“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,” Mikado explains.
“The Kistler system enabled us to accurately measure all the cutting forces needed for a new series of tool holders, and also to compare the process performance for all the tool holders.”
Susumu Mikado, Senior Managing Director at NIKKEN
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 – combined with complete elimination and prevention of any movement or 'pulling-out' of the end mill. Tool holder development and testing made use of a 9255C dynamometer from Kistler. Thanks to its high rigidity and natural frequency, this piezoelectric sensor array (comprising four 3-axis force sensors) measures the cutting forces and moments in the three orthogonal axes with utmost precision. Another benefit of the 9255C dynamometer is its high resolution, so it can capture the smallest dynamic changes – even when large forces are involved. Features such as a wide measuring range (Fx, Fy: ±30 kN, Fz: -10 to 60 kN), ground-isolation sensor integration, and protection class IP67 make the 9255C ideal for heavy-duty applications in R&D as well as production.
“Thanks to Kistler's help, we were able to standardize our process and method for the original workpiece, which measured 150 x 150 x 100 mm. 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 reports.
Driving technological evolution ahead
In 2020, NIKKEN built a new technical center at its headquarters in Japan, equipped with the latest machining technologies to achieve the highest possible accuracy. Mikado again: “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.”
R&D efforts at the new technical center in Osaka culminated in the development of a dynamic double face contact tooling system. This NIKKEN innovation ultimately led to a new tool holder series with many different variants including the dynamic 2LOCK tooling system (BT double face contact), which won the 42nd Technical Award of the JSPE (Japan Society for Precision Engineering) in 2022. The new system delivers far better cutting performance in many respects: elimination of vibrations, smoothness, accuracy and tool life – and the improvements are achieved regardless of material type (e.g. for aluminum, steel, or alloys).
Mikado concludes: “The Kistler dynamometer has helped us to continue developing our solutions, and has even paved the way for some real innovations. 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.”