Hardinge Collet Blocks grip round, hex, square or odd-shaped parts from 1C to 35J sizes for high-production machining applications
Have you considered collet blocks for fixturing multiple parts to machine or process in one setup? Collet blocks can be used horizontally or vertically on mill tables, flat or angled fixture plates, tombstones or rotary trunnions. Sizes are available from the 1C micro medical machining industry up to the 35J mid-range automotive and aerospace industries. Modular collets blocks are compact with a low profile for increased axis travel and for maximum layout of the workspace. A collet can provide certain advantages over a jaw chuck, vise and other clamping methods.
The advantages of using Collet Blocks vs. standard vises or 3-jaw chucks
A collet automatically centers the workpiece for reduced setup time. Centers remain fixed when the fixture is removed from the machine table. A hydraulic quick disconnect handle will allow parts to remain clamped for preloading, loading and unloading pallets. A collet provides equal gripping pressure around the circumference of the part unlike a standard vise or a 3-point contact jaw chuck. Thin-wall parts or delicate materials may crush or distort in a standard vise or jaw chuck. Collets ordered with serrations can add additional gripping power to prevent push-back and radial slipping. Extended-nose collets can provide additional tool clearance. Some collet blocks accept expanding collets to grip a part at the internal diameter.
“When people hear the word “collet”, they tend to think of small round diameter gripping, says Cal Macomber, Director of Sales & Marketing of Hardinge Workholding. 35J collets will grip up to a 3-1/2” (88.9mm) diameter while a step chuck can hold a shape up to 7” (177.8mm) in diameter. Hex, square and custom-shaped collets will hold a variety of shapes.”
Hardinge collet blocks are available in lightweight aircraft-grade aluminum or heavy steel construction. Double-acting pneumatic or hydraulic models are available in dead-length style or pull-back style. Double-acting requires pressure to grip and pressure to release the part so that the part won’t stick or hang up like a single-acting collet block might. Pull-back operation means that the collet is literally “pulled back” or down into the closer as the part is clamped in place via the “draw tube”. Dead-length models feature the ability to actually thread the collet into the closer to a precise location and lock it into place. The collet remains stationary as the closing mechanism moves toward the taper on the collet to clamp the part, then moves away from the collet to release the part being held. Since the collet itself does not move, the part or fixture being held maintains a fixed position from part-to-part allowing for higher precision and part length control to be achieved.
If you’re operating in a region where you frequently lose shop air, or are off-loading pallets, you might consider Hardinge’s fail-safe 5C pneumatic collet block. Air is required during setup to open the workholding. After setup, a unique spring design holds the workpiece at a 1760-pound optimum 5C drawbar force without the use of air. The spring-to-close design also provides the opportunity to use pallet shuttles without the need for air or hydraulic lines. If loss of air should occur during the machining process, parts will remain clamped and concentricity will be maintained without downtime or waste. This design eliminates the risk of scrapping parts, the danger of parts flying off if loss of air should occur, and eliminates downtime associated with chip buildup.
Hardinge offers pneumatic and hydraulic accessories to build your own configurations or will custom design and build complete turnkey solutions. Electronics, dental, heavy equipment, automotive, aerospace, power & hand tools, medical and machine tool are some of the industries currently using collet blocks. “We see collet block applications in the standard job shop including milling, drilling and grinding – but also in the crimping, inspection, testing and assembly environments”, states Cal Macomber. Hardinge manufactures collets, step chucks and expanding collets for use in the collet block. For more information contact Hardinge at 800-843-8801, or visit online at www.hardingetooling.com.