Use a Horizontal Hobbing Machine to Extend Your Gearmaking Operations

EMAG’s CLC Series H machines are versatile additions to the shop floor, enabling gear suppliers to make a wider range of products.

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The EMAG CLC 260 H horizontal hobbing machine. (Image: EMAG.)

The EMAG CLC 260 H horizontal hobbing machine. (Image: EMAG.)

Nothing ensures a smooth manufacturing process like a precision-tuned set of gears. Those gears are produced via the process of hobbing: a specialized milling process for cutting gears, splines and sockets using a hobbing machine. The blank workpiece is mounted and teeth are cut into it by a tool called a hob, which is a cylindrical tool with helical cutters.

Most hobbing machines are vertical hobbers, machines where the blank workpiece is fixed to a vertical spindle and the hob is positioned horizontally. This arrangement is particularly effective for cutting external gears.

However, vertical mounting isn’t always feasible for making longer cuts, such as the splines on the end of a shaft as well as gear wheels and worm gears. “It’s a huge constraint on the hobbing process, especially for loading the part,” said Claudio Montanari, Head of Production at EMAG SU. “The higher you go with the clamp on the part, the higher the machine. That means when you apply force, you can bend, you have higher deviation. And the more you go up the more vibration you have. This can affect the cycle time.”

Those jobs might need a horizontal hobbing machine instead. These machines have a horizontal spindle orientation, meaning the workpiece is positioned horizontally, with a vertically mounted hob. This configuration is well-suited for cutting external gears and splines.

One such solution is the EMAG CLC Series H machines. “The Horizontal CLC 260-H is one of the milestones of EMAG’s CLC machine range,” said Montanari. It can handle a workpiece with a diameter of up to 260 millimeters (mm) and a maximum length of 1,800 mm. A larger machine, the CLC 500 H, can handle a 500 mm part that can be 2,000 mm or 3,000 mm long. Both machines have a stable structure with hand-scraped tangential axes and include a table and milling head equipped with direct-drive axes. They can perform operations that use oil, emulsion or run dry.

Transitioning from one part to another can be done quickly and easily, enabling the production of individual pieces and small batches. The CLC series can also be set up for automated functioning and a steady rest that can support an additional axis. In addition, the hobbing head can tip up to 45 degrees, plus or minus, to avoid any collisions.

Further enhancing the machines’ versatility, EMAG offers optional equipment for skiving, single-part milling, measuring on the machine, deburring and chamfering.

EMAG developed this CLC line to respond to market demands for a machine that can hob a long shaft while avoiding the limitations of a vertical hobber. The vertical variant can be subjected to significant wear and tear; in particular, on the counter bearing which is consistently pushing during long shifts. Depending on the cycle applied to the machine, the head of the machine could require regular adjustment. A horizontal hobbing setup can take significant pressure off the head and therefore reduce the wear.

A key selling point is the CLC series’ versatility. “The machine has lots of options and variants that can be customized according to the requirements of the customer,” said Montanari. “One cut, ready for treatment. One pass.” As a result, the machine has become an instrument of choice in a wide range of industries, from aerospace to automotive. “You can create cut gears or worm gears, as well as shafts and track shafts. It covers a wide range. And according to the specific manufacturing process of the customer, we can adjust the machine accordingly to make the machine more suitable for the customer’s purpose.”

EMAG’s EDNA Cortex software is a particularly powerful tool. The software connects directly to machine control units and can be scaled for local, edge and cloud applications. EDNA Cortex is also modular, with an open software architecture, giving the operator the ability to add additional machines—even from other manufacturers. In addition, it has remote monitoring and diagnostic functionality available, similar to the software used for cobots.

“The software has applications for worm gears, as well as for tangential cycles or radial tangential cycles,” said Montanari. “You enter the cutting depth, the width of the gear approach, distance and synchronous point. This means the head and table are always synchronized because we don’t have gear transmission—only electronic gearing.” The operator can arrange the phase and timing of the gear based on the XCC reference point. “The software is very easy to use, including for beginners, because they only have to enter the data.”

EMAG’s EDNA software enables data-optimized manufacturing.

Another important feature of EMAG’s horizontal hobbing technology is that it can be combined with milling functionality in the same machine. An optional spindle attachment installed on the CLC 260 H’s milling head enables the milling of worm shafts—allowing the CLC Series H machines to mill multiple workpieces at a time. The 260 can cut up to six modules at a time, while the 520 can module 10 to 12.

“You can use the milling cutter to rough the gear, or you can have a special application for sector gear,” said Montanari. “So, you can combine the milling with the milling disc, and the finishing by hobbing on the CYZ axes synchronous point. They move together in sync and refer to every part geometrical element by using an aligning sensor.” Combining the two functions helps to extend the life of the tool, particularly if it’s being used on very hard material.

In an increasingly competitive marketplace, having the flexibility to adjust from one work order to another is crucial for gear manufacturers of all sizes. The versatility offered by EMAG’s CLC Series H machines for specialized horizontal gear hobbing makes it a valuable addition to the shop floor. Not only can these machines accommodate an impressive range of jobs in their own right, they can also function as valuable complements to the work done by a vertical hobber.

Visit EMAG to learn more.