of fastener material to use in your designs to prevent galvanic corrosion.  The basic rules of thumb are (taken from corrosion-doctors.org):

• Harsh Environments (outdoors, high temp, high humidity): the difference in Anodic Index should be less than 0.15V
• Normal Environments (storage warehouses or non-temperature and humidity controlled environments): the difference in Anodic Index should be less than 0.25V
• Controlled Environments (temp and humidity controlled): up to 0.50V difference in Anodic Index can be tolerated

A couple great resources for more detailed information on this subject are the ASM Metals Handbook (Vol 5 and 13) and “Handbook of Corrosion Engineering” by Pierre R. Roberge (2000).

If you’re not the one being wheeled in, when you enter an operating room you’ll see a lot of duplicate hardware. Multiple displays and computers, various sensors and diagnostic devices to monitor the patient. And, none of it knows what the other devices are doing. If every device could communicate over common protocols, at least some of that hardware could be eliminated. This could cut the cost of the devices and reduces the clutter in an already cramped space. Communication could also improve the techniques by which health care is administered. But, is it possible to verify and validate the safety and efficacy of medical devices if they could be connected to unknown current and future products?

In the current system, the answer is probably “No”. But, if inputs and outputs could be strictly enforced and regulated, as is the case with FDA-regulated medical devices compared to the “wild west” of computer and home theater peripherals, perhaps it wouldn’t be so difficult to imagine a future with compatible tools.

The medical device industry has not ignored the potential of device interoperability. In fact, it is a recognized issue. There have been many conference presentations and on the subject, and an FDA held a workshop this past January focused on working out these exact issues. While I don’t expect the solutions to arrive overnight, I do look forward to seeing developments coming down the pipeline.

The Scale

We chose an Acculab 210.4 scale because it was accurate enough (.0001 gram resolution, which is about a tenth of a microliter for room temperature water) and because it has a serial interface that we can call from Visual Basic to easily collect data and put into a spreadsheet. The data stream is limited to about 8Hz, but it was fast enough for our purposes.

Scales with more resolution often come with damping mechanisms to keep them stable. Although the glass cover keeps the air movement down, this one didn’t have a means to damp vibrations, so we needed to isolate the scale ourselves. We used a small table with some rubber feet as the foundation. Then we used one of those heavy engineering textbooks we have so many of on some thick foam and put the scale on top. Considerate use of flexible beams, soft materials, and masses meant the scale was rock-steady without any software averaging required.

The Fluid Connection

To get the fluid onto the scale, we attached tubing with a luer-lock fitting to a long needle inserted into the scale cover through a hole in the top plate and held in place with a thumb-screw. By using a needle instead of just inserting the tubing into the container, we eliminated any contact with the container or scale. we found that any such contact threw the scale out of whack, especially when the fluid flowed through the tubing with momentum.

The question came up as to whether the needle should be above the water-level or below it. If the needle is below the water-level, surface tension on the needle can reduce the weight of the water. However, if the needle is above the water-level, a drop can form at the tip instead of depositing the small volume onto the scale. We needed fine-resolution flow-rate data, so we opted to ignore the surface tension, which we found to be below the resolution of the scale.

Evaporation of the Water

Over the duration of a test, water will evaporate. The rate is dependent upon temperature, relative humidity, and the surface area of the container. Many suggest adding mineral oil to the water to create a barrier layer to supposedly eliminate evaporation of the water. Data showed that the oil layer did reduce the rate of evaporation (from 0.13 g/hr to 0.08 g/hr), although the oil ruined the plastic connections of the tubing by making them brittle and causing them to leak and break. Instead, we drilled a 1/4” hole into the cap of the container for the needle to fit through, which dropped the rate of evaporation by two orders of magnitude. We collected data for various configurations of the water, oil, and lid and plotted them below. So, without using any oil, we were able to drop the rate of evaporation from 0.127 g/hr to 0.002 g/hr.

Volume and Flow Rate

So, how does a measure of weight relate to volume and flow-rate? Well, the density of water is pretty well defined based on temperature (and weight / density = volume). Accounting for the error of this density value, as well as errors in the scale resolution and time resolution provided excellent measurement results by which to evaluate the devices.

There’s little commitment while the design is still in my head. Anything can be changed in an instant.

There’s also little education. I don’t learn anything new from examining a design for the 23rd time. I might catch something based on a mistake I made in the past or other engineers might suggest improvements during an independent design review or impromptu brainstorming session. Everything we see in the design stems from what we already knew, and a few educated guesses.

Once I’ve put it all together in my mind and gotten input from my peers, the only way I can learn more is by building. Put it together, figure out the problems, make improvements. I created the design based on my experience, but the design is still changing. I’m sure I missed something

Maybe the first version isn’t perfect, but I can make it work. Test it. Find the flaws and make a list. Keep going. There’s more to learn.

I make improvements to this design and file away what I’ve learned for next time.

I build a second prototype. There’s more to learn.

When progress slows or I’ve hit a roadblock, it can be frustrating. Maybe I overlooked something critical or my assumptions were wrong. Maybe my prototype is based on a component that just ran out of stock. Whatever the case, when I need some fresh ideas, it’s time for a distraction.

Ideas rarely occur to me when I’m straining to think of them. Instead, they pop into my head when I’m doing something else. I might be driving my car, taking a walk, or reading my kids a story. It’s not always an “Ah, HAH!” moment, but it’s often worth remembering.

But, I’m supposed to be working. I need an idea now! I can’t think of anything! THINK HARDER!

Relax. I can’t force an epiphany. Can I encourage it? When I get stuck on something, one of the best ways for me to get unstuck is to change my environment. I “unplug” – walk away from the computer and iPhone. I get some ice-cream from the market or walk to Federal Hill Park and listen to the leaves blow in the wind. In the quiet, my mind, usually struggling to keep up with my Inbox, Voicemail, and cell phone, starts to race with ideas. I’m flooded with new possibilities.

But, wait. Isn’t that the exact opposite of “making progress” or “working”? Perfect.

Read more about the symbiosis of modeling and prototyping (PDF) for designing microscale parts in an article I wrote that was published in MICROmanufacturing Magazine this month, page 33 (Jan/Feb 2010, Volume 3, Issue 1).

You can read the article in the Summer 2009 printed publication or catch it in the online version, Meeting the challenges of micropart design.

9. Regional products – More and more companies are being drawn to the large, nascent medical markets overseas, in China and India in particular. If you’re also feeling an attraction to these areas, remember that your current product may not suffice, even if it has been successful in the US and Europe. And we’re not talking about the expected things like software or labeling issues.

   Your product was most likely designed to meet specific stakeholder needs for the regions in which it was developed, including the user interface design, product cost and even the per-use cost. Chances are good that what worked in one region will not work in some of the big overseas markets noted above.

   The U.S., in particular, has distinctively different buyers and/or users of technology-based products than China or India or other developing countries. Don’t be surprised if you end up having to significantly re-design the product for some of these overseas markets to better fit the needs of the local region. Your cost model may have to change completely, and may not work at all. Plan for this…don’t get blindsided. You may even want to find a local product developer in each distinctly different region that can provide input for the design.

10. Reimbursement – Reimbursement is central to the business plan of a majority of medical products. We have been surprised to find that this topic is not better researched by some of our clients.

    We’ve seen more than once where the reimbursement research was delayed, purposefully or not, until some later point in the development program. We’ve seen cases where an expected or planned reimbursement model didn’t work or where existing reimbursement codes were wrong or didn’t apply. We’ve even seen cases where there were no applicable reimbursement codes.

    Reimbursement can have a big impact on per unit and disposable cost targets, as well as the upfront development NRE. Give this the attention it deserves. Proceeding without understanding the reimbursement model adds significant business risk.

I hope you found something of interest in the above… and even something that may help you one day with your future development projects. That’s it for this four-part series, but you may see more of these lessons in the future. Don’t be afraid to make mistakes, just don’t repeat them.

6. Technology Development vs. Product Development – We’ve seen this issue arise more often when working with startups and younger companies, but not exclusively. It has to do with recognizing the differences between technology development and product development. Technology development should always precede product development.

   Tech development is centered on fully understanding how the base technology is going to respond in both the normal and abnormal conditions. This might include the development of algorithms and sensitivity studies, looking at interference effects and confounding factors, error terms, etc.

   Product development is taking the fully understood technology and packaging it in a particular form. Of course, there are shades of grey where they overlap, but the concepts are different.

   The problems start when you try to initiate the product development process before you’ve finished with the technology. Many startups make this mistake. They have looked at the normal range of performance parameters, but have not really studied how the technology will perform over an expected range of operating conditions, much less the extreme conditions with a host of error terms.

   Don’t fall into this trap. Fully develop and understand the technology before you start the product.

7. Stay objective – If there ever was an old adage to follow, this is it. Stay objective and use stage gates with formal charters, budgets and schedules to move from one gate to another. Don’t fall in love with ‘your baby’. It takes passion to manage your product / business, but it also takes a clear head.

   There are usually two types of risk in a new product development project: technical risk and business risk. We use an internal process that manages both in parallel, with a chartered stage gate process. Charters are internal agreements we use for each development step on both the technology side and the business side. The charter includes milestones, schedules and cost limits. This is a formal process attended by upper management…and it can be bloody.

   If you’re not ready or you did not meet your charter requirements, don’t expect charity. If this sounds harsh, it’s only because we learned the hard way how deep of a hole you can dig for yourself if you don’t force yourself to stay objective.

8. Spec creep – It’s a term that we’ve all most likely heard and used…small incremental changes to the specification – surprise additions to your original product spec and feature set. They come from both outside the design team (e.g., sales and marketing) and inside the design team.

   Are they a good thing? Depends on your perspective.

   Are they necessary? Sometimes, but probably not as often as the sales folks want you to think.

   They can kill your projected costs and schedule. The PM needs to be on guard and protective of the design and functional specifications that form the foundation for the product. There is a waterfall effect as the product and project matures. Any changes / specification additions made halfway through a project need to be reconciled backward up the waterfall, as well as from that point forward.

   It can make a mess out of your design documentation and traceability. For all you new PM’s, develop your ‘required’ specifications in one document, as well as your ‘nice to haves’ in another. Get official approval / buy-in and then be ready to go to war. Don’t blink, budge or waver in the slightest. Tell the sales manager he/she can have their added feature as part of a post-launch upgrade kit. If a post-launch upgrade is unacceptable, be prepared to explain, in detail, the budget and schedule impact and risk of the spec changes so that all parties can make an informed decision.

Remember, this is just the third part of a four-part series. Check back later for more on the topic.