Surface Residual Stress Gradient Distribution in High Speed Milling of H13 Die Steel

2009 ◽  
Vol 626-627 ◽  
pp. 183-188 ◽  
Author(s):  
Yue En Li ◽  
Jun Zhao ◽  
Cao Qing Yan ◽  
W. Wang ◽  
Shi Guo Han

High speed milling experiments are performed for hardened H13 die steel by using coated ball end milling cutter, the residual stress of the work-piece surface on the feed and cross feed direction are measured, and the distribution characteristics of residual stress is analyzed. The result shows that the residual stress presents gradient distribution on feed direction, and furthermore, the three-dimensional surface micro topography has no close relation with the residual stress. In addition, the cumulative effect is discussed for explaining the phenomena.

2006 ◽  
Vol 514-516 ◽  
pp. 559-563
Author(s):  
Joao P. Nobre ◽  
António Castanhola Batista ◽  
Carlos Capela ◽  
Marcelo Calvete Gaspar

The presented study was carried out in an industrial environment, using existing equipments, tools and materials. A set of tests was performed based on production demands and restrictions, aiming to achieve the lowest surface roughness and beneficial residual stress state. The experimental test surfaces were obtained using high-speed milling (HSM) and precision surface grinding on a DIN X 36 CrMo 17 steel work piece, widely used in injection moulding industry. The grinded surface was considered as a reference surface in order to evaluate the high-speed milling performance. For HSM tests, two types of tools were selected: tungsten carbide end mills with and without a TiAlN multilayer coating. The selected HSM main parameters ranged an upper, middle and lower limit value, considering the standard working values. The residual stress state at machined surfaces was evaluated by X-ray diffraction (XRD). Experimental results are discussed in order to achieve a procedure to select the optimal machining parameters that meet manufacturing specifications.


2021 ◽  
Vol 20 (2) ◽  
pp. 127-131
Author(s):  
A. I. Germashev ◽  
V. A. Logominov ◽  
S. I. Dyadya ◽  
Y. V. Kozlova ◽  
V. A. Krishtal

The paper presents the results of research on the dynamics of end milling of thin-walled work-pieces having complex geometric shapes. Since the milling process with shallow depths of cut is characterized by high intermittent cutting, the proportion of regenerative vibrations decreases, and the effect of forced vibrations on the dynamics of the process, on the contrary, increases. The influence of  axial depth of cut on the vibrations arising during processing, and roughness of the processed surface have been studied in paper.  The experiments have been carried out in a wide range of changes in the spindle speed at different axial cutting depths.  Vibrations of a thin-walled work-piece  have been recorded with an inductive sensor and recorded in digital form. Then an oscillogram has been used to estimate the amplitude and frequency of oscillations. The profilograms of the machined surface have been analysed. Roughness has been evaluated by the parameter Ra. The results have shown similar relationships for each of the investigated axial cutting depths. The worst cutting conditions  have been observed when the natural vibration frequency coincided with the tooth frequency or its harmonics. It is shown that the main cause of vibrations in high-speed milling  is forced rather than regenerative vibrations. Increasing the axial depth of cut at the same spindle speed increases the vibration amplitude. However, this does not significantly affect the roughness of the processed surface in cases when it comes to vibration-resistant processing.


2011 ◽  
Vol 418-420 ◽  
pp. 1141-1147
Author(s):  
Yong Liu ◽  
Li Tang Zhang ◽  
Zhi Hong Xu

High-speed milling is recognized as one of rapidly development machining methods. The article gives details of machining experiments with different aluminum alloys. Through a lot of single factor experiments and the orthogonal multi-factor experiments, and also use method of semi-artificial thermocouple. This paper mainly studies influence of surface roughness and residual stress with changed rotate speed, tooth load and radial depth of cut, and changed law of processing temperature for rotate speed. Though experiments shows that enhancing rotate speed may reduce surface roughness and residual stress within certain limits and the result of experiments is not agree with Carl Salomon’s theory.


2012 ◽  
Vol 500 ◽  
pp. 134-139
Author(s):  
Shi Guo Han ◽  
Jun Zhao ◽  
Xiao Xiao Chen ◽  
Yue En Li ◽  
Qing Yuan Cao ◽  
...  

In this paper, the effects of the variational combinations of cutter inclination angle in feed direction and the feed per tooth on the machined surface hardness were mainly concerned. The cutting forces transformed from the measured cutting forces in OXYZ and the SEM microstructures of the surface layer were analyzed to explore the generation condition of the hardness. Variations of the surface hardness are not apparent with the increment of feed per tooth with the identical other cutting parameters. Inclination angles in feed direction of approximately ranging from 10° to 15° and from 25° to 30°, which correspond to high surface hardness, are suggested to be applied in cutting process when high abrasive resistance is expected. While values of inclination angle approximately equal to 0° and 45° are prior to be chosen when high shock resistance performance is firstly expected. Optimization of the cutting parameters, which could offer guidance to the machining of sculptured surface concerning cutter inclination angle, was presented.


2014 ◽  
Vol 800-801 ◽  
pp. 484-488
Author(s):  
Cai Xu Yue ◽  
Fu Gang Yan ◽  
Lu Bin Li ◽  
Hai Yan You ◽  
Qing Jie Yu

Ball-end milling cutter is widely used in machining complex surface parts , and it is need to select a reasonable geometric parameters of the milling cutter for different work piece materials and shapes and cutting parameters. This article is based on UG secondary development technology to develop the Multi-blade ball-end milling cutter parametric design system, it is automatic, fast and efficient to build all kinds of parameters of double, three and four blades ball-end milling cutter model required for user.


2013 ◽  
Vol 597 ◽  
pp. 125-130 ◽  
Author(s):  
Krzysztof J. Kalinski ◽  
Marek A. Galewski ◽  
Michał R. Mazur

The paper presents the method of the surveillance of the self-excited chatter vibration. At first, the workpiece modal parameters are estimated based on experimental data which leads to verification of computational model. Then, for selected surface points optimal spindle speeds are calculated. By considering sufficient amount of points it is possible to build a map of optimal spindle speeds. Experimental results show that this map may be used effectively for eliminating chatter in case of the process of ball end milling of a curved flexible detail.


2014 ◽  
Vol 800-801 ◽  
pp. 150-154 ◽  
Author(s):  
An Hai Li ◽  
Jun Zhao ◽  
Hong Guo Zheng ◽  
Yong Hong Lu

This paper presents a detailed analysis of chip morphology through an experimental study of high-speed milling of Ti-6Al-4V alloy with PCD tools. Milling tests were conducted for cutting speed range from 125 m/min to 2000 m/min with water-soluble cutting fluid. The collected chips were firstly examined with a digital cameras and the free surface of the chips was analyzed by a scanning electron microscope (SEM). Geographical parameters of chip morphologies were described in saw-tooth/lamella frequency on the free surface and chip width. Experimental results show that the variation of chips in high-speed end milling of Ti-6Al-4V alloy is as follows, long and straight-shaped → spiral-shaped → curly-shaped → irregular-shaped. The free surface of chips exhibits saw-tooth lamella structures. The lamella becomes clearer and more obvious at higher cutting speeds. Within the same measurement distance, there is a sharp decrease in the lamella number within same measuring range. This should be attributed to the enhancement of the thermal mechanical coupled field applied to the chip formation processes.


2015 ◽  
Author(s):  
Sunday J. Ojolo ◽  
Olumuwiya Agunsoye ◽  
Oluwole Adesina ◽  
Gbeminiyi M. Sobamowo

Temperature field in metal cutting process is one of the most important phenomena in machining process. Temperature rise in machining directly or indirectly determines other cutting parameters such as tool life, tool wear, thermal deformation, surface quality and mechanics of chip formation. The variation in temperature of a cutting tool in end milling is more complicated than any other machining operation especially in high speed machining. It is therefore very important to investigate the temperature distribution on the cutting tool–work piece interface in end milling operation. The determination of the temperature field is carried out by the analysis of heat transfer in metal cutting zone. Most studies previously carried out on the temperature distribution model analysis were based on analytical model and with the used of conventional machining that is continuous cutting in nature. The limitations discovered in the models and validated experiments include the oversimplified assumptions which affect the accuracy of the models. In metal cutting process, thermo-mechanical coupling is required and to carry out any temperature field determination successfully, there is need to address the issue of various forces acting during cutting and the frictional effect on the tool-work piece interface. Most previous studies on the temperature field either neglected the effect of friction or assumed it to be constant. The friction model at the tool-work interface and tool-chip interface in metal cutting play a vital role in influencing the modelling process and the accuracy of predicted cutting forces, stress, and temperature distribution. In this work, mechanistic model was adopted to establish the cutting forces and also a new coefficient of friction was also established. This can be used to simulate the cutting process in order to enhance the machining quality especially surface finish and monitor the wear of tool.


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