Mechanism of Variable Helix Tools in Suppressing Chatter Using Process Damping for Machining Titanium Alloys at Low Cutting Speed

2013 ◽  
Vol 773-774 ◽  
pp. 370-376
Author(s):  
Muhammad Adib Shaharun ◽  
Ahmad Razlan Yusoff ◽  
Mohammad S. Reza
Keyword(s):  
Titanium Alloy ◽  
Cutting Speed ◽  
Milling Process ◽  
Cutting Process ◽  
Chatter Vibration ◽  
Process Damping ◽  
High Cutting Speed ◽  
Titanium Machining ◽  
Different Types ◽  
Variable Helix

Titanium is difficult-to-cut materials due to its poor machinability and thermal conductivity when machining at high cutting speed. To overcome this machining titanium alloy problem, this study in interaction between machining structural system and the cutting process are very important. One of the main problems in the cutting process is chatter vibration. Due to chatter problem, the mechanism to suppress chatter named, process damping is a useful method can be manipulated to improve the limited productivity of titanium machining at low speed machining in milling process. In the present study, experiment are conducted to evaluate and study the process damping mechanism in milling using different types of variable tools geometries. These tools are variable he-lix/uniform pitch, variable pitch/uniform helix and variable helix and pitch and uniform helix/pitch. The result showed that the variable helix and pitch tools is very significantly improve process damping performance in machining titanium alloy compare to traditional of regular tools and other irregular tools.

Chatter Stability Prediction of Cutting Process With Process Damping Utilizing Finite Element Analysis

2020 ◽  
Author(s):  
Norikazu Suzuki ◽  
Tomoki Nakanomiya ◽  
Eiji Shamoto
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Vibration Amplitude ◽  
Cutting Process ◽  
Force Model ◽  
Chatter Stability ◽  
Chatter Vibration ◽  
Damping Force ◽  
Element Analysis ◽  
Process Damping

Abstract This paper presents a new approach to predict chatter stability in cutting considering process damping. Traditional chatter stability analysis methods enable to predict stable or unstable conditions. Under unstable conditions, the chatter vibration can increase theoretically infinitely. However, chatter vibration is damped at a certain amplitude in real process due to process damping, i.e., the cutting process is stabilized by means of tool flank face contact to the machined surface. In order to consider the influence of the process damping, a simple process damping force model is introduced. The process damping force is assumed to be proportional to the structural displacement. The process damping coefficient is a function of the vibration amplitude and the wavelength. In order to identify the coefficients, a series of finite element analysis is conducted in the present study. Identified coefficients are introduced into the conventional zero-order-solution in frequency domain. The proposed model calculates chatter stability limit assuming process damping with finite amplitude. Hence, this analysis enables to estimate the amplitude-dependent quasi-stable conditions. Analytical results for thee face turning operation demonstrated influence of process damping effect on resultant vibration amplitude quantitatively.

Stability prediction of milling process with variable pitch and variable helix cutters

2013 ◽  
Vol 228 (2) ◽  
pp. 281-293 ◽  
Author(s):  
Gang Jin ◽  
Qichang Zhang ◽  
Shuying Hao ◽  
Qizhi Xie
Keyword(s):  
Helix Angle ◽  
Milling Process ◽  
Force Model ◽  
Stability Prediction ◽  
Chatter Vibration ◽  
Variable Pitch ◽  
Tool Geometries ◽  
Variable Helix ◽  
Piecewise Continuous ◽  
The Stability

The use of variable pitch or helix cutters is a known means to prevent chatter vibration during milling. In this article, an alternative method based on an improved semi-discretization method is proposed to predict the stability of variable pitch or variable helix milling. In order to consider the effect of distributed system delays attributed to helix variation, the average delays were calculated for each flute after the engaged cutting flutes were divided into a finite number of axial elements. Meanwhile, a straightforward integral force model, which can consider the piecewise continuous regions of the cutting that describe the helix angle is used to determine the cutting force. Through comparisons with prior works, time-domain simulations, and cutting tests, the proposed approach was verified. In addition, the method was applied to examine the effect of tool geometries on stability trends. Several phenomena for certain combinations of pitch and helix angles are shown and explained.

Singulation of Electronic Packages With Abrasive Waterjets

2005 ◽  
Author(s):  
Mohamed Hashish
Keyword(s):  
Flash Memory ◽  
Cutting Speed ◽  
High Volume ◽  
Cutting Process ◽  
Electronic Packages ◽  
Digital Cameras ◽  
Storage Devices ◽  
High Cutting Speed ◽  
Machine Reliability ◽  
Abrasive Waterjets

Abrasive waterjets were used for the first time to commercially singulate electronic chips such as those used for flash memory cards found in digital cameras, cell phones, and USB storage devices. Cutting these components requires high cutting speed, high edge quality, accuracy, and precision. For example, a minimal accuracy needed is about 0.1-mm and a minimum Cpk of 1.33. A relatively small AWJ (~ 0.38 mm) was successfully used to accurately cut chips at speeds of 20 mm/s to 60 mm/s. It was determined that the use of machine vision is critical to meeting the accuracy requirements. The cutting process consisted of piercing starting holes and then cutting shaped pattern cuts to contour the chip components. Drilling holes was performed without delamination and the cutting speed was optimized to meet the intricate chip geometry. Because of the relatively high volume of components to be cut, requiring around the clock duty, process and machine reliability are of critical importance. This paper discusses the results and observation of the cutting process as well as the performance of the system.

Finite Element Analysis of Surface Residual Stress of Titanium Alloy TC4 Based on High Speed Cutting

2012 ◽  
Vol 500 ◽  
pp. 157-162 ◽  
Author(s):  
Zeng Hui Jiang ◽  
Xiao Liang Wang ◽  
Jian Hai Zhang ◽  
Xiao Ye Deng
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Titanium Alloy ◽  
High Speed ◽  
Numerical Study ◽  
Cutting Speed ◽  
Cutting Process ◽  
Residual Tensile Stress ◽  
High Speed Cutting ◽  
Cutting Surface

Due to the complex structures of aviation products made of titanium alloy TC4, residual stress can be generated by the high speed cutting process at their surface which has an important influence on their fatigue strength and also service life. Therefore, in this paper, a 3D finite element model is built to analyze the cutting process with different tool parameters and to investigate the residual stress inside the processed surface. By the numerical study, when the cutting speed is 140 m/min, the residual tensile stress can be generated in the inner cutting surface, while the compressive residual stress in the outer cutting surface. Residual compressive stress can be enhanced by choosing the smaller tool rake angle, the bigger tool relief angle and the bigger cutting edge radius properly.

Precision Machining of Sintered Zirconia Ceramics by High-Speed Milling

2017 ◽  
Vol 11 (6) ◽  
pp. 862-868 ◽  
Author(s):  
Yusuke Ito ◽  
◽  
Naohiko Sugita ◽  
Tatsuya Fujii ◽  
Toru Kizaki ◽  
...  
Keyword(s):  
High Speed ◽  
Bending Strength ◽  
Cutting Speed ◽  
High Hardness ◽  
Milling Process ◽  
Precision Machining ◽  
Zirconia Ceramics ◽  
High Speed Milling ◽  
High Cutting Speed ◽  
Dental Prostheses

Precision machining of sintered zirconia ceramics is expected for various applications such as dental prostheses or artificial femoral heads. However, machining of zirconia is a major challenge because of its high hardness. We have found that the bending strength and fracture toughness of this material decrease with an increase in temperature. To use this characteristic, we propose a high-speed milling process with a cutting speed of more than 500 m/min because high-cutting speed can generate a large amount of heat during cutting. According to the results of trials, precision machining of the surface was possible with a cutting speed of 670 m/min. Moreover, the amount of flank wear was decreased by the high-speed milling. These results confirmed the possibility of precision cutting of sintered zirconia ceramics.

scholarly journals Chatter Behavior in the Milling Process of Inconel 718: Effects of Tool Edge Radius

2018 ◽  
Vol 202 ◽  
pp. 02006
Author(s):  
C H Hoe ◽  
M M Reddy ◽  
V C C Lee ◽  
S Debnath
Keyword(s):  
Inconel 718 ◽  
Elevated Temperatures ◽  
Milling Process ◽  
Machining Process ◽  
Chatter Vibration ◽  
End Mill ◽  
Tool Edge Radius ◽  
Edge Radius ◽  
Tool Edge ◽  
Variable Helix

Inconel 718 is widely used in various high end industries such as aerospace, nuclear plant, petrochemical plants etc. Inconel 718 is used for these applications due to unique mechanical properties such as high mechanical strength at elevated temperatures, high resistance to corrosion, and high strength to weight ratio. The unique properties of Inconel 718 made it difficult to be machined due to rapid work hardening and high cutting temperature. In addition, chatter vibration further increases the difficulty in machining of Inconel 718. In this paper, an experimental study on the effects of tool edge radius to the chatter behaviour was investigated. The dynamic responses of the milling process were recorded and analysed in both time domain and frequency domain. The results showed the variable helix and pitch end mill tool with larger tool edge radius able to mitigate chatter vibration at lower cutting speeds. Variable helix and pitch end mill with specific tool edge radius able to mitigate chatter vibration under the same cutting parameters. Experiments shows proper selection of tool edge radius improves the stability of end milling machining process.

Tool stiffness influence on the chosen physical parameters of the milling process

2012 ◽  
Vol 60 (3) ◽  
pp. 597-604 ◽  
Author(s):  
W. Zębala
Keyword(s):  
Titanium Alloy ◽  
Aluminium Alloy ◽  
Chip Formation ◽  
Cutting Forces ◽  
Contact Point ◽  
Milling Process ◽  
Cutting Process ◽  
Physical Parameters ◽  
Titanium Alloy Ti6al4v ◽  
The Impact

Abstract This article presents our own model researches, relating to the down milling process of Aluminium alloy (Al6061) and Titanium alloy (Ti6Al4V), with a tool made of sintered carbides. These investigations pay the special attention to the impact of the tool rigidity on the process of chip formation. The simulation calculations have been carried out for two cases of the cutting process: case 1 - assuming an ideally rigid construction of a milling cutter (length of tool does not impact its deflection under the cutting forces); case 2 - it is possible that the tool can be subjected to deflection under the cutting forces (length of a tool part is counted from the holder end to the contact point of a cutting edge with the machining material).

scholarly journals 3378 Mist cutting of Titanium Alloy at High Cutting Speed

2011 ◽  
Vol 2011.6 (0) ◽  
pp. _3378-1_-_3378-4_
Author(s):  
Junsuke Fujiwara ◽  
Takaaki Arimoto ◽  
Katsuyuki Sakai
Keyword(s):  
Titanium Alloy ◽  
Cutting Speed ◽  
High Cutting Speed

scholarly journals Effect of fiber flocculation and filling design on refiner loadability and refining characteristics

BioResources ◽  
2008 ◽  
Vol 3 (2) ◽  
pp. 403-424
Keyword(s):  
Cutting Speed ◽  
Total Power ◽  
Short Fibers ◽  
Noticeable Effect ◽  
Floc Size ◽  
High Cutting Speed ◽  
Different Types ◽  
Wide Groove ◽  
Design Characteristics ◽  
Gap Width

The loadability of a pulp refiner was studied using refiner data such as gap movement, total power, no-load power, and net refining power. Two different types of pulp and three different types of refiner filling were used in the study. The floc formation and floc size of each pulp was studied in a flow channel simulating filling grooves. The loadability of the pulp refiner was linked to refining effects such as fiber shortening, and internal and external fibrillation. The trapping point of the refiner, and therefore refiner loadability, was found to be more related to fiber characteristics such as fiber length and coarseness, while being less dependent on refining consistency in the range of 2.0-5.5%. The data on the formation of flocs and floc size was used to explain the trapping of fibers between refiner bars and the refiner gap width. Filling design characteristics such as groove width and cutting speed affect the gap width and trapping of flocs inside the refiner. Fillings with high cutting speed tend to break flocs composed of long and short fibers at the same rate and therefore both types of floc maintain the same gap width. On the other hand, wide-groove fillings with lower cutting speed have a gentler effect and the differences in fiber characteristics are easily reflected in the gap width and trapping point. Fillings with low cutting speed have a greater straightening effect than fiber cutting, whereas narrow-bar fillings have a more noticeable effect on fiber cutting, external fibrillation, and fiber swelling.

Effects of Preheating Temperature at Primary Shear Zone in Laser Assisted Milling Process

2019 ◽  
Vol 825 ◽  
pp. 45-50
Author(s):  
Kamonpong Jamkamon ◽  
Keiji Yamada ◽  
Katsuhiko Sekiya ◽  
Ryutaro Tanaka
Keyword(s):  
Tool Wear ◽  
Inconel 718 ◽  
Laser Power ◽  
Cutting Speed ◽  
Milling Process ◽  
Machined Surface ◽  
High Cutting Speed ◽  
Preheating Temperature ◽  
Conventional Machining ◽  
Table Speed

In this paper, preheating temperature was investigated for the laser assisted machining (LAM) of Inconel 718 under different conditions for the milling test. The experimental results show that the requirement of laser power for the particularly preheating temperature proportionally increased with the table speed. The resultant cutting force for sufficient shearing work material in LAM was lower than conventional machining (CM) approximately 11, 21 and 28% for the cutting speed of 30, 50 and 75 m/min, respectively. The tool wear in LAM could be improved at relatively high cutting speed of 75 m/min and the hardness of machined surface in LAM was slightly higher than CM.

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