Vibration, by causing loosening of parts or relative motion between parts in the specimen, can produce objectionable operating characteristics, noise, wear, and physical distortion, and often results in fatigue and failure of mechanical parts.

The Vibration Test is used to determine the effects on component parts of vibration within the predominant frequency ranges and magnitudes that may be encountered during field service and/or transportation. Most vibrations encountered in field service and/or transportation is not of a simple harmonic nature, but tests based on vibrations of this type have proved satisfactory for determining critical frequencies, modes of vibration and other data necessary for planning protective steps against the effects of undue vibration.

Variable Frequency Vibration is the normal test specified for electronic components and assemblies. Typically the test consists of a platform driven by a simple harmonic motion from a minimum frequency to an upper frequency and return in an approximate logarithmic rate. The motion is usually limited to a peak amplitude at low frequencies and a maximum G level above a corner frequency. This corner frequency may be calculated from:

  f=(a/0.0512d) ½

  Where: a is gravitational units (G)

  d is displacement of a p-p cycle (Inches)

  f is frequency (Hz)

This cycle is typically repeated four times in each of three axes.

Tooling is generally required to attach the component to the shaker platform. The simplest and cheapest is to add holes to Silicon Cert’s existing adaptor plates, if the component has screw attachment holes. If the component has no attachment means, clamping arrangements must be designed and fabricated. These unique clamps are then attached to the adaptor plates. To accommodate all three axes, a magnesium cube is attached to the platform, and the adaptor plates are attached to the cube.

The tooling should allow the accelerometer to be mounted as close to the centerline of the component being shaken as possible. In addition, it is imperative that the tooling be run dry (without test components) in all three orientations to ascertain that the tooling does not have resonances in the frequency range of interest. Characterization of the tooling is strongly recommended as a part of the calibration procedure before running components.

Various standards use different requirements, and are summarized here in a somewhat chronological order:

MIL-STD-202F for Electronic and Electrical Component Parts
Method 201: 10 to 55 Hz, with an amplitude of 0.03”, constantly swept for two hours at a rate of one minute per cycle (10-55-10 Hz).

MIL-STD-750 for Discrete Semiconductor Devices
Method 2056: 100 to 2,000 Hz, 20 G, four times in each of three axes with a sweep duration greater than four minutes.

Method 2057: same as for 2056, but with twice the sweep time, and all specified currents and voltages monitored.

MIL-STD-883 for Microcircuits
Method 2007: 20 to 2,000 Hz, typically 20 G, maximum displacement p-p of 0.060” 
(fc = 81.7 Hz), four times in each of three axes with a sweep duration greater than four minutes.

Telcordia:

GR-468 Reliability Tests for Laser Diodes, Laser Modules, LEDs, LED Modules, Photo Diodes, Detector Modules, Integrated Modulators and External Modulators
See MIL-STD-883, Method 2007

GR-1221 Reliability Tests for Passive Optical Components
See MIL-STD-883, Method 2007 or EIA/TIA-455-11A, Test Condition IV

GR-63 Network Equipment-Building System Requirements: Physical Protection
Office Vibration Test Method: 5 to 100 to 5 Hz. 0.1 G, at a rate of 0.1 octave/minute. One sweep in each of three axes.

Transportation Vibration – Packaged Equipment:5 to 100 Hz at 0.5 G, 100 to 500 Hz at 1.5 G (3.0 G if Prop plane), 0.25 octaves/minute, one sweep.

Failure Mode Analysis:

If components fail during vibration testing, the failure must be identified. Silicon Cert has the expertise and the equipment to perform complete failure mode analysis (FMA) utilizing data analysis, electrical testing, and Scanning Electron Microscopy (SEM), providing a comprehensive report of the findings. All to help YOU in providing the finest, high reliability devices for YOUR customer!

DON’T FORGET - Silicon Cert Laboratories, as a leading reliability testing company with many years of experience, can economically perform Vibration Testing as well as these reliability tests, including:

• Mechanical Shock

• Temperature Cycling

• Accelerated Bias Aging

• Cyclic Moisture

• High/Low Temperature Storage • ESD Threshold

• Damp Heat

• Thermal Shock

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Silicon Cert Laboratories
The Leader in Ultra-Reliability Testing