Reduction of material swelling and recovery of titanium alloys in diamond cutting by magnetic field assistance

Abstract

Ultra precision machining (UPM) is extensively used to fabricate high accuracy products. However, the problematic material swelling/recovery effect due to elastic recovery of materials in UPM remains unresolved. It causes ragged surface and extra engineering tolerance which are unadoptable in extremely precise components. In particular to high elastic recovery rate with low thermal conductivity materials like titanium alloys, swelling effect intensifies during machining. In this study, magnetic field was superimposed on titanium alloys during single point diamond cutting which aimed to minimize the material swelling effect on the machined surface using magnetic field influence. In the experiment, titanium alloys were located at the center of two permeant magnets with strength 0.02T and undergone diamond groove cutting. The experimental results showed the material swelling/recovery on the machined surface was significantly reduced in a presence of magnetic field in comparison to that of diamond cutting without magnetic assistance; the accuracy of depth of cut, width and radius of cutting groove in a magnetic field reached satisfactorily over 98 percent. The proposed machining technology solves the problem of material swelling/spingback of low thermal conductivity materials by a cost-efficient way which is needless of complicated equipment. Keywords: magnetic field; diamond cutting; titanium alloys; material recovery; material swelling *Source Manuscript Click here to view linked References Ultra precision machining (UPM) is extensively used to fabricate high accuracy products. However, the problematic material swelling/recovery effect due to the elastic recovery of materials in UPM remains unresolved. It causes a ragged surface and extra engineering tolerances which are unadoptable in extremely precise components. In particular to high elastic recovery rate with low thermal conductivity materials like titanium alloys, the swelling effect is intensified during machining processes. In this study, a magnetic field was superimposed on titanium alloys during the single point diamond cutting which aimed to minimize the material swelling effect on the machined surface using the magnetic field influence.In the experiments, titanium alloys were located at the center of two permanent magnets with intensity 0.02T and undergone a diamond groove cutting. The experimental results showed the material swelling/recovery on the machined surface was significantly reduced in presence of magnetic field in comparison to that of diamond cutting without a magnetic assistance; the accuracy of depth of cut, width and radius of cutting groove in a magnetic field reached satisfactorily over 98 percent. The proposed machining technology solves the problem of material swelling/spingback of low thermal conductivity materials by a cost-efficient way which is needless of complicated equipment.

Ductile and brittle transition behavior of titanium alloys in ultra-precision machining

“…The materials that are melted become viscous fluid under continuous cutting and the material fluid localizes at the two sides and the bottom of the tool edge. The metal fluid solidifies and expands when temperature of the machined surface decreases 32 , 33 , as a result, the machined surface swells and apparent tool marks are left on the machined surface, introducing the deviation of actual cutting depth from the assigned one. The microscopes of three areas of each machined groove were captured, they are denoted as X, Y and Z as the figures shown.…”

Influencing Factors and Theoretical Models for the Surface Topography in Diamond Turning Process: A Review

“…However, these values are not sufficient for the surface topography model in one feed rate, which means that the distribution functions responsible for the material plastic side flow and material spring back should be supplied. Kong et al and To et al studied the material plastic side flow and recovery in diamond turning process [47,48,49], and Kong et al further pointed out that the effect of material plastic side flow is overwhelmed by the effect of material spring back when the depth of cut is extremely small. Furthermore, the influence of the distribution of the material spring back and plastic side flow on the surface profile in one tool feed is also discussed in [47].…”

Theoretical and Experimental Investigations of Tool Tip Vibration in Single Point Diamond Turning of Titanium Alloys

“…By combining all the above machining factors, tool marks are generated on final machined surfaces because of integral effects of material swelling, and plastic deformation [9,10]. When a diamond tool starts to cut the machined surface, the materials near the tool edge suffer from a plastic side flow because of an insertion of high pressure from the tool edge [11]. That side flow materials finally leave on the machined surface, which the volume of the materials is normally expanded in response to the effect of thermal expansion, and finally, it causes a ragged machined surface, the phenomenon is called the material swelling effect, which is a common drawback in the SPDT of low thermal conductivity materials.…”