Innovation in Motors for Mechatronics

Innovation is the watchword of mechatronics.  The pressure for solutions in alternative energy continue to push the boundaries of design in electromechanical systems.

In the wind energy arena the biggest change has been the shift to direct drive permanent magnet generators.  By eliminating the gear “increaser” to convert the low RPM of the propeller system to a high RPM for a standard high power generator.  This is crucial step in bringing the cost of wind power down. Current systems are weighing in at 100 tons and have to be suspended above water or land 165 feet in order to pick up sufficient wind currents to be economically practical.

There is no single solution that is ideal for wind applications.  One supplier has a generator that is made up of 4 smaller units on a single large ring gear.  This system seems to have significant advantages in reducing the size and weight of the generator and makes maintenance more simple in the event of a failure.

Among the major mechatronic challenges driving change in the motor industry, electric vehicle applications are continually pushing the boundary for energy density and efficiency.  The performance demands of electric vehicles and other mobility applications make every percentage point of efficiency crucial to the range of the target vehicle.  This has led to a rash of new motor and drivetrain designs with a variety performance capabilities.

Each new innovation seeks to organize the basic materials of the electric motor in a new way to improve some aspect of performance.  Electric motors are copper conductors, “soft” magnetic steels and many times, permanent magnets.  The basic costs for copper wire at $5-6 a pound, commodity strip steel is about $.50 per pound but has to be punched in precise shapes, coated with insulation and stacked into larger assemblies, and $16. per pound for permanent magnets.  Complex processes associated with motor manufacturing make motor costs considerable.

In a recent development teams in academia in Australia and the US have developed simple low RPM motor structures based on polymer actuators referred to as “artificial muscle”.  While this development is in its early phases, the simplicity and low cost are significant and very appealing.  A demonstration of the new technology can be seen on YouTube at;  www.youtube.com/watch?v=ZcCPNJR5PCMand it is very much worth the watch.

The only sure thing is that we continue to meet the challenge of new market needs with innovation.

Unique Solutions in Material Handling

Moving products around is mechanical work.  When the work is done by a control system and actuators its mechatronics.  Mechanical work, whether by humans, by horses, by hydraulics, electrics or whatever, is still work.  Figuring out what technology approach will be the most cost effective way to get the work done is the challenge.

Many of the constraints of the work are environmental.  If work is being done outdoors, then temperature and humidity are a factor.  Felling trees and in the forest requires extremely high forces due to the work needed to cut through a tree and drag it to a truck to be hauled off for processing.  Processing trees, even in a plant environment, requires some serious hardware, 125 horsepower band saws are not unusual.

Doing work on a ship or oil rig has additional constraints because of the presence of explosive fumes and fuels.  Often the need to avoid any possibility of igniting a combustible atmosphere causes engineers to apply pneumatic control systems.  Yes, there is still a compressor somewhere to generate the compressed air supply, but that is usually remote or contained to avoid exposure to the volatile atmosphere.

Environmental constraints come in many forms.  Extremely high temperatures push the limits of what is possible.  Making glass, semiconductors, and primary metal processing are all high temperature environments where engineers have developed whole technologies in order to bring us the materials we use in everyday life.

The simplest action of rolling or sliding becomes a real challenge when environmental constraints are added to the work statement.  Sawdust becomes a potential abrasive in woodworking environments that can introduce severe wear in moving parts.  Corrosive and explosion proof atmospheres as well as food industry applications introduce all sorts of chemical compatibility problems that require special materials and processes in order to meet strict guidelines for safety.

As always, resourceful engineers have worked out solutions for all of these difficult applications.  One family of solutions to rolling applications is the use of all ceramic bearings.  No steel, no lubrication.  None is needed because the ceramics are extremely high purity to start with and have extremely high precision surfaces eliminating the need for lubrication.  No outgassing or contamination to worry about.

Other solutions take the form of air bearings and non-contact material handling devices.  Air bearings have become more readily available for conventional applications, but are particularly compelling in large machinery applications where precision is required.  Large flat screen display glass  presents unique challenges that successfully addressed using a combination of air bearing regions and vacuum regions to move the glass without actual contact and with overall flatness measured in millionths of an inch.

A unique solution in pneumatic material handling takes compressed air driven into a funnel shaped recess and creates a vacuum in the center and an air cushion at the edges where the air is exiting.  This creates a vacuum pickup that never quite comes in contact with the part, leaving no marks.  Perfect for solar cell and some food and beverage applications.

Engineers continue to meet the unique challenges of industry and create commerce at the same time.  And that’s what it should be about.

Priorities Continued

Its tough enough getting a new piece of machinery built and working.  Turning out the same product reliably can be a challenge.  Even something as simple as a V belt becomes a lot more complicated when you have to turn parts out by the thousands or tens of thousands.

Getting it done on time and in budget are basic requirements of the challenge.  Over the years the only thing I have learned is that things always take more time and cost more than what was planned.    Good planning rarely eliminates mistakes or discovering an unforeseen problem late in the project that can jeopardize the whole effort.

The fix, if there is one, is building some slack in the project work plan.  So if it is at all possible, plan for 10 percent of the time and money to be set aside for contingency.  This will allow room for corrections to take place within the project plan and help prevent delays to the project deliverables.

Among many competing priorities in machine development, one that is rarely discussed is life expectancy.  Machine life expectancy is more subjective because component selections are not simple and straightforward.  Many decisions will be based on judgement and experience rather than on an explicit technical basis.

Something simple like a pulley may be perceived to be more durable if made of steel instead of aluminum.  But that component decision will increase the load mass.  The increased load will then require a larger motor and drive to power it.  And there are hundreds of similar choices that have to be made just like this.

Sprocket and chain mechanisms are generally indicated when high loads are being powered.  But in a situation where high life expectancy or reliability are involved, may be preferred over belts and pulleys.

Mechanical components of this type are subject to significant variations in cost versus life expectancy. The basic metallurgy of parts will impacted.  In one project, the balancing of load versus durability lead to the use of titanium.  The increased cost of the material was offset by reduced cost in the motor and drive solution.

Plating and coating of parts can be a significant opportunity for improved life.  Nickel plating has excellent performance in low friction, corrosion resistant coatings.  There are a number of hard Teflon coatings that can be used for reducing friction.

The life expectancy question is also connected to the maintenance cost of equipment.  For new machine designs, the maintenance issues are largely unknown and are part of the learning curve.  But the reliability of any piece of equipment is a huge issue.  And a lot harder to engineer in a systematic way.  But always worth the effort.

Optimizing Motion

Optimizing a motion control system is not easy.  There are many tradeoffs that need to be considered.  The strategy needed for each situation tends to be unique based on the problem that is being considered.

One strategy involves speed, torque and time.  These three variables are a connected system that is defined as the mechanical work to be performed.  Speed torque and time must be optimized according to the priority of each variable.  The difficulty is in exploring three variables simultaneously.

Two variable tradeoffs are no problem.   So having a two variable strategy for three variable systems would be really handy.  And as it turns out you can consider any one variable as a constant for the purpose of optimization.  So its easy enough to consider time as constant and optimize torque and speed.

This strategy turns out to work really well.  The speed and torque requirement for a given actuator system was very well defined and had been prototyped with good performance.  But the customer needed to optimize the cost of the design.

The cost of servo systems primarily follows the power requirement.  The more torque needed, the more expensive the servo system.  So the first place to work on cost optimization is the motor drive combination.  If the torque requirement can be reduced, the cost goes down.

So how do we reduce torque? You can either trade off time, or look for ways to reduce the load inertia. If time is a priority, then reducing the load inertia is the way to go.  And reducing the load is most easily dealt with by material substitution.  Steel is pretty strong, but may not be needed.  Aluminum may be a suitable substitute at one third the density of steel but half the strength.  Strength is absolutely required and reducing the weight is going to generate big cost benefits, titanium may turn out to be the best choice.  I have had applications where titanium was the used, and it was the right choice.

Sometimes the materials substitutions can be significant.  It is possible to use plastics like polycarbonate as an alternate to aluminum.  Again, the material strength is lower, but polycarbonate is so light, that more material can be used volumetrically to achieve the necessary strength, and still end up reducing the weight of the load.  So this is a viable option.

In the project I am currently working on, we have reduced the weight of the actuator system by about 25%.   What was really amazing, and unexpected, was that the weight reduction and rearrangement of the load structure resulted in a 56% reduction in the torque required.  The motor and drive has been reduced from a Nema 34 motor to a Nema 23 motor.   And further improvements are expected.

Which is why I like my job.

Magnets and Mechatronics

The world supply of magnets is a hot topic.  The Chinese bought General Motors’ Magnaquench company some years ago and have on their soil one of the largest developed mines of rare earth elements in the world.  According to some analysts, China controls 95% of the supply of Neodymium magnets in the entire world.

Pretty weird.  From a couple of different perspectives.

First of all, the original discovery of Neodymium Iron Boron as a high performance magnet material was paid for by the US military in 1982.   General Motors developed a process that took liquid metal at high temperature, rapidly cooling the material in a spray cast process that resulted in a high quality magnetic material.   So this should go in the history books as another breakthrough of American technology.

The original goal was to find a replacement for Samarium Cobalt which has always been a tricky material to deal with due to the wild fluctuations in the cost of Cobalt.  The other implication here is the fact that the US military felt it was important to maintain stable supply of permanent magnets for missile guidance.  So that makes the sale of Magnaquench to Archibald Cox, who then sold it to the Chinese, a very peculiar thing.  If there was a strategic military interest in permanent magnets, it was not part of the consideration when we lost Magnaquench.

While GM was planning on reduced size and weight for its engine starters as the benefit of neodymium, the entire servomotor industry is standardized on neodymium magnets for its motors.  At almost $1Bil a year in servomotors sold in the US each year, this is a pretty big deal.

The financial markets have been having a heyday with the situation.  Speculation is rife that the Chinese government will continue to tighten supply of Neodymium magnets to the rest of the world. So in addition to the natural effect that pricing will rise due to short supply, speculators will drive prices even higher in the next couple of years as the situation worsens.

And the reason Neodymium magnets are in such demand is that they make great electric motors for industrial automation and for powering electric cars.  So as the electric and hybrid electric manufacturing comes on line, tons of new supply will be needed.  The current plan for wind power also requires large amounts of permanent magnets.  So a lot of the “Green Revolution” will depend on the availability of these materials.

Having attended a couple of industry conferences on magnetics, I have become plugged in to the current state of the industry.  There are huge deposits of ore in the US and Australia.  Actually, neodymium is not particularly rare, which means it isn’t terribly expensive.  But dysprosium, which is needed to stabilize the neodymium magnet against high temperature demagnetization, is quite a bit more rare and makes the permanent magnet a lot more expensive.

The rare earth elements all occur together in the ores, and when the mines are developed, they are graded carefully for the yield per ton of about a dozen different rare earth elements.  So the really important fact is that the two largest rare earth mines in the world, in California and in Australia, will be extremely important in restoring the balance of supply in the near future.

And, in fact, the California mine is already well on its way to supplying the US’s needs.  Because people in the industry, and American and international investors, were smart enough to see the future coming.

More Manufacturing Breakthroughs

The idea of a 3D printing is pretty cool all on it’s own.  But when you can make high strength parts, well, now you’ve really got something.

One variation on 3D printing uses chopped glass fiber and ABS plastic that can be melted and flow the way conventional 3D printing materials behave.  The combination of glass fibers with ABS results in much harder parts and this increase in part strength is just right for many applications.

A straightforward adaptation is to make 3D plastic parts from and cast the part in plaster or a ceramic that can be used as a mold for conventional metal casting techniques.  For many parts, a lot of detail can be captured easily and high quality parts can be produced cost effectively.  If the parts are small, you can print many of them so that they can be connected in a “family” mold.  Again, this is a very well established metal forming technique that is made more cost effective with 3D printing.

Higher strength is possible with a wide range of 3D metal processes.  In one process, metal powder is fused in tiny regions using a focused laser.  As a layer is completed, a screed pushes a fresh layer of powdered metal and the process repeats.  Solid metal parts without machining.

Another method uses metal powder that is combined with water and lubricants and binders so that the powdered metal can be fed through a syringe.  The resulting slurry can be formed into parts using low end printers.  The parts are cured to drive out water and then the parts are ready for sintering.  The resulting parts have 80-90% of the strength of the native material.  All kinds of materials are being experimented with like bronze, steel and stainless steel.

There are even exotic alloys like Titanium that can be formed using 3D printing techniques.  Shapes that are impossible with machining techniques are possible with 3D printing.  And the process also makes possible combinations of alloys that are not possible with other processes.

This leads to a lot of questions about the future of manufacturing.  Will this technology mature to the point where it will displace machining of bulk parts like engine blocks and pistons?  Does 3D printing offer lowering costs for mature manufactured parts?

These are just a few of the possibilities that may be on the horizon.  When it comes to complex parts like plates for fuel cells, the 3D printer may be the breakthrough that is needed to achieve cost performance that make a lot of new technology cost effective.

Does 3D printing represent a lowering of the cost of entry in production parts.  This aspect opens even more questions.  In markets where the tool up to manufacturing something like a car is so high, the 3D printer may create an order of magnitude reduction in those costs.  The cost of new product development can be substantial, so any new technology that lowers development cost is likely to bring a whole of new ideas to the party.

The Future of Manufacturing

The Linux OS was an unparalleled event in technology.  A computer operating system that didn’t crash, was virus proof and could run anything.  Started by Linus Torvalds as a student and following the freeware approach of GNU development tools for processors, Linux was an idealistic approach to solving industry wide problems that individual companies were not able to address.

Linux attracted thousands of participants developing code for all sorts of applications simply because there were opportunities to improve poorly performing applications and make the computing more successful.  There was even a development group making a Linux based software programmable controller.  What a concept!

Not only was Linux a huge success in transforming complex and fragile operating systems, the most innovative aspect was the idea of development communities.  An idealistic approach to the cost of developing complex applications.  Commercialization and profitability took a back seat to solving important problems.

The “freeware” community has made its way into the motion world.  The Arduino development community has created a new processor and code platform that has among its many freeware applications, stepping motor drive circuits.  

There are an emerging number of part making systems such as 3D printers and low cost 3 axis machining systems that make prototype parts directly from solid model programs.  Machining systems are sometimes referred to as subtractive processes, so I suppose that extruding or jet printing wax would be additive processing.  Anyway, part fabrication has really taken off.

Surprisingly, even the part makers are creating their own development community.  Check out makerbot and fabathome on the web.  The effort is focused on developing part fabrication technology that is inexpensive, almost free.  Free plans, kits, parts, drivers, low cost motor drive circuits, everything you need to start making stuff.  Some amazing solutions.

Which raises a really interesting question; Is this the future of manufacturing?  How many new products could be produced using low cost tools?  What kinds of production capacities can be reached with this approach?

Interesting area to speculate on.  If a desktop part maker can be made for less than $1500, how many parts can be made without major problems with the machinery?  This suggests some really interesting possibilities.

Additive part fabrication can take a while, so part throughput is very slow.  So what? If it takes 15 minutes to generate a part, get 10 of them.  Then your down to a part every 1.5 minutes.  At $15,000 how many parts could be generated in a year?  4 parts an hour in a 2000 hour year would be 8000 parts amortized at .19 cents per part.  That means you can throw the part printer out after a year. Wow, that’s a deal.   So if the part makers can hold up for a year, you can throw them out and get new production equipment at the .19 amortization rate.

Seems to me that mechatronic innovation is solving some tough manufacturing problems at levels that may ultimately change how we do manufacturing.

Rapid Prototype Trends

3D solid model software has come a long way.  It  makes complex finite element analysis an integrated feature so that new designs can be explored in hours, rather than days or weeks of building prototype parts and making changes.  New product development costs have been falling consistently since the advent of this technology.

The logical extension of 3D solid modeling software is 3D rapid prototyping.  This technology has also gone through significant changes over the last twenty years to reduce the cost and make it available to a wide audience.  Development of file format conventions have made the link between 3D solid modeling and 3D printing very straightforward.

In its early days, 3D printing started out as stereolithography.   This term was coined for the two laser beams that were used to cure liquid polymer in a large tank.  Precision steering and focusing of laser beams has been around for a while from the laser printer world.  Adapting the laser printer technology resulted in tremendous precision with part accuracy of .001″ in any dimension being easily achieved.  This made evaluating complex fit and function very easy for manufacturers.  At its inception, stereolithograyphy machines were $250,000.  The high price tag made stereolithography the domain of Fortune 500 companies. But for high volume, complex parts like intake manifolds for automotive engines, stereolithography was, and still is, a great way to save money when a new part design is required.

Heat curing a liquid polymer gave way to heating a low melt point polymer to a liquid and dispensing it in small beads as a lower cost solution for making complex shapes.  To the point where there are a wide variety of solid model printers in a desktop package that are priced under $20,000 with really sophisticated features like multicolor part generation, and new low end machines coming in from China at $1500.

Experimentation with different chemistries has created a wide range of options with regard to material strength and imparting unique properties to the parts.  One variation is ABS plastic that is available with glass fill.  This produces much higher strength parts than the polymers.  Another whole branch of 3D printing is dedicated to making metal parts that are too complex or expensive for conventional machining.  Amazingly, the 3D-based solutions are resulting in much lower costs.

The implications are transformational for new product  development.  First, the combination of 3D solid model software and 3D printing technology taken together represent an order of magnitude reduction in the cost of developing new products.  The technology make more information available leading to, hopefully, better design.  This also means that the amortization cost of the development activity is also greatly reduced.  Leading to better goods at lower prices.

The second transformation is that lower development costs mean that the technology can be applied to lower price products.  Previously, these technologies were only cost effective in automotive and medical instrument design applications.  Now, the potential exists to dramatically improve products at lower price and volume levels.  Sneakers, for example, have been impacted by this technology leading to a wide range of new products incorporating a variety of new ideas.

And the transformation is just beginning.  And all of it mechatronics driven.

The Next Industrial Revolution

The industrial revolution was a period of unprecedented expansion of technology that lead to a huge increase in economic opportunity.  It was a period marked with great inventiveness that transformed the Europe and America.  The power of that inventiveness echoes through today.

Similarly, in recent years, there have been a number of significant breakthroughs that offer great potential for the improvement of many current technologies.  But more subtle transformations are taking place throughout the industrial landscape that offer new opportunities yet to be explored.

In many areas of part production, there are solutions that offer reduced cost per part.  The emergence of new CNC’s that are available at the $10,000 level reduces the amortized cost for producing parts by as much as 500%.  Simply put, it you have to produce 1000 parts on a machine tool, the final cost of the part is significantly impacted by the cost of the machine tool.  A $50,000 machine tool will cost $50 per part across 1000 parts.  A $10,000 machine tool will only cost $10 per part.

This economic shift may make it possible to enter a market with an improved price point for an existing product, or create an opportunity to do something new that wasn’t possible because of cost and volume constraints.

In similar fashion the metals industry has consistently worked to developed processes and technology that allow part cost reductions, and more recently, smaller batch sizes for certain applications.  The smaller batch size has the same effect on cost, it lowers the investment cost for improving old designs or coming up with new ones.

The same trend is in place in the controls arena.  Processor technology that used to cost $20. a few years ago is available now for $2-3 and network versions that permit Internet interface are available for around $5.  This makes it practical to embed intelligence and communications in products even if the application is relatively simple.  The low cost is a compelling value in many products.  And in many arenas there are libraries of application code that already exists that may provide 60% or more of the development code for something you are working on.

Energy is still a bit of a limitation.  We don’t have a “Mr. Fusion” nuclear reactor that runs of kitchen scraps.  But things are looking up in this area with lithium based batteries making great strides in energy density.  And there is substantial improvement on the way.

But the real point here is;  Dust if off and Try it Again.  Take those “back of the napkin” sketches you’ve been tinkering with or thinking about and look at them again from the perspective that there dozens of technology improvements out there that will reduce the cost of the product you were thinking about a couple of years ago.  The change in the economics, as amortized cost, or the cost threshold to get your first batch of parts made, are factors that have a huge impact on the feasibility.

It just may be the time for a breakthrough.  A second industrial revolution.

Magnetics 2010 and Motion, Drive & Automation

There is a small industry conference that takes place every year with a lineup of industry experts that is top notch by any standard.  It’s called the Motion, Drive and Automation Conference put on by E-Drive magazine.  This year it is located at the Disney Hilton Resort in Orlando and is taking place on January 28 & 29.   The conference includes a wide range of industry experts from many fields of advanced electric motor design, advanced motor control concepts, power semiconductors and state of the art motor testing system.  There will be a lot of technical and product presentations that showcase leading edge technology in electric motors, precision gear reducers, new technology for motion sensing, and a number of improved power semiconductor devices for the motor control industry.  This is a great place to get up to date on the latest technology that will impact of motor and control technology across many industries over the next few years.

In addition, the Magnetics 2010 Conference will be running concurrently at the same venue.  Magnets are a strategic material without which many motors would simply not operate.  In the ever-changing motor industry, there is always a new design that seeks to make an enhancement over previous solutions, or introduce a new solution to old problems.  Declining prices for Neodymium Iron Boron magnets over the last few years have created a number of novel design shifts which have been instrumental in bringing more varieties of permanent magnet machines into the forefront of motion control and mechatronic technology.  To the point where over the last two years a resurgance of permanent magnet rotor designs have been created to improve the energy denisty and lower the cost of specialty motors in washing machines and air conditioning compressors.

This last development, combined with the forecast increase of hybrid electric car sales coming this year, are expected to increase the sale of permanent magnets by 10-15 percent by 2011.  That’s a staggering jump in a market that is almost exclusively supplied by China.  And there is no assurance that China can meet the forecast production.

The US Department of Commerce usually has a say in the sale of products or businesses to foreign countries that are deemed to be strategic or sensitive technology.  In fact, I got stuck in a situation where my employer was told specifically that we could not sell a CNC controller to a Korean customer.  That’s pretty small potatoes compared to controlling the supply of permanent magnets which influences billions of dollars worth of electric motors manufactured and sold all over the world.  So it strikes me as a little odd that the sale of Magnequench to its current owners, Neo Materials, was completed without a much discussion. leaving the US without a domestic magnet supplier.

There will surely be a lot of discussion about this situation at the conference, and I will be in attendance to get the latest information on the subject.  So look forward to a review of the conference in an upcoming post.

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