POKA YOKE / JIDOKA / SMED AND

KARAKURI
PROJECT TITLE: STRAIGHT PASS IMPROVEMENT IN
AXLE ASSEMBLY CONVEYOR USING JIDOKA SYSTEM

PROJECT TEAM MEMBERS:

1. PRAVEENKUMAR S
2. SRINIVASAN A

COMPANY: ASHOK LEYLAND

1
 Ashok Leyland (AL) - In the business of moving
people & goods for over seven decades - Profile
• A 70-year old pedigree. Founded in 1948 as Ashok Motors, became ‘Ashok Leyland’ in 1955 with equity
participation from Leyland Motors, UK.

• One of India’s largest commercial vehicle manufacturers.

• A comprehensive product portfolio spanning 2.4 to 49 Tonne GVW.

• 7 Manufacturing facilities strategically located pan-India,

• 1 plant in RAK, Dubai, 1 plant in Bangladesh.

• History of Firsts.. To name a few..

– 2012: World’s first front engine fully flat floor bus;
– 2010: CNG Hybrid Plug-in bus

• 70 million passengers travel on our buses every day, nearly 70,000 Stallion trucks in service, we are the largest
supplier of logistics vehicles to the Indian Army……., 7,00,000 of our vehicles keep the wheels of economies
turning.

• Revenue for FY 17-18: 262 Billion, with a track record of unbroken profitability since inception.
2
 Step 1: Problem definition phase
Project Charter
Project Code H22018A005636 Project Leader Name S.Praveenkumar Unit / Function PEP
Project Title Straight pass improvement in Axle assembly conveyor using JIDOKA system

In Axle assembly shop, wheel end assembly will be completed & PTS will be done. Defect free axles will be passed to vehicle
Problem Definition assembly. During Road test, wheel wobbling was observed on a vehicle, which is due to defective axle passed to Chassis assembly. So,
critical defects generation in axle assembly need to eliminated ( zero defects) in Axle assembly

In Scope All Axle models in Hosur 2 unit Out of Scope All other Models

Primary Goal Metric a) Straight pass UoM a) % Baseline 78 Target 90

Consequential Metric/s Rework cost Project Source Vehicle failure observed during Road test inside the plant

KPI/Policy objective Straight pass improvement in M&HCV chassis lines Customer Chassis Assembly
Project Start date 20/03/19 Problem selection 30/03/19 Observation 10/04/19 Analysis 25/05/19
Action 10/06/19 Check 05/09/19 Standardize 15/10/19 Conclude 25/10/19
Team Members Mr.A.Srinivasan (Prod), Mr. Balaji (QE), Mr. N.C.Paranikumar (PP), Mr. N.Bharatkumar (IED)

Approvals Sponsor: R.Raghavan Champion: C.Unnikrishnan PS Facilitator: Sreedhar Reddy

3 Problem Observation Analysis Action Check Standardize Conclude

 Why this project?
CONVENTIO UNITIZED
NAL BEARING
BEARING

Grease filling Every 80,000 NOT

kms REQUIRED
Periodical YES NOT
bearing REQUIRED
replacement

Unitised bearing design was Tyre life Dependent OPTIMISED –

first implemented in Ashok on wheel Additional 5-
Leyland’s Captain Haulage & bearing 10% life
3718 Plus models maintenance expected
Improved bearing life & Standard 80,000 4,00,000
service compared to warranty kms/12 kms/48
conventional bearings months months
whichever whichever is
earlier earlier

4 Problem Observation Analysis Action Check Standardize Conclude

 Why this project?
Common Process for Unitised and Existing
Bearing/ Race Wheel bolt Pole Wheel Brg
Hub Washing Process added in Unitised Bearing Assy
Pressing Pressing fitment
Process removed in Unitised Bearing Assy

Steering and Top and

Axle arm Axle Beam Unique process in Unitised bearing model
Track rod lever Bottom cover
fitment Loading
fitment fitmet

Brake shoe ABS Sensor Circlip fitment

Track setting
Assembly fitment on Hub

Oil seal fitment Hub locknut

Wet setting Dry Setting
& Greasing tightening

Hub Cap Brake chamber Brake drum

Unloading Inference: For Hub locknut tightening, torque of 950 Nm
greasing fitment fitment
need to applied while rotating the hub at 20 rpm

5 Problem Observation Analysis Action Check Standardize Conclude

 Problem description – Vehicle Failure during Road test
Complaints reported / Date: 20.03.2019
Premature failure of front axle due to wobbling in LHS Front axle -
4123 model

Vehicle information
Chassis  no. : MB1NBCHD1KRJA7487
Engine no. : KJHZ100605
Axle no : KJRW101032
Model : 4123
Date of Production : 15.03.2019

QE Observation:
One of the vehicles during road test reported for FA1 axle wobbling issue.
Bearing rollers damaged, scrub marks observed on brake drum which leads to Observation during removal of
poor braking Defective axle

6 Problem Observation Analysis Action Check Standardize Conclude

 Observation – Existing process
Process flow from Axle to Chassis assembly

Axle Assembly shop

Rear Axle
Rear Axle 1 Front Axle
2 Vehicle Test Shop (VTS)
STAGE 1 STAGE 1 Loading

STAGE 2 STAGE 2 Brake shoe Vehicle

STAGE 3 STAGE 3 Lever Assy
failure
occurred
STAGE 4 STAGE 4 Track setting

STAGE 5 STAGE 5 Dry setting

STAGE 6 STAGE 6 Hublocknut

STAGE 7 STAGE 7 Brake drum
Completion of Chassis Assembly shop
STAGE 8 STAGE 8 Shaft assy Axle PTS

STAGE 22
STAGE 4
STAGE 1

STAGE 2

STAGE 5

STAGE 8
STAGE 3

STAGE 6

STAGE 7
Unloading Unloading Unloading

7 Problem Observation Analysis Action Check Standardize Conclude

 Analysis – Insufficient torque (Valid cause)
Present system for Lock nut tightening application Torque data collected for E rad tool controller
S No VIN Date FRONT AXLE Specification LH RH
97 C0444 15.03.2019 KFRW101026 945 953
98 C0445 15.03.2019 KFRW101027 957 942
99 C0446 15.03.2019 KFRW101028 952 956
100 C0447 15.03.2019 KFRW101029 940 946
101 C0448 15.03.2019 KFRW101030 954 955
Pass/ Fail LED 102 C0449 15.03.2019 KFRW101031 902.5 to 997.5 955 947
indicator 103 C0450 15.03.2019 KFRW101032 Nm 760 960
104 C0451 15.03.2019 KFRW101033 953 955
105 C0452 15.03.2019 KFRW101034 950 941
106 C0453 15.03.2019 KFRW101035 954 952
Tool controller 107 C0454 15.03.2019 KFRW101036 948 955
display the torque 108 C0455 15.03.2019 KFRW101037 956 945
after tightening

Inference:
From the torque data, it was inferred that even though torque
1. E- rad torque controlled nut runner with overhead reaction controlled nut runner used for lock nut tightening with LED
system for locknut tightening with accuracy ± 3% indication, one defective axle was produced with less torque
2. Simultaneous locknut tightening & rotating the hub

8 Problem Observation Analysis Action Check Standardize Conclude

 Cause & Effect Analysis– Wheel wobbling
Possible causes Method Observation Inference
Insufficient torque Data Data verification done in
Probable causes for wheel wobbling applied on the validation E-rad torque value record,
lock nut found less torque applied Valid
Material error Man error on the nut for particular
axle.
Locknut Data Data verification done in
Defective bearing tightening not validation E-rad torque value record, Not Valid
Insufficient torque
applied on lock nut performed by found ok
Lock nut thread defect operator
Locknut tightening not
Axle arm thread defect performed by operator Defective bearing Gemba Bearing dismantled & Not Valid
Wheel observation verified. Found ok
wobbling Lock nut thread Gemba Dismantled & verified. Not Valid
defect observation Found ok
Excess hub end play
Nut runner malfunctioning
Axle arm thread Gemba Dismantled & verified. Not Valid
Non-aligning of hub defect observation Found ok

Process error Machine error Non-aligning of Gemba Dismantled & verified. Not Valid
hub observation Found ok

9 Problem Observation Analysis Action Check Standardize Conclude

 Root cause analysis – Insufficient torque (Valid cause)
Reason for defect generation
• Hub locknut loosened during tightening
Why Conveyor Loading Pit

• Insufficient torque applied on hub lock nut STAGE 1

Why
STAGE 2
Less torque applied due to
• Tightening cycle was not completed non- completion of cycle
Why STAGE 3

• Tool was withdrawn before complete tightening Hub Locknut tightening

Why of locknut Enclosing of locknut

with Cap
• Operator forgot to acknowledge the LED
STAGE 6
Why indication due to fatigue
STAGE 7

Inference: Locknut was covered with cap

From the data, it was inferred that even with availability of Poka
STAGE 8 in next stage which prevent to
Yoke in machine, which is not linked to production system to stop check for locknut missing or
the conveyor if operation was missed low torqueing issues
Conveyor Unloading Pit

10 Problem Observation Analysis Action Check Standardize Conclude

 Root cause analysis – Insufficient torque (Valid cause)
Solution Selection matrix What is SCADA?
• SCADA stands for Supervisory Control And Data Acquisition.
Effectivenes
Cost of Time to
s after
# Solutions Implementa implemen implementa Grand Total Rank
tion t • It is a central control system which consist of controllers network
tion
interfaces, input/output and communication equipment.
Camera system to monitor
1 missing of parts/ operation 4 5 4 13 3
skippig • Used to Monitor and control the equipment or devices by data
acquisition & real time monitoring system
Interlinking of Poka Yoke with
2 7 8 9 24 1
conveyor system

Manual inspection of Hub

3 8 4 2 14 2
locknut torque for each axle

Inference:
From the solution selection matrix, it was observed that
“ Interlinking with conveyor using SCADA system” will
be best option with respect to cost, time, effectiveness

11 Problem Observation Analysis Action Check Standardize Conclude

 Identification of critical stages for SCADA implementation
1. Metered grease applicator for Hub 2. Truck Toe in setting equipment Planned stages for SCADA interlock

S.N Machine Stage Type of data

o retrieval

1 Number 2 Variable
marking (Serial No &
machine Spec)

2 E –rad nut 4 Variable

runner (Torque value)

Grease applicator – Dispense 3 Grease 7 Attribute

Wheel alignment machine applicator (OK/ N- OK)
the quantified grease for which will save the value
particular model only if within the 4 Truck cam for 8 Variable
specification toe in setting (Toe value )

Inference:
• Thus, individual machine related Poka Yoke restricted only to particular stage, which may leads to incomplete cycle of
operation. All the critical stages & data type for data collection were finalized.

12 Problem Observation Analysis Action Check Standardize Conclude

 Implementation of SCADA
2
4
Loading

Conveyor

Unloading
SKID

Control

10

11

12

14
13
4

9
6
3

5
2
1

panel

1
3 3 Conveyor will
stop for any
abnormality
Client PC

Production Office Maintenance Office

Master Client PC
PC

Loading of Operator data

Loading of Production plan

13 Problem Observation Analysis Action Check Standardize Conclude

 Benefits of SCADA
Real time monitoring & data acquisition Defect prevention during Model change over

Process applicability configuration

Inference: SCADA will be configured for different models, different process
• Through introduction of SCADA, master system will do the real time 1. Follow the unique process pertained to particular model from
data acquisition & responsiveness to defect generation pre loaded database
• SCADA will stop the production line when the machine malfunction Ex : Model A ( Greasing process – Applicable)
or a defect occurs, in order to prevent defects from being produced Model B ( Greasing process – Not Applicable )

14 Problem Observation Analysis Action Check Standardize Conclude

 Benefits of SCADA
Digital Self Certification card Axle PTS clearance based on SCADA reports Performance Analysis –Maintenance & Production

Inference: Inference:
Computer generated self Inference: Customized report on performance
certification card which generated Axle will be cleared to vehicle, only indicators like OLE, Downtime,
by SCADA instead of manual card based on SCADA cleared axle report Efficiency etc

15 Problem Observation Analysis Action Check Standardize Conclude

 Preventive action – System improvement
Existing FMEA – Hub locknut tightening PFMEA VS Defect Mapping – Axle Assy

PFMEA(Captured)

Yes No

Yes 22 12

Defect
No 128 -

Defects Not captured in PFMEA

Root Cause:
Potential Cause / Failure Mode
identification System inadequate
Inference:
In existing FMEA, failure mode “ Incomplete operation – Hub
lock tightening” process was not covered

16 Problem Observation Analysis Action Check Standardize Conclude

 Preventive action – PFMEA preparation(Before)

17 Problem Observation Analysis Action Check Standardize Conclude

 Preventive action – PFMEA preparation (After)

18 Problem Observation Analysis Action Check Standardize Conclude

 Sustenance & Monitoring of Axle defects
Before SCADA – Effectiveness monitoring

PFMEA(Captured)

Yes No

Yes 22 12
Defect

No 128 -

After

PFMEA(Captured)

Yes No

Yes 12 -
Defect

No 150 - Inference :
After introduction of SCADA in Front Axle assembly, the Straight pass %
increased from 78 % to 91 % against target of 90%

19 Problem Observation Analysis Action Check Standardize Conclude

 Standardization – SOP & FMEA
Standard Operating Procedure (SOP) FMEA updation
updation

20 Problem Observation Analysis Action Check Standardize Conclude

 Standardization – SOP & FMEA

Consequential metric Future Projects

Rew o r k co st p er ax le in R s

Rework cost - Axle Assembly

500
458
450
400
350
300
250 232
200
150
100
50
0
Before After

21 Problem Observation Analysis Action Check Standardize Conclude

 Thank You!!!

22