Practical Evaluation Technology

Dustproofing Evaluation

Testing is carried out under extreme conditions, such as vibration, to ascertain the degree of dustproofing.

Mobile computing devices, which are often used outdoors, require effective dustproofing. With dustproofing evaluation, gasket material is installed in an evaluation container, which is then placed in a dusty environment. The number of particles of dust that successfully penetrate the gasket and end up in the container are then counted using a particle counter. The degree of dustproofing of the gasket material is determined from the ratio of dust particles that penetrated the gasket material to the number of dust particles in the dusty environment. By vibrating the container it is possible to observe the influence of shocks and vibration.

Dustproofing evaluation system overview

Comparison of degree of dustproofing

In a comparison of SCF gasket material and conventional urethane foam it was clear that there was a major difference in the degree of dustproofing.

Drop Impact Evaluation

Using shock wave evaluation and a high-speed camera it is possible to observe what happens when a mobile electronic device is dropped.

A strain gauge and an acceleration sensor are used to evaluate the shock wave when a mobile electronic device is dropped. The degree of strain and acceleration at the time of drop impact are evaluated together with the waveform and used in the evaluation of materials. Use of a high-speed camera makes it possible to observe the impact in minute detail.

Drop impact evaluation system overview

Strain and acceleration waveform at the time of drop impact

Observation of mobile phone deflection at the time of drop impact using a high-speed camera

Material Evaluation

Impacting gasket material with a steel ball and measuring impact absorption using a force sensor.
Speed-reliance evaluation and lifetime estimation is also possible.

Gasket material is used in mobile electronic devices. In order to evaluate the impact absorption rate, gasket material is placed in a pendulum test device and impacted with a steel ball. The impact absorption rate is determined from the force generated on the gasket material. The impact absorption rate can also be determined by changes in compression rate after the gasket material has been compressed. Furthermore, in tests using a servo-type load testing device, it is possible to observe the process from the compression to the unloading of the material using a high-speed camera and evaluate speed reliance over a broad range. In a compression test at a specific speed, it is possible to evaluate stress and strain characteristics and their temperature reliance, as well as estimate lifespan through repeated testing.

Gasket material evaluation overview

Measuring using a pendulum test device.

Observation using a servo-type load testing device and high-speed camera.

Impact Absorption