MACHINERY DIAGNOSTICS AND QUALITY ASSURANCE SYSTEMS

RH Lyon Corp designs and develops advanced diagnostic systems for a wide variety of developmental and industrial applications, including machine condition monitoring and production-line quality assurance systems.

When a machine operates, forces are created that result in vibration and sound. Properly sensed, processed and analyzed, these signals can provide a wide array of useful performance data to determine the "health" of the machine, to control its operations and make it run more efficiently, or to make design or quality control decisions that either improve product performance or eliminate manufacturing problems in a timely way. Although vibration sensors are often used in this application because of their ruggedness and convenience (they can be placed on the exterior of a machine, and the signals they pick up are relatively local to a specific part of the machine), we have also had success using other "non-intrusive" signals (acoustical, electrical).

Production-line machine diagnostics permit evaluation of product quality during the production process. Specifically, data from external measurements may be analyzed to "look inside" and evaluate product quality. Our system architecture for doing this is called SignaTrack™, and is embodied in an integrated production line diagnostic system. Production Quality Assurance diagnostic systems bring value to product manufacturers in a number of ways. Principally, with production-line diagnostics, manufacturing yield will increase for a given product design. From the end-user's point of view, this yield increase results in greater customer satisfaction. The manufacturer will have fewer products returned and will see fewer service calls, which, in turn, will lead to significant cost savings. Satisfied customers set the stage for increasing market share and new market penetration. Manufacturers also realize value internally. Higher yield implies that fewer products will be reworked or scrapped, thus increasing effective utilization of raw materials and components. Finally, production-line diagnostics rapidly identify faulty components or processes; these can be addressed and corrected in "real-time." Rapid identification of production-line faults increases effectiveness of the manufacturing process by reducing both remediation cost as well as reducing spoiled work

PROJECT EXAMPLES

Diesel Engines
Scheduled maintenance on locomotive diesel engines now requires a strip-down for interior inspection. This process is costly. Not only does it put locomotives out of service, it also provides the potential for introducing faults that previously did not exist. But by using remote vibration-based diagnostic procedures developed by RH Lyon Corp, internal faults can be identified without disassembly. This is accomplished primarily through reconstruction of the internal cylinder pressures as a function of time, and detection of valve and injector related events for each cylinder, all from accelerometers mounted on the exterior of the engine.

Production Line Test Fixtures
Acoustic and vibration qualification tests on the production line may be simply implemented using vibration measurements alone. However, to qualify products to a consistent standard, special attention must be paid to the design of proper test fixtures that do not interfere with the product's own vibration signature.

Identification of Transfer Line Assembly Faults
Automotive auxiliary motors are assembled automatically. Occasionally, in the process, a fault may be introduced. However, the result of the fault is often not evident until assembly is complete and the fault well hidden. By using vibration diagnostic procedures, faults can be identified specifically and the aberrant station in the assembly process pinpointed.

Diagnostics of Motor Operated Valves
Motor operated valves are critical components in nuclear steam power plants and in the chemical process industry. Using basic patented technology developed at MIT and at RH Lyon Corp, a portable diagnostic system determines a number of faults, such as bent valve stems, tight stem packing, eroded or corroded valve seats, and motor stall.

Compressor Diagnostics
Failures in reciprocating compressors often involve valve problems - leakage, weakening, or fracture. These faults can be distinguished and identified from the vibrations induced from valve seating. Other faults, such as crankshaft bearing impacts are also identifiable based on RH Lyon Corp techniques.

Jam Detection
Strain measurements made on an extremely long cutting blade can signal that the material beneath the blade is beginning to jam. With this early detection system the production line can be halted before damage to the material or the blade occurs, the problem can be quickly remedied, and downtime can be significantly reduced.


Related Tech Briefs (Acrobat PDF))


Related Article

In-Service Diagnostics of Motor-Operated Valves, Maintenance Journal / February 2003


Related Book

Machinery Noise and Diagnostics, by R. H. Lyon