Drake's heavy-duty rack mill features a fully adjustable magazine loader to handle part lengths from 500 to 750 mm and diameters from 25 to 35 mm.
Cutters for the heavy-duty milling system are designed to produce specific rack tooth geometries at maximum speeds and feeds.
The heavy-duty milling system has substantially improved part quality and surface finish for one automotive supplier.
Drake Manufacturing Services Inc., Warren, Ohio, has built a heavy-duty milling system that creates power-steering racks for the automotive market. As with all Drake machine tools, the rack mill is preprogrammed to run the family of parts manufactured by this first-tier supplier. Drake calls this its PartSmart approach, and the company test runs customers' parts on the machine before it leaves the Drake factory floor.
The milling system is built for stable and accurate machining with a cast polymer base, linear roller ways, and a Fanuc CNC servo system. The machine features a fully adjustable automatic loader with en-trance and exit magazines that hold 10 parts each for part lengths from 500 to 750 mm and diameters from 25 to 35 mm. Cycle time is less than 35 sec.
The 15-kW milling spindle has heavy-duty front bearings and manual drawbar and runs at a maximum of 150 rpm. The cutter is 160 diameter 200 mm length in size, arbor mounted with standard #50 taper, and has outboard bearing support. Cutters produce specific rack tooth geometries at maximum speeds and feeds.
Setup time between parts is kept under 10 minutes by using a menu format on the controller that keeps mechanical adjustments to a minimum and increases operator productivity. On the cutter, a quick-change arbor reduces cutter-change time.
When setting up, the CNC-controlled helix swivel with servomotor and one-million-count encoder feedback provides automatic positioning for a proper cutting angle. The swivel has a ±10° range, and X, Y, and Z travels are 12 66 in. Hydraulic clamps hold parts up to 35 mm in diameter. The system's software is proprietary.
Drake, which is known for manufacturing thread grinders, bore grinders, and gear hobbers, was asked to develop this machine by the parts maker. To date, two machines are in service, one in Mexico and one in Australia.
The cutters are ground on a Drake GS:F flute grinder and a Drake GS:TE external thread grinder, with some special work also performed by a Drake GS:TI/E Drake combination internal/external thread grinder.