Session: 02-04-01: Session #1: Advanced Machining and Finishing Processes

Paper Number: 98919

98919 - A Study on New 5-Axis Turning Method for Non-Axisymmetric 3d Surfaces 

A machining center is a common machine tool that can machine complex free-form surfaces such as press mold, automobile camshafts. When these curved surfaces are machined by the conventional machining center and/or the grinding machine, it takes lot of times to complete with enough accuracy. In addition, when machining with a machining center, the surface of the workpiece will not always be uneven due to pick-feed. Therefore, in the machining of such curved surfaces, it is important to improve the productivity and the surface roughness of the workpiece. In order to solve this problem, this study aims not only to improve the machining accuracy of this curved surface but also to make it possible to machine it in a short time using a CNC lathe. In this study, the NACS-Turning (Non-axisymmetric curved surface turning) method was used. NACS-Turning is an our original machining method in which the driven type rotary tool is controlled and positioned to the surface on the workpiece during turning process. In the precision machining, the shape error must be less than 10㎛. However, in the previous study, the shape error by CNC lathe with 4-Axis control showed 15 to 20 ㎛. This resultof the machining accuracy is not sufficient. To reduce this shape error, we changed the tool to the synchronized rotary tool with 5-axis control. In this study, the spindle of C axis, the moving table with cutting tool of X₁ axis, the other counter moving table of X₂ axis, the spindle feed  table of Z axis, and the tool rotation axis of B axis are adapted. In the 5-Axis machining method, all the axis are controlled with the synchronized manner. This method makes it possible to machine the same rotational position of workpiece with  the same cutting edge on the rotary tool. This provides several advantages. This cutting is executed as if the single point cutting by the conventional turning machine the cylindrical surface. This leads to reduces tool wear during machining. In addition, tool runout can be kept constant in the feed direction. As an experiment, we compared 5-Axis machining with synchronized spindle and tool rotation, 4-axis machining, and machining with non-synchronous rotation. The workpiece used in this experiment is C3604, the spindle and tool speed is 375 rpm, and the rotary tool diameter is 10 mm. 5-Axis machining with synchronized spindle and tool rotation reduces the form error from 1.7mm to 0.6mm and the surface roughness from Rz 9.6 ㎛ to Rz 4.7 ㎛ compared to 4-axis. In 5-Axis machining with synchronizing the spindle and the tool rotation, surface roughness was reduced from Rz15.9 ㎛ to Rz4.7 ㎛ compared to the asynchronous machining. By this method, the spiral cutting marks on the workpiece disappeared. As a result, we achieved that the surface roughness was reduced by 50% compared to 4-Axis machining, and by 70% compared to the non-synchronous machining. However, the shape error has not been reduced to 10 ㎛ or less, so further improvement is needed.

Presenting Author: Narimasa Ueda Kanazawa Institute of Technology

Presenting Author Biography: I graduated from Kanazawa Institute of Technology in 2021. After that, I entered the graduate school of Kanazawa Institute of Technology and belong to Morimoto Research.

Authors:

Narimasa Ueda Kanazawa Institute of Technology
Akane Ishizuka Kanazawa Institute of Technology
Yoshitaka Morimoto Kanazawa Institute of Technology
Akio Hayashi Kanazawa Institute of Technology
Yoshiyuki Kaneko Takamatsu Machinery CO,LTD
Naohiko Suzuki Takamatsu Machinery CO,LTD