QMT Features: March 2013
A quality read
Root cause analysis and corrective actions resolves Amazon’s  supply chain E-book quality puzzle in just 3 days

Spring, the first season of year in 2011, represented a promising beginning and new hope. However, a renowned supply chain management company, which is also an important vendor of Amazon, experienced quite the opposite. What happened?
As it turned out, the E-book devices produced by three suppliers failed to meet Amazon’s requirements. Since the company emphasizes on high quality, they conducted an investigation immediately but could not identify the cause of the quality failure.

In response to this, they decided to seek help from a localized consultant firm which is familiar with the language and the culture of the suppliers, also in the vicinity means it is more cost effective. After considering a few consultants, the company turned to ITQM, a joint venture of Intertek Testing Services Hong Kong Limited and TQM Consultants Co. Limited, to identify and resolve the quality issue once and for all.

Based on the main issues raised by Amazon, they discussed and agreed on the scope of work – ITQM totally understood the needs of the company and provided a comprehensive improvement program plan immediately. In the course of the program, ITQM’s consultants first carried out critical review of the major shortfalls of the factories against the audit checklist requirements exhaustively reviewed all production aspects from frontline staff, software of equipment, records of current production, O/R warehouse and shipments, to document samples, and nothing was left uncovered. From this thorough investigation, the consultants were able to identify the true cause of poor quality and recommend appropriate solutions.

Next, they conducted station-by-station process audit against good manufacturing practice, ergonomics, safety, IE, Kaizen and LEAN concepts and recommended flow and method change to improve quality and productivity. By going through in detail the issues identified in the checklist, the consultants provided professional assistance to establish corrective actions.

The former issues were resolved within just three days of hard work. Ultimately, the factories were able to produce products conforming to Amazon’s requirements and passed its supplier audit in 15 areas. In addition, one of the factories attained 32% reduction on WIP rate and 23% reduction on rework rate. Its productivity remained smooth sustainably. A great relief came upon both the company and its client with the resolution of the quality issues.

In November, the company contacted ITQM again to provide quality improvement service to another supplier in the same supply chain which produces plastic casings for the E-book devices. The casings produced by the supplier has only 60-70% yield, which means up to 40% of the products are defective and do not pass the standard and they would like to improve the yield to 85%.

ITQM discovered that the main problem was that a lot of flash were produced during the molding process and the manual de-flash rework process was seriously affecting the output and quality. At the time being, there were over 30K WIP waiting for de-flash and the daily de-flash output was only 6-7 K while more than 10K was needed. Excessive manpower was involved, there were 12 de-flash lines with about 150 operators. During the course of improving the de-flash yield/output, two other unexpected incidents were found: the weld line at TUB corner and the connector thickness were out of specification. ITQM helped to investigate and resolve the problems all together.

The approaches to resolve the problems included short-term and mid-term strategies. The short-term target was to improve the de-flash process in two ways: increasing the rework efficiency and develop simple tools/fixtures to increase the output and improve quality. ITQM  examined every little area in the de-flash process and refined each steps. For instance:

(1) debris on work bench caused scratch to products; a work platform was introduced which could be cleaned easily after each work cycle, giving a clean surface for next work piece and reduced cosmetic rejects.
(2) Grinding generates dust and dusty working environment is unhealthy to operators and caused cosmetic damage on product. Introduction of Dust collector improved working environment for operators and reduces cosmetic damage on product.
(3) A soft blade cutter bends easily and caused accidental scratch on product while a stiffer blade cutter improved cutting efficiency and lower the chance of accidental scratch on product.
(4) Manual processes such as TUB polishing, grinding and trimming of TPR in-gate by hand are inefficient and difficult to control. Power tools and fixtures were introduced to improve efficiency.

The mid-term target was to refine the molding operation in order to reduce flash. ITQM reviewed the molding parameters, material used, mold tooling structure/design and mold maintenance. The possible causes were indicated and examined one by one carefully. It was found that the fitting of moving slide (a) is critical and should be controlled within 0.025mm while the mold venting (b) should be controlled at about 0.05 mm.

In just one day, the root causes were pointed out and resolved effectively. In just one week, the daily de-flash output increased from 6K to 10K and the overall yield improved from 76% to 85%.

For further improvement, ITQM developed SPC control for critical molding characteristics (flash size, weld line, critical thickness) and designed full set of fixtures for use in the de-flash line in order to sustainably maintain the quality and productivity. They also evaluated different material and processing parameters to minimize flash and reviewed the full production line set up using LEAN concept to optimize efficiency. The final outcome was made sustainable with ITQM’s tailored maintenance services. With these successful cases, ITQM has become the company’s ultimate line of defence to implement immediate solutions under urgent situations. l
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