High-speed machining of titanium alloys using the driven rotary tool

2002 ◽  
Vol 42 (6) ◽  
pp. 653-661 ◽  
Author(s):  
Shuting Lei ◽  
Wenjie Liu
Keyword(s):  
Titanium Alloys ◽  
High Speed ◽  
High Speed Machining ◽  
Rotary Tool

Highlights of the DARPA Advanced Machining Research Program

1985 ◽  
Vol 107 (4) ◽  
pp. 325-335 ◽  
Author(s):  
R. Komanduri ◽  
D. G. Flom ◽  
M. Lee
Keyword(s):  
Thermal Properties ◽  
Tool Wear ◽  
Titanium Alloys ◽  
Tool Life ◽  
Research Program ◽  
High Speed ◽  
Metal Removal ◽  
High Speed Machining ◽  
Advanced Machining ◽  
Nickel Base

Results of a four-year Advanced Machining Research Program (AMRP) to provide a science base for faster metal removal through high-speed machining (HSM), high-throughput machining (HTM) and laser-assisted machining (LAM) are presented. Emphasis was placed on turning and milling of aluminum-, nickel-base-, titanium-, and ferrous alloys. Experimental cutting speeds ranged from 0.0013 smm (0.004 sfpm) to 24,500 smm (80,000 sfpm). Chip formation in HSM is found to be associated with the formation of either a continuous, ribbon-like chip or a segmental (or shear-localized) chip. The former is favored by good thermal properties, low hardness, and fcc/bcc crystal structures, e.g., aluminum alloys and soft carbon steels, while the latter is favored by poor thermal properties, hcp structure, and high hardness, e.g., titanium alloys, nickel base superalloys, and hardened alloy steels. Mathematical models were developed to describe the primary features of chip formation in HSM. At ultra-high speed machining (UHSM) speeds, chip type does not change with speed nor does tool wear. However, at even moderately high speeds, tool wear is still the limiting factor when machining titanium alloys, superalloys, and special steels. Tool life and productivity can be increased significantly for special applications using two novel cutting tool concepts – ledge and rotary. With ledge inserts, titanium alloys can be machined (turning and face milling) five times faster than conventional, with long tool life (~ 30 min) and cost savings up to 78 percent. A stiffened rotary tool has yielded a tool life improvement of twenty times in turning Inconel 718 and about six times when machining titanium 6A1-4V. Significantly increased metal removal rates (up to 50 in.3/min on Inconel 718 and Ti 6A1-4V) have been achieved on a rigid, high-power precision lathe. Continuous wave CO2 LAM, though conceptually feasible, limits the opportunities to manufacture DOD components due to poor adsorption (~ 10 percent) together with high capital equipment and operating costs. Pulse LAM shows greater promise, especially if new laser source concepts such as face pump lasers are considered. Economic modeling has enabled assessment of HSM and LAM developments. Aluminum HSM has been demonstrated in a production environment and substantial payoffs are indicated in airframe applications.

scholarly journals Towards Optimization of Surface Roughness and Productivity Aspects during High-Speed Machining of Ti–6Al–4V

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3749 ◽  
Author(s):  
Adel T. Abbas ◽  
Neeraj Sharma ◽  
Saqib Anwar ◽  
Faraz H. Hashmi ◽  
Muhammad Jamil ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Titanium Alloys ◽  
Material Removal Rate ◽  
Material Removal ◽  
High Speed ◽  
Removal Rate ◽  
Depth Of Cut ◽  
Optimization Approach ◽  
High Speed Machining

Nowadays, titanium alloys are achieving a significant interest in the field of aerospace, biomedical, automobile industries especially due to their extremely high strength to weight ratio, corrosive resistance, and ability to withstand higher temperatures. However, titanium alloys are well known for their higher chemical reactive and low thermal conductive nature which, in turn, makes it more difficult to machine especially at high cutting speeds. Hence, optimization of high-speed machining responses of Ti–6Al–4V has been investigated in the present study using a hybrid approach of multi-objective optimization based on ratio analysis (MOORA) integrated with regression and particle swarm approach (PSO). This optimization approach is employed to offer a balance between achieving better surface quality with maintaining an acceptable material removal rate level. The position of global best suggested by the hybrid optimization approach was: Cutting speed 194 m/min, depth of cut of 0.1 mm, feed rate of 0.15 mm/rev, and cutting length of 120 mm. It should be stated that this solution strikes a balance between achieving lower surface roughness in terms of Ra and Rq, with reaching the highest possible material removal rate. Finally, an investigation of the tool wear mechanisms for three studied cases (i.e., surface roughness based, productivity-based, optimized case) is presented to discuss the effectiveness of each scenario from the tool wear perspective.

scholarly journals A Review on High-Speed Machining of Titanium Alloys

2006 ◽  
Vol 49 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Mustafizur RAHMAN ◽  
Zhi-Gang WANG ◽  
Yoke-San WONG
Keyword(s):  
Titanium Alloys ◽  
High Speed ◽  
High Speed Machining

A New Microstructure-Sensitive Flow Stress Model for the High-Speed Machining of Titanium Alloy Ti–6Al–4V

2016 ◽  
Vol 139 (5) ◽  
Author(s):  
X. P. Zhang ◽  
R. Shivpuri ◽  
A. K. Srivastava
Keyword(s):  
Flow Stress ◽  
Titanium Alloys ◽  
High Speed ◽  
Flow Behavior ◽  
Stress Sensitivity ◽  
Machining Process ◽  
High Speed Machining ◽  
Stress Model ◽  
Mechanical State ◽  
Flow Stress Model

The flow stress in the high-speed machining of titanium alloys depends strongly on the microstructural state of the material which is defined by the composition of the material, its starting microstructure, and the thermomechanical loads imposed during the machining process. In the past, researchers have determined the flow stress empirically as a function of mechanical state parameters, such as strain, strain rate, and temperature while ignoring the changes in the microstructural state such as phase transformations. This paper presents a microstructure-sensitive flow stress model based on the self-consistent method (SCM) that includes the effects of chemical composition, α phase and β phase, as well mechanical state imposed. This flow stress is developed to model the flow behavior of titanium alloys in machining at speed of higher than 5 m/s, characterized by extremely high strains (2–10 or higher), high strain rates (104–106 s−1 or higher), and high temperatures (600–1300 °C). The flow stress sensitivity to mechanical and material parameters is analyzed. A new SCM-based Johnson–Cook (JC) flow stress model is proposed whose constants and ranges are determined using experimental data from literature and the physical basis for SCM approach. This new flow stress is successfully implemented in the finite-element (FE) framework to simulate machining. The predicted results confirm that the new model is much more effective and reliable than the original JC model in predicting chip segmentation in the high-speed machining of titanium Ti–6Al–4V alloy.

Microstructure Sensitive Flow Stress Based on Self Consistent Method

2016 ◽  
Author(s):  
Xueping Zhang ◽  
Rajiv Shivpuri ◽  
Anil K. Srivastava
Keyword(s):  
Flow Stress ◽  
Titanium Alloys ◽  
High Speed ◽  
Machining Process ◽  
High Speed Machining ◽  
Stress Model ◽  
Mechanical State ◽  
Self Consistent ◽  
Consistent Method ◽  
Flow Stress Model

Flow stress in the high speed machining of titanium alloys depends strongly on the microstructural state of the material which is defined by the composition of the material, its starting microstructure and the thermo-mechanical loads imposed during the machining process. Previous researchers have determined the flow stress empirically as a function of mechanical state parameters such as strain, strain rate and temperature while ignoring the changes in the microstructural state such as alpha-beta phase transformations. This paper presents a new microstructure sensitive flow stress model based on the self-consistent method (SCM) that includes the effects of chemical composition, α phase and β phase, as well mechanical state imposed. This flow stress is developed to model the flow behavior of titanium alloys in machining, at speed of higher than 5m/s, characterized by extremely high strains (2∼10 or higher), high strain rates (104∼106s−1 or higher) and high temperatures (600∼1300°C). The flow stress sensitivity to mechanical and material parameters is analyzed. A new SCM-based Johnson-Cook (JC) flow stress model is proposed whose constants and ranges are determined using experimental data and the physical basis for SCM approach from literature. This new flow stress is successfully implemented in the finite element framework to simulate high speed machining process and compared with other types of flow stress models in terms of chip morphology. The predicted results confirm that the new model is much more effective and reliable than the original JC model in predicting chip segmentation in the high speed machining of titanium Ti-6Al-4V alloy.

Chip Fracture Behavior in the High Speed Machining of Titanium Alloys

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Xueping Zhang ◽  
Rajiv Shivpuri ◽  
Anil K. Srivastava
Keyword(s):  
Titanium Alloy ◽  
Phase Transformation ◽  
Titanium Alloys ◽  
High Speed ◽  
Fracture Behavior ◽  
High Strain ◽  
Failure Strain ◽  
Stress Triaxiality ◽  
High Speed Machining ◽  
Strain Intensity

Machining of titanium alloy is a severe fracture procedure associated with localized adiabatic shearing process. Chip segmentation of titanium alloy is usually characterized with adiabatic shear band (ASB) and localized microfracture evolution process. ASB has been recognized as the precursor of fracture locus due to its sealed high strain intensity. Besides strain intensity, stress triaxiality (pressure-stress states) has also been identified as a significant factor to control fracture process through altering critical loading capacity and critical failure strain. The effect of stress triaxiality on failure strain was traditionally assessed by dynamic split Hopkinson pressure bar (SHPB), quasi-static tests of tension, compression, torsion, and shear for finite element (FE) analysis. However, the stress triaxiality magnitudes introduced by these experiments were much lower than those generated from the high speed machining operation due to the fact that ASBs in chip segmentation are usually involved in much higher strain, high strain rate, high stress, and high temperature associated with phase transformation. However, this aspect of fracture evolution related with stress triaxiality and phase transformation is not well understood in literature. This paper attempts to demonstrate the roles of stress triaxiality and phase transformation in chip segmentation especially in the high speed machining of titanium alloy in FE framework. Johnson–Cook (JC) failure model is calibrated by addressing the characteristics of stress triaxiality and phase transformation associated with high speed machining. This research confirms that the selection of failure criterion parameters incorporated the effects of stress triaxiality and the alpha–beta phase transformation is indispensible to successfully predict fracture behavior during chip segmentation process in the high speed machining of titanium alloys.

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