Closure to “Discussion of ‘New Development in the Theory of the Metal-Cutting Process: Part II—The Theory of Chip Formation’” (1961, ASME J. Eng. Ind., 83, pp. 569–570)

1961 ◽  
Vol 83 (4) ◽  
pp. 570-571
Author(s):  
P. Albrecht
Keyword(s):  
Chip Formation ◽  
Metal Cutting ◽  
Cutting Process ◽  
New Development

New Development in the Theory of the Metal-Cutting Process: Part II—The Theory of Chip Formation

1961 ◽  
Vol 83 (4) ◽  
pp. 557-568 ◽  
Author(s):  
P. Albrecht
Keyword(s):  
Shear Zone ◽  
Tool Life ◽  
Chip Formation ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Shear Plane ◽  
Cutting Process ◽  
Chip Formation Mechanism ◽  
Bending Stresses ◽  
Set Up

Introduction of the concept of ploughing into the metal-cutting process lead to the abandoning of the assumption of collinearity of the resultant force on tool face and on the shear plane. With this understanding the tool face force is found to produce a bending effect causing bending stresses in the shear zone. Study of the chip formation mechanism when varying cutting speed showed that increased bending action reduces the shear angle and vice versa. A set-up for the development of an analytical model of the chip formation process based on the combined effect of shear and bending stresses in the shear zone has been given. Application of the gained insight to the design of the cutting tool for maximum tool life by controlling of the chip-tool contact was suggested. Brief introduction to the study of cyclic events in chip formation and their relation to the tool life is presented.

Analysis and Fabrication of a Mechanical Quick-Stop for Research on Chip Formation in Hard Turning Process

2019 ◽  
Vol 889 ◽  
pp. 87-94
Author(s):  
Nguyen Thi Quoc Dung
Keyword(s):  
Chip Formation ◽  
Hard Turning ◽  
Manufacturing Industry ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Cutting Process ◽  
Machining Process ◽  
Machining Parameters ◽  
Machining Processes ◽  
On Chip

Metal cutting is one of the most important machining processes in manufacturing industry. Thorough understanding of metal cutting process facilitates the optimization in selection of cutting tools and machining parameters. There are several methods used for studying phenomena in metal cutting process. Using a quick-top device is an efficient technique for investigation cutting process in which cutting action is stopped so suddenly that the “froze” specimen called the chip root honestly depicts what happened during cutting action. Design strategies of a quick-stop are accelerating cutting tool away from the workpiece or decelerating the workpiece remaining in engagement with the tool. Operation of a quick-stop device can be either mechanically or by explosive. Quick-stop devices can be utilized for various types of machining processes such as: turning, milling, drilling. This paper described the analysis, fabrication, and testing of a quick-stop device which is used for researching on chip formation in hard turning. This device has simple and safe operation which utilizes spring forces to retract the tool from workpiece during cutting. The results of performance at cutting speed of 283 m/min show that the separation distance is quite small, less than 0.2mm so that the deformations on the root chip are close to that while actual machining process. This indicates that the device has satisfied the requirements of an equipment for studying on chip formation.

Self-Induced Vibrations in Metal Cutting

1962 ◽  
Vol 84 (4) ◽  
pp. 405-416 ◽  
Author(s):  
Paul Albrecht
Keyword(s):  
Tool Life ◽  
Chip Formation ◽  
Metal Cutting ◽  
Shear Angle ◽  
Physical Basis ◽  
Cutting Conditions ◽  
Cutting Process ◽  
Force Response ◽  
Dynamic Conditions ◽  
Cyclic Variations

Solution of the problem of dynamic stability for the machine tool-cutting process system depends primarily on the assessment of behavior of the cutting process under dynamic conditions. It has been found that under dynamic conditions, apart from force fluctuations due to variations in cutting conditions, additional force fluctuations take place as a result of cyclic variations of the shear angle in the cutting process. Difference in force response of a cutting process to the static dynamic variations of the cutting conditions has been explained by the presence of cyclic variations of shear angle under dynamic conditions. Peaks of the force wave, resulting from dynamic variation of the cutting conditions, are known to be displaced with respect to the originating wave. This displacement has been thought to be due to a time lag of the whole force response; however a sound physical basis for this point of view has not previously been found. The present investigation provides a physical basis for such observations, showing that the displacement of force peaks is caused by the skewing of the force wave by the presence of asymmetric force pulses due to cyclic variations of shear angle. The same event—the cyclic variation of the shear angle—has been recognized to be a sign of instability of the cutting process in itself, resulting in a cyclic chip formation process. Instability of the cutting process in itself has been found to depend mainly on the cutting conditions and not on the dynamic properties of the cutting system. Analytical expressions derived for the frequency and amplitude of cyclic chip formation have been found to be in a good agreement with the results of measurements of these quantities. Study of the effects of dynamic events in metal cutting upon tool life has revealed propagation of fatigue cracks on the wear land. The propagation of the cracks has been found to be in good correlation with the presence of force pulses due to the cyclic chip formation. The way in which the foregoing event affects the tool life has been reconstructed, allowing selection of those conditions which improve tool life.

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