IMPROVING THE EFFICIENCY OF MILLING HOLES WITH A SMALL-SIZED TOOL IN THE CONDITIONS OF AUTOMATED PRODUCTION

2021 ◽  
Vol 2021 (10) ◽  
pp. 13-21
Author(s):  
Vladimir Davydov ◽  
Aleksandr Nikitenko ◽  
Mihail Gimadeev ◽  
Vera Berkun

The purpose of the paper. In order to solve the problems of increasing the efficiency of machining operations of small diameter holes by milling, the optimal range of cutting modes and helix pitch for the machining strategy with helical interpolation is established. The reduction of labor intensity and costs of hole machining when treating holes in alloyed corrosion-resistant steels is experimentally confirmed. Research methods. In this paper, the issues of machining blind holes by helical interpolation milling with end cylindrical carbide cutters of relatively small dimensions in parts made of 12X18N10T alloy are considered. The features of this machining are availability of significant axial and radial components of the cutting forces with relatively low tool strength. This leads to the fact that a key factor of the tool failure is its mechanical failure, the cause of which is an increase in cutting forces due to the edge of the cutter being chipped. Research results and novelty. It has been experimentally proved that the most rational machining parameters to ensure the specified accuracy and surface quality of the machined holes when using a strategy of helical interpolation milling will be the choice of the helix pitch p = 0.2 mm, the feed range F = 0.075-0.11 mm /tooth, which corresponds to the minute feeds of the milling center 450-675 mm/min. Conclusions. The optimal range of cutting modes is found in the feed range from 450 to 675 mm/min, with a helical interpolation pitch of 0.2 mm. The accuracy and roughness of the holes obtained by milling with end mills with a diameter of 3 mm for steel 12X18N10T is evaluated.

2011 ◽  
Vol 328-330 ◽  
pp. 560-564
Author(s):  
Ba Sheng Ouyang ◽  
Guo Xiang Lin ◽  
Yong Hui Tang

Cutting forces and machining error in contouring of concave and convex surfaces using helical ball end mills are theoretically investigated. The cutting forces are evaluated based on the theory of oblique cutting. The machining errors resulting from the tool deflections due to these forces are evaluated at various points of the machined surface. The influence of various cutting conditions and cutting modes on machining error is investigated and discussed.


Author(s):  
W. Ferry ◽  
D. Yip-Hoi

Cutter-workpiece engagement maps, or cutting flute entry/exit locations as a function of height, are a requirement for prediction of cutting forces on the tool and workpiece in machining operations such as milling. This paper presents a new method of calculating tool-part intersection maps for the five-axis flank milling of jet engine impellers with tapered ball-end mills. The parallel slicing method (PSM) is a semi-discrete solid modeling technique written in C++ using the ACIS boundary representation solid modeling environment. The tool swept envelope is generated and intersected with the workpiece to obtain the removal volume. It is also subtracted from the workpiece to obtain the finished part. The removal volume is sliced into a number of parallel planes along a given axis, and the intersection curves between each tool move and plane are determined analytically. The swept area between successive tool positions is generated using the common tangent lines between intersection curves, and then removed from the workpiece. This deletes the material cut between tool moves, ensuring correct engagement conditions. Finally, the intersection curves are compared to the planar slices of the updated part, resulting in a series of arcs. The end points of these arcs are joined with linear segments to form the engagement polygon that is used to calculate the engagement maps. Using this method, cutter-workpiece engagement maps are generated for a five-axis flank milling toolpath on a prototype integrally bladed rotor with a tapered ball-end mill. These maps are compared to those obtained from a benchmark cutter-workpiece engagement extraction method, which employs a fast, z-buffer technique. Overall, the PSM appears to obtain more accurate engagement zones, which should result in more accurate prediction of cutting forces. With the method’s current configuration, however, the calculation time is longer.


2004 ◽  
Vol 126 (2) ◽  
pp. 408-411
Author(s):  
Ning Fang

This paper presents a new quantitative sensitivity analysis of cutting performances in orthogonal machining with restricted contact and flat-faced tools, based on a recently developed slip-line model. Cutting performances are comprehensively measured by five machining parameters, i.e., the cutting forces, the chip back-flow angle, the chip up-curl radius, the chip thickness, and the tool-chip contact length. It is demonstrated that the percentage of contribution of tool-chip friction to the variation of cutting performances depends on different types of machining operations. No general conclusion about the effect of tool-chip friction should be made before specifying a particular type of machining operation and cutting conditions.


Fractals ◽  
2019 ◽  
Vol 27 (02) ◽  
pp. 1950013 ◽  
Author(s):  
AHMAD THUFFAIL THASTHAKEER ◽  
ALI AKHAVAN FARID ◽  
CHANG TECK SENG ◽  
HAMIDREZA NAMAZI

Analysis of the machined surface is one of the major issues in machining operations. On the other hand, investigating about the variations of cutting forces in machining operation has great importance. Since variations of cutting forces affect the surface quality of machined workpiece, therefore, analysis of the correlation between cutting forces and surface roughness of machined workpiece is very important. In this paper, we employ fractal analysis in order to investigate about the complex structure of cutting forces and relate them to the surface quality of machined workpiece. The experiments have been conducted in different conditions that were selected based on cutting depths, type of cutting tool (serrated versus. square end mills) and machining conditions (wet and dry machining). The result of analysis showed that among all comparisons, we could only see the correlation between complex structure of cutting force and the surface roughness of machined workpiece in case of using serrated end mill in wet machining condition. The employed methodology in this research can be widely applied to other types of machining operations to analyze the effect of variations of different parameters on variability of cutting forces and surface roughness of machined workpiece and then investigate about their correlation.


2012 ◽  
Vol 184-185 ◽  
pp. 663-667 ◽  
Author(s):  
Lin Hui Zhao ◽  
Jian Cheng Zhang ◽  
Wei Su

In micro machining, turn-milling tool wear is a key factor for part surface quality. This paper carries on experiments on end mills wear in micro turn-milling machining, aiming to research the wear form and provide some reference data for developing wear standard of small diameter end mills. To measure wear condition of end mills, machine vision technique is utilized. This paper designs and sets up an online end mill wear measurement system for a micro turn-milling process center. With a series of experiments on small diameter end mills, wear conditions of different cutting positions are researched. Based on analysis of experiment data, wear characteristics and wear rule for micro turn-milling process are summarized in this paper.


Fractals ◽  
2018 ◽  
Vol 26 (05) ◽  
pp. 1850078 ◽  
Author(s):  
HAMIDREZA NAMAZI ◽  
ALI AKHAVAN FARID ◽  
CHANG TECK SENG

It is known that geometry of cutting tool affects the cutting forces in machining operations. In addition, the value of cutting forces changes during machining operations and creates a chaotic time series (signal). In this paper, we analyze the variations of the complex structure of cutting force signal in rough end milling operation using fractal theory. In fact, we analyze the variations of cutting force signal due to variations of tool geometry (square end mill versus serrated end mill). In case of each type of end mill, we did the machining operation in wet and dry conditions. Based on the results, the fractal structure of cutting force signal changes based on the type of milling tool. We also did the complexity analysis using approximate entropy to check the variations of the complexity of cutting force signal, where the similar behavior of variations between different conditions was obtained. The method of analysis that was used in this research can be applied to other machining operations to study the influence of different machining parameters on variations of fractal structure of cutting force.


2016 ◽  
Vol 10 (6) ◽  
pp. 882-890 ◽  
Author(s):  
Noritaka Kawasegi ◽  
◽  
Hiroshi Sugimori ◽  
Noboru Morita ◽  
Toru Sekiguchi ◽  
...  

The purpose of this study is to develop novel cutting tools with micro- or nanoscale textures on their surfaces. Texturing micro- or nanoscale features on a surface allows us to control the tribological characteristics of the tool. For this research, textures were applied to end mills with a diameter of 0.5 mm using a femtosecond laser, and milling experiments were conducted on aluminum alloy to evaluate the developed tools. The applied texture decreased the cutting forces. This effect depends on the shape of the texture: groove textures are more effective for reducing friction and the resultant cutting forces. Periodic textures fabricated through the interference of the laser were effective at reducing the adhesion of the work material. A larger effect was obtained for shallow and large pitch textures. The results indicate that the proposed method is effective at improving the machining performance of small-diameter end mills.


Alloy Digest ◽  
1980 ◽  
Vol 29 (7) ◽  

Abstract CPM REX 25 is a super high-speed steel made without cobalt. It is comparable to AISI Type T15 cobalt-containing high-speed steel in response to heat treatment, properties, and tool performance. CPM REX 25 is recommended for machining operations requiring heavy cuts, high speeds and feeds, and difficult-to-machine materials of high hardness and abrasion resistance. Typical applications are boring tools, drills, gear cutters, punches, form tools, end mills and broaches. This datasheet provides information on composition, physical properties, hardness, and elasticity as well as fracture toughness. It also includes information on forming, heat treating, machining, and surface treatment. Filing Code: TS-365. Producer or source: Crucible Materials Corporation.


Author(s):  
J. C. Outeiro ◽  
O. W. Dillon ◽  
I. S. Jawahir

For improving product sustainability, a number of measures can be adopted during the product design stage for manufacturing. The modeling and control of the residual stresses and surface roughness generated by machining are among the major measures which have been shown to demonstrate the strongest influence on the machined component’s performance during its service life. The proper control of the residual stresses would provide increased product lifetime, reduced part distortion, reduced weight and reduced and less frequent maintenance and inspection of the product while maintaining the same safety level, or perhaps even improving it. This paper presents an analysis of the influence of machining parameters on the residual stresses generated in machining operations. This analysis was performed on several work materials, including carbon steels, stainless steels, Inconel alloys and tool steels. This allows developing a number of feasible means to control the residual stresses during manufacturing.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2575 ◽  
Author(s):  
Giacomo Goli ◽  
Rémi Curti ◽  
Bertrand Marcon ◽  
Antonio Scippa ◽  
Gianni Campatelli ◽  
...  

The set-up of machining parameters for non-ferric materials such as wood and wood-based materials is not yet defined on a scientific basis. In this paper, a new rapid experimental method to assess the specific cutting coefficients when routing isotropic and orthotropic wood-based materials is presented. The method consists of routing, with different depths of cut, a given material previously machined to a round shape after having it fixed on a dynamometric platform able to measure the cutting forces. The execution of subsequent cuts using different depths of cut allows the calculation of the specific cutting coefficients. With the measurement being done during real routing operations, a method to remove machine vibrations was also developed. The specific cutting coefficients were computed for the whole set of grain orientations for orthotropic materials and as an average for isotropic ones. The aim of this paper is to present and validate the whole method by machining selected materials such as Polytetrafluoroethylene—PTFE (isotropic), Medium Density Fiberboard—MDF (isotropic), beech Laminate Veneer Lumber—LVL (orthotropic) and poplar LVL (orthotropic). The method and the proposed analysis have been shown to work very effectively and could be used for optimization and comparison between materials and processes.


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