Rane Madras Lim­ited (RML)

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The Chen­nai-based Rane Madras Lim­ited (RML), estab­lished in 1960, main­tains mar­ket lead­er­ship by sup­ply­ing consistently su­pe­rior qual­ity steer­ing, sus­pen­sion link­age prod­ucts and man­ual steer­ing gears, and ser­vices. It serves a va­ri­ety of in­dus­try seg­ments in­clud­ing pas­sen­ger ve­hi­cles, com­mer­cial ve­hi­cles, farm trac­tors, two-wheel­ers, three­wheel­ers, rail­ways and sta­tion­ary en­gines. Its 5 man­u­fac­tur­ing fa­cil­i­ties, spread across In­dia are in Chen­nai, Pondicherry, Mysore, Varanasi, and Ut­tarak­hand.

RML sup­plies hy­draulic prod­ucts to Son­alika, Swaraj and Es­corts, and steer­ing sys­tems to Ashok Leyland, Daim­ler In­dia and Ger­many, and TAFE. It also sup­plies link­ages to Maruti Suzuki. More than 90% of these prod­ucts are man­u­fac­tured in the Mysore plant and the re­main­ing in Varanasi and Ut­tarak­hand. Hy­draulic prod­ucts are only for farm trac­tors.

The com­pany claims it is strong in hy­draulics and is the mar­ket leader by hold­ing 80% of share with all its cus­tomers. To grow fur­ther, RML is work­ing on new tech­nolo­gies and plan­ning to ex­pand its busi­ness to other ar­eas. Steer­ing sys­tems are of 3 types — man­ual, in­te­gral power steer­ing, and hy­dro­static steer­ing. While there is no hy­draulic cylin­der in in­te­gral power steer­ing, it has reg­u­lar steer­ing gear with hy­draulic as­sis­tance.

Off-road ve­hi­cles like trac­tors, dumpers, bull­doz­ers and load­ers, which run at much lower speeds, con­stantly de­mand power as­sist for steer­ing. A hy­dro­static steer­ing sys­tem is suit­able for such ve­hi­cles since steer­ing is al­ways sup­ported with power and re­quires less than 10% of the steer­ing ef­fort in man­ual sys­tems. How­ever, it needs high-pre­ci­sion man­u­fac­tur­ing.

New tech­nolo­gies

Rane is work­ing on var­i­ous new

tech­nolo­gies like pro­vid­ing ad­di­tional port to op­er­ate other im­ple­ments in the trac­tor. The com­pany plans to launch this prod­uct by mid of 2018. The com­pany is also work­ing on anti-shock HSU sys­tem for trac­tors by pro­vid­ing anti-shock valve, which will pre­vent shock from pass­ing on to the sys­tem. RML cus­tomers have evinced in­ter­est in this prod­uct. It plans to launch this prod­uct shortly.

RML is also work­ing with many en­gi­neer­ing ex­perts to re­duce the cost of HSU by at least 30% by sim­pli­fy­ing it. The prod­uct is ex­pected to hit the mar­ket in the next 12-18 months as it re­quires lot of test­ing.

Re­cently, Auto Com­po­nents In­dia vis­ited RML’s Mysore plant to have a close look at its high-tech and high-pre­ci­sion man­u­fac­tur­ing sys­tems and pro­cesses. The plant, estab­lished in 1984, has 2 units – one is 20,000 sqm fa­cil­ity, which man­u­fac­tures man­ual steer­ing gear and link­age prod­ucts. The other is 2500 sqm is ex­clu­sively for hy­draulic prod­ucts. It man­u­fac­tures Hy­dro­static Steer­ing Unit (HSU), steer­ing cylin­der, steer­ing col­umn and trans­port lock valve, man­ual steer­ing gear and link­ages. The unit 1 has a ca­pac­ity to make around 3.6 lakh steer­ing gears and about 500,000 link­ages. The sec­ond plant has a ca­pac­ity to make 1.20 lakh cylin­ders and 0.24 lakh HSUs.

Hy­draulic steer­ing

The hy­dro­static steer­ing unit used for the trac­tor ap­pli­ca­tions, has dif­fer­ent vari­ants like 80cc,100cc, 120cc etc., It con­sists of a steer­ing con­trol unit, pump, reser­voir with in-built fil­ter and dip stick, hy­draulic cylin­der, pip­ing and hoses. The steer­ing con­trol unit (also known as hy­draulic steer­ing unit) has about 28 com­po­nents, all of them re­quire mi­cron level pre­ci­sion and top-class man­u­fac­tur­ing ca­pa­bil­ity. Ex­cept for fas­ten­ers, bear­ings, seats and springs, all the me­chan­i­cal com­po­nents are man­u­fac­tured in-house to main­tain qual­ity.

Out of the 28 com­po­nents, 6 are unique, pre­ci­sion com­po­nents like sleeve spool (di­rec­tional con­trol valve). Here the cylin­der is in 3 mi­crons, round­ness is 2 mi­crons and the clear­ance 8-12 mi­crons. Very high-pre­ci­sion ma­chines are used to drill 60 dif­fer­ent holes in var­i­ous an­gles and di­rec­tions.

Hy­draulic steer­ing gear is much more crit­i­cal be­cause of its tol­er­ances and func­tion­al­ity than the man­ual steer­ing gear. There­fore, RML has cre­ated an ex­clu­sive fa­cil­ity for hy­draulics to meet the strin­gent dimensional tol­er­ance and the prod­uct spec­i­fi­ca­tion. Though the ba­sic pro­ce­dures are sim­i­lar, the kind of ma­chines used, and er­ror­proof­ing method­ol­ogy fol­lowed for hy­draulics are very dif­fer­ent. It has also in­ducted spe­cial pur­pose ma­chines for high-pres­sure wash­ing, right an­gle cross-hole drilling, ded­i­cated ID grind­ing, higher ac­cu­racy sur­face lap­ping and shrink wrap­ping for dust-free pack­ag­ing.

HSU Hous­ing

Hous­ing is man­u­fac­tured us­ing SG 500/7 ma­te­rial. In­side the hous­ing a lot of in­ter­cross holes have to be made for in­ter­con­nec­tion. In the HSU hous­ing 25 dif­fer­ent holes are made and the di­am­e­ter varies from 2 mm to 15 mm. With spe­cial pur­pose ma­chines the com­pany does the op­er­a­tion and create cham­bers. These cham­bers are called left and right cham­bers. When the steer­ing wheel is ro­tated, the oil from one cham­ber trav­els to the other through these holes. If they are not pre­cise the steer­ing gets struck.

The start­ing op­er­a­tion is turn­ing and boring and it is per­formed in 1 axis ma­chine. The sec­ond op­er­a­tion, called milling, is done in the Vertical Ma­chin­ing Cen­tre (VMC) where 52 in­ter-con­nected holes are made in 3 phases. An­gu­lar drills are also made here. The cy­cle time to make a HSU hous­ing is 9 min­utes. The hi-tech drilling ma­chines com­plete its pro­cesses in 2 min­utes and thus saves time.

The third op­er­a­tion is called cross hold drilling which is a unique op­er­a­tion fol­lowed by laps­ing, and the fifth op­er­a­tion is blind bore hon­ing. Af­ter the pro­cesses, the prod­uct goes for wash­ing. To­tally, there are 6 op­er­a­tions needed to com­plete the hous­ing ma­chin­ing. Then, it will go for heat treat­ment fol­lowed by hon­ing. Then the ex­ter­nal grind­ing is done through match grind­ing for the per­fect mea­sure­ment of in­ter­nal holes in com­po­nents.

Gero­tor

The me­ter­ing unit is called sta­tor and ro­tor and to­gether it is called gero­tor. In the gero­tor there are 7 lobes, where the length and area of each lobe is cal­cu­lated for the num­ber of ro­ta­tions. Nor­mally 3.5 ro­ta­tions from one end to the other is called steer­ing move­ment, and so the num­ber of ro­ta­tions is con­sid­ered to be pri­mary. Based on the cus­tomers’ re­quire­ment, the com­pany man­u­fac­tures the gero­tors in terms of ‘cc’. Gero­tor is made from 16mmCR5 case car­buris­ing ma­te­rial.

Af­ter turn­ing and groov­ing, pro­file grind­ing is done for the gero­tor, which is an im­por­tant and unique op­er­a­tion. Later pro­file ma­chin­ing is done fol­lowed by drilling and heat treat­ment. The same process is done for ro­tor and both are matched. While match­ing, there should not be any vari­a­tion be­tween the lobes and it should be 30 mi­crons. A gero­tor un­der­goes 7 op­er­a­tions.

As­sem­bly line

The RML Mysore unit has a ded­i­cated as­sem­bly line for power steer­ing. Be­fore as­sem­bling HSU, all the com­po­nents un­dergo ul­tra­sonic wash­ing, where elec­tri­cal en­ergy is con­verted to me­chan­i­cal en­ergy. There are 4 cham­bers with 2 mi­cron fil­ters, one with 25 mi­cron and an­other with 10 mi­cron fil­ter. In the first fil­ter the prod­uct un­der­goes high pres­sure wash­ing, tur­bu­lence wash­ing, ul­tra­sonic wash­ing and dry­ing. Then it goes through the sec­ond fil­ter where the con­tam­i­na­tion level will be brought down to 6mg. In this process, 5 HSU sets can be washed at a time.

As­sem­bling of the HSUs are in semi-au­to­mated sta­tions, which has 24 poka yoke for er­ror

proof­ing. Once the com­po­nent is mounted, oil seal and bear­ing washer is as­sem­bled and the spring ten­sion is checked. Then gero­tor is as­sem­bled and bolt­ing is done. Af­ter en­sur­ing that the prod­uct is er­ror less, it goes for test­ing, where 100% in­spec­tion will be done for hy­draulic steer­ing, power steer­ing and other prod­ucts. A prod­uct is in­spected based on 12 pa­ram­e­ters which in­clude in­ter­nal leak­ages, pres­sure vari­a­tion, end-lock po­si­tion­ing, in­put vari­a­tion where 2 Nm torque is re­quired.

Pis­ton & rod

For pis­ton and rod the raw ma­te­rial is cut suit­ably and then fac­ing, turn­ing, thread cut­ting, thread rolling, and in­duc­tion for hard­ness are car­ried out. Tem­per­ing is done to give uni­for­mity in the flow of the in­ter­nal struc­ture. Then is the grind­ing fol­lowed by chrome plat­ing for cor­ro­sion re­sis­tance and sur­face hard­ness. Af­ter this the prod­uct goes to the as­sem­bly line. Once the pis­ton and rod are as­sem­bled into a unit, leak test­ing is done to de­tect even minute leaks at 240 bar pres­sure, though the nor­mal work­ing pres­sure is only 40 bar.

Af­ter the test­ing for HSU and cylin­der the unit goes for primer paint­ing and dry­ing pro­cesses. Af­ter com­ing out of the oven, the prod­ucts reach the PDI and are packed and dis­patched to the re­spec­tive cus­tomers.

The TQM way

RML started TQM ac­tiv­i­ties in 2001 and by con­tin­u­ous im­prove­ment year af­ter year it re­ceived Dem­ing Prize in 2007 and Dem­ing Grand Prize in 2012. RML’s strength in tech­nol­ogy has re­ceived a boost with im­proved qual­ity lev­els. The Mysore plant is cer­ti­fied for ISO 9001/2001, OHSAS and TS 16949. Last year this plant recorded a turnover of Rs 225 crore and this year, it is an­tic­i­pat­ing10-12% growth.

The com­pany’s fo­cus is on hy­draulic prod­ucts, since the growth of the man­ual steer­ing gears are com­ing down. In the hy­draulics busi­ness the com­pany started with Rs 9 crore turnover. This year it is ex­pect­ing Rs 30 crore and by FY 19-20 Rs 50 crore. The change from man­ual steer­ing to hy­draulic steer­ing was about 30% last year and this year it will reach up to 40-45%. RML has started sup­ply­ing power steer­ing to Mahin­dra & Mahin­dra, which ac­counts for more than 54% of the do­mes­tic sales.

The sec­ond unit of RML Mysore plant has the ca­pac­ity to make 1.20 lakh cylin­ders and 0.24 lakh HSUs

Gowri Kailasam, Pres­i­dent, Steer­ing & Link­age Busi­ness, RML (third from left) and D. Satheesh Ku­mar, Vice Pres­i­dent - Op­er­a­tions, RML (fifth from left) along with the core team.

The Unit 1 of the Mysore plant man­u­fac­tures steer­ing gear & sus­pen­sion link­ages, and has a ca­pac­ity to make 3.6 lakh gears.

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