Reliability Test-Electronic Products
Reliability Test To Electronic Products
With evaluation purpose to implement electronic product various reliable is named as reliability test, generally speaking, reliability tests refer to aspects as below:
1.To expose respective defectives of electronic products in R&D, pilot stage to evaluate reliability performance of product to achieve expectual status;
2.Provide important information to monitoring and control production process in production stage;
3.Implement reliability test to verify, evaluate, determine standard products;
4.To expose and analyze electronic product failure law as well as relevant failure mode as well as failure mechanism under various environmental condition and stress condition;
5.Provide important basis to improve product reliability, make and improve reliability test scheme as well as basis for customer to select electronic products;
As per different product and different test objectives, various reliability test method are available to be introduced to carry out;
Classification of Reliability Test:
1.Classified by Environmental condition: Reliability Test can be divided into tests includes simulation test and field test with environmental conditions under various certain stresses;
2.Classified by Test Project: Reliability Test can be divided into environmental test, life test/endurance test, accelerating test as well as other special-purpose test;
3.Classified by Test Objective: Reliability can be divided into screening test, compliance test and acceptance test;
4. Classified by Test Property: Reliability test can be divided into destructive testing & non-destructive testing;
Generally, in accordance with common classification, reliability can be divided into 5 types:
A. Environmental Test
B. Life Test/Endurance Test
C. Screening Test
D. Field Test
E. Compliance Test
1.Environmental Test is introduced to verify adaptability & availability of electronic products in various environmental conditions such as vibration, impact, temperature, thermal shock, damp heat, salt fog, low pressure, and performs an important role to evaluate reliability and stability of electronic products among other test methods;
2.Life Test is a method to study and research properties of product life, which can be implement and completed in laboratory room through simulation test method. Life test is one of the essential and primary test projects of reliability test. Life test requires to gather and collect relevant data to establish a failure law and failure mode that combines factors such as time and failure (damage) condition after electronic products are placed in certain test environment.
By life test, it is an easy access to know and master key data of electronic products that shall cover life properties, failure law, failure frequency, mean life span as well as various possible failure modes in life test. Introduced with relevant scientific failure analysis, it is a proper method to figure out failure mechanism which lead into product failure, and be taken as basis to perform reliability design, reliability prediction, continuous improvement of product quality and determine rational selection, batch assurance test etc.
The test method to decrease test cycle without changing failure mechanisma and conditions but increase stress is defined as accelerating test.
Finally, life test implementation is available to evaluate reliability level of electronic product and improve new product reliability level through quality feedback.
3.Screening Test is a non-destructive test to implement exhaustive test for electronic products with test objective is to select product with special properties or to sort early failured product to improve application reliability of electronic products. Mostly, electronic productsin production, because of defective of materials or out of control for production process will make those defectives exposed. Sorting those defectives will guarantee the reliability level of electronic product in actual usage.
Characteristics of Reliability Screening Test:
A. This kind of test is sampling test, but full-range at 100% test;
B.This kind of test can improve entire reliability level of qualified product, but it is limited to improve inherent reliability of electronic products, as it is: it is impossible to improve life span for every single electronic product.
C. It is wrong method to determine screening result by reject rate from screening test. As per high reject rate, there are various reasons such as defectives from product design, components & parts, technique and process or because of high stress strength of testing environment and condition; as per low reject rate, it may be the reasons such as less defectives from product design, or insufficient stress strength or test cycle.
Generally speaking, it is known to all that determining screening result by screening reject rate Q & screening resultβ: rational screening method shall be βvalue larger while Q value in medium.
Implementation of Simulation test is limited by test equipment condition, commonly, single stress condition or two stress condition can be applied for simulation test, with obvious differences from actual environmental condition, it is not enough to expose quality of electronic product actually and fully.
Differs from simulation test, field test is implementing on site, which is the best and close method to reflect the actual quality and reliability level of electronic product. The data and test result from field test is valuable and essential for reliability prediction, design and assurance of electronic products.
Compliance Test aims to carry out reliability test to evaluate the reliability level of electronic product. It is a technical scheme made from sampling theory, as it is, on the condition of electronic product qualified and not be rejected to implement compliance test.