The Hardinge QUEST SUPER-PRECISION GT27 gang-tool turning center is designed for machining small diameters, complex and tight tolerance parts, and other challenging requirements. The GT27 offers a continuous machining accuracy of 0.0002” on diameter, part roundness variation of 0.000015” and part surface finish of 8 micro-inch. Bar work up to 1-1/16”/27 mm and chucked parts as large as 4” in diameter (using a step chuck) can be machined on the GT27, with the ability to hold the same accuracy 10 years down the road, the company says.
The Hardinge GT27 is unlike other gang-tool machines in that it includes interchangeable top plate and a quick-change collet-ready spindle. The top plate secures to the dovetailed cross slide and is interchangeable for quick and accurate tooling changes that can be performed in under a minute. Pre-tooled top plates can be quickly interchanged within 0.0002” repeatability to produce a new part or family of parts. Hardinge’s collet-ready spindle provides maximum rigidity and gripping power because the collet seats directly in the spindle with minimum overhang from the spindle bearings. In this design, the spindle accuracy is transferred directly to the workpiece. Additionally, the HARCRETE machine base is 10 percent stiffer than cast iron, resulting in improved dynamic stability with one-third less vibration at the spindle and a 30-percent increase in tool life. This provides significantly better part surface finishes than cast iron. Size repeatability, surface finish quality and thermal stability are hallmarks for Hardinge lathes.
The Hardinge GT27 can be used as a stand-alone unit, a higher capacity system with a bar feed, or as a fully automated system with a robot. Bar whip or chatter that may be found to some degree in Swiss turning, is not an issue with the GT27 because the bar or chucked part is gripped close to the spindle bearings, the company says.
Editor PickMore Than Metal
Modern Machine Shop magazine doesn’t cover only the machining of metals. Here are some interesting tidbits about machining non-metallic materials from a few of my past stories.