Published 3/1/2007

Relieving Bottlenecks At The Measurement Station

Throughput is as much an issue in measurement as it is in machining. Likewise, multipart setups can improve measurement throughput in much the same way they contribute to machining throughput. A special part fixture used in conjunction with an automated contour and surface-roughness measuring system allows four workpieces to be checked one after the other, with no operator intervention.

Mark Albert

Editor Emeritus, Modern Machine Shop

Throughput is as much an issue in measurement as it is in machining. Likewise, multipart setups can improve measurement throughput in much the same way they contribute to machining throughput. Consider the special part fixture shown at IMTS 2006 by Mitutoyo America Corp. (Aurora, Illinois). This fixture allows a Formtracer CS-3100 contour and surface-roughness measuring system to check four workpieces, one after the other, with no operator intervention.

The fixture is essentially a multitiered rack consisting of a steel post on which modular bracket arms are bolted. The arms are set back successively from to top to bottom to provide clearance for the drive unit/measurement head.

The system is servo-driven for automatic CNC measurement. According to the company, one key to automatic multipart measurement is the incorporation of an absolute scale in the Z2 (height position) axis. This eliminates the need for origin point resetting each time the system is repositioned to repeat a measurement routine on a new part or on additional sections of the same part.

The point of the display was to show how relatively simple fixturing enhances the productivity of a measurement system. This theme is carried over to other optional accessories that the company offers for automating measurement. These include horizontal and vertical rotary tables, programmable tables for Y-axis movement, 2D/3D auto leveling and combinations of these add-ons.

However, combining contour and surface roughness measurement in a single unit represents the system’s main contribution to saving setup time and reducing measurement steps. Finally, high speeds and feeds reduce cycle time in machining as well as in measurement, so the Formtracer is designed for high speeds: 3.15 ips (80 mm/s) in X and 0.79 ips (20 mm/s) in Z.