Gear Grinding Solutions from CUMI

Mr. Ramesh K, Senior Associate Vice President - Head of Technology, CUMI
May 14, 2019

From aeroplanes to ships, from automobiles to locomotives, from medical devices to material handling equipments, everything is now expected to work at higher efficiency, be more reliable, be compact and cost lower. Gears form an integral part of all these machines. Gear manufacturing is a highly skilled and critical machining process. It requires application expertise and sophisticated tools & machines. The transmission industry now aims at increasing power density, reducing gear noise and improving energy efficiency levels in gear boxes. For gears, it translates into tighter tolerances, higher profile accuracy and improved surface finish. Gear Grinding, a very precise finishing operation, helps in achieving the desired finish. CUMI constantly works on solving such challenges and offers comprehensive solutions for gear grinding needs.

Abrasives are materials used to grind, abrade or clean work pieces to achieve the desired shape and finish. Abrasive technology is challenged by work piece materials, stringent surface quality requirements, manufacturing process changes and aggressive cost targets. Gear grinding is one of the critical processes in forming transmission components. This involves a relatively high contact area between the tool and work piece and is extremely sensitive to mechanical and metallurgical damages.

Challenges in gear grinding processes
As far as materials and design aspects are concerned, requirements of aerospace industry, automobile industry, and energy sector have pushed the envelope in developing special materials and tolerance limits by design. Advancements in grinding machines with multitasking features has resulted in many advantages such as reduced set-ups, reduced tooling and fixturing and increased work piece accuracy and most importantly even throughput. The increasing demand for high efficiency and noise emission of gears pushes the gear grinding process to its limits. With the widening range of applications for automatic planetary transmissions and increased number of speeds, gears in average get smaller and smaller, while production volumes are increasing. The same applies to industrial applications. The movement towards the smaller gears result in shorter grinding times. Over the past decade, productivity and profile accuracy, no burn and fatigue strength in hard gear finishing are the challenges that a grinding wheel manufacturer faces.

Due to current economic conditions as a solution provider, tool suppliers in the industrial market place are consistently challenged by our customer need to reduce costs. This calls for immediate action to check costs and provide customers with a suitable solution that addresses the Total Cost of Ownership.

TCO - Gear grinding wheels
CUMI's constant innovation and product upgradation, through in-house R&D and strategic alliances with global leaders in grinding technology, have ensured international recognition as a manufacturer of quality abrasives and a provider of total grinding solutions. At CUMIs state of the art facility for making gear grinding wheels with new engineered micro crystalline abrasives, advanced new profiling system, breakthrough engineered ceramic bonding designs and revolutionary manufacturing technologies, all come together under one roof for the development and production of the next generation of bevel and cylindrical gear grinding tools. CUMI has been providing gear grinding solutions which includes Single rib and Multi rib gear grinding wheels.

CUMI Grinding Wheels for Gear Grinding

Higher productivity with predictable performance
Productivity and migration of machining to grinding demands the higher material removal in the grinding process and in turn reflect higher Qw. CUMIs engineered abrasives with specific geometry coupled with functional bonds helps in achieving Qw of 12 mm3/(mm*s) per flank. These engineered grains are not only tough but have a low bulk density. The uniqueness of shape and distribution gives more interconnected porosity and good accessibility of coolants to grinding zone. High level of porosity ensure uniform stock removal. These next generation wheels increases the throughput, significantly reduces the wheel dressing frequency, minimizes the possibility of grinding burn and offers reliable and consistent grinding performance (Figure 1).

Features and Benefits

Grind and Finish
Super finishing the working surfaces of gears and their root fillet regions results in performance benefits. A super finished surface of gear tend give free of stress raisers, damaged metal and peak asperities, all of which reduce the life of the gears. These gears will experience reduced friction, lower operating temperature, less wear, better scuffing resistance, and better contact fatigue resistance. The process of continuous grind and finish has been a accepted practice in gear industry. CUMI has developed a wheel for grinding and finishing of gears. The finishing portion of wheel is made with high resilience polymer bonded fine abrasive. The resilience of the finishing wheel can be altered to suit the work piece and grinding parameters (Figure 2).

Carborundum Universal Limited (CUMI), India, is a part of the US$ 4.8 billion conglomerate Murugappa Group. It is a fully integrated surface engineering company with capabilities ranging from manufacture of high performance abrasive grains, bonds, application engineering and design of abrasive wheels for diverse and demanding precision applications across industries. For more information visit