Power is being transferred from a central location to machines through belts and shafts. The requirement to transmit power was formerly addressed by the use of single-tooth keyways. But today a more elegant solution moves away from chain drives and axles to driveshafts and gearboxes through spline assembly. Splines come in various forms but they all share a common characteristic, that is complexity which demands high accuracy metrology for quality. The manufacturing process of producing splined shaft involves hobbing with the use of a form cutter.
In order to determine the geometry of a spline, the main features that have to be considered include the tooth profile, pitch of the teeth and the degree of straightness along the tooth.
The conventional and established method of measuring splines is tactile inspection. However, it is ideal only for sample inspection but is not suitable for production control because the inspection time takes longer than the production cycle time. With the advent of optical sensors, metrology takes a step higher wherein complete part and individual features are captured. The switch to optical solution of measuring the complete profile of splined shaft is done by spinning the part in one revolution. Compared to tactile solution, more detailed information is captured at a much faster rate using optical scan, capturing up to a thousand points per second.
The new optical system eliminates the time consuming process of pitch measurement of splined shaft. The optical sensor can be used in three various ways: single-point mode, continuous scanning mode and sensor-specific ‘spin-scan’ mode. Under the continuous scanning mode, the CMM parameters adjust to suit the surface being measured. It is the VHSS that is used to modify the speed of scanning across the axes. Whereas in spin-scan mode, it is the part which is rotated at speed while the sensor remains stationary. This technique enables part features to be programmed and captured easily and quickly, reducing cycle times by up to 80%.
The combination of these high-performance technologies produces a high throughput and more precise metrology solution for production processes. This ultimately results to significant improvement in throughput without decreasing the accuracy in part production.