Collet-Ready Rotary Tables, Indexers Reduce Job Cost

June 30, 2011
Hardinge fixtures will accept a range of standard tooling to grip parts of various shapes and sizes.
Hardened collets, step chucks, or expanding collets will seat directly in a Hardinge collet-ready spindle so the machining process remains close to the spindle.

Using fixtures to grip parts on a rotary device involves quite a lot operator intervention, for setting up, clamping and locating the part, and changing from one job to another. Do not overlook the time needed to design and produce the fixture itself. All of this accumulated time lengthens the production time and increases the cost of the part.

There is an alternative. Hardinge recommends collet-ready spindle rotary tables and indexers, which will accept a wide variety of standard tooling to grip parts of various shapes and sizes so that operators can produce more parts per hour at a lower cost per part.

Production cost isn’t the only advantage of using a collet-ready rotary unit. Part quality is a factor and it begins at the spindle. Parts machined closest to the spindle bearings provide the highest accuracy with less wear on the rotary device. A hardened collet, step chuck or expanding collet will seat directly in the Hardinge collet-ready spindle with the machining process closest to the spindle. Minimal overhang from the spindle bearings ensures that spindle accuracy is transferred directly to the part being machined. Fixtures that are not hardened will lose positioning accuracy over time. Fixtures add weight to the spindle and move the cutting location further away from the spindle bearings.

Hardinge is known for its precision and Super-Precision® collet-ready turning centers, and builds those A2 spindles into their rotary tables and indexers for precision and the convenience of quick setup and changeover with no adapter required.

Collet-ready spindles will accept collets, step chucks, Sure-Grip® expanding collets, FlexC quick-change vulcanized collet systems, custom collets, manual chucks and Sure-Grip® power chucks. Many shops may be able to share the tooling with an existing CNC lathe. Hardinge indicates the collets and chucks will automatically center the part whether it is round, hexagon or square. It also will occupy less storage space than custom-made fixtures. Shops that may choose to continue using some existing fixturing may use a simple adapter.

This chart lists all of the gripping options offered by a Hardinge collet-ready spindle rotary device.

The capacity chart shown here lists all of the gripping options offered by a Hardinge collet-ready spindle rotary device. You can eliminate and replace heavy fixturing with higher precision, less expensive workholding products. Your pre-machined part could be gripped on a threaded or tapered outside diameter; an internal diameter; a square; a hex or any custom shape; or over a shoulder. Rough or slippery stock, thin wall and out-of-round parts, short grips, recessed grips and off-center parts are no problem. Castings, moldings, stampings and machined parts are held rigidly and accurately, while tubing can be held without crushing or distorting.

Collets will seat directly in the spindle for maximum gripping power and rigidity, providing the most accurate positioning available. Step chucks are simply oversized collets with a stepped-out face to grip larger part sizes using a closer, Hardinge explained. Step chucks provide extra grip force for short grip parts because the collet is closed against an opposing taper with 360-degree contact. Step chucks can have more than one gripping diameter for end-to-end machining or multiple use.

Hardinge Sure-Grip® Expanding Collets are used to grip the internal diameter of parts ranging from ⅛ in. up to 4 in. Hardinge quick-change FlexC Collet Systems have a special accuracy of within 0.0004 in. (0.01 mm). FlexC collets (42 and 65mm) are ideal for job shops that frequently change setups throughout the day because the collet heads change out in seconds. S-master style FlexC collets are available in 65 millimeter for shops that predominantly use S-pads with their other machines. 4-Jaw manual chucks will grip round, hex and square parts.

The Hardinge Sure-Grip® 3-Jaw Power Chuck mounts directly on the rotary spindle to grip larger diameters and offers considerable grip strength. 3-Jaw chucks will grip round and hex shapes. Hardinge slotted face plates are precision ground for accurate locating of odd-shaped parts with guaranteed perpendicularity to the centerline of the spindle.

Hardinge custom manufactures OD and ID gripping solutions for hard-to-grip parts, odd shapes, sizes and materials such as glass and plastics. These solutions typically seat directly in the spindle to provide rigid and accurate part placement while cutting setup and changeover times to just a fraction of the time it would have taken using a special fixture. Hardinge has years of experience in manufacturing custom solutions for gripping the most challenging parts.

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