Development of the MC Series of High-resolution Balances (Mass Comparators)

The following describes the newly developed MC Series of high-resolution electronic balances. The market for these balances will also be discussed, including the commercialization and technology of general-purpose electronic balances.

Mass sensors known as electronic balances have comprised a majority of the weighing instrument market for a considerable time. Electronic balances display measurement values digitally so no special knowledge of analog instruments is required to perform weighing. As a result, anybody can measure the mass of many types of items easily and accurately. This is one of the reasons that electronic balances have developed new markets, along with cost reductions of electronic components and control circuits.

Electronic balances have expanded their market scale through usability and low cost but their measurement principles have not fundamentally changed since they were developed. New measurement principles for weighing have not been proposed for decades and mass traceability is still guaranteed by 1 kg standard in France. Of the seven SI units (length, mass, time, current, temperature, luminous intensity, and substance (mole)), only mass requires a physical guarantee of accuracy. Because of this requirement, mass is considered a specialist field that requires accuracy management with a calibration weight. This is one reason that high-resolution balances are needed as mass comparators.

The practical measurement principles of general-purpose electronic balances fall under the following four methods: electromagnetic equilibrium, strain gauges (load cells), electrostatic capacitance, and tuning forks. The technological background of each method will be briefly described below.

1.    Electromagnetic equilibrium: This method uses a fulcrum and lever. For example, an unknown mass is placed on the left side of a lever and a balancing force is generated on the right side of the lever through the fulcrum. Electromagnetic force is used to generate this force. The electromagnetic force mentioned here is Lorentz force, as taught in high school physics classes using Fleming’s left-hand rule. In other words, when current flows perpendicular to magnetic flux flowing in the magnetic circuit, a force is generated in proportion to the current at a right angle to the flow of the current and the magnetic flux. The current required to balance the mass (force) on the left side of the fulcrum determines mass. The resolution acquired by this method is very high for a balance. For a general-purpose balance, the rate of the minimum display value called sensitivity against the capacity is about one over several hundred thousand. Mass sensors that use electromagnetic equilibrium are mainly used for high-resolution electronic balances and there are analytical balances with resolutions of one over several million to several hundred million. Analytical balances used in research require high sensitivity and currently most use the electromagnetic equilibrium method.

2.    Load cells: Using electrically resistant wires called strain gauges, load cells detect the strain caused by a load as a change in the electrical resistance. Several strain gauges are affixed to what is called a spring material, which has a Roberval structure. Since the strain of metal used in the elastic deformation is very small, a Wheatstone bridge circuit is used to detect the difference of the contraction and elongation detected by the strain gauges and increase output level. Commercial products using this method achieve practical resolutions of one over several thousand to a hundred thousand. Electronic balances that use strain gauges are used in a wide range of fields, including part management in production facilities and for academic experiments.

3.    Electrostatic capacitance: This method uses a Roberval mechanism with electrodes to detect capacitance changes in two areas, the area displaced (moveable area) and not displaced (fixed area) by the load. Displacement by the load changes positions among the electrodes. Accordingly, the change of electrostatic capacitance among the electrodes is used to measure mass. Resolution is typically one over several thousand or below so this method is generally used for low-resolution instruments like kitchen and bathroom scales.

4.    Tuning forks: With the tuning fork method, the natural frequency of a tuning fork is changed by tension (load) applied to the tuning fork. For example, a mass is placed on the left side and a vibrating mechanism placed on the right side via a fulcrum. The vibrating mechanism detects excitation and frequency using a piezoelectric element. If the mass is changed, the natural frequency varies accordingly. This results in a change in free vibration frequency with the same excitation, which is used to acquire the mass. Since the frequency is counted to acquire the mass, no analog/digital conversion is required, unlike the three methods above. The tuning fork method has a resolution of one over several tens of thousand to several hundred thousand, giving it a performance level between the electromagnetic equilibrium and load cell methods. It is used as the mass sensor of general-purpose balances.

While the four methods have their positives and negatives, the electromagnetic equilibrium method is fundamentally different from the other three methods from a technical point of view. In the electromagnetic equilibrium method, the force equilibrium is achieved without changing the lever position via the fulcrum. The mechanism is always controlled to return to its original state. This method follows the principles of balances made centuries ago. It is referred to as the null method because the balanced position of the lever is not changed. The other three methods are premised on the fact that the measurement mechanism is somehow displaced. Stated more clearly, they are like spring balances. The mass (load) displaces the measurement mechanism so this method is called the displacement method.

Balances using the null method and the displacement method have very different resolutions and stabilities. The reason for this difference is the mass sensor area, which is completely made of metal. Its elastic limits and mechanical features are too inadequate for the high resolution required for balances. Mathematically speaking, the limits of the displacement method can be exceeded by lowering the amount of displacement and improving the electrical sensitivity. In reality, reducing the displacement to be detected causes a drop in signal level and increases interference from noise. As a result, resistance to interference such as vibration weakens, which causes a significant drop in display stability and response speed. It can be said that the resolution performance of the displacement method is limited due to the features of metal. Until a low-cost metal that is lightweight and consistently high in elasticity is developed, the current practical resolution of one over several hundred thousand is the technical limit of the displacement method.

On the other hand, since the electromagnetic equilibrium method uses the null method, it is not affected by the features of the structural material in principle. Furthermore, a control method is used to constantly monitor the position of the lever. The magnetic damping effect provided by electromagnetic induction in the magnetic circuit makes it possible to provide control feedback at high gain. Because of these benefits, the electromagnetic equilibrium method has the strong vibration-proofing and high-speed response required for high resolution. This is why the high-resolution electronic balances for production lines, which require vibration-proofing and high-speed response, all use the electromagnetic equilibrium method.

The lineup of electric balances that A&D designs and sells are mostly electromagnetic equilibrium and load cell types. Recently, the market has been demanding balances with higher resolution. One reason for this demand is the establishment of Japan Calibration Service System (JCSS) standards for calibration weights and scales. These standards have increased the need for mass comparators, balances that can calibrate counterweights. In addition, demand has risen for high-precision measurement management for production line measuring devices. These requests from new markets mean that there is a need for balances that can display values with an extra decimal place over current general-purpose balances.

These demands pushed us to develop mass comparators using the GX/GX-K Series of general-purpose balances, which use the electromagnetic equilibrium method. In fact, the ability to stably display an extra decimal place was confirmed when product development started 10 years ago. However, the difficulty of dealing with corner errors and achieving adequate performance over the entire weighing capacity resulted in the product being shelved as a general-purpose product. This time, thanks to a complete set of options like the auto-centering pan, the MC Series is able to handle these issues. The specifications of the four models available at launch are listed below, and the maximum resolution is 1/10,000,000.

Model             Capacity           Minimum display          Resolution
MC1000             1 kg                    0.1 mg                     1/10,000,000
MC6100             6 kg                       1 mg                        1/6,000,000
MC10K             10 kg                      1 mg                      1/10,000,000
MC30K             30 kg                    10 mg                        1/3,000,000

Using the four models above, it is possible to perform calibration of standard weights from 500 g to 20 kg, which are OIML standard F1 level or lower (F2, M1, M2). We intend to expand our range of models of high-resolution balances to meet future market demands. We hope these new products are used not only as mass comparators for calibration weights, but also as equipment for testing and research, new fields in which Japanese companies are strong, and for quality control and production lines in production facilities. This will help create new measurement instrument markets and contribute to improved quality and productivity in the workplace.

Development of the BM Series of Analytic Balances

A&D has been developing electronic balances since its inception 30 years ago. When the company was founded, it felt as if the company was always trying to catch up with industry leaders, who had over 100 years of experience. However, the company’s establishment coincided with a period of advancements in the digitization of measurement devices. Furthermore, we seriously pursued cost performance by both drawing out basic performance and cutting costs. This increased profits in a comparatively smooth manner short time after the company was founded. As a result, our share of weighing instruments in Japan is over 60% based on units sold. However, the high-precision end of our lineup has only reached semi-micro analytical balances with a minimum display of 10 µg.

There are currently no manufacturers producing micro-balances in Japan and there are only a few recognized manufacturers in the world. That is why entering the micro-balance market has been a longstanding issue for A&D. While the economy still has not recovered from the effects of the financial crisis of 2008, crisis can present opportunity. We felt that it was imperative for us to develop micro-balances in Japan, so several years ago we started product development.

During development, we focused on measurement performance, which we felt was the most important issue. In other words, our main goal was to somehow decrease the various disturbances that cause trouble during measurement at the microgram level, and yet make the balance easy to use. We knew from our experience producing balances that static electricity is the biggest problem for analytic balances with a minimum display of 0.1 mg or less. We have established that the biggest cause of error when measuring in the winter on the Pacific side of Japan, where the humidity is 40% or less, is static electricity, not only from the sample being measured, but also from the user.

In addition to static electricity, a slight temperature difference between the sample and atmosphere and the resulting convection also cause measurement errors. Buildings swaying from wind or vibrating slowly after earthquakes can also cause unstable measurements. People are generally not conscious of low frequency vibrations or static electricity, so the resulting unexplained variation in measurement results is seen as a hard-to-solve problem unique to the site.

There are three ways to eliminate the abovementioned problems (excluding vibration): (1) proactively eliminate static electricity from the sample, (2) reduce the influence of breezes, including convection from heat, and (3) shield the balance from external static electricity. When we set out to develop the new balance, we aimed to add these three features. It took three years to realize these advanced functions as we tackled these issues one by one. A fanless, direct-current ionizer to powerfully eliminate the charge of the sample without generating a breeze and a dedicated anti-static chamber were installed. A double-ring breeze break structure was used to retain usability. A glass breeze break with added electrical conductivity was used to create a strong shielding effect against external static electricity sources, including the operator.

The development of these technologies led to the release of the BM Series of micro-balances. The BM Series of analytical balances has many advanced functions. It can eliminate charges of several kilovolts from items in one second or less without generating a breeze. Its (open-space) weighing chamber, with no secondary breeze break inside the breeze break, retains a level of usability comparable to standard analytic balances and is capable of a repeatability of 2.5 µg. Finally, its static shielding keeps measurement values stable even when the user, who may have a charge buildup of 10 kV, comes near.

The BM Series has six models with a maximum resolution of 1/25,000,000, with the 3 main models having high resolutions of 20 g x 1 µg, 250 g x 10 µg, and 500 g x 0.1 mg. This series is positioned as an advanced analytic balance that can measure at the microgram level but is available at a reasonable price.

We envision the BM Series being used in many fields. For example, it can be used for measurement of dust required for environmental measurements, PM measurements as prescribed by European automobile gas emission regulations (Euro4, 5), sampling and injection for chemical analysis, and the management of micro-coating amounts, micro-extractions of powder, and quantity management of coating material.

We can see several target users for the BM Series. This includes researchers using current semi-micro balances (10 µg) who want to move up to measurements of 1 µg and quality control staff who want stricter measurement accuracy but are unsure about using the expensive micro-balances currently available. The BM Series provides these users with balances with the same level of usability as existing balances but a better level of precision. By stressing its quality performance, we hope that the BM Series will be widely known as an analytic balance that stresses performance and contributes to the analysis field through its strong cost performance.

Development of the Top-Loader Type Analytical Balance

In this installment, I would like to summarize the development of the HR Series of analytical balances, which occurred 17 years ago. The main focus will be on top loaders and new projects.

The HR Series is A&D’s first analytical balance with the same construction as a general-purpose balance. This development story starts about 20 years ago, just after I joined A&D. During the development of this new product, I experienced success and failure and learned many important lessons. The following are the events that occurred during this development.

In the balance industry, balances with a minimum display lower than 0.1 mg are called analytical balances. Nowadays, top-loader analytical balances make up a majority of the analytical balance market and can be considered the mainstream type. However, top-loader analytical balances had just made their first appearance when we developed the HR Series. As the name “top loader” implies, these balances have a weighing pan on their top surface. The term has become an industry term for current general-purpose pan balances.

When I joined A&D, the structure of general-purpose and analytical balances were clearly different. Most general-purpose balances were top-loader models. Meanwhile, analytical balances had a breeze break in front and a large weighing sensor in back. Stretching from this sensor area in the back to the breeze break (the weighing chamber) was an arm, which held the weighing platform on its tip. At the time, all analytical balances were built like this, and the industry took it for granted that analytical balances had this kind of structure. This was around the end of Japan’s economic bubble and when I had taken charge of and finished development of a general-purpose balance series, which is the HX Series, for the first time right after joining the company. The HX Series was a multi-function device. It used finite-element magnetic field analysis software that I had created and it had been newly designed from the magnetic circuit. I was proud of my work. However, its extravagant specifications and attendant high prices doomed it to failure. It sold poorly outside of automatic units for production lines, where it was praised for its quick response.

While the economy of the time is a factor in whether a product is successful, spending over 2 years and 100 million yen to create a product I was really proud of and having it not sell was quite troubling. Fortunately, the HX Series contained the HX-100 model, which had a capacity and minimum display of 100 g and 0.1 mg. At the time, it was rare for a top-loader analytic balance to have a capacity of 100 g. The fact that the development of the series produced a model with specifications of 100 g × 0.1 mg was evidence that the HX Series was of high quality. This experience, along with a review of our desire to make a sellable product based on the weighing sensor I spent so long developing, resulted in the idea of making a full-fledged series of analytical balances along the lines of the HX-100.

Compared with traditional analytical balances, top loaders have half the material costs, including the sensor area. For argument’s sake, if I could get a performance level of 0.1 mg at a capacity of 200 g, which is typical of analytical balances, the top loader would be an extremely attractive product owing to its excellent cost-performance ratio.

I therefore performed testing to confirm a basic performance level of 200 g × 0.1 mg with the goal of developing an analytic balance based on the HX-100. The results determined that there was potential for a commercial product. I later had a meeting with the sales department related with the new product to present the data and propose a project for the new product. I felt that contents of my presentation showed the promise and I was sure that the project would be endorsed at the meeting. However, the reaction within the company was quite surprising to me. I was showered with negative criticism such as, “there’s no way you can make a general-purpose, top-loader type analytic balance; putting out a half-baked product would just lower our market reputation”, and “the structure of analytical balances is fixed, customers will never accept a top-loader analytic balance”. In the end, I was told to stop development on the new product.

Obviously, I was disappointed. However, I didn’t have enough experience or ability to object and publicly accepted the official decision of the meeting. Privately, I refused to stop development and continued testing behind the scenes. After a period of constant worry, things eventually turned around.

The cause for this was that our European competitors took the lead in the market and started offering top-loader analytical balances at a low price in the Japanese market. After this, people in the company who opposed the commercialization of top-loader analytical balances disappeared.

In a comparatively short time, A&D completed its first top-loader analytical balances, the HR series, and put them on the market. The HR Series gradually became known in the market for its high cost-performance ratio. While 20 years have passed since sales started and our competitors have changed all of their products to new models, the HR Series remains a strong performer, with sales of several thousand units per year.

The fact that the series has maintained its marketability for so many years is evidence of its excellent integrated ability at development, including its performance, price, and specifications. The fact that it has been a consistent seller over the years makes me feel as if the development was blessed. Later on, the GR Series of semi-micro balances, which is a top-loader model with a sensitivity of 0.01 mg, was developed based on the HR Series. Recent top-loader products have reached the microgram level using the SHS/C-SHS, a next-generation sensor.

The experience of developing the HR Series played a large role in the development progress of these new products. It is often said that project and technological ideas that are unanimously approved at meetings never succeed. This occurs because most of the people at the meeting are naturally field specialists who understand the status quo, which becomes the criteria of evaluation. At such times, new projects designed to change the status quo no surprisingly run against conventional wisdom. Naturally, when the status quo is the reference point, these new projects can come off as bizarre ideas. This phenomenon seems to happen in many aspects of life, not just business.

The number of Japanese conscious of innovation is decreasing and a long time has passed since Japan became a country of critics. As a result, the allowance for change in society is declining and there is an increased sense of stagnation. This may go beyond this discussion but if a manufacturer’s developers are not innovators, there is no way to develop new products. If the next generation of engineers maintain their personal beliefs and develop the ability to plan new products in the course of day-to-day activities, I feel that business results will improve. I also think that this will finally reinvent the stagnating Japanese economy and society.

I am placing my hopes on the good sense and great efforts of the young engineers who will lead society forward, and, in some sense, stubborn individualists.

Development of the AD-1688 Weighing Data Logger

On a visit to a user who makes weighing instruments a few years ago, I was asked if there wasn’t an easy way to record the weight value displayed on balances.

At this site, they were using balances for measurement work. They wrote down the weight data and then manually entered it into a computer. The manager told me he had 3 problems: the work was too labor-intensive, errors sometimes occurred during the handwriting and manual data entry process, and it was a pain to carry the computer to the weighing location. Thinking about the user’s requests, I could see that simple paper-based records were not enough to get the job done. Many people enter large amounts of weight data into a computer, save it as files, and then make reports and presentations. I also realized that it was important that the PC input method be as easy as using a USB memory device.

USB memory can be used to pass data between computers as a batch without need for special software. Consequently, the AD-1688 weighing data logger we planned for development used dedicated cables to send weight data from the communication port of a weighing device (balance or scale) to its stereo jack and then to directly transfer this data to a computer via a USB port. All of this was done without any special software.

This idea was commercialized and resulted in the ability to batch connect weighing devices and computers just like using a USB memory device. The weight data imported into the computer could be directly entered into any open program, such as an Excel sheet or notepad application. Again, this did not require any special pre-installed software, making it a very convenient recording media.

For portability, AD-1688 was made about the size of a business card and the weight of a large egg (60 g). The unit also included a protective cap for the connector. When used, the unit met IP65 specifications (dustproof and rainproof), making it easily pocketable.

Mr. Dodate of the R&D division 5 was responsible for the mechanical design. He used 3 cases, including the cap to protect the communication ports, to achieve this dustproof and rainproof construction. The assembly does not require a single screw. When people see the finished product, the case structure seems ordinary, but completing the proposed new assembly and insertion case was a lot of hard work.

There has never been a product like the AD-1688 on the market. All manufacturing, from PCB wiring to assembly and outgoing inspection, has been entrusted to a high-quality factory in Mr. Dodate’s home prefecture of Akita.

The reason that domestic production was chosen was to speed up the product development cycle. In other words, it was decided it was best to increase focus on fundamental development work by cutting out the extra time and quality control issues that come with overseas production. Even industrial equipment, which is limited run unlike commercial-off-the-shelf products, naturally requires cost cutting. However, as a Japanese manufacturer, we prioritize guaranteed product quality over mass production efficiency and decided it was best to concentrate resources such as time on planning and development of new products.

We expect the conveniently handy AD-1688 weighing data logger to be recognized as a high-value product for wide use in the management of research and production lines and solve problems you might not even know you have.

Development of the FZ/FX-i Series of General-Purpose Balances

A&D developed and released the FZ/FX-i Series of low cost, general-purpose balances as an entry-level version of the GX/GF Series in 2006. When A&D entered the balance market about 30 years earlier, it captured a tremendous share of the measurement instrument market for the first time with the release of the previous FX/FY Series. We decided it was necessary to widen the selection of models for users and released the new FZ/FX-i Series, with the GX/GF Series being an advanced version of our general purpose balances.

Another important issue was redevelopment of the FZ Series. This series had an internal calibration mass and was intended to be an advanced model to the previous FX/FY Series but never made it to market.

The new FZ/FX-i Series had three development objectives.
1)  Thorough cost cutting, including in the cost of the sensor, and improved quality of the internal calibration
    mass mechanism
2)  High-speed response (weighing in 1 second or less like the GX/GF Series)
3)  IP65 dust and waterproof configurations (The world’s first waterproof general-purpose scale with a minimum
    resolution of 1 mg)
All these objectives were achieved, but here I will focus on summarizing the development principles and important points with regard to cutting costs.

This is always a matter of debate within the company, but it is often said that cost-cutting discussions have nothing to do with customers and should not be mentioned publicly. However, manufacturing in Japan has started to decline in recent years and the root causes are considered to fall under the following 2 points.
– The cost of finished products made in Japan is no longer a competitive advantage in the international market.
– Products based on technology developed in Japan do not succeed in the international market.

While Japan disseminates a lot of new technology, other Asian countries continue to grab the world market from it. This is in part due to Japanese business practices, particularly in industry, that make the incorporation of new products and ideas difficult. Furthermore, conservative management decisions and a tendency to overlook technology mean that technological success is not linked to market success.

As most people know, Japan has a history of leading technological development. In the past, it was DRAM. More recently, it has been flat panel technology (for mobile phones and liquid crystal televisions) and solar power. Going forward, it will likely be secondary batteries and LED lighting. Despite these technological successes, Japanese electronics manufacturers are clearly being beaten in the world market.

This may go beyond the scope of this article, but even if Japan completely loses the market for finished products to other Asian countries, it is important to remember that a significant portion of components of the products mentioned above are made in Japan. This includes the raw materials and assemblies, in addition to the manufacturing machines and the analyzers that measure the performance and quality of components and products.

In other words, in fields that demand simplicity, advanced functionality, and low cost we find that Japanese manufacturers have maintained their centuries-old pride in quality and remain market leaders. For example, if manufacturers want to stay in business, they must continually cut costs while maintaining part performance to keep cost performance high, and the field of electronic balances is no exception. To achieve this, developers set goals for performance and cost reduction as high as they can, and whether they can achieve them is an important piece of the product development puzzle.

It is said that 80% of cost and quality is determined at the design stage. Looking at what was mentioned above from another angle, we can see the accuracy of this expression.

With this background, the development of the FZ/FX-i Series involved further miniaturization of the Super Hybrid Sensor (SHS) used in the GX/GF and the increased use of precisely pressed parts to reduce machining costs.

Furthermore, to reduce the use of expensive die cast case parts, they were used for the top of the case only, with pressed stainless steel parts used for the bottom. All parts, including the mass sensor, internal calibration mass mover, and electric board, were hung from the rigid upper case. Even the miniaturization of the magnetic circuit in the sensor area, which contains expensive rare earth magnets, was subject to cost cutting and it was necessary to achieve the required high rate of leverage. Consequently, a double lever with two fulcrums was created and a structure that unified the fulcrum and tension flexure (hanging band) of the secondary lever was proposed. To realize this, an integrated precision press part was used for the first time in the industry. These press parts were metal plates with a thickness of 1 mm punched to a width of about 0.3 mm. In the industry, it is generally recommended to press at a width greater than the thickness of the plate, so these parts have exceeded technical limitations. Thanks to these advances, we succeeded in making the cost of the mass sensor of the FZ/FX-i Series 1/4 the cost of the mass sensor on general-purpose balances before the development of the SHS. One additional task involved the internal calibration mass mover. Here, we switched from using an expensive, frequently faulty gear motor that raises and lowers the weight by cam to a direct acting pneumatic mechanism that uses a pressure pump and cuff (accumulator) from blood pressure monitors.

This allowed us to greatly cut the cost of the internal calibration mechanism as well. A by-product of using pneumatic pressure was the elimination of uncertainty regarding the position of the internal mass when the power is suddenly turned off. Since the pressure is always released when the power is switched off, the internal calibration mass returns to a specified position and does not load the mass sensor. This greatly reduces damage to the sensor at times like shipping. Failure of the internal calibration mechanism makes weighing itself impossible and our solutions successfully eliminated these problems. The ingenious idea to use pneumatic pressure is a good example of how a new idea can cut costs and guarantee fail-safe operation in the workplace.

Up until now, A&D balances for the Japanese market, with a few exceptions, have been completely made in Japan. While domestic production has been declining in Japan, we still believe that the cost and quality of a product are mostly determined during its design. By coming up with original ideas, as well as understanding and using the manufacturing support infrastructure that remains in Japan, we will continue to create products based on the technology and social infrastructure of Japan, and in our own small way contribute to the preservation of industry in Japan. With technology and domestic infrastructure as a base, we will sustain manufacturing in Japan and provide new products to the world market.

Development of the MX Series of Heat Drying Moisture Analyzers

This is the fourth installment in a series of development stories and summarizes A&D’s development of a heat drying moisture analyzer.

A&D has been developing scales and balances since our inception 34 years ago and has been manufacturing weighing equipment for over 30 years. In the beginning, our low name recognition made it difficult to sell products based on the A&D brand and we often entered into OEM supply arrangements with partner companies as a result.

This was also the case for heat drying moisture analyzers where mass measurement technology is used, and we supplied only the mass sensors for a long period. Technically speaking, heat drying moisture analyzers are composed of a heater and a highly sensitive embedded balance as its mass sensor. This combination of a highly heat-susceptible balance and a heater that reaches a temperature of 800 °C presents many design issues.

Addressing these issues to suppress the temperature conditions that are so harsh for the balance requires a complete design solution. Consequently, we were concerned for many years that supplying the mass sensor elements alone limited the completeness of a product. As a result, about 8 years ago, we decided to take up the challenge of creating a product using 100% A&D technology that produced the ultimate level of performance in the environments where moisture analyzers are used.

When we were planning development, there was a manufacturer with overwhelming share and name recognition in the heat drying moisture analyzer market in Japan. This caused some within A&D to say that market reception and sales would likely be poor if we released a product under the A&D brand, no matter how distinctive it was.

Nevertheless, we held the opinion that the market always recognizes sophisticated, high performance products available at a low price and moved forward on the difficult road of product development. This included establishing our own heating technology, since our department did not possess any.

The first obstacle was the cost of the halogen heater. While there were other heating methods available, including infrared lamps and sheath heaters, we decided it was best to use a halogen heater since we felt that the demand for short measurement times would grow stronger in the future.

There were several leading products in the market that used horseshoe-shaped halogen heaters around the outside of the pan to ensure even temperatures over the surface of pan, but we found these horseshoe-shaped heaters to be extremely expensive. Alternatively, when low cost, straight halogen heaters were used, several heaters had to be lined up to heat the pan surface evenly. On top of this, no which method we used, we found it hard to heat the pan surface evenly and we were unable to eliminate uneven heating. We were also concerned that these complex constructions would drive production costs too high.

Another problem with these existing designs was that the halogen heater and the heated sample share the same space. If volatile portions soil the halogen heater, the halogen cycle might break and cause the heater to burn out or the level of heat generated might drop. Obviously, we were concerned about the problems this would create for users.

Right from the start of development, we thought that somehow a single straight halogen heater could heat the pan evenly. Looking back now, this was a quite bold proposition. At first, we considered using a reflector to reflect the light and devised various ideas for the material, surface reflection, angle, size, and shape of the reflector. Still, we were not able to prevent the single straight burn line that was left on the sample on the pan.

After reviewing the reasons why the pan surface was not heated evenly, we thought that the problem might be that the light (heat) of the heater was hitting the sample directly. Instead of using a reflector, we decided to place glass in between the heater and sample. The glass receives the light, increases in temperature, and gives off secondary radiation. Accordingly, we later named this method Secondary Radiation Assist (SRA).

Since the heat-resistant glass is under the halogen heater, it receives the light before the sample. The glass is thermally conductive so its surface heats up evenly and its secondary radiation spreads uniformly over the entire pan. While making several prototypes, we performed tests with corn grits on the pan. When the corn grits were baked evenly and the color of the entire surface changed, we realized that we were on our way to developing a new type of moisture analyzer.

Heat drying moisture analyzers produce volatile components during heating and are therefore the measurement equipment that is most susceptible to soiling. A by-product of using the SRA is that contamination sticks to the glass of the SRA instead of the surface of the heater. Since the easy-to-clean flat glass of the SRA prevents contamination, lamp exchanges are greatly reduced, resulting in reduced management costs and maintenance time.

The unit also has seven layers of insulation to protect the heat-susceptible balance from the 200 °C temperature of the pan. We were able to perform temperature correction in the optimal locations of the balance and achieve a final sensitivity of 0.001% (10 ppm). Our top-class MS70 unit has a sensitivity of 10 ppm and can be used to manage the moisture of plastic material (resin pellets) before the injection molding, which many considered impossible with heat drying methods. We consider the performance improvements of measurement equipment that resulted from the development of the MS70 to be a good example of pioneering and shaping new markets from new measurement possibilities.

We also developed Rs-Temp, software designed for product usability in basic operations and beyond. It automatically finds the optimal heating temperature for unknown samples in 30 minutes and has excellent graphical functions to visualize moisture rates in real time. This software is included as standard on a CD-R. Also included as standard is sodium tartrate dihydrate, which is provided as a reference standard for moisture rates due to the crystallization water in its molecular structure. We believe that the standard inclusion of sodium tartrate dihydrate acts as our guarantee as a manufacturer and shows our accountability for product performance.

As we have proposed and realized the above solutions at a reduced cost, the market has steadily acknowledged our success and made A&D into a recognized brand. As evidence of this, we hold an overwhelming market share in Japan for moisture analyzers with a resolution of 0.01%.

In summary, the development of the MX series of moisture analyzers has shown us that to succeed in existing markets it is crucial to challenge the status quo, pursue the necessary performance standards and underlying needs of products, and propose concrete solutions.

Development of the SV Series of Tuning-fork Vibro Viscometers

A tuning fork vibration viscometer is not the kind of product you hear of very often. This is not surprising since, while there are many viscometers available, A&D is the only company in the world making and selling viscometers based on our unique tuning fork vibration technology. Viscometers in labs and research facilities are typically capillary or rotational types. Several companies make vibratory viscometers for production lines, but these use a rotary reciprocating motion with a high frequency of several kHz. Only A&D makes a model that uses a low frequency reciprocating motion like a tuning fork.

A tuning fork generates sound using the phenomenon of resonance at the same frequency. A tuning fork-type viscometer resonates its sensor plates at a natural frequency like a tuning fork and determines viscosity from the drive force (electromagnetic force) required to maintain constant amplitude. This method gains its high sensitivity from its tuning fork structure.

Technology to resonate an oscillator at the relatively low frequency range of 30 Hz was difficult to develop and had never been used in a product, even more than 50 years after the theory was developed. About 20 years ago, a cement company proposed a viscometer using this method and then about 15 years ago joined with A&D. By that time, however, the person responsible for the development was no longer with the company and work on the technology had stalled.

At that time, the product was still in its early stages so its viscosity measurement range was narrow and its cost was high. As a result, only about 10 units were sold a year. Later, another section within the company spent about 5 years trying to redevelop the technology but failed to complete a finished product. Then one day, the company president came and asked me to complete the vibration-type viscometer and so our section took up development of the viscometer.

Over five years of development had already been done in-house and the product had reached the pre-production stage. However, the development team that had worked on the project up to that point had broken up before the product was completed. It was surmised that pressure of product development might have been too mentally stressful for the development team.

When we first started development, things were a bit like a scavenger hunt. In the remains of the troubled project, we found a few completed items, like die assemblies. In the end though, most of the non-structural, technical elements had to be newly developed. Thankfully, our department was able to apply the technical expertise it had gained from developing digital balances. We were able to adapt the fulcrum used with digital balances and reused balance technology for the voice coil elements of the electromagnetic drive member. One particularly difficult area was the electronics. Even here, we were able to adapt the high resolution A/D converter technology of our electronic balances to achieve a high level of sensitivity. In the mass production stage, we struggled with issues such as getting a resonance point of 30±0.02 Hz, but ultimately we leveraged our electronic balance production technology to produce a new viscometer that had the same high accuracy and low cost as our balances.

The target viscosity measurement range was 0.30 to 10,000 mPas, with a minimum and maximum display of 0.01 mPas and 10,000 mPas, respectively. Technically speaking, the resolution was 1/1,000,000. There had never been a viscometer with such a high resolution, nor one that maintained a low viscosity sensitivity of 0.3 mPas and yet whose measurement was easy and stable.

To put a viscosity of 0.3 mPas in more concrete terms, water at 20 °C has a viscosity of approximately 1.0 mPas, meaning a viscosity of 0.3 is about 1/3 the viscosity of water. This is close to the viscosity of acetone, the liquid with the lowest viscosity. This excellent sensitivity made it possible to measure viscosity at a level that had been impossible up until that point.

After we completed the development described above about 6 years ago, we started selling the SV Series of tuning fork　vibro viscometers as a new type of viscometer. There was quite a bit of skepticism toward this new type of viscometer as a general-purpose viscometer and the series did not sell well in the Japanese market early on. However, there were researchers who were unhappy with existing products and they quickly accepted the new viscometer, thanks to its ability to measure a lower level of viscosity and perform consecutive viscosity measurements over temperature changes and state changes from liquid to solid, which other viscometers had been unable to do up until that time.

The series was also well received in the European and other foreign markets. A manufacturer famous for measurement devices for particle size distribution found them excellent as a viscosity measurement method for base materials that determine Brownian motion, and SV was quickly set up as an optional device. As a result, the SV Series gradually gained acceptance as a viscometer. In the last few years, the SV Series has been recognized as part of the viscometer market, which is attested by the fact that, for example, the series is a recommended measurement instrument for oil viscosity at a leading oil company in Japan.

Our tuning fork vibro viscometer is already listed as a measurement instrument compliant with Japan Calibration Service System (JCSS) viscosity standards and the process for Japanese Industrial Standards (JIS) standardization is underway. Furthermore, we have proposed that the physical value measured by vibratory viscometers (viscosity x density) be described as “static viscosity” to distinguish it as a new concept separate from the established values of kinetic viscosity and viscosity.

A&D has considerable experience pioneering and expanding Japanese technology overseas. Considering that this tuning fork vibro viscometer was developed from unique technology developed in Japan and that the vibration method can measure a new physical quantity (static viscosity), we believe it best to quickly establish standards in Japan first. After that, we would like to proactively promote this new method to the rest of the world and let people know about the measurement abilities of our tuning-fork vibro viscometer.

Development of Mass Sensors for Precision Balances

In 2000, we started selling the GX / GF Series precision balances. Thankfully, the series has been well received by users and continues to sell today even 10 years after its debut. Three years ago, we developed and released the FZ-i / FX-i Series as a line of more economical precision balances. The GX / GF Series and the FZ-i / FX-i Series incorporate mass sensors, the Super Hybrid Sensor (SHS) and the Compact Super Hybrid Sensor (C-SHS) respectively. This time, I would like to talk about the background market demands, development processes, and technical solutions concerning these sensors.

In the past, the leading challenge in developing balances was the ability to measure a minute weight value in a stable manner, and it was recognized that balances required a long time to display a stable weight value. Nowadays, however, manufacturing is highly sophisticated, and it is increasingly necessary to achieve both high-level quality control and high productivity, two seemingly irreconcilable propositions.

It took us around two years to develop a mass sensor that could meet such demands, which became the SHS. When we were developing the SHS, it was generally believed that balances could not be used in production lines. This was because precision balances (e.g. 3 kg capacity × 10 mg readability) of the time would take 2 to 3 seconds before the weighing value became stable, but most production line systems required an operation cycle of one second or less. Meanwhile, it was said, and still is even today, that mass measurement is the most sensible way to judge and control quality precisely and at a low cost. This is attributable to the fact that mass measurement realizes a level of control that is beyond the capability of a CCD camera. Examples include monitoring internal defects of tablets or porosities of precision die-casts, or controlling minute applications of oil or grease.

The development of the SHS involved a hybridization of a high stiffness spring material used for load cells and a high-resolution electromagnetic component used for electromagnetic balance sensors. There was no precedent for the combination of Roberval-structure spring material and an electromagnetic balance component, and many engineers here at A&D were in fact against the idea. However, if we had gone as far as to integrate everything from the Roberval structure, fulcrum flexures, tension flexures and beams, as was proposed by several manufacturers already, there would have been various obstacles, such as difficulties in production and repair, and limited choices in processing method. Consequently, we would have had to procure expensive materials and then force the extra costs on end-users in the form of more expensive goods.

Hence, we deliberately did not integrate the structural materials that break easily, such as the fulcrum and tension flexures, and left them as independent elements. Moreover, we adopted a unified Roverbal structure, which had a strong history with load cells using strain gauges and was easy to mass-produce, and thereby cut down the production cost as much as possible. By these means, we successfully established the SHS technology as our unique mass sensor. After some improvements that we made later to the SHS, we have now commercialized high-sensitivity balances with (1) a high stabilization speed of 0.5 seconds, (2) a high resolution of 1/1,000,000 (1 kg capacity × 1 mg readability), and (3) a readability of 1 µg. Furthermore, we also developed the C-SHS, whose production cost is even lower, and incorporated it into the FZ-i / FX-i precision balances. With the C-SHS, we were able to reduce the cost of a weighing sensor by three quarters compared with old electromagnetic balance sensors made before 2000 and accentuate user-friendliness in the field, including ease of maintenance.

Apart from the precision balances, the SHS has also been applied to moisture analyzers of the heating and drying method, the AD-4212 Series, which are special weighing instruments to be used in automated machines in production lines, and accuracy testers for pipette volumes. The scope of its applications continues to expand.

These are our basic observations of the development of the SHS. To tell you the truth, however, when we started the development, we were being pressured by the trend toward the sophisticated integration of sensor components as proposed by our competitors. We were also criticized by the sales division, who said that A&D would fail to stay current with the market and technology if it employed a hybrid sensor. We were in a tight spot as engineers.

I remember that we felt we had no way out and were agonizing every day to find solutions. One day, while I was in a bus during a trip to Europe, I came up with the idea of intermediate integration, which marked a clear difference from full integration. Building on this idea, we kept creating further solutions and finally arrived at a new principle, which was the SHS as it is today.

We repeated testing with trial samples for about two years, and we were very happy when we achieved target specifications. Fortunately, the move from the trial samples to the ramp-up of the GX / GF Series as new precision balances went fairly smoothly, as we were able to utilize our existing infrastructure of highly advanced production engineering as well as gather our in-house elemental technologies of hardware and software.

Based on this experience, we again realized that when working on a difficult theme such as developing a new sensor, it is important to face reality and accurately grasp the situation in order to inspire ideas, and then work continuously to realize those ideas.

Development of Production Line Weighing Instruments

We have developed high precision weighing sensors, the AD-4212C Series, that satisfy the requirements of production line systems.

While the economy in Japan has long been struggling, certain market segments, albeit not many, continue to grow. These include the industries of primary and secondary batteries, solar batteries, flat panel displays (FPD), and light emitting diode (LED) lighting. These growing markets are linked to environmental issues and predicted to maintain a high growth rate into the future.

In a growth industry, development of products that offer something new is always a focus of attention. At the same time, however, it is important to consider how to ensure quality, which influences both product performance and productivity. For lithium-ion secondary batteries in particular, the quantity of encapsulated electrolyte greatly influences performance in various ways. Likewise, controlling the quantities of resist-ink injected into panels, resin used for coating, adhesive, and solder paste in production lines is considered increasingly important.

Consequently, such production lines require compact weighing instruments that are highly precise, responsive, durable, as well as resistant to dirt. The AD-4212C Series was planned and developed as a product that can satisfy all these requirements for production line systems. Specifically, the weighing sensor has a width of 59 mm, so that a pitch of 30 mm is possible when aligned in two rows, head to head. As an example of its responsiveness, the model with 600 g capacity and 1 mg division (1/600,000 resolution) has a stabilization speed of 0.5 sec., currently the fastest in the world for this kind of range. Furthermore, the product is protected against dust and water at the IP65 level (meaning it withstands water jetting from any direction), another aspect unique to A&D for weighing instruments with a sensitivity of 1 mg. As for endurance, it has withstood 1,000 repeated measurements in our on-going endurance test, and our goal is to achieve 100 million repeated measurements, which will take about two years. Since the AD-4212C Series is meant to be installed and used with multiple units in concentration, we adopted the form of an electromagnetic digital load cell (EM-DLC) so that digital weighing data is output directly from the weighing sensor. In addition, we set up CC-Link and BCD output options using a special remote controller, the AD-8923.

In order to realize the many specification targets set for the AD-4212C Series, we had to solve a number of difficult problems: (1) optimizing the mass sensor (hardware), electric circuits, and control software to obtain an ultra-fast response, which is a feature of the electromagnetic sensor, (2) installing a shock absorber in a narrow space to heighten durability, (3) decreasing the width of the Compact Super Hybrid Sensor (C-SHS), which is used in our existing precision balances, (4) placing a diaphragm for waterproofing around the pan-support boss, and (5) internalizing all the electric circuits into the weighing sensor. It was particularly difficult to place a diaphragm around the pan-support boss while still attaining a sensitivity of 1 mg to achieve the contradictory goals of high environmental resistance (against dirt) and high precision. By reconciling these two conflicting factors, the AD-4212C Series defies the conventional wisdom of the weighing instrument industry.

We hope that the AD-4212C Series will be useful not only for automatic manufacturing machines, but also for applications under special environments such as a vacuum, help improve the quality and productivity of components for devices that reduce CO2, and become a tool to advance technologies in new fields in future industries.

Development of Devices for Pipettes

A&D now offers pipette accuracy testers and leak tester for pipette inspection.

For the development of the series of pipette accuracy testers, we considered pipette calibration business prevalent in Europe, and adopted the gravimetric method, which uses a balance for volume verification. The leak tester and the pipette accuracy testers offer a new way to routinely manage pipettes on-site through leak tests and dispensed volume measurements. In particular, the leak tester AD-1690 is the world’s first product that easily detects leakage in a pipette including the area around its piston and enables the user to judge quickly whether the pipette can be used or not. Although the functions of the AD-1690 are rather simple, we are confident that the product goes a long way in relieving the accuracy concerns of users.

A&D has been developing electronic balances since its establishment more than 30 years ago. By leveraging our balance technology, we have also made efforts to cover more types of physical quantity measurements. For example, we have released such products as moisture analyzers and viscometers to measure moisture rates and viscosities of substances. This time, our focus was on the development of a device with a new function, the measurement of volume dispensed from pipettes. In order to obtain volume from mass, it is necessary to know the density of the measured liquid beforehand. Distilled water is generally used to determine pipette volume since its physical properties are well defined. The conversion factor from mass to volume is called the “Z factor.”

Our developmental challenges revolved around three points. First was the calculation of the Z factor. Second, a balance readability of 1 μg (1 nL) was required. This was necessary because high precision pipettes (called micropipettes) at their smallest have a nominal volume of 2 μL, which requires a display readability of 1 nL (1 μg) for accuracy verification. Finally, a means was necessary to minimize water evaporation during the volume measurement without compromising operability.

The second point was especially difficult and took time to resolve. For one thing, A&D had never produced a balance with a display readability of 1 μg. Furthermore, the balance had to be small and portable so that accuracy verification could be performed at the different locations pipettes are actually used. We solved these problems by adding another decimal place to the existing AD-4212B, which was a production line balance with a readability of 10 μg.

For an ordinary balance, linearity is required for its entire weighing range and a stable weighing result has to be displayed for a certain period. However, quick weighing with a high sensitivity equivalent to a mass comparator is preferred when weighing minute volumes. We developed special software that calculates the Z factor, detects the stable mark display of the balance, and imports the weighing data automatically. Using this software, we achieved measurements of 1 μg (1 nL) with high stability and repeatability. Moreover, we also developed our unique evaporation trap, which, while allowing easy access for the tip of the pipette, passively controls the evaporation of the test liquid inside. The evaporation trap was made a standard attachment for the pipette accuracy tester to reduce the measurement uncertainty.

Technologies for minute volume measurements have yet to take root in the market. We hope that our leak tester and the accuracy testers will be used for the daily, on-site management of pipettes to help provide compliance with ISO regulations, GLP, and SOP, and enhance the quality and productivity of research.