Ultra-Precision, Ultra-Fast Grinding of Small Tools

The latest generation CNC system from NUM Corporation (Naperville, IL) used by the full linear NTG 6RL 5-axis tool and cutter grinding machine from Star SU LLC (Hoffman Estates, IL) is based entirely on the open architecture of the Flexium+ CNC platform that fully automates the high speed production and reconditioning of complex cutting tools. The NTG 6RL can handle fluting, tertiary grinding, relief grinding and automated wheel change with NUMDrive X modules that provide the drive flexibility needed to accommodate a variety of third-party linear and direct drive torque motors, as well as high frequency grinding spindle motors. This machine is capable of very high grinding and surface finish accuracies, combined with unprecedented grinding speeds.

“The higher bandwidth of the DriveX servo drive and improved internal processing of the Flexium+ CNC platform is managed by a double-precision IEEE 754 floating point for capabilities that extend down to sub-picometer accuracy,” explained Steven Schilling, the general manager of NUM. “This gives machine tool manufacturers like Star Cutter the opportunity to create machines that can grind even the smallest tools with superb accuracy.” Another key attribute of the Flexium+ platform is that it can run grinding programs as large as 40 MB directly from the NCK memory. And for very complex grinding cycles, the CNC system can execute cycles directly from the system’s disk drive via a high speed data transfer protocol. This increased capacity and speed helps Star Cutter users to expand their CAD/CAM grinding operations. Application areas include the processing of advanced materials and aerospace components, in addition to medical devices and tools.

The new Star Cutter grinding machine also features a novel servo-assisted popup mechanical steady rest that makes full use of the ‘detachable axes’ facility of Flexium+ systems equipped with NUMDrive X modules. This enables users to simply place the rest into the machine for the production of longer parts and quickly remove the full motor/mechanical assembly when it is not needed. Focusing on an intuitive user experience, the operator station features an entirely new design that reduces button pushing, significantly simplifying machine setups and daily operations. The optional 6-axis robotic part loader essentially programs itself from the NUMroto tool files, requiring minimal user inputs. Notifications can be set to alert shop personnel of process completion or of issues encountered during unattended production. This machine is also designed for ease of integration with other forms of industrial automation and handling robots.

The Flexium+ platform offers a wide variety of system communication busses, including EtherCAT, CAN and EtherNet IP. Measured process or post-process data can be fed back to the CNC system’s NUMRoto software to provide on-the-fly corrections, facilitating adaptive real-time control of the entire grinding process. Shop floor data can even be shared easily with the rest of the plant and to the cloud with NUM’s built-in MTConnect interface.

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NUM has also released Version 4.0 of their renowned NUMROTO tool grinding software that provides numerous enhancements, including new features for ball nose and corner radius tools, automated documentation of fully dimensioned wheel packages, and grinding spindle power monitoring to facilitate adaptive grinding on specific machines. The software’s 3D simulation facilities now offer coolant holes in the 3D blank and DXF comparison profiles, as well as an all-new measurement mode. NUMROTO software is preferred by many manufacturers of machines used for the production and re-sharpening of end-mills, drills, step drills, form cutters and other cutting tools. It provideNUMROTO softwares a more direct and efficient path between tool design and manufacture with its integrated modeling-simulation-interpolation chain, which avoids the sequential CAD-to-CAM and CAM-to-CNC translation phases of conventional software approaches and provides a true WYSIWYG output. This enables users of tool grinding machinery to sidestep multiple data format changes and emulations.

NUM also offers innovative new software that enables CNC machine tool builders and retrofitters to provide their customers with exceptionally easy-to-use workpiece programming and machine control facilities for precision grinding applications. Forming the latest application-specific addition to their Flexium CAM suite of CNC software, the NUMgrind package simplifies machine tool programming for an extensive range of tasks, including external and internal cylindrical grinding, surface grinding, wheel shaping and dressing. NUMgrind is specifically designed to simplify the creation of G-code programs for CNC machine tools through the use of a highly intuitive graphical human machine interface (HMI), conversational-style ‘fill in the blanks’ type dialogs or a combination of the two. Unlike conventional CAD/CAM workstation tools for generating CNC machine tool control programs, NUMgrind is intended for use in the production environment. It enables shop floor personnel to handle everyday machining tasks such as grinding very quickly and efficiently – and the work can be easily shared among several people and several machines.

NUMgrind works in conjunction with embedded CNC grinding and dressing cycles and direct hyperlinks to several production files, such as wheel/part data sheets, CAD files and/or other pertinent grinding production data to facilitate efficient manufacturing of a diverse range of workpieces, covering various different wheel forms and part types. It can be configured for a wide variety of machine configurations such as OD/ID grinders, surface grinders, centerless grinders, etc. The cylindrical grinding package includes OD/ID grind cycles for 2-axis (X/Z) horizontal or vertical grinding machines and also offers an inclined axis capability. The dressing station can be table-mounted or rear-positioned to accommodate a wide range of machines. Standard forms or profiled wheels can be dressed with single point, double point or roller dresser. For surface grinding, NUM offers full grinding cycles for 3-axis (X/Y/Z) machine configurations with built-in wheel dressing capabilities similar to that of the OD/ID cylindrical grinding package.

Machine production time is very efficient due to HMI pages that guide the machine operator through a step-by-step process in setting up the machine for each part. Standard dresser setup and part setup cycles prompt the user to jog the axes to specific locations on the machine in order to teach the dresser and part zero program positions. These cycles enable the user to quickly and easily calibrate their machine for a wide variety of parts and wheels. As soon as the data entry session is complete, the program is generated automatically, stored, and made ready for execution. The result is a modular, easily modifiable program that will produce the desired grind process.

In conjunction with NUMgrind, Flexium 3D (NUM’s graphical simulation software) provides the operator with another very useful tool to further enhance productivity. Once a part program is generated through NUMgrind CAM, the operator can simulate the grinding cycle through Flexium 3D. The software can be configured in a variety of different ways to match many standard cylindrical and surface grinding machines. It can be used directly at the machine or as a standalone program for grinding process verification. This software gives the operator more power to ensure that the generated programs match their desired outcome before grinding occurs on the machine.

The entire Flexium CAM suite of CNC software, including the new NUMgrind package, is designed for use with the latest-generation Flexium+ CNC platform. “The concept behind Flexium CAM software is to provide a straightforward, easy-to-learn programming method,” added Schilling. “Our new NUMgrind package includes cycles for a wide variety of cylindrical and surface grinding operations. The OEM or retrofitter receives a control system with a complete, world-class grinding solution built-in, which eliminates the need for any additional software that can take years to develop.”

NUM Corporation, 603 East Diehl Road, Suite 115, Naperville, IL 60563, 630-505-7722, sales.us@num.com, www.num.com.

Star SU LLC, 5200 Prairie Stone Parkway, Suite 100, Hoffman Estates, IL 60192, 847-649-1450, sales@star-su.com, www.star-su.com.