Since the year 1968, Ashoka Machine Tools Corporation has been manufacturing girth gears for ball & rod mills, sugar mills, bull gears and ring gears. Also the gears in single piece and multiple segments. These Kiln Girth Gear are fabricated in castings, and special ring rolled forged rims as well. We at Ashoka utilize state-of-the-art technologies in designing and manufacturing processes, so as to enhance reliability, performance and longevity of the gears. We bring forth complete solution for open power transmission drive, with the support of our vast experience and comprehensive expertise in this engineering field.
Our complete package includes gear casting, heat treatment (volume hardening), quenching, case carburizing and other heat treatment for precise gear cutting along with precision grinding to make a perfect finish ready-to-install gear.
General Gear Manufacturing Procedure
Split / Girth Gears Ring Gears
8.5 m Dia x 50 Module
Ball mills, rod mills, rotary kilns, rotary coolers, dryers for cement plants,
power plants, steel plants, mineral grinding & processing plants etc.
Sugar Mill Gears
8.5 m Dia x 50 Module
Crusher mills, crush rolls for sugar plants
5.0 m Dia x 50 Module
Ball mills, rod mills, rotary kilns, rotary coolers, crusher mills, mining, steel plants,
power plants, paper plants, fertilizer plants, grinding applications, heavy machinery etc.
4.0 m Dia x 40 Module
Gear reducers, open gearing for various industrial sectors specified above
1.9 m Dia x 30 Module
Gear reducers, machine tools and various other applications for above specified
Site Audit & Gear Inspection:
Keeping the remaining working life of girth gear in mind, its condition is evaluated at the site time-to-time. Also the advices on existent gear life and need of new gear are made after the audit findings.
In order to create detailed manufacturing drawings, a complete dimensional inspection is done on existing gear at the site that helps in the production work. The inspection also covers drilled chips collection (if it is required and possible) for hardness tests, and for chemical analysis as well.
Based on needful mechanical properties the selection of appropriate grade material is done, it covers alloy steels & carbon steels, graded irons, SG iron etc., phosphorus bronze and others. We offer pinions and gears in cast as well as forged forms. Also, various global material standards are utilized such as ASTM (USA), BS (British), AISI (USA), GS (German), JIS (Japanese) and IS (Indian) standards.
Casting & Fabrication:
Casting / forging is manufactured keeping minimal necessary machining in mind, for all applicable and required faces & surfaces. In order to attain the coveted mechanical properties, the casting or forging is volume-heat treated in specific enclosed furnaces with right temperature controls. For chemical testing, we use the latest spectrometers, universal testing machines for mechanical properties, and equotip type hardness testers. Heat treated casting is then tested for internal and surface flaws using non-destructive testing along with Magnetic Particle Inspection. Moreover, Ultrasonic Testing (UST) is carried out to have accurate results.
Joint facing is thoroughly performed on each girth / split gear on each side of the joints. It is achieved with the help of special horizontal floor borers (SKODA, UNION). Further, appropriate machining is also performed for having a perfect finish work. In some cases finish machining is done after the heat treatment and preliminary turning, and in a few cases after one round of teeth cutting.
Turning job is performed on special vertical turret lathes (BERTHIEZ, FRORIEP, DORRIES), after the joint facing. Required appropriate machining work is similar to the joint facing operation.
Teeth cut is carried out on finish turning of the gear by using special hobbing machines (MAAG, WMW). Generally, teeth cutting is performed in more than two cuts - one for major chunk of the metal and another for finishing work. Stresses are made during the teeth cutting owing to the large volume of metal cut. After the first rough cut the job is stress relieved.
Various types of heat treatments are carried out on the gears or pinions. The gears are heat treated on case-to-case basis in order to relieve stresses that are generated during machining. Also, the jobs may be induction hardened for surface, where high range of hardness is needed. Case carborizing and nitirding are some other forms of hardening. Moreover, the jobs are polymer / oil quenched so as to control & maintain the needful range of hardness.
Types of heat treatments offered:
The tasks of gear inspection are carried out by using special hand, automatic instruments, mechanical instruments and testers manufactured by well-known companies like MITOTOYO etc. Various tests cover material tests like mechanical testing and hardness testing, chemical testing, and dimensional measurements. Also, we perform non destructive testing for internal flaws which includes magnetic particle inspections (MPI) and ultrasonic testing (UST). Moreover, developer penetrant testing (DP) is executed for surface crack detection. Gear tooth profiles are tested with special instruments such as profiles testers and vernier calibres.
We at Ashoka perform stage wise inspections in order to bring forth the finest engineering work. Also third party inspections agencies like SGS, LLOYDS, DNV, MOODY, TPL, etc. have frequently visited our workplace for witnessing of aforementioned tests.
On Site Installation
We provide on-site installation of the gears and pinions manufactured by us. Supervising expert is assigned to the site, however, installation tools, local workforce and lifting equipment such as movable cranes are to be provided by client. In some special cases we can also undertake the entire job of installation, but it depends on the geographic location of the site.
After Sales Support
We provide life-time after sales technical support to our industrial customers for all our supplied gears and pinions. The support covers services that help to smooth the work process, and on-site support is rendered on chargeable basis.