Sakai increases the efficiency of its dimensional inspections with a new approach

Product: Metra 3d
Industry: Industrial Machinery and Heavy Equipment

Many companies are now accelerating their efforts to reform the way they work, and in Japan, where there is a shortage of engineers, the manufacturing is the industry that has the most pressing need to address this issue. In addition, with the retirement of the baby boomer generation of veteran engineers, many companies are facing the challenge of passing on skills to younger workers, and an increasing number of companies are working to improve the efficiency of measurement work at production sites, which had been inefficient.

In the past, manual measurement using callipers was the common method, and it took an enormous amount of time to measure styrene foam curved and free-form shapes. In addition, measurement work often tends to rely on the tacit knowledge of veteran employees, and it can take several man-hours to compare the measurement results with the original CAD data. Also, in order to ensure measurement accuracy, the production line must be temporarily stopped, which in some cases leads to inefficient operations.

Sakai Model Making Corporation is a manufacturer that makes the most of its technology and experience, accumulated over more than half a century, to produce a variety of models, including casting models for flans, V-process, automatic molding machines, molds, resin mold, and full-mold. The company’s business model is to take orders directly from machine tool manufacturers and work in association with casting manufacturers, flexibly changing the shape, size, and number of models delivered on a case-by-case basis in response to customer requests. Sakai Model Making was facing the same measurement problem.

In addition to these measurement issues, Sakai Model Making Corp. also faced the challenges of dealing with a declining workforce due to the falling birthrate and aging population, passing on skills, training young workers, and work styles evolution. We interviewed the core members of the project about the 3D measurement efforts undertaken by Sakai Model Making Corp.

Urgent need to improve dimensional inspections, which are too generic and inefficient.

Before shipping a model, quality assurance through dimensional inspection is essential. The measurement was conventionally done by hand, which is a highly difficult task because many of the models are castings, contain many curved surfaces, and have complex shapes. In addition, since most models are made of styrene foam, which is soft and brittle, great care must be taken when measuring them. Dimension evaluation was performed by carefully applying a ruler or a convex gauge to each spot, and in the case of complex curved surfaces, a special gauge may have been specially made for measurement.

The size of castings varies from palm-sized to as large as 10 meters. Naturally, since the model is the part that carries the foundation, the delivery of a high-quality and high-precision model is required.

The dimensional accuracy required for model making is between 0.5 mm and 1 mm, but it is not realistic to manually measure each detailed dimension of a model. Therefore, it was necessary to determine which dimensions were important when releasing the molds or finishing the castings and to correctly evaluate the measurement points. In addition, only I could make the final evaluation during the pre-shipment inspection. Therefore, I sometimes spent almost the entire week before shipment doing nothing but inspections. I had no choice but to stop quotations and other work while inspections were being conducted.

Sakai Model Making Corp. Representative Director Mr. Naruhito Sakai

The pre-shipment dimensional evaluation at Sakai Model Making Corp. was a manual process, a technique that Mr. Sakai had acquired through trial and error and by feel over many years. “Because of this reliance on tacit knowledge, it was difficult to formalize and pass on to other staff within the company”, he says.

“Had we continued with the same system as before, it would have been difficult to maintain our customers’ trust for the future. To break out of this situation and improve our operations, we decided to move to a digital approach,” said Mr. Sakai.

MetraSCAN 3D was chosen for its overwhelmingly fast measurement speed and compactness

As a means of improving the measurement process, Sakai Model Making Corp. turned its attention to 3D scanners, which can scan actual curved surfaces and complex shapes simultaneously with a laser and digitize them as 3D data. Mr. Isonuma took the lead and began comparing products.

The biggest drawback common to all the 3D scanners we were considering at the time was the measurement speed,” said Isonuma. One product took eight hours just to measure, and we thought this was not practical.

Sakai Model Making Corp. Technical Engineer Mr. Yasuhumi Isonuma

The slow measurement speed was a deal breaker to Sakai Model Making Corp.’s models, many of which were also large and included a considerable number of measurement points. In addition, the factory was cramped with processing equipment, and a large measuring machine would have overwhelmed the limited workspace.

To enable anyone, regardless of experience, to perform 3D measurements, compactness is a must. Also, measurement speed is important to respond quickly to customer requests. When we were looking for a 3D scanner that met these requirements, we learned that a casting manufacturer we do business with was using a handheld MetraSCAN 3D with exactly these features, so we immediately contacted the manufacturer. When we tried the MetraSCAN 3D, we found that the scanning speed was very fast and the 3D data could be visualized in real time on the PC screen while the measurement was in progress. We ended up selecting this scanner as it was the only solution meeting all the requirements.

The ability of the MetraSCAN 3D to scan large objects at high speed and to perform accurate 3D measurements of complex shapes in a short time was a decisive factor in our decision to introduce the system.
The scan results are visualized in real time on the PC screen using the included VXelements software, allowing the user to check on the spot whether the scan was done well enough to create 3D digital data of the product quickly and efficiently, while avoiding unnecessary rework.

Another advantage of the MetraSCAN 3D is that it can measure both large and small objects, and large objects can be scanned without the need to recombine and realign data later. Furthermore, since there is no need to attach targets, measurements can be performed one after another, even if there are dozens of objects to be measured. This is a unique feature of the C-Track, which was developed for automated self-positioning systems that can perform 3D measurement of large objects with high accuracy and speed.

Standardization and simplification of measurement work dramatically improve work efficiency

After implementing MetraSCAN 3D, the system administrator at Sakai Model Making Corp. saw immediate results in the measurement operations.

Anyone can learn calibration and measurement using the MetraSCAN 3D with just a simple explanation of its operation. Of course, it takes some time to be able to edit data and create data for inspection, but the measurement work itself was learned by new employees on their first day on site.

MetraSCAN 3D is a high-performance CMM, yet it is easy to operate. New employees who have been with the company for only a few months quickly learn to operate it, and they are now measuring products as part of their daily work.

Mr. Sakai continued, “When I used to measure the dimensions of medium-sized models manually, the measurement work alone used to take a day and a half, but MetraSCAN 3D has reduced the time to half a day. I still make the final evaluation myself, but now that I am free from measuring and reporting, I no longer have to spend a week just for pre-shipment inspections. The time saved can now be effectively utilized for making quotations,” he says.

Currently, Mr. Isonuma uses 3D data to create processing data, which is then checked by the system administrator before being converted into machining data. The assembled products are then measured with the MetraSCAN 3D, and the design data and the 3D data obtained from the measurement are superimposed and compared. In addition, since the measurement results are stored as 3D data, a quality assurance system for customers after delivery has also been established. It is not just a matter of improving inspection efficiency; the business process itself is being digitized.

Data measured by the MetraSCAN 3D is compared with CAD data in VXinspect, the included software, and after the measurement work is easily performed, the data is stored as product shipment inspection data by Sakai Model Making Corp.

Accelerating business efficiency with 3D data to begin a new era

Sakai Model Making Corp. plans to further automate its work system, including pre-shipment inspections, to create an environment in which operations can be carried out mainly by younger workers without relying on skilled workers. The company also plans to utilize MetraSCAN 3D and 3D data not only in the inspection process, but also in the manufacturing process. As part of this plan, the company plans to use 3D printers as well, aiming to further improve operational efficiency.

“The recent Corona problem and geopolitical issues have made the procurement of wood and other materials unstable, and prices have skyrocketed. In addition, the company will lose credibility if it does not address the SDGs. To address these social issues, we will work to further improve efficiency using 3D data,” said Mr. Sakai, expressing his plans for the future.

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