APresentation on a six sigma Project

1

Presented To:Mr. Rakesh KumarAsst. Professor Mech. Engg.Jagannath University

Presented By:Mr. Suraj Kumar GuptaB.Tech(ME)8th sem

2

SIX SIGMA PROJECT

PREVENTION OF SCORING ON BEARING SHELLS

(QUALITY ASSURANCE)

Under Guidance

Mr. Rishikesh Dabhade

Why 6 Sigma??? Six Sigma seeks to improve the quality of

process outputs by identifying and removing the causes of defects (errors) and minimizing variability in manufacturing and business processes.

A six sigma process is one in which 99.99966% of the products manufactured are statistically expected to be free of defects (3.4 defective parts/million).

3

4

5

JAN FEB MAR APR MAY JUN

YEAR2014PHASE

Control

Define

Measure

Analyse

Improve

PLANNED ACTUAL

DMAIC TIME PLANDMAIC TIME PLAN

DMAIC

6

DEPARTMENT INVOLVEMENTDEPARTMENT INVOLVEMENT

DMAIC

DEPARTMENT D M A I CRECTIFICATION AREA

WASHING AREA ASSEMBLY LINE CRANKSHAFT LINE CYL. BLOCK LINE CAMSHAFT LINE

7

8

PROJECT TITLE: Prevention of Scoring on Bearing Shells

PROJECT DESCRIPTION:In the last month January 2014 , during Bearing Inspection it has been found that bearing shells of many engines got scored. Total numbers of engines (having scored bearing shells) were 23 in January, while in previous year, each month had maximum 4 Nos. engines having scored bearing shells.

SCOPE:Area: Cylinder Block line, Crankshaft line, Camshaft line, Assembly line, Washing & Rectification areaApplicable Plants: Tata Motors, JamshedpurMain Parts: Crankshaft, Cylinder block & bearing shells

GOAL:Elimination of root causes for negligible or no scoring on Bearing Shells during BI

TIMELINE:24TH January 2014 to 30th June 2014

TEAM MEMBERS:Project Sponsor : Mr. S K Sinha (AGM, Engine Machining)Project Mentor : Mr. Rishikesh Dabhade (Sr. Manager, Crankshaft line)Project Promoter : Mr. Ohm Prakash (Manager, Crankshaft line)Project Leader & Member : Mr. Suraj Kumar Gupta

PROJECT CHARTERPROJECT CHARTER

DMAIC

9

Defect Definition?Scoring in bearing shells of MBs & CPS and in some engines also on journals of MBs & CPs, due to which many engines were brought for BI (Bearing Inspection).

Why this Project? This project is undertaken to determine and eliminate the causes of bearing shells scoring and reduce the chances of bearing failure.

Business Results:•Reduction in changing of bearing shells•Reduction in the number of engines for BI•Reduction in rework of crankshaft•Increase Customer satisfaction

.

Project Title: Scoring in Bearing Shell of Main Bearing & Crank Pin BearingScoring in Bearing Shell of Main Bearing & Crank Pin Bearing

EnginesEnginesMr. Suraj Kumar GuptaMr. Suraj Kumar GuptaProject leader:

Project CTQ’s:•Crankshaft machining & cleaning •Cylinder block cleaning•Assembly cleanliness

Project Function :

BUSINESS CASEBUSINESS CASE

DMAIC

10

What is Voice of Customer indicating ? VOC indicates that the

cleanliness of oil hole of crankshaft & cylinder block are not proper and oil hole chamfering is not good.

DMAIC

What is Voice of Customer ?In Bearing Inspection it has

been found that bearing shells of many engines got scored, if they did not get scored then at least every engines which are brought for BI had circumferential lines on inner surface of bearing shells and/or on journal.

11

What is Bearing Inspection ( BI ) ?

DMAIC

Bearing Inspection is an important activity after engine testing. Every 50th engine after testing is brought in rectification area for BI where all the MBs caps & con rod caps are untorqued and then remove them from engines.

After that, all MBs & CPs and their caps including their bearing shells are checked and verified with QA Inspector for dent mark or any type of damage/scratch mark on the bearing shells.

Since BI found NOK in many engines so every 25th engine after testing is going to collect for BI.

12

CTQ FLOWDOWNCTQ FLOWDOWN

DMAIC

13

SUPPLIER INPUT PROCESS OUTPUT CUSTOMER

S I P O C S I P O C

Rotate the engine 180° and untorque oil sump mtg bolt and remove oil sump

ASSEMBLY LINE

COMPLETE ENGINE

REASSEMBLED ENGINE

DISPATCHING AREA

BEARING INSPECTION OPERATION SEQUENCE

If NOK in BI

DMAIC

If OK in BI

Engine Testing

Load the engine on working fixture, untorque drain plug & remove the engine oil in a jar

Check & verify all bearing shells for dent mark or any type of damage/scratch

Untorque oil pump mtg bolt & remove the oil pump

Untorque con rod 1&6, 2&6, 3&4 and all MB caps

Reassemble the engineChange the bearing shells

and/or crankshaft

14

15

MONTHWISE BEARING INSPECTION DETAILS

DMAIC

16

MB wise scoring (Oct’13 to Jan ‘14)

DMAIC

Types of scoring

• Deep dent mark

• Light dent mark

• Scratch

• Circumferential scoring

• Deep & Light lines

17

DMAIC

Deep dent mark

18

DMAIC

Light dent mark

19

DMAIC

Scratch

20

DMAIC

Circumferential scoring

21

DMAIC

Deep & light lines

22

DMAIC

BEARING INSPECTION IN FEB’14

23

ENGINE NO.

CRANK SHAFT NO.

MB1

MB2

MB3

MB4

MB5

MB6

MB7

CR1

CR2

CR3

CR4

CR5

CR6

BVY1575 BFc14A0398 LS DS

BVY1600 BFc14A0488

BVY1625 T14A0564 LS

BVY1650 BFc14A0486

BVY1675 T14A0528 L

BVY1700 T14A0604 DS

BVY1725 BFc140424 LS LS

BVY1745 BFc14A0695 LS

BVY1775 T14A0567 L

BVY1800 T14A0248 L L CS L L

LS :Light Scored , DS :Deep Scored , CS :Circumferential scored , L :Lines

DMAIC

BEARING INSPECTION IN FEB’14

24

ENGINE NO.

CRANK SHAFT NO.

MB1

MB2

MB3

MB4

MB5

MB6

MB7

CR1

CR2

CR3

CR4

CR5

CR6

BVY1825 BFc14A0543 L L

BVY1850 BFc14A0550 LS

BVY1815 T14A0554 L L L L L L L

BVY1897 T14A0208 LS

BVY1818 T14A0366

BVY2350 T14B0276 LS

BVY2400 T14B0156

BVY2450 BFc14A0697 L L L

BVY2700 BFc14B0052

BVY2750 BFc14B0196

LS :Light scored , L : Lines

DMAIC

25

Possible factors of bearing scoring Dirt Chips Insufficient oil supply Overheating Improper machining of engine components Misalignment of engine components Assembly errors Bearing clearances

26

DMAIC

27

Scoring on bearing shell

Camshaft Crankshaft

Bearing shell Cylinder block Assembly

DMAIC

Oil pump

Dust or chips in oil hole

Improper Oil hole chamfering

Poor Journal surface finish

Cause & Effect DiagramCause & Effect Diagram

Dust or chips in oil hole

Burrs on cam bush

Errors in lock groove

Burrs on gear teeth

Dust or chips in oil hole

Run out of MBs greater than max value

Dirt on bearing back

Dirt in lubrication system

Material defects Use of std. size

bearing shell in undersized or

oversized journalVariation in critical

dimension

Low oil pressure

Oil cooler

Imperfect cooling

Crankshaft lineStation No:

Process Cause

170 OHC & Inspection(before induction hardening)

Improper chips cleaning of oil hole gallery after drilling due absence of air gun with 6ϕ pipe.

410 OHC & Deburring •Larger & square shape of emery paper(grit 120) not polishing high point at oil hole opening. There is no predefined centre point of rubber & emery paper.•Improper chips cleaning of oil hole gallery of crankshaft due absence of air gun with 6ϕ pipe.•Due to Manual operation of chamfering operator sometimes forget to polish any oil hole opening with grit 120.

28

DMAIC

Crankshaft lineStation No:

Process Cause

430 Lapping Cutting oil not filtered properly because magnetic separator not working properly.

440 Washing Insufficient pressure due to jammed washing nozzles.

460 Final inspection •There is no magnetic equipment(stick) to remove chips from oil gallery.•There is no mean of checking of bearing scoring

29

DMAIC

Cylinder block lineStation No:

Process Cause

470 Cam bush pressing During cam bush pressing , burrs generate on the outer surface of cam bush. In many cyl.block these burrs are present even after washing.

490 Lock groove on MB milling

Improper fixing of cyl.block on fixture leads to height loss or height gain and further lead to error in lock groove.

550 Final inspection of cyl.block

•Improper cleaning of oil gallery , when operator blow the air from air gun then some chips are move to other position but remains in the cyl.block.There is no magnetic equipment at inspection point of cyl.block to remove the chips from oil gallery.

30

DMAIC

Camshaft lineStation No:

Process Cause

40 Oil hole drilling Four different holes are drilled (oil hole ϕ 6, eccentric ϕ 3, MB4 & MB1 ϕ 4) but operator uses single device to apply compressed air for removing of chips from all the holes.

130 Gear buffing Buffing wire pattern of buffing wheel got irregular due to which burrs of gear teeth can not be removed properly.

31

DMAIC

Assembly lineStation No:

Process Cause

SBL 03 Placing of upper bearing shell on bore of cyl.block

The presence of a foreign particle trapped between the bearing back and itshousing will lead to a raised area, with the ensuing risk of contact between thisprotruding high-spot and the journal.

SBL 05 MB cap fitment with lower bearing shell

The presence of a foreign particle trapped between the bearing back and itshousing will lead to a raised area, with the ensuing risk of contact between thisprotruding high-spot and the journal.

SBL & LBL

The presence of dirt particles entrained in the lubrication system during assembly(working hours) and non-working hours.

32

DMAIC

BEARING

MB E3

( Menon Bearing Euro 3 )

Part No: 252703123119

Application: 497/697 main bearing lower

33

DMAIC

34

DMAIC

35

36

37

THANKS