Evolution Of The Toolholder

Toolholder manufacturer Nikken Kosakusho Works Ltd. in Osaka, Japan, relies on accurate measurements and comprehensive cutting force data from a Kistler dynamometer to advance its solutions for demanding machining applications, both in Japan and Europe. (Kistler Group is headquartered in Winterthur, Switzerland, and Kistler Instrument Corp. is in Amherst, New York.)

In addition to high-performance toolholders, Nikken manufactures CNC rotary tables, reamers and a range of other tooling products for high-level machining applications. Since its founding in 1958, the manufacturer has expanded to over 750 employees across more than 16 countries worldwide. Nikken supplies customers in industries such as aerospace, healthcare, motorsport, power engineering, energy, molding and die casting. (Lyndex-Nikken Inc. is in Mundelein, Illinois.)

In 2014, the toolholder specialist opened the Nikken Innovation Centre Europe (NICe) at Rotherham in the U.K. This flagship facility is equipped with eight advanced machining centers for full-scale R&D work on machining applications.

“That was also when we started working with Kistler measurement technology, and we’ve continued to do so successfully ever since then,” said Susumu Mikado, senior managing director at Nikken. “The objectives in R&D are to correlate all data on cutting forces X, Y and Z with parameters such as the velocity command and torque command of the 3-axis servo motor, the spindle torque, and the accuracy and stability of the cutting surface, and to comprehensively evaluate this data. The Kistler system enabled us to accurately measure all the cutting forces needed for a new series of toolholders, and also to compare the process performance for all the toolholders.”

Nikken developed the products in its X-Treme Chuck series for demanding aerospace and energy applications. They provide high repeatable accuracy and excellent runout characteristics while preventing endmill movement, or “pulling- out,” according to the company.

Nikken relied on the 9255C dynamometer from Kistler. With its portfolio of piezoelectric dynamometers, Kistler can provide solutions for multiple machining applications, including milling, drilling, turning and grinding, from micromachining to heavy-duty cutting. Dynamometers from Kistler are reportedly used in many R&D applications, and they also play a key part in optimizing production processes.

Thanks to its rigidity and natural frequency, this piezoelectric sensor array (comprising four 3-axis force sensors) used by Nikken measures enables precise measurement of cutting forces and moments in the three orthogonal axes. Another benefit of the 9255C dynamometer is its high resolution, allowing it to capture fine dynamic changes — even in the presence of large forces. Features such as a wide measuring range (Fx, Fy: ±30 kN and Fz: -10 to 60 kN), ground-isolation sensor integration and protection class IP67 make the 9255C suitable for heavy-duty applications in R&D and production.

“Thanks to Kistler’s help, we were able to standardize our process and method for the original workpiece, which measured 150 mm × 150 mm × 100 mm (5.9" × 5.9" × 3.9"). Our product was originally developed to manufacture jet engine components made of a special titanium alloy. The dynamometer’s great performance, ease of use and data quality, backed up by excellent service from Kistler were major factors in the success of our project,” Mikado said.

The 9255C dynamometer from Kistler is a multiple-component force sensor for robust and precise dynamic measurements in demanding applications. Kistler Group

In 2020, Nikken reports that it opened a new technical center at its headquarters in Japan, equipped with the latest machining technologies to achieve the highest possible accuracy.

“In view of that, we moved the Kistler dynamometer to our new center. Since then, the 9255C has delivered an enormous volume of cutting data on different types of shanks and chucks, not only for basic evaluation, but also to support the specification of material characteristics,” Mikado said.

R&D efforts at the new technical center in Osaka resulted in the development of a dynamic double- face-contact tooling system. This Nikken innovation is at the core of a new toolholder series with many different variants, including the dynamic 2Lock tooling system (BT double face contact).

“The Kistler dynamometer has helped us to continue developing our solutions and has even paved the way for some real innovations,” Mikado explained. “The technical support we receive from Kistler Japan is also very good, not only for commissioning and basic knowledge exchange, but also when it comes to optimizing the measuring chain and the entire R&D system, including aspects such as interfaces and data processing.”