Ultra-High Speed Machining of A356-T6 Aluminum Alloy for Automotive Applications

2004 ◽  
Author(s):  
Eu-Gene Ng ◽  
Mohamed A. Elbestawi ◽  
Mihaela Dumitrescu
Author(s):  
Roman V. Kazban ◽  
James J. Mason

Even though many models for machining exist, most of them are for low-speed machining, where momentum is negligible and material behavior is well approximated by quasi-static plastic constitutive laws. In machining at high speeds, momentum can be important and the strain rate can be exceedingly high. For these reasons, a fluid mechanics approach to understanding high-speed, very high-speed, and ultra-high-speed machining is attempted here. Namely, a potential flow solution is used to model the behavior of the material around a sharp tool tip during machining at high speeds. It is carefully argued that the potential flow solution is relevant and can be used as a first approximation to model the behavior of a metal during high-speed, very high-speed, or ultra-high-speed machining events; and at a minimum, the potential flow solution is qualitatively useful in understanding mechanics of machining at high speeds and above. Interestingly, the flow solution predicts that there is a stagnation point on the rake face, not at the tool tip as is usually assumed. Because the stagnation point is not at the tool tip, the flow solution predicts a significant amount of deformation in the workpiece resulting in large residual strains that may lead to a temperature rise on the finished surface.


2014 ◽  
Vol 2014.49 (0) ◽  
pp. 121-122
Author(s):  
Yasuyoshi SAITO ◽  
Takeshi YAMAGUCHI ◽  
Kei SHIBATA ◽  
Yuki KADOTA ◽  
Takeshi KUBO ◽  
...  

Author(s):  
Said Jahanmir ◽  
Michael J. Tomaszewski ◽  
Hooshang Heshmat

Small precision parts with miniaturized features are increasingly used in components such as sensors, micro-medical devices, micro-fuel cells, and others. Mechanical micromachining processes, e.g., turning, drilling, milling and grinding are often used for fabrication of miniaturized components. The small micro-tools (50 μm to 500 μm diameter) used in micromachining limit the surface speeds achieved at the cutting point, unless the rotational speeds are substantially increased. Although the cutting speeds increase to 240 m/min with larger diameter tools (e.g., 500 μm) when using the highest available spindle speed of 150,000 rpm, the cutting speed with the smaller 50 μm tools is limited to 24 m/min. This low cutting speed at the tool tip is much smaller than the speeds required for efficient cutting. For example, in macro-milling of aluminum alloys the recommended speed is on the order of 60–200 m/min. The use of low cutting speeds limits the production rate, increases tool wear and tendency for burr formation, and limits the degree of dimensional tolerance and precision that can be achieved. The purpose of the present paper is to provide preliminary results that show the feasibility of ultra high-speed micro-milling of an aluminum alloy with respect to surface quality and burr formation. A new ultra high-speed spindle was used for micro-milling of an aluminum alloy with micro-end-mills ranging in diameter from 51 μm to 305 μm. Straight channels were machined to obtain an array of square patterns on the surface. High surface cutting speeds up to 340 m/min were achieved at 350,000 rpm. Inspection of the machined surfaces indicated that edge quality and burr formation tendency are related to the undeformed chip thickness, and therefore the cutting speed and feed rate. The quantity of burrs observed on the cut surfaces was generally small, and therefore, the burr types were not systematically determined. Cutting with the 305 μm tool at a cutting speed of 150 m/min produced an excellent cut quality using a chip thickness of 0.13 μm. However, the cut quality deteriorated as the chip thickness was decreased to 0.06 μm by increasing the cutting speed to 340 mm/min. This result is consistent with published data that show the dependence of bur formation on ratio of chip thickness to tool tip radius. The channel widths were also measured and the width of channels cut with the small diameter tools became larger than the tool diameter at higher speeds. The dependence of the channel widths on rotational speed and the fact that a similar variation was not observed for larger diameter tools, suggested that this phenomena is related to dynamic run-out of the tool tip, which increases the channel width at higher speeds.


2009 ◽  
Vol 69-70 ◽  
pp. 384-388
Author(s):  
Qin Xi Shen ◽  
Gui Cheng Wang ◽  
Hai Jun Qu ◽  
Yun Ming Zhu

The end surface angle of workpece is one of key factors that affect burr sizes and shapes. In this paper, the burr formation process of different end surface angle is simulated with elastic plastic nonlinear element method based on ABAQUS. The influence of end surface angle of workpiece on burr formation processes in high-speed machining 2024 Aluminum alloy is analyzed. The influence of end surface angle on burr sizes and shapes is studied based on equivalent shear strain and negative shear angle. The results have investigated the mechanisms of burr formation fundamentally, which is the basis of burr minimization.


1973 ◽  
Vol 187 (1) ◽  
pp. 625-634 ◽  
Author(s):  
G. Arndt

As part of the search for a new cutting mechanism, a few largely empirical investigations into ultra-high-speed machining (velocity greater than 500 ft/s) have been performed in the past. A comprehensive review of this and other work related to machining at very high cutting speeds is presented and the physical factors predominating in UHSM are discussed. As a consequence of this a new theory of cutting forces at ultra-high speeds is presented, based on inertia and temperature effects, adiabatic shear, and strain-rate dependent yield stress. This theory shows that workpiece properties greatly influence force behaviour, the latter determining the feasibility of machining at ultra-high speeds.


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