Bourn & Koch now offers NUM's Flexium CNC on its 400H Series II 7-axis horizontal gear hobbing machine and intends standardizing on this control technology for many existing and new designs.
All seven axes on the 400H Series II gear hobber, including the 560 Nm workpiece spindle motor, are controlled by NUMDrive C servo drives and a Flexium 68 CNC system.
Capable of accommodating workpieces up to 400 mm (16") in diameter, the 400H has an axial travel capability of 1,168 mm (46") as standard and can be customized for the production of even longer parts.
Advanced CNC systems from NUM are helping U.S. machine tool manufacturer Bourn & Koch, Inc. to extend its competitive edge in the market by using state-of-the art machine control software. Following a successful project to migrate control of powerful 7-axis horizontal gear hobbers to NUM's Flexium CNC platform, the company is now standardizing on this control technology for an extensive range of its gear production machines.
Bourn & Koch chose to upgrade to NUM's Flexium CNC on its 25H - 400H Series II gear hobbers, starting with the 400H. According to a spokesperson, the speed and power of this machine means that it can replace as many as seven older style gear production machines, making it a popular choice with companies machining large precision components such as bull and cluster gears, worms, shafts, splines and pinions. Capable of accommodating workpieces up to 400 mm (16") in diameter, the 400H has an axial travel capability of 1,168 mm (46") as standard and can be customized for the production of even longer parts. Customers are typically prime and sub-contract manufacturers producing mechanical power transmission components and systems for the defense and aerospace, oil/gas drilling, mining, heavy equipment and power generation industries.
Bourn & Koch has partnered with NUM Corporation for over 25 years and today uses NUM's CNC systems in many of its gear shaping, hobbing and grinding machines, as well as in various other types of metal removal machines, and for numerous CNC upgrade and machine retrofit projects. Both companies and their customers benefit from this collaboration. Jointly-developed conversational software has been cited by a number of Bourn & Koch customers as a factor in their machine purchasing decisions.
The human machine interface (HMI) on the 400H gear hobber makes full use of the software's capabilities by combining a conversational style dialog with powerful graphics, which means that the machine operator does not have to use or even know about ISO languages. To produce a part, the operator simply inputs machine set-up information such as cutting speeds, workpiece and tooling geometry via simple fill-in-the-blank menus, while graphical images provide clear and unambiguous views of the hob tool and resultant gear part. All calculations involved in creating the machine control program for a particular part are handled automatically.
The company decided to migrate the design to NUM's Flexium CNC platform as a matter of course. Tim Helle, President of Bourn & Koch, explained, "We offer customers a choice of CNC - NUM is the standard on most of our gear hobbers - and have a policy of using the latest technology to maximize the performance and cost-effectiveness of our machines. This approach also results in progressively simpler machine operation, with less need for training, and means that spares are readily available, which contributes to machine uptime and reduces customers' support costs."
In this instance, moving to NUM's Flexium CNC also had technical advantages. The system's faster block processing and loop update times offered the opportunity to reduce the machine's cycle time and further improve its accuracy. Flexium also features more on-board NC memory, a wider and unified set of PLC software development tools and increased freedom for OEMs to create application-specific HMIs. This additional control and HMI customization flexibility allowed Bourn & Koch to enhance various aspects of the gear hobber's operation.
When the latest 400H Series II gear hobber is offered with NUM CNC, the entire machine is based on NUM motion control technology, with the sole exception of its (C-axis) workpiece spindle motor, which is a special liquid-cooled direct drive unit capable of generating 560 Nm of torque at 110 RPM. In addition to a Flexium 68 numerical control kernel (NCK) - which is the most powerful model that NUM produces and is capable of controlling up to 32 fully interpolated axes or spindles - and its associated PLC, NUM is supplying all the I/O, drives and servomotors that are used on the machine.
According to Tim Helle, "We have received technical support from NUM Corporation to assist us in making the transition from Axium to Flexium CNC systems and have already started using this CNC platform across our range of gear hobbers. Longer term, we intend on offering NUM's Flexium CNC technology on all of our new gear hobbing machines."
All seven axes of the gear hobber, including the workpiece spindle motor, are controlled by the Flexium 68 CNC and NUMDrive C servo drives. The radial (X) and axial (Z) feed axes, as well as the hob head shift (Y), hob head swivel (A) and tailstock (W) axes, are all programmable and are driven by NUM BPH series medium inertia servomotors. The force applied by the tailstock servo can be changed on-the-fly during the machine cycle to accommodate the changing mass of the part and prevent the introduction of any lead error. The hob cutter spindle (B-axis) is driven by an asynchronous NUM AMS motor fitted with a high resolution multi-turn encoder, controlled by a NUMDrive C servodrive. A further NUMDrive C module controls the machine's direct drive workpiece spindle motor.
For simplicity and ease of operation, the 400 H gear hobber is equipped with a NUM FS152i operator panel and keyboard mounted on the front external face of the machine with an ergonomic swing arm. The panel combines a 15" touch sensitive screen with an integrated industrial PC running the Windows Embedded operating system and equipped with a solid state disk and dual core processor to provide a fast and responsive HMI. A number of machine functions, such as positive/negative jog and speed override of selected axes, together with emergency stop, can also be controlled remotely using a cable-linked portable hand wheel.
The machine utilizes the full 4-axis electronic gearbox capability of NUM's gear hobbing technology, NUMgear, to help speed production of complex gear parts. In conjunction with built-in high-speed synchronization facilities, this allows the axial and radial feeds and the hob head shift axis to be geared to the workpiece spindle. Use of the electronic gearbox is entirely automatic. The machine operator merely needs to enter basic gear manufacturing data, such as the number of teeth, the number of tool starts, the gear module (the 400H can handle a gear module of 6.4) and the helix angle to define and activate a specific electronic gearing function.
Particular attention has been paid to tool wear management. The software continuously monitors the condition of the hob tooling and employs a pre-programmed tangential hob shifting sequence to help ensure that an efficient cutting edge is always engaged during gear generation. The entire process is automatic - it can even be invoked during a machine cycle - and the operator is prompted whenever it is time to check or replace the hob. Undamaged hobs can be reground or recoated many times before they are worn out, which helps to keep tooling cost to a minimum. Hob head synchronization is maintained throughout the shifting process to minimize disengagement/re-engagement times and prevent tool or workpiece damage.
Bourn & Koch also makes use of the software's non-contact automatic gear alignment feature to improve throughput on the 400H by enabling a workpiece that already has teeth to be automatically synchronized to the cutting threads of the hob cutter. This is mainly employed for gears that are being re-cut or for hard re-hobbing (or skiving) of helical or spur gears after heat treatment to reduce distortion errors.
"Bourn & Koch is one of our most valued customers and a key business partner," said Steven Schilling, General Manager of NUM Corporation. "It has a large installed base of customers that use machines equipped with NUM's CNC systems, many of whom regard ease of operation as a prime machine tool differentiator. The company's decision to adopt Flexium as the CNC platform for all its NUM-based offerings is a considerable accolade, both technically and commercially. We are now in the process of increasing the level of in-depth product training that we provide for its engineering, machine start-up and customer support teams to help support this initiative."
For more information contact:
Steve Schilling
NUM Corporation
603 East Diehl Road, Suite 115
Naperville, IL 60563
630-505-7722
sales.us@num.com
www.num.com
Bourn & Koch Inc
2500 Kishwaukee Street
Rockford, IL 61104
815-965-4013
sales@bourn-koch.com
www.bourn-koch.com