Demand for difficult-to-cut materials in the industry has been increasing. It is important to develop the most appropriate standard products that can be applied over a wide range of applications for difficult-to-cut materials. We interviewed four members of the tool development department about their experience in the development of inserts for these materials.
Q: Would you give our readers some background information?
Sugaya: The need for difficult-to-cut materials has been growing in a number of industrial sectors, such as aircraft, automotive and medical. In order to respond to this need, we initiated a product development project to focus on machining difficult-to-cut materials. There is a wide variety of products and parts using these materials, however, the tool performance required by each of these differs significantly. We wanted to develop a standard tool that could be applied over a broad range of conditions. We first discussed target priorities with Sales Department staff, who have an intimate knowledge of customer needs and the people in Material Development. Based on these discussions, we selected the aircraft industry as target and started development of inserts, optimised to machine titanium and superalloys.
Q: What challenges did you face during the development process?
Sugaya: The mechanism that causes damage to cutting edges while machining difficult-to-cut materials such as titanium and superalloys is quite different from that which causes damage to general metals such as cast iron and steel. We focused on reducing boundary wear and realising long tool life.
Sugawara: We first thoroughly analyzed existing tools. The damage caused during machining depends on slight differences in condition, making it very difficult to evaluate performance. Therefore, we used as many samples as possible during experimentation and based our analysis of each sample on a larger number of criteria than is customary. During this analysis, we found that rake angles and honing sizes to be the most important elements in reducing damage.
Sugaya: The prototype with a large rake angle and small honing size reduced damage during initial machining; however, tool life when machining super alloys was very difficult to predict accurately due to the difficult nature of the heat resistant super alloy material group. This means that each application‘s parameters needs fine tuning to obtain optimum results. It was found that a key point in realising long tool life over a wide range of super alloy applications was to reduce boundary wear as much as possible. We experimented to find the best form of cutting edges that would cover many applications.
Ichinoseki: We went through a process of trial and error. Since we discussed rake angle and honing size in detail before development, we were able to devote a significant amount of time and effort on the production of prototypes, form measurements, machining evaluation and analysis when compared with previous development projects. Once we produced a prototype, we continued testing for three days. Although computers helped make the development more efficient, the repetition required to ensure accuracy required both persistence and patience. Our efforts paid off however, by allowing us to find the most suitable rake angle and honing size for each product.
Sugaya: Though trial and error we designed three types of breakers to respond to the needs of the market and launched them as a series in 2013. The LS breaker, which has a 20-degree rake angle and excellent chip control, the MS breaker, which has a 15-degree rake angle and prevents boundary wear, plus the RS breaker, which has a 10-degree rake angle and prevents chipping are now available for different applications. These products have been highly regarded for their sharpness and their ability to cover a wide range of applications beyond superalloy machining has meant they have gained a reputation for versatility. We are pleased that our products have met with such great approval.
Masuno: We significantly increased AI content over the existing (Al, Ti) N to give a high-degree of hardness stabilization, and this led to a significant improvement in abrasion and resistance to chip welding. We succeeded in improving performance more than 25% over existing products and when combined with the optimum cutting edge geometry, the overall performance of inserts for difficult-to-cut materials was further increased.
Q: What was the priority in development?
Ichinoseki: As developers we were particularly careful about design. The pursuit of functionality in chip breaking led to a final design that looked like a delta wing shape. This helped promote the appearance of each product to give the strong impression of high performance as an insert for superalloys.
Sugawara: Many different types of ISO inserts are available for turning applications. While we have maintained the basic performance of the prototype, we also provide a wide range of geometries combining different sizes, clearances and corner radii. To prevent delay in product launch, we also worked to create a system that would allow us to complete our design process in one-third of the time that was required for existing products.
Sugaya: The greatest advantage of bringing four people of different ages and levels of experience together was that we could combine our individual know-how. Mr. Ichinoseki put the experience he has accumulated over his long career into the design manual we used, I can recommend that young designers read this very important work. I want to continue learning the technology developed by such experienced individuals and pass it on to the next generation.
Ichinoseki: I also think that the cheerfulness and positive outlook of our team leader, who was the youngest member of the team, put everyone at ease and helped a lot in developing these products.
Q: Do you have a message for your customers?
Ichinoseki: We are currently only selling negative type inserts, but we are also planning to release a range of positive inserts. After we introduced the products to the market, we discovered that both they and the technology used in their development could be applied to small parts machining. Therefore we will also continue developing smaller sizes.
Sugaya: Although they are for difficult-to-cut materials, they can be used for stainless and some other types of steel. I hope our customers take advantage of this versatility. We will expand this to a wide selection of geometries to enhance use over a wider range of businesses.
Sugawara: We have also implemented new ideas to ensure efficiency. The know-how we have accumulated in this project will be helpful in future development, and I am very happy that we could deliver these products to our customers so quickly.
Masuno: We will continue developing new materials and technology to provide high-quality and high-performance products.
Inserts designed for turning difficult-to-cut materials MP/MT9000 Series