Products shipped by sea may endure turbulent conditions

Products shipped by sea may endure turbulent conditions

Data for a (Time Waveform Replication) TWR test is often collected in moving vehicles

Data for a (Time Waveform Replication) TWR test is often collected in moving vehicles

TRANSPORTATION TESTING AND PACKAGE DESIGN VERIFICATION

Much of the world’s most sensitive electronics, medical devices, and specialized tools are manufactured thousands of miles away from their end users and must survive road, rail, sea, and air transportation before reaching a customer. The articles are subjected to a wide range of vibrational environments through a variety of transportation methods and must arrive in flawless condition.

Now a staple of quality assurance, transportation tolerance is governed by multiple industry standards including ASTM D999 and ASTM D4728 methods for shipping containers. MIL-STD-810G dictates vibration tests for various modes of transport, as well as the duration and speed of the journey.

One of the most important factors of transportation testing is accurate simulation of the field environment. Unlike the abrupt, high energy of a Shock test, or the controlled, slow moving Sine Sweep, a Random vibration profile closely mimics the actual road, rail, sea and air transportation conditions, and is often the main technique recommended by official standards.

The constantly randomized vibrational frequency and acceleration levels resemble well the turbulence experienced on a truck, a plane, or a shipping container on rough ocean waves. A Random test can be further customized to reflect total mileage and time in transport.

One of the best methods for transportation testing is to subject a package to the identical road vibrations it would experience on a vehicle. This can be accomplished through a TWR test. Rather than waiting to measure this vibration until the product is already in transport, the data can be collected first and reproduced in a controlled environment to identify any packaging problems before it’s too late. Crystal Instruments’ CoCo-80 and Spider-20 have the capacity to record up to 16 and 4 accelerometer channels, respectively, for extended periods of time. Both units are lightweight, compact, and convenient to place anywhere on the targeted mode of transport. With the time waveforms of the sample journey recorded, the data can be processed, tailored with Waveform Editor and reproduced as a vibrational profile safely back in the lab. A Spider-81 controller unit can easily reproduce the resultant waveform as a shaker profile using the Time Waveform Replication (TWR) feature.

It is in a manufacturer’s best interest to invest in the most robust vibration testing possible, as the cost to replace damaged goods could far exceed the expense of thorough vibration testing.

To learn more about Crystal Instrument’s vibration controllers, click here.

To learn more about Crystal Instrument’s portable data recorders and analyzers, click here