GMT Actuators


Production of the air cylinders and single/triple actuators required for the GMT primary mirror test cell are underway at Texas A&M. More than 160 air cylinders have been assembled and tested and are currently being integrated into complete actuators. In collaboration with the GMT engineering group our lab has developed the assembly and test procedures for each air cylinder as well as procedures for integrating the air cylinders into the single or triple actuator castings. After completion the actuators will be shipped to the University of Arizona to be installed in the primary mirror test cell.

Air Cylinder Assembly

Parts arrive from various machine shops and need to be cleaned to remove any residual metal shavings or oil residue. Industrial ultrasonic cleaners are used for the initial cleaning. Parts are then rinsed with distilled water and Isopropyl alcohol.

Figure 1: Parts are cleaned before assembly using an ultrasonic cleaner.

Machined parts and all required hardware are collected into kits to ensure all parts are available before assembly starts, and also to allow for verification that no parts were left out during assembly (the kit should be empty after assembly is complete).

Figure 2: The lab has four work stations, each with a complete set of the required tools to allow multiple air cylinders to be assembled simultaneously.

Air Cylinder Testing

Each air cylinder undergoes a functional test to verify that it is able to apply and maintain the required forces. Cylinders are also tested for air leakage by pressurizing to 120PSI, isolating the cylinder with valves, and tracking the pressure drop over 20-40 minutes.

Integration of Actuators

Individual air cylinders are configured for either a single or triple actuator (addition of load cell and mounting hardware, rod end distances are set) and then air cylinders are assembled into actuator castings. Completed actuators are once again tested for functionality and then packaged for shipping in custom shipping boxes with a folder of test data for each enclosed actuator. Each box contains either two single actuators, or one triple actuator. Boxes are shipped either 4 or 8 to a standard 4’x4’ pallet.