Toward Precision and Perfection

The gear industry of the country is constantly in search of a solution to combat the present-day hurdles in producing ideal gears. Nimble Machines, a division of UCAM, offers CNC gear hobbing machines that promise to fit the bill.

Today, the Indian gear industry is facing the challenge to produce high-quality, noiseless gears in a required volume at a highly competitive price. This is making gear manufacturers seek machine tools and technologies to meet these needs. The current market trend is to move away from the conventional or refurbished gear hobbing machines towards CNC gear hobbing machines which are highly reliable and productive.

Direct Drive Technology

Direct Drive technology in hob spindle and work tables has given a cutting edge to CNC gear hobbing machines. Direct drive spindles offer higher torque with higher speed up to 4,500 rpm as against 1,000 rpm in conventional belt driven spindles. With higher cutting speed, cycle times have drastically reduced with Carbide Hobs. Spindles with built-in motors are more
reliable and maintenance- friendly due to less number of mechanical parts.

CNC gear hobbing machines are now available with torque motor driven rotary tables as against worm gear tables. The advantages of direct drive tables are their higher response, reliability, speed and torque.

Higher hobbing accuracy to avoid finishing gear cutting operations

Direct drive technology in CNC hobbing machines allows higher spindle revolution for higher cutting speeds which, together with quality hobs, is able to improve the accuracy in the gear hobbing up to DIN class 7. With the improved accuracy on hobbing machines, one can avoid finish gear cutting operations like gear grinding and shaping.

Managing hob life and improving process efficiency

Using common hob for roughing and finishing operations is a compromise for the hob life, as cutting conditions are different for both operations. For example: roughing operations produce higher volume of chip thickness and need higher gaps in the gashes. Whereas for finishing operations higher cutting speeds can be used as chip thickness is less.

With programmable Hob Shift feature of CNC gear hobbing machine, separate hobs for rough and finish gear cutting are mounted on the same arbor. This improves the tool life as tool wear and tear in rough gear cutting does not affect accuracy in finish gear cutting. Same can be further improved by using multi-start hobs for roughing and single-start hobs for finishing.

Also, multiple hobs can be mounted on the common arbor to cut multiple gears on a component in single set-up, thereby reducing cycle time and increasing productivity.

Automatic loading and unloading of components

With reduced cutting time due to improved cutting tools and parameters, it is vital to reduce non-cutting time to achieve optimum cost per piece. To meet this requirement, CNC gear hobbing machines are now available with options for auto loading / unloading of components. Ring loader is the most preferred option due to its short cycle time for loading and unloading. Ring loaders are available with two or fo

ur stations. Four-station ring loaders are used to cut down the change-over time further, as well as for additional operation like deburring. These machines are also supplied with conveyor mechanisms for transporting parts for easy loading unloading.

Crowning to reduce gear noise

Gear noise due to improper gear profile has been a problem in gear train mechanism. Crowning of the teeth has helped in reducing the gear
noise. Crowning involves the variation of thickness of the gear tooth and ensures the contact in the center. It also helps in minimizing misalignment issues caused due to inaccurate machining of shafts, housing etc. Crowning can also reduce the lead problems in the gears which cause gear to wear unevenly.

Noah series of CNC gear hobbing machines

Noah series produced by Nimble Machines, a division of UCAM Pvt Ltd, are high-speed, high-performance, 6-axes gear hobbing machines. These machines come with vast features like Direct Drive technology, crowning gear software, and automation for loading and unloading. These are capable of cutting splines, sprockets, helical gears, and spur gears up to 12 modules and accuracy class up to DIN 6-7.

Author:

Rajesh Gawhale

Head –Nimble Machines

rajesh.gawhale@nimblemachines.co.in

Noah series of machines are built with the latest technologies to produce the best quality gears for Indian users, thereby eliminating the dependency on foreign suppliers for high-end gear hobbing machines.