Advanced Metrology for the Aircraft Industry Precitech Inc.

The aircraft engine and turbine power industries has always demanded precise measurement methods for reducing engine vibration, maximizingbearing life and identifying engine piece part irregularities. To meet this challenge, Precitech has developed the Aerospect Stack Prediction System, SPS-1000. This instrument enables the operator to inspect individual compressor engine components and predict the stack alignment of its parts to achieve a final tolerance. An acceptable system stack will minimize the unbalance in a final balance procedure, significantly reducing the overall time spent in final assembly.

Precitech uses its proven modular components, a precision air bearing spindle, heavy duty tilt and centering worktable, rigid gage posts and gage arms. An industrial grade computer, digital I/O interface, gaging board and monitor are housed within an air-conditioned electrical cabinet for dependable operation even under the most severe shop floor conditions. All components are secured to a toolroom grade granite plate with adjustable isolation mounts dampening any floor vibrations.

Precitech's SPS-1000 Windows® software measures each piece part for concentricity, perpendicularity and runout. This data is stored and serialized for use in a stack prediction. After all the serialized piece parts are inspected the resultant data is recalled from memory, and a final piece part angular orientation is calculated and presented on the monitor. All guesswork for stacking individual parts is removed using this method of stack prediction for compressor or rotor assemblies.

The SPS-1000 uses four gages simultaneously to measure out-of-roundness, concentricity, perpendicularity, runout, flatness and parallelism of a part. This reduces set-up time and eliminates unnecessary gage handling. Two gages are mounted to each gage post 180º apart and are identified in the part edit program configuration.

An encoder within the rotary table displays angular orientation used for alignment of the piece parts being inspected for final stack prediction. The two gage posts swing out for ease of part loading and lock into position for the inspection process.

Standard programs of the SPS-1000 include Tilt Center, which guides the operator through the steps that level and center the part to acceptable tolerances for piece part inspection. Piece Part Inspection inspects the part for acceptable geometric parameters. Stack Prediction calculates a group of parts to optimize the final stack. This information is retrieved from the individual part serial numbers. The Part Edit program is used to create and modify parts for inspection. Part diameters, heights, gage orientations and serial numbers are entered into this program file. A Diagnostics program is included for evaluating spindle encoder counts, encoder channels and calibration reports.

The Aerospect SPS-1000 Stack Prediction Gage comes in two versions:
1) A "tall profile" primarily for piece part inspection. (SPS 1000T)
2) A "low profile" gage for piece part and stack prediction (SPS 1000L)

For more information, please contact Precitech's Metrology Department by email wmroz@precitech.com or at 603-357-2511.
©2002 Precitech Inc.