Productivity improvement preventive actions for hard defect failure reduction at hard disk drive assembly process

• Main Author: Ramachandran, Eswari Devi
• Format: Thesis
• Language: English; English
• Published: 2014
• Subjects: TS Manufactures
• Online Access: http://eprints.utem.edu.my/id/eprint/14749/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=92236

Hard defect failures in hard disk drives are detected from the first level failure analysis of the Final Quality Assurance failed drives at Company AB. The hard defect failures are then send for second level failure analysis to determine the potential root cause of the failure. High hard defect failures causes low lot acceptance rate which delays drives shipment due to long lead time and also deliver poor quality drives to customer. The recovery activity for FQA failure lots also requires additional space and tester. The aim of this project is to reduce hard defect failure at Final Quality Assurance through three objectives; (i) to identify and analyze potential root causes of the hard defect failures, (ii) to develop a model of prevention action and (iii) to validate the preventive action model effectiveness. The analysis of data is based on six weeks Final Quality Assurance failed tested data of product 'A' trend analysis using QUALITY DATABASE system and sampling of two drives per week for Aslab second level FA for continuous five weeks. 5 Whys and FMEA are performed to determine the potential preventive action and preventive action model is developed. Pre and post DPPM and lot acceptance rate results are monitored and compared to validate the effectiveness of the preventive actions after one month. Results show the actuator component from U supplier show significant trend from QUALITY DAT ABASE analysis as well as the AsLab results. Three potential root causes of hard defect failures have been determined as incoming material cleanliness, poor screening at backend test and assembly cleanliness. The main actions implemented are temporary stop U actuator supplier; introduce hard defect long test screen REV Q at backend and briefing and awareness on assembly related findings. From the implementation the main actions, observed 92.8% hard defect failure dppm reduction and LAR above 70% is achieved. The benefits of this project are the reduction of failed lots due to hard defect failures, minimiz.e the rework activity and also improve customer satisfaction. The result is based on comparable sample size and show significant with P value <0.05. For the future work, the proposed model can be improved using the application of Fuzzy Logic for data storage and data retrieval.