POKA YOKE
ERROR IS HUMAN NATURE BUT INTELLIGENCE IS ALSO HUMAN NATURE SO NEVER STOP ,FINDING WAYS OF NOT MAKING MISTAKES
POKA YOKE (Mistake Proofing)
WHAT IS MISTAKE PROOFING
A SYSTEM For Organismic Work that
Excludes any risk of error even by the beginner
Allows everyone to operate without mistake
Prevents error that are about to occur
INFORMATIVE INSPECTION
ACTIVITY : USE OF S.Q.C.
CHECK AND DISCOVER DEFECTS
PROVIDE FEEDBACK
ACTING ON THE BASIS OF THE
FEEDBACK
RESULT :Time delay, defective Parts in line
JUDGEMENT INSPECTION
ACTIVITY :
CHECK FINISHED PRODUCT
ELIMINATE DEFECTIVE ONES
RESULT : COST INCREASES
ZERO QUALITY CONTROL
SOURCE INSPECTION
USE OF CONTROL MECHANISM
PREVENT ERROR TURNING INTO A DEFECT
Applications of POKA-YOKE
TOOL DESIGN
MANUFACTURING PROCESS
OPERATORS (ADHERANCE TO S.O.P.)
DETECTION DEVICES
METHODOLOGY
Speak to the Job / Machine
EXAMPLE ...1
Problem: Job loading in reverse direction causing job rejection , damage to tool & m/c geometry.
Aim : to ensure correct loading of job .
IDEAS AFTER BRAINSTORMING
1) Use of proximity sensor to detect reverse loading of job.
2) Use of photo-sensor.
3) Instructions for operators
4) Separate fixture to keep the incoming job ,to enable the operator to load the job correctly.
5) Painting the correct & wrong end of the job with different colours. 6) Use of colour sensors to differentiate between correct & wrong end of the job. 7) To provide work-rest for the job. 8) To provide the mechanical stopper. 9) To increase the diameter of the job at the wrong end, so that the job will not get held between the jaws before operation.
5) Painting the correct & wrong end of the job with different colours. 6) Use of colour sensors to differentiate between correct & wrong end of the job. 7) To provide work-rest for the job. 8) To provide the mechanical stopper. 9) To increase the diameter of the job at the wrong end, so that the job will not get held between the jaws before operation.
BENEFITS.
M/C ACCIDENT AVOIDED.
EXAMPLE …2
PROBLEM: T/M CASE NOT CLAMPED ON PUMP JIG , RESULTING IN REJECTION.
AIM: TO ENSURE START OF THE DRILLING OPERATION ONLY WHEN T/M CASE IS FULLY CLAMPED BY PUMP JIG.
IDEAS AFTER BRAINSTORMING
1) Separate hydraulic clamping unit.
2) Rack & pinion arrangement for operating the jig plate.
3) Proximity sensor to detect the shift of t/m case before operation.
4) Sensing the clamping operation with limit switch & audio/visual indication for the operator.
IDEAS AFTER BRAINSTORMING
5) Inhibiting the drilling operation unless fully clamped signal is provided by limit switch. 6) Job clamping sensing by air pressure & pressure switch. 7) Use of through beam fiber optic sensor to detect the gap between job & the fixture.
IDEAS AFTER BRAINSTORMING
5) Inhibiting the drilling operation unless fully clamped signal is provided by limit switch. 6) Job clamping sensing by air pressure & pressure switch. 7) Use of through beam fiber optic sensor to detect the gap between job & the fixture.
BENEFITS.
Poka-Yoke: with this habit you will never forget to take your cellphone
NO REJECTION OF T/M CASE.
EXAMPLE …3
Problem: skew drilling of main oil gallery , resulting in rejection & field failure.
Aim: to ensure position of rotary table after indexing.
IDEAS AFTER BRAINSTORMING
1) Use of servo motor to turn & correctly position the rotary table.
2) Provide mechanical stopper.
3) Use of proximity sensor to detect the correct table position & its interlock with spindle start command.
4) Paint mark on the locator to know the correct position of the table. 5) Audio indication for the operator at the end of one drilling cycle to check the proper positioning of rotary table.
IDEAS AFTER BRAINSTORMING
1) Use of servo motor to turn & correctly position the rotary table.
2) Provide mechanical stopper.
3) Use of proximity sensor to detect the correct table position & its interlock with spindle start command.
4) Paint mark on the locator to know the correct position of the table. 5) Audio indication for the operator at the end of one drilling cycle to check the proper positioning of rotary table.
BENEFITS.
NO REJECTION OF CRANK CASE DUE TO SKEW DRILING OF MAIN OIL GALLARY HOLE.
EXAMPLE …4
PROBLEM: T/F CASE GETTING REJECTED BECAUSE OF MANUAL OVERTRAVLE OF SADDLE IN VERTICAL DIRECTION DURING FINISH CUT ON FN3 MLLING M/C.
AIM: TO STOP MILLING OPERATION AS SOON AS SADDLE IS OVERTRAVELS.
IDEAS AFTER BRAINSTORMING.
1) Marking on setting dial for vertical saddle stroke.
2) Use of limit switch to sense the over travels position & stop the m/c control.
3) Use of mechanical stopper on the slide.
4) Replace manual operation with automatic cycle . 5) Restrict the movement of setting dial at the point of finish cut.
IDEAS AFTER BRAINSTORMING
1) Marking on setting dial for vertical saddle stroke.
2) Use of limit switch to sense the over travels position & stop the m/c control.
3) Use of mechanical stopper on the slide.
4) Replace manual operation with automatic cycle . 5) Restrict the movement of setting dial at the point of finish cut.
BENEFITS.
NO REJECTION OF T/F CASE .
ADDITIONAL POKA-YOKE
Work seat failure.
Depth control in tapping of blind holes.
Inhibiting the cycle start after job is clamped between centers.
To avoid the re-cutting of same gear on the m/c.
ADDITIONAL POKA-YOKE
To ensure proper resting of job on jig plate of multidrill m/c.
To avoid missing of drilling operation on H.M.T radial drill.
To detect incomplete drilling operation on H.M.T drill m/c
ERROR IS HUMAN NATURE BUT INTELLIGENCE IS ALSO HUMAN NATURE SO NEVER STOP ,FINDING WAYS OF NOT MAKING MISTAKES
POKA YOKE (Mistake Proofing)
WHAT IS MISTAKE PROOFING
A SYSTEM For Organismic Work that
Excludes any risk of error even by the beginner
Allows everyone to operate without mistake
Prevents error that are about to occur
INFORMATIVE INSPECTION
ACTIVITY : USE OF S.Q.C.
CHECK AND DISCOVER DEFECTS
PROVIDE FEEDBACK
ACTING ON THE BASIS OF THE
FEEDBACK
RESULT :Time delay, defective Parts in line
JUDGEMENT INSPECTION
ACTIVITY :
CHECK FINISHED PRODUCT
ELIMINATE DEFECTIVE ONES
RESULT : COST INCREASES
ZERO QUALITY CONTROL
SOURCE INSPECTION
USE OF CONTROL MECHANISM
PREVENT ERROR TURNING INTO A DEFECT
Applications of POKA-YOKE
TOOL DESIGN
MANUFACTURING PROCESS
OPERATORS (ADHERANCE TO S.O.P.)
DETECTION DEVICES
METHODOLOGY
Speak to the Job / Machine
EXAMPLE ...1
Problem: Job loading in reverse direction causing job rejection , damage to tool & m/c geometry.
Aim : to ensure correct loading of job .
IDEAS AFTER BRAINSTORMING
1) Use of proximity sensor to detect reverse loading of job.
2) Use of photo-sensor.
3) Instructions for operators
4) Separate fixture to keep the incoming job ,to enable the operator to load the job correctly.
5) Painting the correct & wrong end of the job with different colours. 6) Use of colour sensors to differentiate between correct & wrong end of the job. 7) To provide work-rest for the job. 8) To provide the mechanical stopper. 9) To increase the diameter of the job at the wrong end, so that the job will not get held between the jaws before operation.
5) Painting the correct & wrong end of the job with different colours. 6) Use of colour sensors to differentiate between correct & wrong end of the job. 7) To provide work-rest for the job. 8) To provide the mechanical stopper. 9) To increase the diameter of the job at the wrong end, so that the job will not get held between the jaws before operation.
BENEFITS.
M/C ACCIDENT AVOIDED.
EXAMPLE …2
PROBLEM: T/M CASE NOT CLAMPED ON PUMP JIG , RESULTING IN REJECTION.
AIM: TO ENSURE START OF THE DRILLING OPERATION ONLY WHEN T/M CASE IS FULLY CLAMPED BY PUMP JIG.
IDEAS AFTER BRAINSTORMING
1) Separate hydraulic clamping unit.
2) Rack & pinion arrangement for operating the jig plate.
3) Proximity sensor to detect the shift of t/m case before operation.
4) Sensing the clamping operation with limit switch & audio/visual indication for the operator.
IDEAS AFTER BRAINSTORMING
5) Inhibiting the drilling operation unless fully clamped signal is provided by limit switch. 6) Job clamping sensing by air pressure & pressure switch. 7) Use of through beam fiber optic sensor to detect the gap between job & the fixture.
IDEAS AFTER BRAINSTORMING
5) Inhibiting the drilling operation unless fully clamped signal is provided by limit switch. 6) Job clamping sensing by air pressure & pressure switch. 7) Use of through beam fiber optic sensor to detect the gap between job & the fixture.
BENEFITS.
Poka-Yoke: with this habit you will never forget to take your cellphone
NO REJECTION OF T/M CASE.
EXAMPLE …3
Problem: skew drilling of main oil gallery , resulting in rejection & field failure.
Aim: to ensure position of rotary table after indexing.
IDEAS AFTER BRAINSTORMING
1) Use of servo motor to turn & correctly position the rotary table.
2) Provide mechanical stopper.
3) Use of proximity sensor to detect the correct table position & its interlock with spindle start command.
4) Paint mark on the locator to know the correct position of the table. 5) Audio indication for the operator at the end of one drilling cycle to check the proper positioning of rotary table.
IDEAS AFTER BRAINSTORMING
1) Use of servo motor to turn & correctly position the rotary table.
2) Provide mechanical stopper.
3) Use of proximity sensor to detect the correct table position & its interlock with spindle start command.
4) Paint mark on the locator to know the correct position of the table. 5) Audio indication for the operator at the end of one drilling cycle to check the proper positioning of rotary table.
NO REJECTION OF CRANK CASE DUE TO SKEW DRILING OF MAIN OIL GALLARY HOLE.
EXAMPLE …4
PROBLEM: T/F CASE GETTING REJECTED BECAUSE OF MANUAL OVERTRAVLE OF SADDLE IN VERTICAL DIRECTION DURING FINISH CUT ON FN3 MLLING M/C.
AIM: TO STOP MILLING OPERATION AS SOON AS SADDLE IS OVERTRAVELS.
IDEAS AFTER BRAINSTORMING.
1) Marking on setting dial for vertical saddle stroke.
2) Use of limit switch to sense the over travels position & stop the m/c control.
3) Use of mechanical stopper on the slide.
4) Replace manual operation with automatic cycle . 5) Restrict the movement of setting dial at the point of finish cut.
IDEAS AFTER BRAINSTORMING
1) Marking on setting dial for vertical saddle stroke.
2) Use of limit switch to sense the over travels position & stop the m/c control.
3) Use of mechanical stopper on the slide.
4) Replace manual operation with automatic cycle . 5) Restrict the movement of setting dial at the point of finish cut.
BENEFITS.
NO REJECTION OF T/F CASE .
ADDITIONAL POKA-YOKE
Work seat failure.
Depth control in tapping of blind holes.
Inhibiting the cycle start after job is clamped between centers.
To avoid the re-cutting of same gear on the m/c.
ADDITIONAL POKA-YOKE
To ensure proper resting of job on jig plate of multidrill m/c.
To avoid missing of drilling operation on H.M.T radial drill.
To detect incomplete drilling operation on H.M.T drill m/c
