Woodward listens to its customers. Rather than use mechanical fasteners on their hot valve throttle plates, one customer requested that they weld the plate to the valve rotation shaft. Woodward responded by implementing a high precision robotic TIG welder in their hot-valve assembly area. This new welder allows Woodward to accurately control all of the key welding factors — arc pulse frequency, amperage, voltage, amount of filler wire, and more — to produce the highest quality product they can build.

An advanced vision system and semi-automated fixturing ensures that the throttle plate is properly centered in the valve bore and locates the center of the weld area. The welder then welds the plate from the center out. In less than 30 seconds (for an 80 mm valve), the system positions the throttle plate on the shaft to within one thousandth of an inch, welds one side of the plate, flips the entire assembly, and welds the other side. After welding, the vision system looks at each weld to ensure a solid weld and conformity to standards. They currently weld valve plates from 40 mm up to 220 mm diameter.

This system ensures a solid, repeatable weld. Why all of the extra effort? In actual use on an engine, the extremely hot gasses flowing through the valve causes the plate to grow and shift slightly. Accurately positioning the plate in the valve bore, and welding from the center out accommodates for plate shift during the high temperature operation of the valve. Over the valve’s lifetime, this process minimizes valve wear prolonging the life of the valve.

All of the assembly information about each valve and the welding process is stored, by valve serial number, in a management information system database. This information is used to track part to part variation, process flow and improvement, ensure that assembly procedures were followed and track any possible warranty issues.

While this new robotic welding process is currently used only on the hot-valve assembly line, Woodward is looking into and planning to use the process on future products.

To get more information, or to request a quote for one of Woodward’s products, please click here.

This announcement originally appeared in Woodward’s Energy Controls Newsletter, January 2016 Edition. Narrative modified from first person to third.