New calibration technology for advanced machining centers

More accurate manufacturing has been enabled by innovative machine tool measurement hardware and software systems

Kern Microtechnik GmbH is one of the world’s leading companies in the field of precision machining. The company from Eschenlohe in Upper Bavaria has been setting new standards for years, especially in 5-axis machining. For 60 years now, Kern has been successful around the world with innovative products and services bearing the coveted Made in Germany mark. 

Alongside the manufacture of advanced machining centres, Kern also offers contract manufacturing services. This combination allows for a continuous exchange of knowledge and experience between design, manufacture and real-word usage, which guarantees advanced process know-how and the constant improvement of machines.

Each individual machining centre created at Kern must be perfectly measured and adjusted during production and commissioning. With the help of volumetric calibration technology, the highest precision and therefore consistent high quality can be ensured across an entire working area. 

With the aim of further improving and automating the extremely complex calibration of 5-axis machines in the micrometre accuracy range, the experts at Kern found what they were looking for at the Hexagon stand at the EMO 2019 trade show. In the ETALON LINECAL and ETALON X-AX LASERBAR calibration processes, two innovative solutions were presented that had the potential to meet Kern’s demanding requirements.

Kern_3_800x428The use of these calibration systems fundamentally simplifies the recording of geometric deviations in compact multi-sensor measuring systems, coordinate measuring machines (CMMs) and machine tools. When used together with Hexagon’s TRAC-CAL software, machines of the highest accuracy can be calibrated fully automatically. This combination allows for the determination of positioning deviations, straightness deviations, yaw, roll, pitch and squareness of the axes to each other with the highest possible accuracy. Volumetric calibration data can be displayed directly in control-specific formats. In combination with the high reproducibility of the Kern machining centres, with their unique temperature management system, this creates a perfect symbiosis.

In close cooperation with Kern Microtechnik, a customer-specific fixture was designed for the company’s latest innovation, the Kern Micro HD. The know-how of the two specialist teams complemented each other during development, and Kern’s high requirements were a welcome challenge for the Hexagon team. 

With LINECAL, it is now possible to carry out the calibration and acceptance of the Kern Micro HD linear axes fully automatically. Comparative measurements with previous procedures have confirmed the unrestricted usability of the procedure, and this with a simultaneous reduction in the complexity of commissioning. 
For Kern, the introduction of  Hexagon measurement technology is a further step towards expanding our technology leadership.For customer service, Kern decided to use the X-AX LASERBAR, due to its universality and small size. Like LINECAL, it is based on interferometric length measurement. Unlike LINECAL, the measuring beam is guided in a very smooth-running telescopic tube with magnetic ball joints, which is “clicked” into two magnetic ball nests between the spindle and the rotary table. The machine is then controlled by Hexagon’s TRAC-CAL software through a predefined measurement path; no fine alignment or special set-up by the operator is required.

Hexagon’s ETALON X-AX LASERBAR can also detect possible deviations of the axes without operator influence. A new option developed by Hexagon also makes a fully automatic process on 5-axis machines possible.

Kern_2_800x428“Hexagon technology helps us to achieve calibration of our high-precision 5-axis machines in a shorter time by means of automated measurement sequences,” explains Sebastian Guggenmos, CEO Kern Microtechnik. “The Hexagon X-AX LASERBAR will also enable our service department to diagnose machines in the field even more effectively, and calibrate them if necessary. For Kern, the introduction of Hexagon measurement technology is a further step towards expanding our technology leadership.”

Case study: Kern Microtechnik, Eschenlohe - Germany

Case study: Kern Microtechnik, Eschenlohe - Germany