forward revrese pressure not ok

INDIA / C I L CARRARO

Manufacturing -AssemblyProblem Solving Technique

Forward / Reverse pressure Not ok during

TLB testing

Assembly Line: TLB

Leader Name: Pradeep Pokhariyal

Date of Commencement: 25-Jan-2015



PROBLEM – Identification & Definition

• Problem Selected: Forward & Reverse pressure values not within

specification at TLB Functional testing machine

• Target Date: 31-Jan-2015

• Current Level: 7147 ppm (Jul’14 to Dec’14)

• Project Leader Pradeep P Assembly

• Project Members Balkrishna Bhos Assembly

Uday Patil Assembly

Amol Ghodake Assembly

Rajendra Dhawale Assembly

Satish Gawari Tooling

Dinesh Deokar Process QA

Prashant Daware Technology




TLB loaded at Functional testing machine connect the Hydraulic units for- Total flow, Lube

flow, Lube pressure, Forward & Reverse pressure, Hydraulic diff. lock pressure & convertor.

At same time oil filled Transmission by oil filling hole. Scan the main transmission, distributor

& pump barcode on machine scanner to start the cycle. Oil warms upto 60deg.

Cycle starts – There are several phase of TLB tests like Reversal move, Hydraulic Brake test, Brake pressure switch Test, HDL test, Oil warming, 4WD test( for 4WD model), 4WD shaft rotation, Modulation test & Gear test. We test the TLB at 900 & 2200 RPM.

Forward pressure is used in – Reversal move, Hydraulic brake test, HDL test, oil warming, 4WD shaft rotation, Modulation test, Gear test.

Reverse pressure is used in - Reversal move., Hydraulic Brake test, HDL test, oil warming, Modulation test, Gear test.

Transmission will be tested OK- If all these phases are within specification.

Minimum value for Fwd. & Rev. press- 10.7Maximum value for Fwd. & Rev. press- 13.5When fwd & rev pressure not come within specification then functional Testing machine rejects job for “Reverse & Forward pressure not ok”

Also :-ΔP of (FWD-REV) ≤ 0.3 bar; Transmission gets rejected if the difference is more than 0.3 bar



Consequences-

• In order to repair the defect of Forward or reverse pressure not ok the

transmission needs to be half dismantled.

• Rework consumes resources like manpower, time, material etc which adds

to the cost of the company.

Reverse Pressure ValveForward Pressure Valve




Forward pressure out of range or not ok problem




PROBLEM - Identification & Definition

• Trend chart of Testing fallout for Rev / Fwd pressure not ok

12

15

12

7

3

9

7524

9180

8130

6757

2622

7317

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0

2

4

6

8

10

12

14

16

Jul'14 Aug'14 Sep'14 Oct'14 Nov'14 Dec'14

TLB fallout trend for Rev / Fwd Pressure Not Ok

qty ppm




• Data from July’14 to Dec’14

• Only in Old test rig, 10 jobs are tested okay after re-testing by removing

air (special provision made on this machine- possible cause)

• 60% problem is in 4WD TLB1 and 40% in 2WD TLB1

23, 40%

25, 43%

10, 17%

Machine wise fallout

new machine Fallout old machine Fallout

old machine Re-Tested

6509, 40%

9675, 60%

Model wise fallout

2 WD TLB1 4 WD TLB1




• Data from July’14 to Dec’14

• In 59% cases the input shaft seal ring is getting damaged or cut

24, 59%

14, 34%

3, 7%

Action Taken to repair the defective

Input Shaft Seal Ring Changed Distributor Changed

Remove the Burr In Rear Hsg



ANALYSIS – Cause & Effect Diagram



ANALYSIS – Cause & Effect Diagram

Root cause identified by cause & effect diagram-

1. Sharp edges on input shaft seal ring compression tool.

2. Seal ring compression tool got loose from its hinge supports.

3. Step & Ovality found in seal ring compression tool.

4. Seal ring retaining tool has entry radius not as per tool drawing.

5. Contamination found in seal ring retaining tool.

6. Input shaft guide tool design not effectively guide the input shaft in transmission.

7. Burr / metallic chip in Rear housing input shaft oil holes.

8. Brushing operations to clean Rear housing oil holes & inspection missed by casting QA

inspector.

9. Washing operator miss the operation of air blowing in oil holes.

10. Input shaft guiding tool knobs shortage.

11. Loading operator touch the seal ring by hand to check the seal ring position.

12. Rework operator assemble input shaft without using input shaft guide tool.

13. Seal ring cut during entry inside rear housing.



ACTION – To eliminate each Root CauseSr.

NoRoot Cause Action Plan

Target

Date

1.Sharp edges on input shaft seal ring

compression tool.

Introduce a 1.5mm chamfer to remove sharp edges to avoid the

chances of seal ring cut.07-Jan

2.Seal ring compression tool got loose from

its hinge supports.Retightened all bolts & Review tool condition in weekly basis 07-Jan

3.Step & Ovality found in seal ring

compression tool.Replace the damaged / worn out tool 07-Jan

4.Seal ring retaining tool has entry radius not

as per tool drawing.New tool to be ordered as per design 19-Jan

5.Contamination found in seal ring retaining

toolTraining to concerned operators to clean the tool before use –OPL 06-Jan

6.Input shaft guide tool design not effectively

guide the input shaft in transmission.Designed a tapered outer diameter on Guiding tool. 19-Jan

7.Burr / metallic chips in Rear housing input

shaft oil hole

Brushing operation to be implemented before burnishing of I.D. of

input shaft in Rear Housing – Machine Shop15-Jan

8.Brushing operations to clean Rear housing

oil holes & inspection missed by casting QA

inspector

Training to concerned operators for brushing & inspection –OPL 08-Jan

9.Washing operator miss the operation of air

blowing in oil holes.Training to concerned operators to clean the oil holes –OPL 08-Jan



ACTION – To eliminate each Root CauseSr.

NoRoot Cause Action Plan

Target

Date

10. Input shaft guiding tool knobs shortage Knobs to be provided on line 12-Jan

11.Loading operator touch the seal ring by

hand to check the seal ring positionTraining to concerned operators to not touch the seal ring –OPL 09-Jan

12.Rework operator assemble input shaft

without using input shaft guide tool.Training to concerned operators to use the tool –OPL 09-Jan

13.Seal ring cut during entry inside rear

housing

Oil application in rear housing input shaft hole for easy entry & rotate

the input shaft to certify correct seal ring fitment12-Jan



ACTION – Seal compression tool correction

AfterBefore

Introduce a 1.5 mm chamfer at edges of

compression tool to reduce the seal ring

damage chances

Seal ring damages due to Sharp edges in

Seal ring compression tool



ACTION – Reconditioning of seal compression tool

AfterBefore

Bolts Retightened & Operator review tool

condition in weekly basis

Seal ring compression tool bolts & hinge

support bolts got loose



ACTION – Seal retaining tool as per drawing

AfterBefore

Replace the Old Wrong Tools with new

Correct tools. New retaining tools has entry

radius as per drawing

Seal ring cut due to retaining tool entry radius

is not as per drawing



ACTION –

AfterBefore

Cleaning process of retaining tool at input

shaft sub assly started.

• Training to concerned operators to clean

the tool before use.

• OPL displayed on line.

• Cotton box provided at stage

Contamination or Burr found in seal ring

Retaining tools



ACTION – Brushing operation is implemented in Rear housing Input shaft hole. This

operation is doing before burnishing of Rear housing I.D. That activity is already implemented

at supplier end. We have implemented this also in Machine Shop to reduce the Burr & metallic

chips in Rear Housing.AfterBefore

Implemented Brushing operation in

machine shop after oil holes drilling &

before Burnishing.

Burr at oil holes in Rear housing



ACTION – Designed a tapered outer diameter on Guiding tool in such a way that input

shaft easily insert in rear housing without any deviation. Due to this Seal ring can not contact

with rear housing AfterBefore

Input shaft guiding tool redesigned with

tapered outer diameter. At top side O.D. is

20.5mm & at bottom O.D. is 21.50mm to

21.80mm.

Old design of Input shaft guiding tool. O.D.

from top side – 20.5 & from bottom 20.5mm



ACTION – Oil application in rear housing input shaft hole for easy entry & rotate the input shaft to

certify correct seal ring fitment

AfterBefore

Oil applied at rear housing entry chamfer .

Introduced oil application at entry chamfer

of Rear housing due to which input shaft

easily insert in rear housing without

damaging the seal ring.

Rear housing without oil application.

Seal ring cut at rear housing entry chamfer

during input shaft insertion



Process sheet Revised - stage 2 – input shaft inserting



STANDARDIZATION – Permanent Elimination of Problem

• List of Documents changed1) OPL- Sl. No.: TLB- 27, Format no.- OPL- TLB- 00 - Sand / Burr in Rear housing & front housing oil holes.

2) OPL- Sl. No.: TLB- 28, Format no.- OPL- TLB- 00- Sand / Burr in Rear housing & front housing oil holes.

3) OPL- Sl. No.: TLB- 29, Format no.- OPL- TLB- 00- Seal ring retaining tool cleaning by lint free cotton.

4) OPL- Sl. No.: TLB-30, Format no.- OPL- TLB- 00- use seal ring retaining tool during Input shaft loading & Rework operator.

5) Process sheet Revised - stage 2 – input shaft inserting- Doc. Rev. level- 01, Revision date- 27/01/2015, Doc. No.-

PS_TLB_4WD_ISHAFT_MAL_02.

6) Process sheet Revised - stage 2 – input shaft inserting- Doc. Rev. level- 01, Revision date- 27/01/2015, Doc. No.-

PS_TLB_2WD_ISHAFT_MAL_02.

7) Process sheet need to be revised at machine shop.

8) Seal ring compression tool design changed- Tool no.- 582801.

9) Input shaft guiding tool design changed – Tool no.- 682778.

• Training given to concerned people- All operators of TLB line including

casting quality person.

• Additional audit checks-1) Trained & informed to shift in charge to Review the Compression tool condition on 1st working day of every week.

2) Trained & informed to shift in charge to Review the Retaining tool condition on 1st working day of every week.

Project Leader- Pradeep pokhariyal Production Head- Mr. Sunil puranik

Quality Head- Mr. Naveen Gaalav Technology Head- Mr. Pradyot Halde