8D报告范本.pdf

BENQ Corporation 8D Report Final The 8D report applies to System Product Process 8D Report No To be filled by quality only And their type is Internal External for Customer Supplier Ver 2 0 Date 2004 4 2 Customer ESLEPSON Process what needs to be corrected KIWI Model Panel Board LCD Defected when ESL OQA inspecting Date month date year 2004 02 24 2004 03 17 Originator who fills gray spaces Prepared By Monitor Wei Reviewed by Kams Yu Approved by Alan Zhu 1D Problem Definition and Analysis The description with tangible data when this could be possible what the problem is about how it comes up how much it represents where it shows up when was detected and the reasons to solve it What what the problem is about how describes it what it is etc ESL feedback that they found 4pcs LCD defect samples in OQA section Detail information refer to the below No S N Reject date Defect phenomena in ESL OQA 1 EUA40501049 7S 2004 02 24 LCD no display 2 EUA40501064 7S 2004 02 24 LCD Wrong Code display and no display 3 EUA40900361 0S 2004 03 15 LCD Wrong Code display and no display 4 EUR410003798 S 2004 03 16 LCD Wrong Code display and no display When BenQ members confirmed the OQA defect machine could not to dulpicate they took back 10 pcs similar failure from ESL production line for further analysis 8D Report How how it was presented how it happens how is explained etc The defect symptom in ESL production line mainly are LCD Blur or No Display and Display wrong Code When When it was seen first time how long it has been identified etc 2004 02 24 2004 03 17 Where In which machine which areas physical place location etc ESL Factory in Shenzhen China 2D Teamwork Building Total documentation of the resources involved in problem solving methodology Team Leader YW Leong Kams Yu Team Number Aubert Liu Sandy Shi Alan Zhu Agatha Qin Andy Niu Tony B Zhu Michael Shen Monitor Wei 3D Containment Actions Summary of provisional actions and or remedies that suspend immediate and absolutely the effects of the problem avoiding consecutive claims of RMA LCD Display abnormal LCD No Display Risk Assessment 1 The failure 4 LCD of the ESL OQA rejected was not easy to dulpicate at normal tempareture and in chamber test 40 Included the ESL OQA failure and most the failure in production line 2 It is not belong to intermittent because it also hard to find again even We tried to duplicate many many times 3 We took 57pcs Panel board reject by hair dryer sorting put in chamber the test result as below Panel Board evaluation Test Report Chamber Qt y PD sorting by hair dryer 40 degree 15s Normal Temp 4050after2Hrs 5050after1Hrs 6050after1Hrs 35Wrong Code OK OK OK OK 20Blur OK OK OK OK 2NO Display OK OK OK OK 4 We also assemblyed NG panel board which rejected by hair dryer into finsish goods then done drop Vibration and high temperature high humidity test the result as below Evaluation For KW LCD Abnormal Display Qty Normal Tempareture After Hair Gun Drop HH HT 60 degree 90 Vibration OK Wrong Code 1 ok 8 OK Blur 7 ok OK Wrong Code 1 ok 8 OK Blur 7 ok OK Wrong Code 1 ok 8 OK Blur 7 ok 5 The failure rate was not become more higher than before in ESL detail data as below Week WK401 WK402 WK403 WK404 WK405 WK406 WK408 WK409 WK410 WK411 Failure Rate 0 08 0 07 0 04 0 12 0 06 0 17 0 11 0 06 0 13 Base on the above Conclusion The risk for the shipment of finish goods is very low Containment Action Date Resp The containment action is using hair dryer to tighten inspect before we find the root cause For finished goods On hold all the finished goods and replace the Panel Board with the good one after sorted marking L on the cushion For Panel Board Re testing the Panel Board PCBA and sorting with the hair dryer 55mm distance to the LCD taking along 15 18 Seconds Temperature 40 45 and marking L on label Start From 2004 03 17 Andy Niu Machael Shen For the LCD 1 Inspecting all the LCD to check the PIN distance 2 Phasing the same method with the hair dryer 80mm distance to the LCD Temperature 45 50 to sort all LCD include in the stock Marking the sorted material with white dot Start From 2004 03 18 Andy Niu The Verification and Conclusion about Containment Action After the containment action the failure rate of LCD is down to Zero in BenQ Victory production line 4D Root Cause Definition Identification of original cause and capable to eliminate the problem and all secondary effects also removes immediate containment actions mentioned below marking L Marking L on the cushion Problem Analysis Logic to conclude the root cause Step1 BenQ dispatched members to ESL on Mar 9 and analysis and co work with ESL colleagues We did the test for ten pcs LCD on Mar 9 that have been rejected by production line The result as follows No S N Rejected by ESL line ESL TE confirm then ESL TE confirm again on 3 10 BenQ confirm on 3 10 After Hair Dryer 1 R407003700 Wrong Code No display OK OK Wrong Code 2 R407005808 Blur Blur Wrong Code OK OK 3 R407R06775 Blur Blur OK OK 4 R407000771 Blur Blur Blur Wrong Code Blur Wrong Code Blur 5 R409001288 Blur Blur Blur Blur Blur 6 A402004013 Blur Not clearly OK OK Blur 7 R407006116 No display No display OK OK Error 8 R407002033 Wrong Code Wrong Code Wrong Code Wrong Code Wrong Code 9 R407003974 No display OK OK OK OK 10 R407004804 Wrong Code Then No Display No display OK OK Wrong Code Following is the detail failure picture provided by ESL LCD Display Blur Conclusion 1 2pcs of them are always failure and we found pin1 is too close to pin2 of the LCD 2 6pcs of them are not dulpicated at normal tempareture but could be dulpicated at high tempareture by hair dryer 2pcs was not carried to BenQ for further analyzing LCD No Display LCD Display Wrong Code Root Cause Step2 Why PIN1 too close to PIN2 will cause the failure 1 Because PIN1 Ground Pin too close to PIN2 Power Pin and when they inserting into the PCB board it will cause pin contact NG because of the distortion force Because Pin1 too closed to Pin2 will always cause the failure so it not the root cause for the ESL OQA failure at that time we also push our supplier continue to improve it Why 6pcs are not dulpicated at normal tempareture but could be dulpicated at high tempareture by hair dryer happens and what is the root cause We summerized the possible cause for LCD abnormal display when hair drying as the following 1 To Identify Panel Board Soldering problem We double checked the appearance of the defective no any abnormal is found about pin damage and cold soldering Conclusion PCBA soldering process is not the main cause 2 To Identify LCD defective problem We replaced the LCD and found the set is ok and exchange the NG LCD to the good set same symptom appears in the set Conclusion It is LCD defective to cause the abnormal display Analysis the root cause of LCD abnormal display when hair drying First we should know the inside structure of the junction point of pin to glass From it if CARBON Contact NG or UV Glue solidify NG will cause the failure PIN GLASS ITO UV GLUE CARBON UV Glue have Little gas hole PIN Damage PIN Material change LCD Abnormal display when hair drying UV Glue Solidify Ability bad IC Material NG ITO Material change Carbon Position and Dimension NG PANEL BD Soldering NG 3 To Identify for IC material ITO PIN problem 1 After the Appearence check it is easy to got Conclusion PIN damage and ITO open is not the root cause because the unit PIN ITO didn t any abnormal 2 KGP checked that there are not any change for ITO and PIN material 3 KGP checked that IC material NG is not the root cuase Conclusion IC material ITO and PIN no any problem and is is not the root cause 4 To Identify for if UV glue has little gas hole will cuase the failure KGP had done the experiment clarify if there are little gas holes in the UV glue also not effect LCD display Conclusion Little gas holes in UV glue is not the root cause 5 Identification for if Carbon contact situation NG will cause the failure KGP had done the experiment clarify that the carbon contact situation not the major cause Condition Dimension Condition 1 Condition 2 Condition 3 Pin dimension 0 8 0 6 0 6 C Carbon Edge to Glass edge 0 5 0 2 0 85 0 2 0 85 0 2 D Carbon Center to ITO Center 0 3 0 3 0 3 E PIN Center to ITO Center 0 2 0 2 0 6 Input With hot gun 50 30 S 350 375 383 Output With hot gun 50 30 S 331 371 383 Yield Rate With hot gun 50 30 S 100 00 98 93 100 00 Input With hot gun 50 50 S 350 375 383 Output With hot gun 50 50 S 350 374 383 Defective item N A 1pc missing line N A Yield Rate With hot gun 50 50 S 100 00 99 73 100 00 Conclusion Carbon contact situation not the root cause Purpose Detail Result Conclusion Confrim little gas hole is the root cause or not Compared the yield rate Almost Same yield rate little gas hole is not the root cause 6 Identification for if UV Glue solidify NG is the root cause We suspected that UV glue not solidify okay will cause the pin resistance NG and pin will contact abnormal then will cause the power supplier abnormal and final result in that the LCD display NG when heating so we do below experiments to verify it KGP did two experiment for 30PCS LCD which were all OK in room temperature but failed with hair dryer the result as below 1 15pcs after UV5000mJ cm2 Function ok at the normal and high temperature 2 15pcs which are display blur at high temperature will be ok after UV5000mJ cm2 Normal40Normal40Normal40 115pcsokblurokok 215pcsokblurokblurokok First TestSecond TestAfter UV 5000mJ cm2 ItemQt y To duplicate UV light energy not enough will cause the LCD abnormal display KGP use different UV light energy to reproduce the symptom it can be duplicated the detail result as below Use the experiment s failure LCD contrast low 6pcs to do verify as below NO Failed UV condition Failure Symptom UV 5000 With cover UV5000 With AL foil 1 1162 mj cm2 Blur before heating Blur before heating ok 2 1162 mj cm2 Blur before heating ok 3 1162 mj cm2 Blur after heating ok 4 1180 mj cm2 Blur after heating ok 5 1750 mj cm2 Blur after heating Blur after heating ok 6 2500 mj cm2 Blur after heating Blur after heating ok Remark UV5000 with cover UV5000 with AL foil Conclusion Poor solidify ability of the UV GLUE will cause PIN contact NG and cause LCD diplay abnormal when heating Form the experiments we got the conclusion 1 UV light energy not enough will cause the UV glue solidify not enough 2 The cover used at present will cuase the actually UV evergy become low becuase of the high from the cover level to LCD UV position is large and will shield some of the energy Below is the analysis result for defective LCD Test Method Power Supply Spec Power Supply Test Reselt Test LCD ITO 5V 3 8V This could also verify the root cause Root Cause Verification Verify through Experimentation that the root cause detected could provoke that the problem shows up or not Therefore through the above identify process we can make conclution UV light energy not enough will cause the UV glue solidify not enough and cause the LCD abnormal display when hair drying That is When BenQ audited the KGP and found they are not well control for UV shinging energy the major point as below 1 UV energy changing knob had possibility to be adjust by oparator and will possilbe cuase the UV energy not enough if someone changes it to mistaken spec 2 UV Energy cover is too high and will shield some of the energy and will cuase the UV glue energy solidify not enough 3 UV energy calibration maintanence system not so good to trace the actual status 5D Permanent Corrective Actions Long Term Actions directed to eliminate the root cause into an efficient and long term way as well as all the previous corrective actions taken into a provisionally manner Action Defect Occurrence Corrective Action Date Resp BenQ UV light energy not enough UV Glue Solidify not enough PIN CONTACT NG Power Supplier Abnormal LCD display Abnormal 1 Adding KGP into the important supplier auditing list and will regularly perform process audit and continuously to monitor the Key parameter and action follow up status 2 Update IQC LCD inspect standard add hair dryer inspection in IQC for each lot 2004 04 05 2004 04 05 Agatha Qin Alan zhu KGP LCD supplier The action to the pin too close 1 Change the material transfer type to conveyer to avoide material piled 2 Add one person do appearance check so that they had enough time to check 3 Change add UV glue from manual to auto machine 2004 4 5 2004 4 5 2004 4 13 KGP KGP KGP The actions for the UV GLUE ultraviolet radiation shining energy not enough 1 KGP had notice production line to fix people and remain no change for this station on 2004 3 23 2 Fixing the UV energe contol knob from two side taping to bolts fixing UV 3 UV ernerge increase to 3800200mJ cm2 and adding it to SOP for well control Why we conclusion 3800200mJ cm2 is enough for UV glue solidify we done the below experiment to verify the spec Arraging 70pcs LCD used different UV energy from 1000mj cm2 to 5500mj cm2 10pcs a group solidify one side then testing the pin pull force The relationship about different UV energy and the LCD PIN contact porformence From the testing result above 3500mj cm2 would meet the pin force spec 1 5KG and per buffer and productivity considering 3800200mJ cm2 is decided 2004 03 30 2004 04 23 KGP KGP PIN Pull Force Testing Method 4 Modify UV control knob to make it can control exactly 5 100 testing the LCD with hair dryer in process Defect Detection Corrective Action The action to the pin to