An Investigation of Workpiece Temperature in Orthogonal Turn-Milling Compound Machining

Author(s):  
Fangyu Peng ◽  
Yizhi Liu ◽  
Sen Lin ◽  
Rong Yan ◽  
Sheng Yang ◽  
...  

A thermal model estimating workpiece temperature in orthogonal turn-milling compound machining for the case with noneccentricity between rotation axes of workpiece and tool has been established in this paper. Milling tool and machining history were discretized into infinitesimal elements of equal size to deal with complicated cutter geometry and intermittent cutting procedure. The geometries of milling tool and workpiece were analyzed to calculate the instantaneous chip thickness, axial depth of cut, and angles of cutting entry and exit. Heat source during cutting process was considered as instantaneous moving rectangular heat source and heat conducting function in infinite solid thermal conductivity was developed. Experiments measuring cutting force and workpiece temperature were launched to test validity of this model and figure out the importance of effects those factors have on workpiece temperature from variance analysis of orthogonal experiment results. Furthermore, simulations to calculate peak temperature of workpiece were carried out by this model with relevant machining parameters and the results matched conclusions from experiment well.

Author(s):  
Alptunc Comak ◽  
Yusuf Altintas

Turn-milling machines are widely used in industry because of their multifunctional capabilities in producing complex parts in one setup. Both milling cutter and workpiece rotate simultaneously while the machine travels in three Cartesian directions leading to five axis kinematics with complex chip generation mechanism. This paper presents a general mathematical model to predict the chip thickness, cutting force, and chatter stability of turn milling operations. The dynamic chip thickness is modeled by considering the rigid body motion, relative vibrations between the tool and workpiece, and cutter-workpiece engagement geometry. The dynamics of the process are governed by delayed differential equations by time periodic coefficients with a time varying delay contributed by two simultaneously rotating spindles and kinematics of the machine. The stability of the system has been solved in semidiscrete time domain as a function of depth of cut, feed, tool spindle speed, and workpiece speed. The stability model has been experimentally verified in turn milling of Aluminum alloy cut with a helical cylindrical end mill.


1999 ◽  
Vol 121 (2) ◽  
pp. 257-264 ◽  
Author(s):  
H. D. Jerro ◽  
S. S. Pang ◽  
C. Yang ◽  
R. A. Mirshams

One of the primary goals in the design of a diamond blade cutting system is to reduce the cutting force. By understanding the fundamentals of the kinematics of the sawing operation, these forces can be lowered and even optimized with respect to the machining parameters. In this work the material chipping geometries have been mathematically defined and derived through kinematic analysis. These geometries are bounded by four curves and depend on the parameters: depth of cut h, blade diameter D, transverse rate of the workpiece νT, peripheral speed of the saw blade νP, and grit spacing λ. From these chipping geometries, chip area and thickness relations have been obtained. A relation for the mean chip thickness to grit spacing ratio (tc/λ) has also been obtained as a function of the nondimensional machining parameter ratios, h/D and νT/νP. The effects of these parameters on tc were also investigated. It was found that increasing ω and D, reduces the chip thickness. Contrarily, increasing νT, λ, and h, increases the magnitude of the chip thickness. A review of older chipping models was performed, comparing well with the developed model. The results show an excellent agreement between the new model and the older ones. However, at moderately small to large h/D values the new model yields a more exact result. Thus, for h/D values greater than 0.08, it is recommended that the kinematic model be used to compute tc and other pertinent sawing parameters (i.e., grit force and grinding ratio) which are a function of tc.


Author(s):  
S.P. Sundar Singh Sivam ◽  
V.G. Umasekar ◽  
Ganesh Babu Loganathan ◽  
D Kumaran ◽  
K. Saravanan

This study presents the optimization of machining parameters on ZE41 Mg alloy fabricated by gravity die casting and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). Focus on the optimization of machining parameters using the technique to get minimum surface roughness, cutting force, thermal stress, residual stress, chip thickness and maximum MRR. A number of machining experiments were conducted based on the L27 orthogonal array on computer numerical control vertical machining center. The experiments were performed on ZE41 using cutting tool of an ISO 460. 1-1140-034A0-XM GC3 of 20, 25 and 30mm diameter with cutting point 140 degrees, for different cutting conditions. TOPSIS and ANOVA were used to work out the fore most important parameters cutting speed, feed rate, depth of cut and tool diameter which affect the response. The expected values and measured values are fairly close. Finally, the study for optimizing machining process is surveyed and results show improvement in real experiments.


2014 ◽  
Vol 887-888 ◽  
pp. 1184-1190 ◽  
Author(s):  
Yi Zhi Liu ◽  
Fang Yu Peng ◽  
Sen Lin ◽  
Rong Yan ◽  
Sheng Yang

Workpiece temperature in orthogonal turn-milling compound machining was studied with experimental method in this paper. The orthogonal turn-milling process was simulated through engagement of a milling tool and cylindrical surface on a five-axis milling center. The cutting parameters were designed into an orthogonal parameter table of seven factors three levels based on factors having effects on workpiece temperature. Variance analysis of data achieved from this experiment was carried out and conclusion about the order of effects each factor has on workpiece temperature was drawn.


2017 ◽  
Vol 50 (4) ◽  
pp. 89-96 ◽  
Author(s):  
Şehmus Baday ◽  
Hüdayim Başak ◽  
Fikret Sönmez

In this study, the analysis of cutting forces on medium carbon AISI 1050—to which different spheroidization heat treatments were applied—was conducted by the mixed-level Taguchi orthogonal experiment design method. In the experiments, besides the parameters of feed rate, depth of cut and cutting speed having effect on cutting forces as a factor in orthogonal design, the spheroidization time and temperature parameters were also used. By the performed orthogonal experiment design method, the values of cutting forces were estimated using the five-factor, two- and three-leveled Taguchi L36 (22 × 33) mixed orthogonal experiment design method. The effectiveness of the machining parameters on the cutting force was revealed by performing analysis of variance test. Moreover, the effectiveness rates of the parameters were also determined in the study as per the signal noise rates. Consequently, it has been observed that the feed rate is more effective on the cutting forces compared to other parameters.


Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 755
Author(s):  
Chen-Yang Zhao ◽  
Chi-Fai Cheung ◽  
Wen-Peng Fu

In this paper, an investigation of cutting strategy is presented for the optimization of machining parameters in the ultra-precision machining of polar microstructures, which are used for optical precision measurement. The critical machining parameters affecting the surface generation and surface quality in the machining of polar microstructures are studied. Hence, the critical ranges of machining parameters have been determined through a series of cutting simulations, as well as cutting experiments. First of all, the influence of field of view (FOV) is investigated. After that, theoretical modeling of polar microstructures is built to generate the simulated surface topography of polar microstructures. A feature point detection algorithm is built for image processing of polar microstructures. Hence, an experimental investigation of the influence of cutting tool geometry, depth of cut, and groove spacing of polar microstructures was conducted. There are transition points from which the patterns of surface generation of polar microstructures vary with the machining parameters. The optimization of machining parameters and determination of the optimized cutting strategy are undertaken in the ultra-precision machining of polar microstructures.


2020 ◽  
Vol 5 (1) ◽  
pp. 2
Author(s):  
Wenshuo Ma ◽  
Jingjun Yu ◽  
Yiqing Yang ◽  
Yunfei Wang

Milling tools with a large length–diameter ratio are widely applied in machining structural features with deep depth. However, their high dynamic flexibility gives rise to chatter vibrations, which results in poor surface finish, reduced productivity, and even tool damage. With a passive tuned mass damper (TMD) embedded inside the arbor, a large length–diameter ratio milling tool with chatter-resistance ability was developed. By modeling the milling tool as a continuous beam, the tool-tip frequency response function (FRF) of the milling tool with TMD was derived using receptance coupling substructure analysis (RCSA), and the gyroscopic effect of the rotating tool was incorporated. The TMD parameters were optimized numerically with the consideration of mounting position based on the maximum cutting stability criterion, followed by the simulation of the effectiveness of the optimized and detuned TMD. With the tool-tip FRF obtained, the chatter stability of the milling process was predicted. Tap tests showed that the TMD was able to increase the minimum real part of the FRF by 79.3%. The stability lobe diagram (SLD) was predicted, and the minimum critical depth of cut in milling operations was enhanced from 0.10 to 0.46 mm.


2018 ◽  
Vol 49 (2) ◽  
pp. 62-81 ◽  
Author(s):  
Shailendra Kumar ◽  
Bhagat Singh

Tool chatter is an unavoidable phenomenon encountered in machining processes. Acquired raw chatter signals are contaminated with various types of ambient noises. Signal processing is an efficient technique to explore chatter as it eliminates unwanted background noise present in the raw signal. In this study, experimentally recorded raw chatter signals have been denoised using wavelet transform in order to eliminate the unwanted noise inclusions. Moreover, effect of machining parameters such as depth of cut ( d), feed rate ( f) and spindle speed ( N) on chatter severity and metal removal rate has been ascertained experimentally. Furthermore, in order to quantify the chatter severity, a new parameter called chatter index has been evaluated considering aforesaid denoised signals. A set of 15 experimental runs have been performed using Box–Behnken design of experiment. These experimental observations have been used to develop mathematical models for chatter index and metal removal rate considering response surface methodology. In order to check the statistical significance of control parameters, analysis of variance has been performed. Furthermore, more experiments are conducted and these results are compared with the theoretical ones in order to validate the developed response surface methodology model.


2010 ◽  
Vol 447-448 ◽  
pp. 51-54
Author(s):  
Mohd Fazuri Abdullah ◽  
Muhammad Ilman Hakimi Chua Abdullah ◽  
Abu Bakar Sulong ◽  
Jaharah A. Ghani

The effects of different cutting parameters, insert nose radius, cutting speed and feed rates on the surface quality of the stainless steel to be use in medical application. Stainless steel AISI 316 had been machined with three different nose radiuses (0.4 mm 0.8 mm, and 1.2mm), three different cutting speeds (100, 130, 170 m/min) and feed rates (0.1, 0.125, 0.16 mm/rev) while depth of cut keep constant at (0.4 mm). It is seen that the insert nose radius, feed rates, and cutting speed have different effect on the surface roughness. The minimum average surface roughness (0.225µm) has been measured using the nose radius insert (1.2 mm) at lowest feed rate (0.1 mm/rev). The highest surface roughness (1.838µm) has been measured with nose radius insert (0.4 mm) at highest feed rate (0.16 mm/rev). The analysis of ANOVA showed the cutting speed is not dominant in processing for the fine surface finish compared with feed rate and nose radius. Conclusion, surface roughness is decreasing with decreasing of the feed rate. High nose radius produce better surface finish than small nose radius because of the maximum uncut chip thickness decreases with increase of nose radius.


2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Abdolreza Bayesteh ◽  
Junghyuk Ko ◽  
Martin Byung-Guk Jun

There is an increasing demand for product miniaturization and parts with features as low as few microns. Micromilling is one of the promising methods to fabricate miniature parts in a wide range of sectors including biomedical, electronic, and aerospace. Due to the large edge radius relative to uncut chip thickness, plowing is a dominant cutting mechanism in micromilling for low feed rates and has adverse effects on the surface quality, and thus, for a given tool path, it is important to be able to predict the amount of plowing. This paper presents a new method to calculate plowing volume for a given tool path in micromilling. For an incremental feed rate movement of a micro end mill along a given tool path, the uncut chip thickness at a given feed rate is determined, and based on the minimum chip thickness value compared to the uncut chip thickness, the areas of plowing and shearing are calculated. The workpiece is represented by a dual-Dexel model, and the simulation properties are initialized with real cutting parameters. During real-time simulation, the plowed volume is calculated using the algorithm developed. The simulated chip area results are qualitatively compared with measured resultant forces for verification of the model and using the model, effects of cutting conditions such as feed rate, edge radius, and radial depth of cut on the amount of shearing and plowing are investigated.


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