Advancements in Dimensional Inspection of Helicopter Gearboxes and Transmission Cases

Seeking an operationally simple alternative inspection method from the prior concept of expensive dedicated gages (composite gage systems built to inspect one specific part number), Bell Helicopter Textron purchased a computer assisted Zeiss UMM-800 Universal Measuring Machine. This paper discusses the new concept and its immediate success with the tasks of intersection and alignment inspection of the Model 222 Transmission Cases and Gearboxes. Included are discussions on accuracy, speed of inspection, versatility, simplicity of operation for both inspector and programmer, and the future possibility of a similar system as a true quantitative inspection technique for spiral bevel gear tooth forms.