subject: Vibration Testing – Answering the Whys and Hows? [print this page] Vibration Testing Answering the Whys and Hows?
Machinery, be it heavy, electronic or computer, is part of almost every product these days. That said, steadfastness and proper functioning of its components is of paramount importance. Vibration analysis and shock testing is one of the most dependable methods and engineering applications for testing the integrity of machine-based products.
Some might wonder why we bother with vibration testing at all. The simple reason is to test its reliability, functionality and structural integrity. Heavy equipment, motors and controls and manufacturing industries are areas where vibration measurement can be critical.
In the lifecycle of a product, whether permanently fixed or portable, there are four stages wherein it will definitely have to endure vibrations and shocks: Manufacture: In the manufacturing process the equipment is often subjected to shock and vibration; for example, when a circuit board is dropped on the assembly bench. Transportation: Most equipment, especially heavy machinery, is manufactured in parts and assembled on site. During this transportation, the equipment is subjected to a lot of mechanical stresses. Installation: During installation and assembly on-site, the equipment has to withstand much manual handling. Operation: The assembled and installed machine will inevitably experience shocks and vibrations induced by factors in its environment in the course of its operational life span, for example, engine- and gearbox-induced vibration on road vehicles and aircraft.
Machines literally "talk" to experienced professionals during vibration testing to reveal their problems and faults. The key to success is to understand what the machine is saying and condition it accordingly.
Comprehensive hardware and software equipment is used during vibration testing. Vibration testers are the primary equipment required for this process and are useful in determining severity and frequency of vibrations wherever changes in these values are of importance. The essential individual components are the controller, the amplifier, the shaker and the software which is assembled to devise a vibration tester.
When using vibration analysis for evaluations, a consistent method of collecting and analyzing the data is necessary. Some of the common diagnostic strategies for vibration analysis include using Broadband vibration meters: Here, the maintenance technician has little warning to plan a repair, and risks catastrophic failure. High-frequency vibration: Using techniques such as shock pulse or ultrasonic energy is very effective at early detection of bearing wear. However, these techniques usually lack the ability to detect the many machinery faults that manifest themselves with vibration at lower frequencies. Narrow band spectral analysis: This method involves using relative acceptance criteria that can accurately provide early warning of defects. The portable vibration testers are ideal for this technique. Data is collected using two frequency ranges at a single point on an equipment part. It can be used to diagnose a wide range of machinery problems such as imbalance, misalignment, impeller clearance problem, looseness and resonance.
A variety of versatile vibration testers are available to suit your specific testing needs. Heavy machinery requires large-scale vibration testers whereas portable vibration testers are perfect for smaller electronic equipment. Choose the correct one to make your machinery shock-resistant.
