Fifty to 70 percent of machined automotive components require only 90-degree indexing movements during milling and drilling operations, according to Patrick Yeko, sales manager for Pascal Engineering, Inc. (Elk Grove Village, Illinois). For these applications, repeatable workpiece indexing to 12, 3, 6 and 9 o’clock positions is more important than the ability to rotate to numerous angular positions.
These types of machining applications drove Pascal to develop its compact MDX indexing table. The MDX uses a roller gear cam design to index a workpiece 90 degrees in 0.5 second, in conjunction with an integral, three-piece Hirth coupling that acts as a fully mechanical locking system. These two design features allow index positioning accuracy of ±5 arc seconds. Also, by using the Hirth coupling as the locking mechanism, an external brake (required for indexers using worm gears) is unnecessary.
A roller cam on the main shaft guides cam followers on the turret of the indexer’s workholding table to rotate the table in 90-degree increments. Once indexed into position, a different cam on the shaft actuates a lever that locks the Hirth coupling—and the table—into a new angular position. The motor that rotates the main shaft is driven by an M-code sent from the machine tool’s control to the indexer’s inverter control.
The company offers two MDX models. An MDX06 version offers a table diameter of 160 mm and spindle inner diameter of 35 mm. A larger MDX08 unit has table and spindle inner diameters of 200 mm and 48 mm, respectively. Both models offer an optional rotary coupling with multiple oil or air passage connections for powered workpiece clamping and part detection. A center hole in the coupling also allows for coolant delivery. End supports are available with an integral nitrogen gas spring balancing system, allowing smooth indexing of eccentric workpiece loads.