27 Apr super precision turning
Hardinge Super Precision hard turning centres reduce cycle times by 82%.
Hardinge Super Precision hard turning centres eliminate the need for the grinding operation to finish the part, reducing set-up time by 70% and cycle time by up to 82%. In addition, they achieve accuracies down to 0.5 microns, half the size of a bacterium.
The automotive and aerospace industries require ever more precise parts with tighter tolerances. 95% of the precision turning market achieves tolerances of +/- 12 microns, which is not precise enough for today’s market demand for tighter tolerances. Thus, semi-finished parts have to be sent to a final grinding process to achieve the required accuracy. Conventional turning is not capable of producing the required parts in a single step.
The industry needs ever more precise machine tools, to achieve the increasingly demanding geometrical tolerances in roundness, cylindricity, straightness and sphericity. At the same time, industry also demands lower surface roughness. In many cases, a precision CNC lathe and a grinding machine could get the job done, although this involves two machines and two operators. Super Precision hard turning eliminates the need for grinding.
More precision on harder parts
Hard turning is defined as a single-point cutting process on parts with hardness values above 45 HRC on the Rockwell scale. However, typical hardness on hard turned parts will be between 58 and 68 HRC.
The precision hard turning process is similar to conventional turning, so its introduction into the normal factory environment does not require major operational changes. Typical materials for hard turning encompass a wide variety: alloy steels, bearing steels, hot and cold work tool steels, high speed steels, cast steels, aerospace alloys, hard chrome coatings, etc.
Super Precision turning centres combine highly advanced design and the integration of the best hardware/software into a production machine tool. These machines are capable of producing very accurate results in a systematic and repeatable way with minimal human intervention. The main sectors and companies that can benefit from this type of machine are: pattern/caliper manufacturing, bearings, tooling, mould/stamping and companies that currently perform grinding.
Super Precision turning works to a tolerance range of 0.5 to 6 microns, overlapping with other technologies such as diamond tool turning, grinding and ordinary precision turning. While the vast majority of today’s precision machine tools offer resolutions (encoders, optical scales, etc.) of 1 micron, new industry standards require machines with lower resolutions. We are talking about 0.1 microns (10 times lower). Accuracies that the vast majority of current manufacturers cannot offer.
However, Hardinge’s new Super Precision lathes can achieve accuracies that were previously only achievable with special machines for turning with diamond tools. That is, cylindricities of less than 1-2 microns and turning with overall accuracies in the 2-micron range.
Accuracy in size and shape
In addition to dimensional accuracy, manufactured parts must meet geometric tolerance standards, including roundness and cylindricity. Super Precision turning excels in this area, as it is capable of producing parts with very low surface roughness and form tolerances with high accuracy, whether 2D or 3D.
The outstanding precision with which Hardinge Super Precision lathes are able to produce is only possible with an extremely stable base. Super Precision lathes must have extraordinary rigidity and unparalleled stability to be able to counteract the forces that occur during machining. This stability prevents deformation due to temperature variations and torsion that may occur, resulting in extremely precise parts with very high performance.