Operational Behavior of Graded Diamond Grinding Wheels For End Mill Cutter Machining

The varying related material removal rate during deep grinding of cemented carbide end mill cutters results in an unevenly wear of the grinding wheel. This causes a reduced geometrical precision of the manufactured tools. Consequently, the intervals between dressing steps are reduced and the dressing infeed increases. The aim of this research project is therefore to design a tailored grinding tool with uniform wear behavior. To address this situation, the grinding tool load is determined simulatively along the width of the grinding wheel. From this an equation is derived to adapt the bonding layer properties to the local load differences. First investigations show that two different concentrations zones in the abrasive layer of the grinding wheel improves the wear behavior already. This indicates that a further reduction of the wear difference is possible by a more uniform gradient. A simulation is performed to define a knowledge based gradient with more than two concetration zones. This allows a more precise load optimized adaptation of the grinding layer properties to the geometry to be ground in terms of wear behavior. Grinding tools manufactured on this basis are used for flute grinding of end mill cutters. A reduction of the wear difference over the grindig wheel width of 52% and an improved cutting edge quality of these are demonstrated.

Digital Generating Method for Cylindrical Helical Gear based on Indexable Disk Milling Cutter

To solve the problem of low efficiency in digital generating machining for producing small or medium batches of helical gears, a method to improve the machining efficiency with an indexable disc milling cutter is presented in this paper. First, the mathematical model of the tooth profile and the indexable disc milling cutter are established. Second, according to the spatial free-form envelope theory, the overall planning scheme of the tool path is given; the relative position and the relative transformation matrix of the tool and tooth profile during digital generating machining using the indexable disc milling cutter are solved, the simulation cutting and actual cutting experiments are conducted, and the cutting efficiency per unit time and cutting simulation time of the two tools under the same deformation conditions is obtained through a finite element analysis experiment. The results show that the cutting efficiency of the indexable disc milling tool was 2–3 times higher than that of the end mill cutter.

Modeling of tool vibration and its effect on roundness and surface roughness of hole in helical milling of Inconel 718

Relative vibration between the cutter and workpiece has an influence on the surface generation and dimensional accuracy. In the present work, prediction models were developed for roundness and surface roughness of hole in terms of amplitude and frequency of tool vibration. The proposed methodology carried out a theoretical investigation on the effect of tool vibration components in X- and Y-directions on the mill cutter end point to estimate hole roundness and surface roughness. Series of helical milling experiments were conducted at different levels of spindle rotational speed, cutter orbital speed, and axial depth of cuts using 10- mm and 8- mm diameter mill cutters on Inconel 718. Predicted values of the roundness and surface roughness of hole were compared with predicted values and verified accuracy of the proposed prediction models. The experimental results indicate a good agreement with the predicted value. At spindle rotational speed of 2000 r/min and cutter orbital speed of 50 r/min, the measured and predicted values of the roundness were found to be almost same as the required roundness. The surface roughness was found to be very less at 50 r/min of cutter orbital speed.

Chatter Detection in Milling of Carbon Fiber-Reinforced Composites by Improved Hilbert–Huang Transform and Recurrence Quantification Analysis

In the paper, the problem of chatter vibration detection in the milling process of carbon fiber-reinforced plastic is investigated. Chatter analysis may be considered theoretically based on data from impact test of an end mill cutter. However, a stability region obtained in such way may not agree with the real one. Therefore, this paper presents a method that can predict chatter vibrations based on cutting force components measurements. At the beginning, a stability lobe diagram is created to establish the range of experimental test in the plane of tool rotational speed and depth of cut. Next, an experiment of composite milling is performed. The experimentally-measured time series of cutting forces are decomposed with the use of the improved Hilbert–Huang transform (HHT). To detect chatter, statistical methods and recurrence quantification analysis (RQA) are used. However, much better results are obtained when new chatter indexes are proposed. The indexes, derived directly from the HHT and RQA methods, can be used to build an effective chatter prediction system.

Investigation of input variables on temperature rise while end milling Al/SiC metal matrix composite

Purpose The purpose of this paper is to find out the optimal level as well as the influence of end mill cutter geometrical and machining parameters while machining metal matrix composite. End milling is carried out on Al 356/SiC metal matrix composites (MMC) using high-speed steel (HSS) end mill cutter. The optimum level of input parameters such as helix angle, nose radius, rake angle, cutting speed, feed rate and depth of cut are calculated for minimum temperature rise. Design/methodology/approach L27 Taguchi orthogonal design, signal-to-noise (S/N) ratio, are applied for conducting experiments, and to find the optimal level of input parameters for minimum temperature rise, respectively. Analysis of variance (ANOVA) is used to analyze the significance of input parameters on temperature rise. Findings It is found that the optimal combination of helix angle 400, nose radius 0.8 mm, rake angle 80, cutting speed 30 m/min, feed rate 0.04 mm/rev and depth of cut 0.5 mm have generated minimum temperature rise. From ANOVA analysis, it is found that rake angle influence is more on output performance followed by cutting speed and nose radius compared with other machining and geometrical parameters. Originality/value The influence of geometrical parameters such as helix angle, nose radius and rake angle of end mill cutter on temperature rise while machining MMC has not been explored previously.

Surface Quality Comparison of Down and Up cut Technique on CNC Milling Machine toward ST-37 Steel Material

The purpose of this research is comparing down and up cut technique on milling process toward ST-37 steel material by using HSS Ø12 mm end mill cutter. The surface roughness result of down cut technique is achieved Ra 2.39 μm which is equivalent to N7 roughness level at lowest cutting speed 20 m/mnt. Moreover, the highest roughness Ra 3.61 μm obtained at highest cutting speed 30 m/mnt which is equivalent to N8 roughness level. While, the quality of up cut technique yield the roughnes Ra 3.94 μm, equivalent to N8 roughness level at lowest cutting speed 20 m/minute, whilst, Ra 6.01 μm that equivalent to N9 roughness level on highest cutting speed condition 30 m/minute. The surface roughnes value achieved between N7-N9 level (ISO). Down cut technique is recommended in order to achieve good surface quality, because it could be generate lower surface roughness on material. Tujuan dari penelitian ini adalah membandingkan teknik down cut dan up cut pada proses freis terhadap material baja ST-37 dengan menggunakan end mill cutter diameter Ø12 mm. Hasil kekasaran permukaan dari teknik down cut adalah Ra 2,39 μm yang setara dengan level kekasaran N7 pada kecepatan potong terendah 20 m/mnt. Selanjutnya, kekasaran tertinggi Ra 3,61 μm diperoleh pada kecepatan potong tertiggi 30 m/mnt yang setara dengan level kekasaran N8. Sementara itu, kualitas teknik up cut menghasilkan kekasaran Ra 3,94 μm yang setara dengan level kekasaran N8 pada kecepatan potong terendah 20 m/mnt, sedangkan Ra 6,01 μm yang setara dengan level N9 pada kecepatan potong tertinggi 30 m/mnt. Harga kekasaran permukaan material diperoleh di antara level N7-N9 (nomor kekasaran ISO). Teknik down cut direkomendasikan untuk memperoleh kualitas permukaan yang baik, karena teknik ini dapat menghasilkan kekasaran permukaan yang lebih rendah pada benda kerja.

A Survey on the Effects of Cutting Parameters on Surface Roughness When Milling 40Cr Steel Using End Mill Cutter

In this paper, the empirical research on the effects of cutting parameters on surface roughness when milling 40Cr steel with face mill is conducted. The cutting parameters in this study include the cutting speed, feed rate and depth of cut. The tests are conducted in the form of Central Composite Design. The analysis shows that, for both Ra and Rz: (1) the feed rate has the greatest effect on surface roughness, followed by the degree of influence of the depth of cut, cutting speed with insignificant effects on surface roughness. (2) only the interaction between the feed rate and depth of cut have a significant effect on both Ra and Rz; the interaction between the cutting speed and feed rate, the interaction between the cutting speed and depth of cut have negligible effects on the surface roughness. In addition, the regression equations showing the relationship between Ra, Rz and cutting parameters is developed in this study.