MMC Magazine

Chip collection tools were introduced 30 years ago

Chip collection is an eternal theme in metal cutting. The improper handling of chips can lead to a wide range of problems, including compromised quality of the machined surface and damage to the cutting edge. Generally speaking, the focus of improvement has traditionally been on chip breakers and coolants. However, around 30 years ago Mitsubishi Materials approached this problem from a completely different perspective. Suction, like using a vacuum cleaner during cutting, was applied. In 1986, this idea was incorporated into Qing cutters. This special tool was designed to improve chip collection during face milling for automotive engine cylinder blocks. Not only do chips have the potential to damage the interior surface of the cylinder block, they also need to be removed, which significantly affects both the quality and efficiency of processing. In order to address these issues, it was proposed to collect the chips during cutting. This is the history of Mitsubishi’s chip-collection tools.

Evolving Qing cutters

The first Qing cutter (QSV type) was introduced in 1986. It adopted a dust-collector system which lifts chips with a guide plate and then vacuums them through a casing with a collector. While the chip collection capability is highly stable, it requires hoses and a collector that are relatively expensive. To improve convenience, a second Qing cutter was developed (QWA type) at the beginning of the 1990s that applied a double-air system. It works by pumping air into the case to create a cyclone to blow the chips, and then collects them with an air-amplifier. This was very effective in processing cast iron and aluminium and was adopted by many customers.

The third type of Qing cutter was developed in the late 1990s. Returning to the basic concept of chips not being collected, but instead being discharged away from the workpiece. This was achieved using by centrifugal force to automatically direct the chips toward a conveyor and thereby alleviate the need for both the dust collector and air. In addition, it allows a design with a very simple structure, which helps to keep the price of the tool relatively low and enables the use of automatic tool changers on machining centres.

Following the introduction of these innovative developments, a wide range of chip collection tools were developed and sold by many other manufacturers. However, the support and maintenance for these are costly. In addition, cellular manufacturing has advanced as a part of chip prevention and this has caused a gradual decline in the demand for chip collecting tools. This prompted many tool manufacturers to withdraw from the manufacture of them; however, Mitsubishi Materials has continued manufacture to meet the existing demand.

The establishment of the most advanced Qing NEO

In 2015, Mitsubishi Materials started on the development of the 4th Qing cutter, the Qing NEO, upon request from Toyota Auto Body Co., Ltd. Qing NEO comprises an arbor, a bearing, a locknut and a case that covers the cutter. This collects chips generated around the edge of the tool and discharges them from the base of the arbor to an external collector, it is an effective design that exerts a high chip-collection rate. While only face milling cutters were mounted on the 1st to 3rd Qing cutters; which limited the variations, Qing NEO is capable of using a wide range of tools, including face milling, profile milling and deep hole cutters. The airflow speed around the edge of the tool blade is 10,000 – 40,000 mm/s, which sufficient to collect chips and they are forced into the channel installed in the arbor, and then into the case via centrifugal force generated by the airflow and the tool rotation. Currently, advancement of the development of Qing NEO is underway for an automatic tool change type and also under consideration is the application of Qing NEO to turning tools.

Looking back on development

Horiike: I was involved in the development of the 2nd and 3rd Qing cutters. Although customers had already asked us to develop a Qing cutter to machine metal moulds, we did not have three-dimensional CAD or the technology required to analyze fluid phenomena such as sucking chips and our manufacturing technology was not sufficiently advanced for the development of such a product. However, recent progress in a wide variety of technologies has allowed us to design mechanisms that could not have been thought of in the past. We hope this new Qing cutter will be as popular with customers as the previous versions have been.

Sato: Qing NEO was successfully manufactured because we could imagine the final output at the initial stage of design. I gained knowledge about chip collection tools and related technology, including chip collectors, hoses and bearings, that are not related to the usual tool development and this broadened my horizons as an engineer. I would like to focus on the reduction of costs to increase customer satisfaction and expand the lineup of the cutters to broaden the range of use.

Special Talk: Toyota Auto Body Co., Ltd.

Ideal teamwork could develop Qing NEO

Toyota Auto Body Co., Ltd., with which we jointly developed Qing NEO, was established in 1945 as a truck body manufacturer in Toyota Group. It has expanded business to include commercial vehicles, mini-vans and SUVs. Through a consistent domestic development and production system, its products have effectively responded to market needs. Furthermore, the company has also engaged in the design and development of a wider range of products. These include welfare vehicles and devices that support elderly and disabled transport, as well as micro-electric vehicles that are slated to become the next generation in personal mobility. In this feature, we ask Mitsumasa Okuda, Akihiro Idota, and Satonori Matsumoto of Toyota Auto Body to give us the backstory of the development of Qing NEO with Mitsubishi Materials.

Automation of metal mold processing

– How did the joint development of Qing NEO come about?

Okuda: The Metal Mould Section manufactures press molds for body panels and because the press moulds for commercial vehicles, mini-vans and SUVs are large, means they generate a large amount of chips during machining. Currently, dealing with the chips requires that machining be brought to a halt, taking valuable time away from production. Since the automation of processing is essential for reducing costs and increasing productivity, chip removal is an important issue. We knew that there was a tool designed for chip collection during machining and we thought that using this might be the right approach to realizing more effective automation.

– When did you start working on the automation of press mould manufacturing?

Okuda: We decided to change the fundamental method of metal mould manufacturing in 2012. As an important part of this we discussed the reduction of waste during individual manufacturing processes. It was at that point that we considered the benefit of developing a dedicated tool for chip collection.

Sato: Our first meeting was in June 2015.

Idota: We first drew rough pictures to illustrate our concept and paid a visit to the Mitsubishi Materials Tsukuba Plant. At first we weren’t sure if Mitsubishi Materials would accept such a complicated request, however, the staff there were eager to become involved.

Okuda: Although Mitsubishi Materials had manufactured the Qing cutter, we wanted a cutter designed specifically for mould machining, which meant Mitsubishi Materials would have to start from scratch. However, their enthusiasm to work with us on this was clear from the start, which pleased us greatly.

Sato: Thank you so much for your kind words. When I heard their request for the first time, I was a little worried about whether or not we could meet their needs. What they needed would require us to defy gravity to collect the chips and we had to give it a great deal of thought. My experience in developing drills helped me to conceptualize a new shape and when this concept began to evolve in my mind I felt we would probably be able to succeed.

Matsumoto: Although we had difficult requests every time we talked, they quickly found solutions that met our needs. Prototype improvement after each inspection was also very quick, which made me feel very confident about their work.

Idota: We presented our request in June and by the mid-September, Mitsubishi Materials had completed a prototype; including the main body and the case, and not just a design model.

Sato: When we carried out the in-house inspection in September, we confirmed that there was no abnormality in machining; including chatter marks, and the chip collection rate exceeded 90%,

Partnership seeks magical machining

Okuda: When I saw the machining test, I was amazed. Since having chips during machining was natural for me, it was incredible to see that they were automatically disposed of.

Sato: We were very happy that everyone was amazed to see no chips during machining. That motivated us to strive for even greater customer satisfaction. It was exhilarating to impress customers by delivering performance that surpassed their expectations.

Idota: Mr. Sato was very helpful and responded quickly to meet our expectations. He always found solutions to issues we brought up at meetings and included them in the next prototype.

Sato: Everyone was very happy to be able to solve the problems we encountered. It was my first experience discussing problems and solutions with customers in joint development, and we took our time and discussed all issues until we were satisfied that we had come up with the best solution. I enjoyed working with Toyota Auto Body staff.

Idota: In November of each year, we present technical improvements that we have been working on. One presentation I gave was on Qing NEO using a prototype that I had asked Mitsubishi Materials to have ready for me on a short deadline. I showed the chip removal operation and everyone in attendance was impressed with its effectiveness.

– Did the development go smoothly?

Idota: The shape of the workpiece and style of machining sometimes created problems such as interference between the case and arbor or a reduced chip collection rate. However, we worked diligently to identify the cause and create a solution for each problem that we encountered.

Sato: During machining on a 75-degree angle, we still have a lot of uncollected chips. This is an issue we need to focus on from now.

Okuda: When we changed the entire design to eliminate the interference between the case and arbor, the chip collection rate was already at about 96% to 97%, and more than 90% on slopes. We were satisfied with the results, but Mr. Sato worked to make those results even better. A major goal, using Qing NEO with an ATC, should be attainable and we are still looking to identify ways to reduce manufacturing costs.

Idota: The relationship we developed during this joint development allowed us to feel comfortable about exchanging opinions freely and honestly; and this led to success. We continue working together with the hope of bringing manufacturers of peripheral equipment and processors into future projects.

– Before we finish, I would like to ask you what it is about metal cutting work that interests you.

ato: At first glance, metal cutting looks very simple; but in fact, it is very complicated. Each customer has unique goals, such as chip removal, the elongation of tool life and achieving a good finished surface, and there are many different ways to approach these. As we achieve each goal, I feel the satisfaction of seeing that we are moving closer to the ideal.

Matsumoto: For me, it is that the value of what we have planned and carried out can be quantified. For example, chip cleanup has been reduced from one hour to just a few minutes, meaning overall machining time has been halved. Our achievements are clearly visible and it brings me great satisfaction when everyone else involved is satisfied.

Okuda: While value has been shifting from products to services, the desire to create equipment capable of increasing quality and reducing costs will continue. I am proud that the machining of metal moulds are a part of what creates value in products.

Idota: There are still many undeveloped fields, and Qing NEO was one of these. Additionally, materials that are hard to cut with existing technology are constantly being developed, meaning there is always a great potential for the creation of innovative metal cutting technologies.

Okuda: Toyota Auto Body has often customized existing tools; however, we rarely develop tools from scratch jointly like this with another company. I would like to find more business partners that are willing and able to work like this with end users. I am confident that despite the challenge it presents, halving the current machining time will be possible. I would like to realize the ideal machining method for press moulds.