Setco Develops Small Cartridge Spindles for Computers

Showing its versatility in the design and manufacture of spindles, Setco Sales Company (Cincinnati, OH) has developed compact cartridge spindles that run up to 33,000 rpm for 15,000 hours for use in computers, peripherals, and office equipment. The spindles were designed to meet stringent customer cost requirements and have a 7-year life expectancy to match the life of office production equipment.

Though, the spindles don't have the ruggedness needed to withstand the high cutting forces typical of machine tools such as milling, boring, grinding, and other metalcutting applications, they do meet customer demand for precision, compactness, and reliable operation at speeds up to 33,000 rpm. Working closely with the manufacturers and modeling the new spindles after its existing cartridge spindle design, Setco was able to reduce overall engineering time and meet the customer's size and tolerance demands— "on-time and to budget," says Bob Hodge, Setco Group VP-engineering.

Two compact precision spindle designs were developed. One operates in the range of 1200 to 19,000 rpm and handles axial and radial thrust loads of 135 lb. A second spindle runs from 2400 to 33,000 rpm and handles loads of 45 lb. Each spindle was made of 416 stainless steel to resist the corrosive effects of coolants used in the customer's cutting processes. For added spindle bearing longevity, the smaller 1.870 in. diameter spindle had built-in air purge.

"For bearing selection, we focused on using minimum sizes and pre-load to make spindle size and stiffness match the customer's light-duty processing requirements," Hodge explains. "To ensure that both spindles provided precise axial and radial rotation within a TIR runout of 0.0001-in., plus maintain 15,000 hours of reliable production life, we supported the spindle's rotating shaft with duplex angular contact bearings at the front and the rear."

Design of the spindles, manufacture of components, clean-room assembly, runoff testing, and final certification were done at Setco's HQ plant in Cincinnati.

The Setco Group, a CRL Industries Company, designs, manufactures, and services Setco brand precision spindles and Master brand precision slides used in automotive, construction, die/mold and general metalworking.

The Setco Group, 5880 Hillside Ave, Cincinnati, OH 45233; phone: 800-637-3826