NUMgear now includes a high performance CNC product for gear production machines that use threaded wheel grinding.
The accuracy of NUM's Fast Gear Alignment function eliminates the need to acquire acoustic signatures during dressing or grinding.
NUM offers a high performance CNC for gear production machines that fully automates threaded wheel grinding. Incorporating high-speed gear alignment technology, the CNC system is designed to reduce grinding machine threading-in times to accelerate throughput. It is designed for machine tool manufacturers seeking to improve the performance of their gear production machines, or to help companies expand their gear manufacturing range with threaded wheel grinders.
Based on NUM's new-generation Flexium+ CNC platform, the threaded wheel grinding product joins the company's NUMgear suite of gear production software. Originally developed for gear hobbing applications, the capability of NUMgear has been extended to include a range of gear manufacturing processes, including shaping, grinding and honing.
NUM developed the latest addition to its NUMgear portfolio while helping an Asian gear manufacturing machine company improve the performance of a prototype threaded wheel grinder. To improve grinding speed compared with current levels, NUM decided it needed to develop custom technology software. The principal aims were to reduce the time overhead of learning the teeth positions of the hardened gear prior to grinding, and improve the accuracy of the gear grinding process.
At the heart of the system is a high-performance electronic gearbox that allows all master axes - such as the grinding, X, Y and Z axes - and the spindle (C-axis) to be fully synchronized. As part of the development work on the new threaded wheel grinder, NUM has added a major new capability to the gearbox, which is now able to predict the acceleration of axes as well as their speed, in order to minimize synchronization time. Together with the Fast Gear Alignment, it forms part of the NUMgear threaded wheel grinding application.
During gear production, threading-in, the process of bringing the grinding wheel into contact with the gear blank, involves continuously adjusting the position of the grinding wheel relative to the workpiece. A similar process is employed when bringing the machine's dressing wheel into contact with the grinding wheel. Using acoustic emission sensors to learn the sound signatures of a master gear and then using them to control positioning during production runs is a common technique for automating processes like this. However, the speed and accuracy of NUM's newly-developed Fast Gear Alignment Function eliminates the need for this entirely, according to the company. As an example, aligning the grinding wheel with a 180 mm diameter gear with 71 helical teeth takes just 0.5 of a second - without any need to acquire acoustic signatures or make manual adjustments.
A second aim of NUM's development required that the gear grinder CNC control should generate gears as accurately as possible. The latest machine from NUM's Asian customer produced gears with a tooth profile quality of DIN class 7. During the development process, NUM found that the diamond plated dressing wheel did not come up to specification. To overcome this problem without incurring major tooling costs, NUM decided to support its customer by helping to modify the technology programs. The positive results of this action exceeded expectations, and NUM's solution can help a machine to consistently grind gear teeth profiles to within 3.5 microns, comfortably achieving DIN class 3 - an improvement of four class levels, according to the company.
"The latest gear grinding development is an example of one of the major principles underpinning NUM's business philosophy: a willingness to customize its CNC technology for machine makers," said a company spokesperson. "NUM supports this with a decentralized R&D structure that locates engineering staff around the world to allow it to work closely with machine builders. In this case, the new gear grinding solution was jointly developed by NUM's HQ in Switzerland and the company's technology center in Chanzhou, China."
For more information contact:
Steve Schilling
NUM Corporation
603 East Diehl Road, Suite 115
Naperville, IL60563
630-505-7722
sales.us@num.com
www.num.com