A robot that automatically measures viscosity and pH

This technology automates the entire series of processes involved in testing, from opening and closing sample containers, taking measurements, washing and drying measurement devices, and sending on the measured data. Capable of continuously measuring up to 60 samples in succession. The installation of this technology has resulted in a reduction in the time spent on evaluations, which can account for as much as 40% of a researcher’s daily work hours, thereby generating time for creating new value.
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Automating Crucial Work

Lion develops a broad range of products. For example, even when it comes to a single detergent, there are various purposes, usage locations, and methods of use.

Viscosity and pH are key factors affecting the function of liquid detergents. For instance, with laundry detergents, pH influences the effectiveness of stain removal from clothing. Viscosity is also engineered with ease of use by consumers in mind. For example, dishwashing detergents are often mildly viscous so that they adhere to sponges without dripping off like water. On the other hand, consumers might become frustrated with a fabric softener that takes time to pour into its measuring cap due to its being too viscous.

Measurements of pH and viscosity are thus an indispensable, albeit routine, part of the product development process. Throughout the product development process, many candidate formulations must be designed with the measurement of pH and viscosity being a necessary step for almost each one. To ensure that a desired performance is attained and maintained for the duration of a given storage period, virtually every candidate formulation must be tested. If 20 different formulations are to be tested with regard to 5 different criteria, this means that there will be 100 samples to be tested.

Until now, Lion’s laboratories have measured the pH and viscosity of each compound one by one by hand, a process that often takes more than half a day. In fact, when the time invested by each individual is totaled, the annual amount of time spent on pH and viscosity measurements can exceed 5,000 hours.

Mr. Mori, who oversees the R&D department’s DX strategy promotion, provides the following explanation for his decision to, among other jobs, automate pH and viscosity measurement.

“While the measurement of pH and viscosity is an important step in the development process, we felt that efficiency needed to be increased due to the sheer volume being processed. We considered lowering the number of items to be measured, but felt that doing so could potentially compromise the quality of our products and prevent us from offering consumers true peace of mind. Therefore, we decided that because of its importance, this work demanded automation, which would be the best way to increase efficiency without lowering conditions or the number of items measured.”

Quantifying and Reflecting Researcher Experience

While there are commercially available devices that can automatically measure pH alone, there is no device that can simultaneously measure viscosity and pH, so it was necessary to develop a new device. Mr. Mori explains why they chose to take on the more challenging task of measuring these items simultaneously rather than independently.

“Since the measurement of both pH and viscosity in most of Lion’s laboratories involves a sequence of steps, we reasoned that automating just one of them would not increase the overall efficiency of our operations. In fact, before this project, we had developed a cooperative robot that dispensed liquid products into containers and tightened the lids as part of sample preparation. The introduction of this robot was expected to significantly reduce the time required to dispense the product into containers, however, because sample preparation involves not just dispensing samples into containers and closing the lids, but such specific tasks as attaching labels explaining test conditions, the researchers asked that we do all of the work in an integrated manner. We have concluded that automating only a portion of the entire process will fail to bring considerable benefits to researchers as the resulting process will call for supplemental manual work.”

Thus, the objective of this project was to create a system that, once the sample to be measured is decided on, the robot can be turned on and it will automatically measure pH and viscosity. The data is subsequently transmitted to the researcher’s PC after the measurement process is completed.

Even though an outside specialized manufacturer handles the development of the robot equipment, without being involved in the actual research, it is impossible to know the functions of robot that would be most useful in the field. With the help of other researchers and the field experience of Mr. Mori and Mr. Suda, the team repeatedly identified and quantified each movement, applied their findings to the robot and made adjustments.

“When measuring pH by hand, the electrodes must be cleaned and the water wiped off manually without causing damage. Because the robots used are not capable of such delicate movements, we decided to use air to blow off the water droplets. To this end, we had to experiment a lot to figure out the best configuration, as we had no idea about the intensity of the air blown and the length of time required for drying the electrodes.” — Mr. Suda

The viscometer, which measures viscosity by inserting a spindle rod into the sample and rotating it to measure the force exerted by the sample on the spindle, was also calibrated through an iterative process. The measurement results can be inaccurate if air bubbles infiltrate the sample. In the manual method, the sample bottle is tilted by hand and the spindle inserted at an angle to prevent air bubbles from getting into the sample; however, with the robot, it is difficult to angle the bottle; thus, the process was adjusted by modifying the speed at which the spindle is inserted, rotated and removed in order to prevent the infiltration of air bubbles. In addition, the procedure is repeated and a video recording made to verify the results.

“It is a continuous process of tedious adjustments. Initially, there were unanticipated problems. For instance, the robot was set to open sample lids when in a certain position, occasionally, however, they were lying in an unexpected position. In such situations, we carried out on-site inspections to infer the cause of the issue based on the location of the lids.” — Mr. Suda

Even if a system operates smoothly, it means nothing if the measurement results are inaccurate. Therefore, accuracy was meticulously improved by carefully comparing the results with those obtained from manual measurements. Furthermore, every effort was made to meet the needs of the field in order to facilitate the researchers’ active use of the robot in their work, and as a result, the robot has become an indispensable tool.

Helping Researchers Share Their Concerns Beyond Their Own Products

The pair go on to explain how the work that goes into internal DX promotion gave them a sense of fulfillment that is distinct from the satisfaction they get from product development.

“Through this project, we’ve had more opportunities to listen to the voices of those in the field who are in charge of other products, and have been able to better understand the problems they actually face. We have always had communication beyond the products we were in charge of, but I think the development of this robot has brought us closer together. I am very pleased to hear that the use of the robot has made the research process easier.” — Mr. Suda

“Since joining the company, I have felt that measuring pH and viscosity took up a significant amount of our workday. This time, however, we were able to solve the problem with the assistance of various people and were able to share a sense of accomplishment. Going forward, I hope to further promote DX by introducing more updated robots and leveraging data through AI.” — Mr. Mori

【PICK UP】Comments from the field on the introduction of pH and viscosity measuring robots

Products, contents, and affiliations are as of the time of the interview. (Interviewed Sep 2023)