SURFACE TEXTURE ANALYSIS AFTER BALL END MILLING WITH VARIOUS SURFACE INCLINATION OF HARDENED STEEL

2014 ◽  
Vol 21 (1) ◽  
pp. 145-156 ◽  
Author(s):  
Szymon Wojciechowski ◽  
Paweł Twardowski ◽  
Michał Wieczorowski

Abstract In this paper, an analysis of various factors affecting machined surface texture is presented. The investigation was focused on ball end mill inclination against the work piece (defined by surface inclination angle a. Surface roughness was investigated in a 3D array, and measurements were conducted parallel to the feed motion direction. The analysis of machined surface irregularities as a function of frequency (wavelength A), on the basis of the Power Density Spectrum - PDS was also carried out. This kind of analysis is aimed at valuation of primary factors influencing surface roughness generation as well as its randomness. Subsequently, a surface roughness model including cutter displacements was developed. It was found that plain cutting with ball end mill (surface inclination angle a= 0°) is unfavorable from the point of view of surface roughness, because in cutter’s axis the cutting speed vc ~ 0 m/min. This means that a cutting process does not occur, whereas on the machined surface some characteristics marks can be found. These marks do not appear in case of a* 0°, because the cutting speed vc * 0 on the fill I length of the active cutting edge and as a result, the machined surface texture is more homogenous. Surface roughness parameters determined on the basis of the model including cutter displacements are closer to experimental data for cases with inclination angles a* 0°, in comparison with those determined for plain cutting (a= 0°). It is probably caused by higher contribution in surface irregularities generation of plastic and elastic deformations cumulated near the cutter’s free end than kinematic and geometric parameters, as well as cutter displacements.

1970 ◽  
Vol 2 (1) ◽  
Author(s):  
A.K.M.N. Amin, M.A. Rizal, and M. Razman

Machine tool chatter is a dynamic instability of the cutting process. Chatter results in poor part surface finish, damaged cutting tool, and an irritating and unacceptable noise. Exten¬sive research has been undertaken to study the mechanisms of chatter formation. Efforts have been also made to prevent the occurrence of chatter vibration. Even though some progress have been made, fundamental studies on the mechanics of metal cutting are necessary to achieve chatter free operation of CNC machine tools to maintain their smooth operating cycle. The same is also true for Vertical Machining Centres (VMC), which operate at high cutting speeds and are capable of offering high metal removal rates. The present work deals with the effect of work materials, cutting conditions and diameter of end mill cutters on the frequency-amplitude characteristics of chatter and on machined surface roughness. Vibration data were recorded using an experimental rig consisting of KISTLER 3-component dynamometer model 9257B, amplifier, scope meters and a PC.  Three different types of vibrations were observed. The first type was a low frequency vibration, associated with the interrupted nature of end mill operation. The second type of vibration was associated with the instability of the chip formation process and the third type was due to chatter. The frequency of the last type remained practically unchanged over a wide range of cutting speed.  It was further observed that chip-tool contact processes had considerable effect on the roughness of the machined surface.Key Words: Chatter, Cutting Conditions, Stable Cutting, Surface Roughness.


2014 ◽  
Vol 657 ◽  
pp. 53-57 ◽  
Author(s):  
Sándor Ravai Nagy ◽  
Ioan Paşca ◽  
Mircea Lobonțiu ◽  
Mihai Banica

Machining of Complex Concave or Convex Surfaces Requires the Use of Ball End Milling Cutters. Obtaining the Expected Surface Quality Compete Various Technological Factors which should be Taken into Account. Following the Machining of the Surface with Different Inclination Angles between the Cutting Tool Axes and the Machined Surface, Significant Changes of the Surface Roughness have been Observed. Based on the Tests Performed, we can Determine the Range of the Tool Inclination Angle, which is the Best for the Surface Quality. we have also Made a Correlation between the Cutting Speeds, Inclination Angle of the Cutting Tool Toward the Machined Surface for an Obtained Surface Quality. the Presented Results are Based on Experimental Research in Industrial Conditions by Using CNC Machine Tools with 5 Axes. the Tests have been Performed on the C45 Material, Heat Treated to 34HRC.


2011 ◽  
Vol 486 ◽  
pp. 91-94 ◽  
Author(s):  
Jabbar Abbas ◽  
Amin Al-Habaibeh ◽  
Dai Zhong Su

Surface roughness is one of the most significant parameters to determine quality of machined parts. Surface roughness is defined as a group of irregular waves in the surface, measured in micrometers (μm). Many investigations have been performed to verify the relationship between surface roughness and cutting parameters such as cutting speed, feed rate and depth of cut. To predict the surface produced by end milling, surface roughness models have been developed in this paper using the machining forces by assuming the end mill cutter as a cantilever beam rigidly or semi- rigidly supported by tool holder. An Aluminium workpiece and solid carbide end mill tools are used in this work. Model to predict surface roughness has been developed. Close relationship between machined surface roughness and roughness predicted using the measured forces signals.


2015 ◽  
Vol 809-810 ◽  
pp. 27-32
Author(s):  
Sandor Ravai-Nagy ◽  
Ioan Paşca ◽  
Mircea Lobontiu ◽  
Mihai Banica

In the context of the increasingly frequent use of curved surfaces in the design of products surrounding us, ball end mills are at present the only usable tools in the cutting of complex surfaces, either concave or convex. This aspect, once correlated with the need to reduce the surface roughness, which means an increase in the cost of processing, directs our research to those on the milling with ball end mill. In this way we can identify the optimum cutting data in terms of costs to ensure the prescribed surface roughness. The paper is based on a set of experiments on the correlation of roughness with the parameters of the cutting process, for the C45 material treated with heat at 54HRC. The paper presents a part of a complex industrial research in this area and is complementary to the published works [1, 2]


2004 ◽  
Vol 471-472 ◽  
pp. 307-311 ◽  
Author(s):  
Xian Li Liu ◽  
Fu Gang Yan ◽  
Y.F. Li ◽  
Yong Jun Wang ◽  
H.M. Pen

There is a bright future for hard cutting technique because of good machining flexibility, high efficiency, no pollution. This paper presents effect rules of cutting parameters (cutting speed, feed, depth of cutting) on integrality of machined surface (surface roughness, surface hardness, surface hardened depth, residual stresses, surface texture) based on orthogonalization test. Optimal cutting parameters are selected according to these rules. Surface roughness (Ra) is up to 0.6µm in terms of selected optimal cutting parameters.


2014 ◽  
Vol 800-801 ◽  
pp. 576-579
Author(s):  
Lin Hua Hu ◽  
Ming Zhou ◽  
Yu Liang Zhang

In this work, cutting experiments were carried out on titanium alloy Ti6Al4V by using polycrystalline diamond (PCD) tools to investigate the effects of the tool geometries and cutting parameters on machined surface roughness. Experimental results show machined surface roughness decreases with increases in the flank angle, tool nose radius and cutting speed within a limited range respectively, and begins to increase as the factors reaches to certain values respectively. And machined surface roughness decreases with increases in feed rate and cutting depth respectively.


Author(s):  
Hirohisa Narita

Abstract An optimum experimental condition, which realize good surface roughness in cross direction both contour and scanning lines, for radius end mill against some inclined surfaces is obtained and some features is these cutting processes is discussed in this paper. The optimum experimental condition, which consists of cutting type (or feed direction), spindle speed, feed rate, depth of immersion, inclination angle, corner radius of end mill and cross feed, is obtained and the influence degree of these parameters is calculated by using Taguchi method. The experiment is carried out based on L18 orthogonal array. Based on the influence degree and geometric contact status due to unique shape of radius end mill, some feature of radius end milling is introduced. As a result of the contour line machining, a scallop height is very influenced by the inclination angle and the corner radius, and surface machined by bottom edge must not be remained. Regarding the scanning line machining, “go-up” is good for the feed direction. Big corner radius is also suitable because side edge does not contact to workpiece. In other words, the cutting force in radial direction becomes small. Furthermore, the surface roughness of the scanning line machining is smaller than the one of the contour line machining.


Author(s):  
Shinnosuke Yamashita ◽  
Tatsuya Furuki ◽  
Hiroyuki Kousaka ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
...  

Abstract Recently, the demand of carbon fiber reinforced plastics (CFRP) has been rapidly increased in various fields. In most cases, CFRP products requires a finish machining like cutting or grinding. In the case of an end-milling, burrs and uncut fibers are easy to occur. On the other hand, a precise machined surface and edge will be able to obtain by using the grinding tool. Therefore, this research has been developed a novel the cBN electroplated end-mill that combined end-mill and grinding tool. In this report, the effectiveness of developed tool was investigated. First, the developed tool cut the CFRP with side milling. As the result, the cBN abrasives that were fixed on the outer surface of developed tool did not drop out. Next, the end-milled surface of CFRP was ground with the developed tool under several grinding conditions based on the Design of Experiment. Consequently, the optimum grinding condition that can obtain the sharp edge which does not have burrs and uncut fibers was found. However, surface roughness was not good enough. Thus, an oscillating grinding was applied. In addition, the theoretical surface roughness formula in case using the developed tool was formularized. As the result, the required surface roughness in the airplane field was obtained.


2014 ◽  
Vol 800-801 ◽  
pp. 465-469
Author(s):  
An Shan Zhang ◽  
Xian Li Liu ◽  
Shu Cai Yang ◽  
Qi Zhang

Complex cavity generally is machined in 3 axis or 3+2 axis machine tools, it has large amount of metal to be removed. For complex cavity machining, the cutting speed of ball end mill`s head point is zero, which makes its end milling ability poor; Torus cutter `s flat bottom width is wide, which causes curvature interference and concave-uncut. So this article designs a new kind of cutter for complex cavity roughing and semi-finishing, which can improve ball end mill`s poor end milling ability and decrease flat-end width. The simulation results show that the new cutter`s feasibility of machining complex cavity is better, and it can obviously reduce the amount of owe cutting compared with the torus cutter; At the same time, the new cutter can improve machining efficiency by 32.4% compared with the ball end mill, and good surface can also be generated.


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