Corrective Actions Derived from Failure Mode Analysis (FMEA)
In the process of failure mode analysis (FMEA), in addition to strengthening the design, improving product reliability and controlling process differences to reduce the failure rate, the probability, severity and detectability of the causes of various failures are also reviewed. In addition to the incoming inspection process In addition to setting effective control points and control methods during inspection and shipment inspection, the process of Environmental Stress Screening (ESS) is also added. The optical characteristics are inspected as qualified but the products with defective reliability are effectively screened before shipment to prevent The inconvenience and loss caused by the outflow to the customer. At present, we judge that using temperature and humidity cycle and drop test as the environmental stress screening process will effectively improve reliability.
Taking the actual production optical splitter as an example, before the product leaves the factory, it needs to go through a temperature and humidity cycle test to release the thermal stress of the optical fiber, and it is used as the first screening procedure before leaving the factory.
When screening optical splitters with poor reliability due to potential defects in materials, it is necessary to analyze the factors causing the failure of the drop test to establish the second screening process of the optical splitter. In the example, the frequency response of the substrate is firstly performed. Analyze (Frequency Response) as shown in the figure below, and establish the incoming inspection procedure of the substrate, and improve the purchase and installation procedure of the optical splitter to ensure that the optical splitter can be designed to verify its impact resistance by Shock Testing (Shock Testing) to 3000G Some of the above products can even reach 8000G (the test data is shown in the figure). During the inspection and screening during mass production, Drop Testing, which is more time-efficient and cost-sensitive, can be used. The tools used in the drop test are passed by the testing organization Measure the acceleration value (G) when falling at different heights, and then determine an effective screening method according to the product characteristics and the requirements of GR-1209. After the environmental stress screening, the reliability of the product will be greatly improved.
With years of experience in product analysis and quality improvement in the production of optical splitters, through the organization and operation of FMEA, product design has been strengthened and effective control points and control methods have been established. The ESS process has also been set to improve the reliability of optical products. At present, the optical passive device market is generally sluggish, and the market is full of low-priced passive devices. Customers are often attracted by it. However, when considering product reliability and price/performance ratio, if you use products with poor reliability, it may be caused by the initial failure. The purchase price is low and the cost is reduced, but the maintenance cost will be greatly increased in the future. The continuous improvement of quality to meet the higher needs of customers is the same purpose of all device manufacturers. Reasonable prices for customers, high quality, high reliability and good splitters and other optical passive components can become customers' most reliable business partners and occupy a place in the market.