Stability Prediction for Low Radial Immersion Milling

2002 ◽  
Vol 124 (2) ◽  
pp. 217-225 ◽  
Author(s):  
M. A. Davies ◽  
J. R. Pratt ◽  
B. Dutterer ◽  
T. J. Burns
Keyword(s):  
Stability Theory ◽  
High Speed ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Peripheral Milling ◽  
Flexible Mode ◽  
Milling Operations ◽  
Radial Depth ◽  
Tool Diameter ◽  
Low Radial Immersion

Traditional regenerative stability theory predicts a set of optimally stable spindle speeds at integer fractions of the natural frequency of the most flexible mode of the system. The assumptions of this theory become invalid for highly interrupted machining, where the ratio of time spent cutting to not cutting (denoted ρ) is small. This paper proposes a new stability theory for interrupted machining that predicts a doubling in the number of optimally stable speeds as the value of ρ becomes small. The results of the theory are supported by numerical simulation and experiment. It is anticipated that the theory will be relevant for choosing optimal machining parameters in high-speed peripheral milling operations where the radial depth of cut is only a small fraction of the tool diameter.

scholarly journals Toolpath and machining parameters optimisation of the cavities of a knee prosthesis tibial insert

2020 ◽  
pp. 095440542096167
Author(s):  
Francisco J Lopes ◽  
António Completo ◽  
João Paulo Davim
Keyword(s):  
High Speed ◽  
Knee Prosthesis ◽  
Cutting Tools ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Test Part ◽  
Radial Depth ◽  
Tibial Insert ◽  
Nc Machine ◽  
Two Stages

The main purpose of this paper is to demonstrate the applicability of conventional cutting tools in the machining of a custom tibial insert of a knee prosthesis. This study also aims to reduce the roughness and minimise the production time. In this work, the optimisation of cutting strategies and parameters was achieved through the design and construction of a test-part containing the most important complex surfaces of the femoral cavities, the focus of the study. The milling was carried out in accordance with the Design Of Experiment and the Taguchi method and was performed in two stages to reduce the number of analysed factors. The achieved parameters are applied to the machining of a modelled tibial insert made of UHMWPE, using a NC machine with three axes. The initial parameters studied were the cutting method, axial and radial depth of cut, the direction of the feed and the feed rate. Three strategies were studied: two Blend, resulting in radial and spiral toolpaths, and one Parallel. According to the spiral strategy, an arithmetical mean roughness of Ra = 1.1 µm was obtained, representing an improvement of 45% relatively to the initial phase value of 2.0 µm, with the Parallel toolpath. An overall improvement of 34% in time efficiency of the finishing operation was achieved after changing the machine settings. This study supports the conclusion that high-speed milling is an expeditious process to produce customised tibial inserts.

Chatter Stability Prediction in High Speed Milling Considering Multi-Degree of Freedom

2010 ◽  
Vol 431-432 ◽  
pp. 373-376
Author(s):  
Shan Shan Sun ◽  
Wei Xiao Tang ◽  
Xi Qing Xu
Keyword(s):  
High Speed ◽  
Spindle Speed ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Stability Prediction ◽  
High Speed Milling ◽  
Stability Lobes ◽  
Milling Operations ◽  
Critical Requirement ◽  
Multi Mode

Chatter problems occurring during high speed milling affect the quality of the finished workpiece and, to a lesser extent, the tool life and the spindle life. Therefore, the prediction of stable milling regions is a critical requirement for high speed milling operations. In this paper, a dynamic model of a high speed spindle system considering the multi-mode dynamics is elaborated for the purposed of stability prediction. A stability lobes diagram (SLD) shows the boundary between chatter-free machining operations and unstable processes, in terms of axial depth of cut as a function of spindle speed. These diagrams are used to select chatter-free combinations of machining parameters. The proposed method enables a new stability lobes diagram to be established that takes into account the effect of spindle speed on multi-mode dynamic behavior.

Cutting Temperature and Cutting Forces Investigation Based on the Taguchi Design Method when High-Speed Milling of Titanium Matrix Composites with PCD Tool

2016 ◽  
Vol 836-837 ◽  
pp. 168-174 ◽  
Author(s):  
Ying Fei Ge ◽  
Hai Xiang Huan ◽  
Jiu Hua Xu
Keyword(s):  
Cutting Force ◽  
Feed Rate ◽  
Cutting Forces ◽  
High Speed ◽  
Volume Fraction ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
High Speed Milling ◽  
Radial Depth

High-speed milling tests were performed on vol. (5%-8%) TiCp/TC4 composite in the speed range of 50-250 m/min using PCD tools to nvestigate the cutting temperature and the cutting forces. The results showed that radial depth of cut and cutting speed were the two significant influences that affected the cutting forces based on the Taguchi prediction. Increasing radial depth of cut and feed rate will increase the cutting force while increasing cutting speed will decrease the cutting force. Cutting force increased less than 5% when the reinforcement volume fraction in the composites increased from 0% to 8%. Radial depth of cut was the only significant influence factor on the cutting temperature. Cutting temperature increased with the increasing radial depth of cut, feed rate or cutting speed. The cutting temperature for the titanium composites was 40-90 °C higher than that for the TC4 matrix. However, the cutting temperature decreased by 4% when the reinforcement's volume fraction increased from 5% to 8%.

A Comprehensive Study on Surface Roughness in Machining of AISI D2 Hardened Steel

2012 ◽  
Vol 576 ◽  
pp. 60-63 ◽  
Author(s):  
N.A.H. Jasni ◽  
Mohd Amri Lajis
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
End Milling ◽  
Cutting Speed ◽  
Hardened Steel ◽  
Depth Of Cut ◽  
Feed Speed ◽  
Radial Depth ◽  
Aisi D2 ◽  
Coated Carbide

Hard milling of hardened steel has wide application in mould and die industries. However, milling induced surface finish has received little attention. An experimental investigation is conducted to comprehensively characterize the surface roughness of AISI D2 hardened steel (58-62 HRC) in end milling operation using TiAlN/AlCrN multilayer coated carbide. Surface roughness (Ra) was examined at different cutting speed (v) and radial depth of cut (dr) while the measurement was taken in feed speed, Vf and cutting speed, Vc directions. The experimental results show that the milled surface is anisotropic in nature. Surface roughness values in feed speed direction do not appear to correspond to any definite pattern in relation to cutting speed, while it increases with radial depth-of-cut within the range 0.13-0.24 µm. In cutting speed direction, surface roughness value decreases in the high speed range, while it increases in the high radial depth of cut. Radial depth of cut is the most influencing parameter in surface roughness followed by cutting speed.

Effect of Machining Parameters and Wear Mechanism in Milling Mold Steel AISI-P20 and AISI-1050

2014 ◽  
Vol 590 ◽  
pp. 294-298
Author(s):  
Pichai Janmanee ◽  
Somchai Wonthaisong ◽  
Dollathum Araganont
Keyword(s):  
Wear Mechanism ◽  
Feed Rate ◽  
High Speed ◽  
Removal Rate ◽  
Milling Process ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Aisi P20 ◽  
Steel Aisi ◽  
Quality Surface

In this study, effect of machining parameters and wear mechanism in milling process of mold steel AISI-P20 and AISI-1050, using 10 mm twin flute type end mill diameter. The experimental results found that characteristics of milling surfaces and wear of the mill end were directly influenced by changes of parameters for all test conditions. As a result, the quality of milling surfaces also changed. However, mould steels which had the good quality surface is AISI-1050, with roughnesses of 2.120 μm. Quality milling surfaces were milled by using the most suitable parameter feed rate of 45 mm/min, a spindle speed of 637 rpm and a cut depth level of 3 mm, for both grades. Moreover, material removal rate and duration of the milling process, the milling end mills affect wear of the edge in every bite when the feed rate is low, high speed and level depth of cut at least. It was found that limited wear less will affect the surface roughness (Ra) represents the good quality surface.

SURFACE ROUGHNESS OF MAGNESIUM ALLOY AZ91D IN HIGH SPEED MILLING

2016 ◽  
Vol 78 (6-9) ◽  
Author(s):  
Mohd Shahfizal Ruslan ◽  
Kamal Othman ◽  
Jaharah A.Ghani ◽  
Mohd Shahir Kassim ◽  
Che Hassan Che Haron
Keyword(s):  
Surface Roughness ◽  
Magnesium Alloy ◽  
Feed Rate ◽  
High Speed ◽  
Cutting Parameters ◽  
Experimental Result ◽  
Depth Of Cut ◽  
Polishing Process ◽  
High Speed Cutting ◽  
Radial Depth

Magnesium alloy is a material with a high strength to weight ratio and is suitable for various applications such as in automotive, aerospace, electronics, industrial, biomedical and sports. Most end products require a mirror-like finish, therefore, this paper will present how a mirror-like finishing can be achieved using a high speed face milling that is equivalent to the manual polishing process. The high speed cutting regime for magnesium alloy was studied at the range of 900-1400 m/min, and the feed rate for finishing at 0.03-0.09 mm/tooth. The surface roughness found for this range of cutting parameters were between 0.061-0.133 µm, which is less than the 0.5µm that can be obtained by manual polishing. Furthermore, from the S/N ratio plots, the optimum cutting condition for the surface roughness can be achieved at a cutting speed of 1100 m/min, feed rate 0.03 mm/tooth, axial depth of cut of 0.20 mm and radial depth of cut of 10 mm. From the experimental result the lowest surface roughness of 0.061µm was obtained at 900 m/min with the same conditions for other cutting parameters. This study revealed that by milling AZ91D at a high speed cutting, it is possible to eliminate the polishing process to achieve a mirror-like finishing.

The Ledge Tool: A New Cutting Tool Insert

1985 ◽  
Vol 107 (2) ◽  
pp. 99-106 ◽  
Author(s):  
R. Komanduri ◽  
M. Lee
Keyword(s):  
Titanium Alloys ◽  
High Speed ◽  
Cutting Tool ◽  
Metal Removal ◽  
Face Milling ◽  
Cemented Carbide ◽  
Depth Of Cut ◽  
Peripheral Milling ◽  
Cemented Carbide Tool ◽  
Edge Wear

The salient features of a simple, wear-tolerant cemented carbide tool are described. Results are presented for high-speed machining (3 to 5 times the conventional speeds) of titanium alloys in turning and face milling. This tool, termed the ledge cutting tool, has a thin (0.015 to 0.050 in.) ledge which overhangs a small distance (0.015 to 0.060 in.) equal to the depth of cut desired. Such a design permits only a limited amount of flank wear (determined by the thickness of the ledge) but continues to perform for a long period of time as a result of wear-back of the ledge. Under optimum conditions, the wear-back occurs predominantly by microchipping. Because of geometric restrictions, the ledge tool is applicable only to straight cuts in turning, facing, and boring, and to face milling and some peripheral milling. Also, the maximum depth of cut is somewhat limited by the ledge configuration. In turning, cutting time on titanium alloys can be as long as ≈ 30 min. or more, and metal removal of ≈ 60 in.3 can be achieved on a single edge. Wear-back rates in face milling are about 2 to 3 times higher than in straight turning. The higher rates are attributed here to the interrupted nature of cutting in milling. Use of a grade of cemented carbide (e.g., C1 Grade) which is too tough or has too thick a ledge for a given application leads to excessive forces which can cause gross chipping of the ledge (rapid wear) and/or excessive deflection of the cutting tool with reduced depth of cut. Selection of a proper grade of carbide (e.g., Grades C2, C3, C4) for a given application results in uniform, low wear-back caused by microchipping. Because of the end cutting edge angle (though small, ≈ 1 deg) used, the ledge tool can generate a slight taper on very long parts; hence an N.C. tool offset may be necessary to compensate for wear-back. The ledge tool is found to give excellent finish (1 to 3 μm) in both turning and face milling. In general, conventional tooling with slight modifications can be used for ledge machining. The ledge tool can also be used for machining cast iron at very high speeds.

Tool Wear Characteristics in High Speed Milling of Ti-6Al-4V Alloy with Nitrogen Gas Medium

2006 ◽  
Vol 315-316 ◽  
pp. 588-592 ◽  
Author(s):  
Wei Zhao ◽  
Ning He ◽  
Liang Li ◽  
Z.L. Man
Keyword(s):  
Tool Wear ◽  
High Speed ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
High Speed Milling ◽  
Radial Depth ◽  
Oil Mist ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

High speed milling experiments using nitrogen-oil-mist as cutting medium were undertaken to investigate the characteristics of tool wear for Ti-6Al-4V Alloy, a kind of important and commonly used titanium alloy in the aerospace and automobile industries. Uncoated carbide tools have been applied in the experiments. The cutting speed was 300 m/min. The axial depth of cut and the radial depth of cut were kept constant at 5.0 mm and 1.0 mm, respectively. The feed per tooth was 0.1 mm/z. Optical and scanning electron microscopes have been utilized to determine the wear mechanisms of the cutting tools, and energy spectrum analysis has been carried out to measure the elements distribution at the worn areas. Meanwhile, comparisons were made to discuss the influence of different cutting media such as nitrogen-oil-mist and air-oil–mist upon the tool wear. The results of this investigation indicate that the tool life in nitrogen-oil-mist is significantly longer than that in air-oil-mist, and nitrogen-oil-mist is more suitable for high speed milling of Ti-6Al-4V alloy than air-oil-mist.

Optimization of Cutting Parameters for High Speed End Milling of Single Crystal Silicon by Diamond Coated Tools with Compressed Air Blowing Using RSM

2012 ◽  
Vol 576 ◽  
pp. 46-50 ◽  
Author(s):  
M.A. Mahmud ◽  
A.K.M. Nurul Amin ◽  
M.D. Arif
Keyword(s):  
Single Crystal ◽  
High Speed ◽  
End Milling ◽  
Single Crystal Silicon ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Crystal Silicon ◽  
Design Expert ◽  
Coated Tools ◽  
Optimization Of Cutting Parameters

This paper presents the thorough experimental analysis on high speed end milling of single crystal silicon using diamond coated tools. Experiments were conducted on CNC milling machine. The design of the experiments was based on the central composite design (CCD) technique of Design Expert software. Response Surface Methodology (RSM) was used to develop mathematical imperial model to establish a correlation between machining parameters (cutting speed, feed and depth of cut) and machined surface roughness in high speed end milling of single crystal silicon using 2mm diameter diamond coated tools. The optimum machining parameters were determined using the optimization tool of Design Expert software based on the desirability function. Finally, confirmation tests were performed to validate the developed model.

Cutting Forces and Surface Roughness in High-Speed End Milling of Ti6Al4V

2013 ◽  
Vol 589-590 ◽  
pp. 76-81
Author(s):  
Fu Zeng Wang ◽  
Jun Zhao ◽  
An Hai Li ◽  
Jia Bang Zhao
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Cutting Forces ◽  
High Speed ◽  
End Milling ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Wide Range ◽  
Radial Depth ◽  
Coated Carbide

In this paper, high speed milling experiments on Ti6Al4V were conducted with coated carbide inserts under a wide range of cutting conditions. The effects of cutting speed, feed rate and radial depth of cut on the cutting forces, chip morphologies as well as surface roughness were investigated. The results indicated that the cutting speed 200m/min could be considered as a critical value at which both relatively low cutting forces and good surface quality can be obtained at the same time. When the cutting speed exceeds 200m/min, the cutting forces increase rapidly and the surface quality degrades. There exist obvious correlations between cutting forces and surface roughness.

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