American Entrepreneurship 101

In my travels, I continue to find people hard at work doing something that has never been done before.  With the hope of making a profit while doing it.  Just such a situation came up recently when I met with the owner and founder of Transcon Steel.

Among the mainstays of an industrial economy is construction, housing and commercial in particular.  While these industries are incredibly competitive, there is always room for innovation.  Precisely because it is a mature, competitive industry, really ground breaking solutions are sometime hard to find.

Transcon Steel is a small startup company in Georgetown Texas that makes structural steel building systems.  The innovation comes from the fact that Transcon roll forms flat sheet metal into structural shapes that are highly optimized to reduce weight and increase strength.  The steel structural shapes are formed into large panels with compressed foam which results in structures that are super light weight and extremely high strength.

The new structural panels permit construction of buildings in a variety of applications.  So called “temporary housing” for oilfield crews in remote area can be built in hours instead of days.  Heating and cooling costs are a fraction of conventional structures.  All of which leads to increased opportunities to serve unique construction applications with better solutions.

Transcon’s big challenge will be to create the manufacturing resources needed to produce the structural panels in very large numbers.  The enabling technology of the manufacturing processes?  Mechatronics. The roll forming of sheet metal is a classic application requiring high performance drives to de-reel the strip steel rolls and servo actuators to follow the roll throughout the various forming process that take place to make the final product.

The compressed foam requires unique tooling to form large rectangular panels that can be filled with foam, compressed with hydraulic actuators and cured with heat and pressure to form the final super dense structures.  Amazingly, the cores are made from material that is similar to the conventional styrofoam cups we use for coffee, yet, when the basic material is processed correctly, it becomes strong enough to withstand blows from a sledgehammer.  When it is bonded to an already strong steel frame, you have a complete building system that has incredible structural strength and insulation value.

Transon is negotiating enough new business that it will need a new facility 4 times the size of it’s present location and will hire CAD designers and plant personnel to support it’s manufacturing needs.  If they are successful at marketing the technology in other countries, it will be more of the same.  Lots of it.

And that is how job creation is done.  Someone with an idea, willing to work hard, taking risks, finding people to come alongside and help, to deliver a solution.  Making lives better by employing people, and by delivering a product that provides shelter at a lower cost than the traditional products in the building market.

American Entrepreneurship.

Doing More In the US

The old business school motto, doing more with less, can have some interesting applications.    American manufacturing is going through a rennaisance of sorts.  Across many industries there are substantial efforts to bring more manufacturing back to the US.

A lot of it is precisely ‘doing more with less’.  How do we make the same quality of parts at prices low enough to compete with foreign competition?  It’s not easy when the typical pay scale for manufacturing labor is $8 a day in some parts of the world.

There are a couple of obvious components to price competition that don’t get a lot of attention.  Scrap rates and delivered cost.  When a US company buys parts from offshore, any defective parts are very costly.  The direct shipping cost, duties and processing fees are additional and can be 10-15%.

During my years at Rockwell Automation, we investigated the cost of selling US products in different parts of the world.  Depending on where in the world we are talking about, the shipping and logistics can accumulate between 25 and 40% additional cost to the product being sold.

So the cost of scraps and logistics are the minimum cost hurdles for companies seeking to export their products to the US.  Low cost producers have to make parts cheaply enough that the landed cost and scrap rates cost out less than the price of producing them in the US.

Doing more manufacturing in the US requires finding creative ways to lower costs.  That is the second area that is undergoing change.  American manufacturing technology is finding ways to reduce machinery and process costs.  And this area of effort may provide key strategies that will help the US gain back ground in the pursuit of more world class manufacturing.

Innovation processes like additive manufacturing allow fabrication of metal parts with no machining.  For higher levels of precision there are new machine tools that can do final machining to less than 0.001″ accuracy and the costs of machine tools are lower than ever.  These are the keys to producing high quality parts at lower costs.

There are unique mechatronic solutions that can improve machinery performance across a wide range of applications.  The Acme screw which is very inexpensive, has limited accuracy but plenty of torque handling capability.  What happens if you can add a very inexpensive linear feedback technology to the simple low cost Acme screw?  You get a really high resolution linear motion system that is very inexpensive.

The great news is that these products are currently available.  And that means that making better machines that make better parts at lower cost is practical, achievable and there are no technical challenges.  Common off the shelf parts will get it done.

Servo or Drive?

When does a rotating load require a drive or a servo?  I run into this issue on a weekly basis.  Everyone has their own answer.   As much as this may be a matter of opinion for most people, there are some guidelines that can help make this question more straightforward.

Some people define servo’s as closed loop versus drives which are open loop.  The term servo does require that there is a feedback device to provide the loop closure.  But there are many AC drive vendors making closed loop inverters to enhance the performance of the motor.  AC drives with feedback are generally used where positioning is required.  So the feedback element is not the determining factor for defining if an application is AC or DC.

The overall power level may define one versus the other, but not always.  Brushless servo motors are generally limited to 7″ or 8″ diameter and an equivalent horsepower rating of 20-30 horsepower.  There are frameless motors with even higher horsepower ratings.  But  the size and power rating are strictly a function of manufacturing and marketing constraints.  For a major manufacturer, the question is really, how many motors of a given size are we going to sell?  Based on the high cost of Neodymium permanent magnets, a larger servomotor is going to be very expensive.

But overall power ratings are not limited when you consider products from specialty companies like Powertec.  Powertec takes standard AC motor frame designs and increases the power density by adding embedded permanent magnets on the rotor.  Since the magnets are Ferrite, which aren’t as expensive, they are much more economical and allow designs as big as 400HP.  So power level by itself doesn’t determine what technology to use.

The real answer is in the load conditions.  What is the dynamic response required for the target application?  The rate of change of the load is the key.  Most AC drives are specified in terms of the frequency response or dynamic response of the power electronics.  This important parameter is expressed in Hertz.

Dynamic response is the ability of the drive to regulate speed when the load varies.  The load torque can change significantly, usually 90-100%, and the drive will recover the set speed within the time defined by the dynamic response.  Typically, an open loop AC drive has a 10 hertz dynamic response, which means that it will regulate to 1/10th of a second.

AC drive technology has improved to the point where dynamic response can reach 200 Hertz when a rotary encoder is added to the motor.  This means the drive can regulate load variations wiithin 5 milliseconds.  Which is pretty fast when the load mass is high enough to require a motor of 25 horsepower or larger.

The basic physics are simply that the bigger the load, the slower the dynamic response.  You just can’t make a ton of rotating mass change speed really quickly.  And that’s how the controls should respond.

Nippon Pulse Introduces Green Drive Linear Actuator

Nippon Pulse has announced the introduction of its newest linear servo product, the Green Drive linear actuator. The Green Drive is an all-inclusive linear direct drive actuator suited for high-performance applications requiring high force, accuracy, and precision.

Features of Nippon Pulse’s Green Drive include:

• Acceleration (peak) force of up to 600N for 40 seconds
• Effective stroke lengths between 10mm and 1540mm
• Cooling systems that can increase rated force up to 20%
• Rated force between 13N and 150N
• Position repeatability of ±0.05mm
• T-slots for easy and quick integration into applications
• Position sensors, temperature sensors, interpolation electronics
• Four different feedback output types: analogue SIN/COS, Digital Bus BISS-C, Digital A/B TTL Linedrive Incremental, and Absolute SSI
• Color coded quick connectors
• High-performance slide bearings

The Green Drive currently is available in two sizes, the G16x series and G25x series. The G16x series features a shaft (magnets) with a 16mm diameter and the G25x a 25mm shaft diameter. The G16x series is 66mm wide and high, while the G25x series is 88mm wide and high. Each has varying lengths depending on the required effective stroke.

Nippon Pulse will be highlighting the Green Drive at the ATX West tradeshow in Anaheim, CA in mid-February. Those interested in the Green Drive can visit booth #4348 to learn more about the actuator.

Nippon Pulse America, Inc.
www.nipponpulse.com

Minarik Drives Announces Distribution Agreement with Kaman Industrial Technologies

Minarik Drives is very pleased to announce that it has signed and implemented a National Distribution Agreement with Kaman Industrial Technologies.  This agreement will further enhance a partnership that will provide Minarik Drives with 200 new locations and will provide Kaman Industrial Technologies a premier DC drive and drive systems product line.

“We are very pleased to add Kaman Industrial’s selling capability and the value added approach they brings to their customers to our already strong distribution channel.” said John Hegel, President of Minarik Drives.  “Kaman’s penetration into the user and OEM markets will open doors for us that had been previously inaccessible and will help us serve a greater cross section of business across the U.S.”

Minarik Drives is an independent company that specializes in low to medium power electric drive and power applications.  It has been a standard, and a leader, in the DC drive business for almost 60 years.  With design engineering and manufacturing headquartered in S. Beloit, Illinois, it provides standard and customized solutions at a globally competitive price.  More information about Minarik Drives is available at www.minarikdrives.com or by calling 815-624-5959.

Next Generation Manufacturing

As a follow on to the last post, I have been investigating the cost of manufacturing equipment.  The classic machine tool is the most widely used piece of equipment for fabricating just about anything made out of metal.  The machine tool has been quietly undergoing it’s own revolution since it’s inception in the 1950′s.

The traditional metal cutting machine tool has been around since the 1800′s and was entirely manually operated.  Since the machines were manually operated, the dexterity of the operator became a major factor in accuracy and repeatability of part manufacturing.  Because of the skill required, we still have the term “master machinist” in circulation, even though most machining today is automated.

During the Second World War, the Air Force was confronting the difficulty of manufacturing airplane parts.  Through the work of John Parsons and MIT, the first “punch card” controlled machine tool was built.  Parsons’ company was using early punch card computers to generate a larger number of points along the curve of a wing brace.  The numerical information was then used directly by machinists as a look up table for manually positioning a milling tool.  Parsons realized that if they could motorized the manual process, it could greatly increase the speed of the machining process, lowering costs dramatically and increasing accuracy at the same time.

Gordon Brown’s Servomechanisms group at MIT has recently been working on early forms of closed loop dc motor control for the gun turret on B-29 bombers.  By combining these recent technologies to numerical punch card calculation approach the first Computer Numerical Controlled Machine Tool was demonstrated.

The rest, as they say, is history.  The lessons learned in computer numerical control have been instrumental in every major field of manufacturing.  Cars, electronics, robotics, would not be feasible or cost effective without the underlying control technology of CNC.

Which brings me to a 2 major points as we contemplate the next generation of manufacturing.

Additive manufacturing is maturing rapidly with a wide range of materials, steels and titanium are now available, and precision is improving at the same time.   The surface finish requirements for a large number of parts cannot be achieved with a strictly additive process.  The new wave of additive manufacturing requires a complementary subtractive technology at complementary prices.

Secondly, while there are an increasing number of machine tools at low cost, they are not CNC.  This will likely be the next “breakout” technology.  There are a number of technical hurdles that have to be addressed in terms of reducing the cost to a level comparable with the Makerbot.  With the current generation of dedicated motion controller chips, lower cost step motors and low cost feedback technology, this should be a slam dunk.

Get your pencils out and get after it!  There’s some serious money to be made here.

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.

Friction, Friend or Foe?

Friction is rarely talked about in motion control circles (pun intended for those paying attention).  It is the “waste” energy in mechanical systems.  We spend a lot of time and sometimes cost, trying to eliminate it.  Many times we just ignore it.

This was the case when a friend of mine was designing a material handling system for newspaper bundles.  A very exotic conveyor system with 8 servo driven belts and a design that involved 10 pages of hand calculations of inertia.  We shipped the servos and sent out a field engineer to start up the project only to find out that the motors and drives were too small.  The designer had forgotten to account for friction.  In this case the frictional load was 3 times the mechanical load due to the unique belt and roller configuration.

So the first lesson is; don’t forget to look at friction as 1 of 3 components of the torque load.  The three being; steady state torque, torque of acceleration and friction.

Then there is the fanciful wishing that there wasn’t any friction to worry about.  Kind of like doing experiments in the space station and having no gravity.  It’s fun to think about, but there are few real world situations where this is likely to work.  The only exception is air bearings.  Of which there are a few.

If you have ever played air hockey, air bearings are like that.  Parts in motion tend to stay in motion when there is no friction to worry about.  And that would be good in a lot of applications.  No friction will generally result in smaller servos, so there are savings in the hardware requirement.  No friction means no mechanical wear, nothing to service as the machine runs up cycles.  No friction also means high speed motion is a lot easier to achieve.

Cars coast to a stop because of friction.  That’s a good thing.  Without friction, parts would end up flying off the conveyor instead of going where you want them to go.  In conveyor belt applications there is usually a lot of friction and that helps the system slow down and stop.

So the second lesson is; friction can be your friend.

In between systems with friction and systems with no friction, there are rolling bearings.  Systems like the Bishop Wisecarver “Vee Guide” are among many products on the market are examples of this.  Rolling element bearings have very low coefficients of friction, so losses are low and therefore the energy needed to overcome them is very low.  This also results in very low wear, so maintenance on this type of mechanism is also low.

The are dozens of linear actuators on the market and each vendor has developed unique bearing solutions, whether sliding or rolling, that perform well at varying price points.  There are no universal rules for selection.  The typical criteria are move speed, positioning accuracy, life expectancy and cost.

Programming Software and Control

Writing software for control applications isn’t the easiest thing.  It’s probably been 15 years since I had to write any actual code for a control application.  I have scripted and taught training classes in PLC programming and am very familiar with ladder logic programming and Boolean instructions, although I am less familiar with the latest editing software which has become very sophisticated.

A few weeks ago, I had the opportunity to write a couple of small “C” programs in a training class and re-discovered why I don’t like to write control software.  I don’t have much background in C programming.  It’s not that C programming is inherently good or bad, it’s just another language.  What is difficult to deal with is each controller having it’s own library of C language instructions.

It’s not that any particular language difficult, it’s that every language is iterated on different controllers and the instruction set and programming quirks have to be learned on each platform.  Ladder Logic instructions have become largely standardized and the difference from one platform to another are becoming less and less significant.  Turning discrete inputs and outputs on and off is pretty straightforward.  Reading analog signals, doing some mathematical operations and setting analog outputs is also fairly straightforward.   Even when there a lot of I/O to deal with, the knowledge base required to understand the applications of the technology are ultimately very repeatable.

The variations of how to do motion control on different platforms are very significant.  Each controller company has to come up with a complete programming environment that defines how to command the controller to execute motion tasks.  The creation of commands and processor executables requires coding and testing the code over man years of development.  This is a complex form of knowledge capture and there are a lot of nuances as programmers come up the learning curve before good effective programming environments can be created.

This is part of the reason why the motion control field hasn’t progressed as much as other control disciplines.  There is no agreement on any standard programming methods past trapezoidal move profiles.  The situation becomes more complex because each motion control vendor develops its own programming environment based on the selection of processor platforms and what its programmers come up with for the programming suite.  This creates a barrier to entry for new companies, and makes improved code solutions problematic.

Many of the PLC programming suites include dialog boxes that provide scripting for the motion commands in the ladder logic program.  The technology is readily available to make a high level motion programming suite that is processor independent and capable of addressing 80-90% of all motion control applications.  This will make motion more accessible to a wider audience and simplify the programming aspects of motion and machine control.

We need to bring the industry into the 21st century and make everyone’s lives a little easier.

Control System Theory and Feedback

Control system performance is based on feedback.  Control of electric motors, however, continues to be a bit mysterious because the common conventions associated with motor control are often driven by cost considerations.  The feedback component is often target for elimination in cost constrained systems.

Control systems can be described as “open loop” or “closed loop” depending on the whether or not the system being controlled is well characterized.  Many forms of motor control seek to be “open loop”, that is, without the use of a feedback device.   However, this notion should be modified to open loop meaning without an explicit feedback device. This is because great effort is expended to “infer” what is going on in the motor through various means. The most common of which is current.

In the world of electric motors, the alternating current motor of Nicola Tesla is well understood, and rarely requires a feedback device.  Motor speed is derived from the frequency of the power being supplied minus losses depending on the details of rotor construction and how a specific load affects the motor.  The standard ac motor has a small amount of rotor “slip” from 1800 rpm to 1750 rpm which reflects the magnetizing current losses in the motor and magnetic features in the rotor that would be needed to maintain perfect synchronism with the line frequency.

Load variations can be measured by sensing the current in the line going to the motor.  So there is a feedback element available from which a great deal of information can be derived.  This is where the ambiguity about feedback comes in.  The current needed to run the motor with no load is fixed value, so more current read on the motor leads is load, until the motor reaches locked rotor current or stall.

In brushless dc systems a similar approach is used.  Detecting the zero crossing point of the phase current establishes precise timing of the rotor speed and is used to regulate timing of current pulses to all three phases of the motor.  In this way even the brushless dc motor can be operated without an explicit feedback sensor.    However the tradeoff here is very poor low speed regulation of the motor which makes this approach unsuitable for many applications.

From a control system standpoint, feedbacks are the last, slowest loop in the control scheme of the motor.  This makes sense in the context of position control as it is normally executed in a PLC or motion controller.  However, this makes load regulation more of a challenge since the actual error detection of the control system is being done a level removed from the actual load.

A host of mathematical tools from the signal processing domain have traditionally been employed to characterize the lag created by the control system and the interaction of the controls at varying speeds. All of which works well, but has also lead to “rules of thumb” that are not very clearly understood and which are sometimes misleading.

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