The EXRAIL - a roller guide developed to meet the needs of the new generation. Tomohiko Kikuchi, Assistant Manager of R&D Department and Project Leader of the EXRAIL development, speaks of its features and advantages, development story, and the craftsmanship of Nippon Bearing, which is highly praised both inside and outside of Japan.

Q1　What lead you to develop the EXRAIL？

We had a plan to develop a "Roller Guide that represents NB and will be well known throughout the world," so we formed a small team to start its development. Our company has a long history of manufacturing linear ball bearings, but not as many linear guides with rollers. Therefore, we were looking to strengthen that line of products.

Q2　What are the applications for roller guides in the industry？

Well, they are mainly used for machine tools. The only difference is whether the rolling element is a ball or roller, but the roller bearings are able to take on more load in comparison to ball bearings, and are used in applications for high load. Linear guides with rollers are more commonly used in Europe than Japan.

Q3　Why did you survey end users prior to development？

We needed to know what specific features should be added on roller guides to come in the future, and had to understand the needs of the industry. So we visited more than ten machine tool and other manufacturers, who would be the main end users, and asked for their opinions and requirements. During our interview, some customers mentioned that dynamic frictional resistance doesn't have to be reduced, but required a product with high damping capability. Other customers needed a product with smaller amounts of dynamic frictional resistance when the guide is driven.

Q4　How did surveying end users change the course of development？

Our main focus was to have the EXRAIL implemented on highly precise machine tools. In order to do that, the product needed to have performance that exceeds that of competitors. With this in mind, we proceeded the project with a strong focus on "High Rigidity," rigidity that exceeds industrial standards, "High Motion Accuracy," the ability to move the guide smoothly without high vibration during movement, and "High Damping Capability," an important essence for machine tools.

Q5　What points did you focus on about needle rollers？

After discussing how to achieve high rigidity and high motion accuracy, we decided to incorporate needle rollers, which are long and have reduced diameter. The smallest EXRAIL block has needle rollers with a diameter of 2 mm, and a length of 8 mm. By fitting multiple needle rollers in a limited space the load received by each roller is dispersed, which reduces elastic deformation, and this helped us achieve higher rigidity. Furthermore, by reducing vibration of the rolling elements during movement, we were able to achieve high motion accuracy.

Q6　What challenges did you have in the development process？

It was difficult to design a recirculated raceway to incorporate as many rollers as possible. It was also not an easy task to select a material for the needle roller's retainer. Since the retainers circulate infinitely, material that has flexibility and the ability to withstand ablation was needed. We used stainless sheet metal (metallic foil), which has high fatigue endurance, and tested it with various grades but none of them worked, and replaced it with a resin film to strengthen the material. The retainer required a mold for each variation of material or size, and had to be tested for duration each time, so this was the aspect which took up the most time and work.

Q7　Do you have any final words to the customers as
the Project Leader for the EXRAIL？

I am proud to say that the EXRAIL is by far higher performing than any other competitors' linear guides, thanks to the incorporation of the unique needle rollers. Parts with higher precision are always in need for machine tools, so I believe that one component will have an enormous impact. In order to meet these challenges, the new roller guide EXRAIL features High Rigidity, High Motion Accuracy, and High Damping Capability, all advantages which exceed the performance of roller guides currently in the market. I believe that the EXRAIL will expand the possibilities for machine tools such as semiconductor equipment and meet your expectations.

We interviewed Hiroaki Watanabe about the EXRAIL's design. He is the president of PLANE Co., Ltd., and has extensive experience in product development with many well known manufacturers, and worked for frog design, a company famous for designing Macintosh products from the second generation Macintosh and on.

Q1　How did you become involved in the design of EXRAIL？

I first heard from Nippon Bearing when they told me they were looking for a product designer. I have never designed a machine part, but I used to collect bearings, nuts, and gears, and always had an interest. Bearings are already exceptional products even without the touch of a designer. I was always touched by its elaborateness and delicacy, and since it was a product that met my principles, I always wanted to design one if I had a chance.

Q2　What are your principles in designing？

Many people see design as a "decoration," but I disagree. Rather, I think design lies in removing the unnecessary things, think about what is most important, what is most necessary, leave those concepts, and to remove all the rest that are unnecessary.

Q3　What was your first impression when you saw the EXRAIL？

It was close to perfection, and only needed some adjustment of the surfaces. I started to brainstorm ways to accentuate it without adding much. On the other hand, I heard that this was the first time Nippon Bearing worked with an outside designer, and thought they didn't need our services if Nippon Bearing thought of design as a "decoration".

Q4　What did you pay special attention to in designing the EXRAIL？

Again, the EXRAIL itself didn't need much modification in its design, as it was already close to perfection. On the other hand, it was important that the EXRAIL's high performance was communicated through its design. The EXRAIL's performance highly exceeds that of other manufacturers' roller guides. This is due to its needle rollers, but the needle rollers are built in and can not be seen from the outside. The challenge was to communicate this advantage, which is not easily seen, and how best to communicate Nippon Bearing's brand image through its design.

Q5　What is the EXRAIL's design concept？

Nippon Bearing's corporate colors are orange, green, and blue. I used orange, a symbol of "vitality," for the color of the NB Brand Emblem so that it stands out from the black and silver components. The EXRAIL has an extremely high performance, yet one can not see this from the outside. I'm sure the engineers and staff at Nippon Bearing involved in the development of this product take great pride, and we wanted to express that feeling. The orange emblem symbolizes the pride of the makers and is also a "sign of quality," a promise of the value it provides. The orange emblem, a mark of its high quality, shows that both the maker and user can take pride in the EXRAIL.

Q6　What were you careful about in the development process？

I didn't want the design to interfere with the performance of the EXRAIL, and I imagined how the parts were structured inside, and suggested to insert the emblem in between parts instead of adding it on later. By doing so, the emblem will not fall out when the product is being used. The emblem is L shaped, easy to recognize and takes on a 3-dimensional shape when light reflects on it, and by adding it on both corners, I made it so the emblem is apparent from any angle. This is a product that the engineers spent many months and years to reach completion, so I felt it was my mission to finish it well.

Q7　Any final thoughts working with Nippon Bearing？

The engineers easily understood what I wanted to do, and the communication process went smoothly. We didn't have a huge gap in our ideas of the final design of the product. There usually are differences in opinion that occur with new clients, but even if there are struggles during the design process, I want my clients to say that "we want to do our best and challenge ourselves".