Technological Assurance of Manufacturing Effectiveness on CNC Machining Centers

2020 ◽  
pp. 344-384
Author(s):  
Viliam Zaloga ◽  
Vitalii Ivanov ◽  
Ivan Pavlenko ◽  
Ivan Dehtiarov
Keyword(s):  
Metal Cutting ◽  
Cnc Machining ◽  
Machining Accuracy ◽  
Metal Cutting Machine ◽  
Technological Parameters ◽  
Machining Processes ◽  
Multiproduct Manufacturing ◽  
The Given ◽  
The Relationship ◽  
Production Conditions

The chapter is devoted to the solving of the problem of increasing the efficiency of lever-type parts machining due to the introduction of flexible fixtures ensuring multi-axis machining. The relationship between the design and technological parameters of the parts were discovered, which is the fundamentals for the analysis of parts and the search for the fixture layout for the given production conditions. An innovative approach to the design of technological processes for lever-type parts machining is proposed, which is based on the principle of intensification of machining processes, design and technological features of the parts, functional and technological capabilities of modern metal-cutting machine tools. A mathematical model of machining accuracy of parts depending on the level of fixture flexibility is obtained. It is analytically and experimentally proved the feasibility of using flexible fixtures for multi-axis machining of lever-type parts in multiproduct manufacturing.

Possible examinations of stone machining focused on the relationship between technological parameters and surface quality

2013 ◽  
Vol 4 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Zs. Kun ◽  
I. G. Gyurika
Keyword(s):  
Surface Roughness ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Theoretical Background ◽  
Motion Path ◽  
Depth Of Cut ◽  
Manufacturing Cost ◽  
Technological Parameters ◽  
The Relationship ◽  
Manufacturing Time

Abstract The stone products with different sizes, geometries and materials — like machine tool's bench, measuring machine's board or sculptures, floor tiles — can be produced automatically while the manufacturing engineer uses objective function similar to metal cutting. This function can minimise the manufacturing time or the manufacturing cost, in other cases it can maximise of the tool's life. To use several functions, manufacturing engineers need an overall theoretical background knowledge, which can give useful information about the choosing of technological parameters (e.g. feed rate, depth of cut, or cutting speed), the choosing of applicable tools or especially the choosing of the optimum motion path. A similarly important customer's requirement is the appropriate surface roughness of the machined (cut, sawn or milled) stone product. This paper's first part is about a five-month-long literature review, which summarizes in short the studies (researches and results) considered the most important by the authors. These works are about the investigation of the surface roughness of stone products in stone machining. In the second part of this paper the authors try to determine research possibilities and trends, which can help to specify the relation between the surface roughness and technological parameters. Most of the suggestions of this paper are about stone milling, which is the least investigated machining method in the world.

Determination of optimal coordinates for switching processing cycles on metal-cutting machines

2021 ◽  
Vol 23 (1) ◽  
pp. 56-67
Author(s):  
Vilor Zakovorotny ◽  
◽  
Valery Gvindjiliya ◽  
Keyword(s):  
Metal Cutting ◽  
Cutting Speed ◽  
Subject Area ◽  
Cnc System ◽  
Machining Processes ◽  
Processing Efficiency ◽  
Tool Replacement ◽  
Cutting Path ◽  
The Given ◽  
Cutting System

Introduction. One of the ways to improve the efficiency of processing on machines is to coordinate the CNC program with the changing properties of the dynamic cutting system. If this takes into account the tool wear and the associated with it changes in the parameters of the dynamic cutting system, then the cutting speed to ensure the minimum wear rate is reduced along the cutting path. The corresponding feed rate is reduced even faster, since it is necessary to ensure a constant deformation displacement of the tool relative to the workpiece. The evolution of the properties of the cutting process (for matching with which the trajectories of the operating elements of the machine are corrected) depends on the power of irreversible transformations of the energy supplied to cutting. This reduces the processing efficiency. Therefore, a new for the considered subject area problem of determining the coordinates of the tool movement relative to the workpiece is formulated, starting from which further processing is economically inexpedient. In this case, it is necessary, after processing the next part, to ensure the replacement of the tool and carry out its changeover. Subject. A metal-cutting machine of a turning group, the trajectories of the executive elements of which are controlled, for example, by a CNC system. The purpose of the work. Mathematical simulation and methods for determining the coordinates at which it is necessary to replace the tool. Method and methodology. The necessary conditions for the optimality of determining these coordinates are proved. Mathematical tools are provided that allow calculating the coordinates at which the given manufacturing costs take the minimum value according to the given trajectories. The probabilistic characteristics of evolutionary trajectories are taken into account. Results and discussions. The analysis of the efficiency of using the technique in industry depending on the cost of the machine and tool together with its replacement and readjustment is given. The proven optimality conditions and the given mathematical tools complement the knowledge about the optimization of controlled machining processes on machines. Conclusions. The results of the study show new options for the organization of tool replacement, aimed at improving the efficiency of processing by software methods using a CNC system.

Crankshaft Mould CNC Machining Based on CAD/CAM Technique

2016 ◽  
Vol 693 ◽  
pp. 1704-1710
Author(s):  
Ting Ting Guo ◽  
Xian Ying Feng ◽  
Teng Jiao Sun
Keyword(s):  
Tool Path ◽  
Cutting Tool ◽  
Cnc Machining ◽  
Machining Accuracy ◽  
Technological Parameters ◽  
Tool Selection ◽  
Machining Center ◽  
Method Selection ◽  
Cad Cam

Taking the CY4105 crankshaft mould as the research target, this paper introduced the CNC machining method based on CAD/CAM technique. At first, structure of the mould was introduced. Then, machining method was introduced, including blank setting method, cutting tool selection, machining method selection and technological parameters setting method. After that, generation method of the mould machining programs was introduced, including tool path and G codes generation. At last, the mould was machined by a vertical machining center, and the results show that the machining accuracy is high.

EXPERIMENTAL RESEARCH OF THE NON-VIBRATING METHOD OF LAYING CONCRETE MIXTURE IN CANAL CLADDING

2021 ◽  
pp. 88-94
Author(s):  
V. YA. ZHARNITSKY ◽  
◽  
P. A. КОRNIENKO
Keyword(s):  
Experimental Research ◽  
Slope Angle ◽  
Experimental Studies ◽  
Concrete Mixture ◽  
Technological Parameters ◽  
Preliminary Heating ◽  
Experimental Stand ◽  
Concrete Mixtures ◽  
The Relationship ◽  
Production Conditions

The results of experimental studies are presented which make it possible to correct the technological parameters of laying the concrete mixture in the cladding of newly erected or reconstructed water supply canals. The studies were carried out on an experimental stand simulating the cannel profi le with a variable slope angle from 15° to 90°. The stand slope is covered with a conditional soil model in the form of a rough surface. To determine the relationship between the speed of the vibromold movement, the parameters of the concrete mixture, the profi le of the canal and the parameters of the concrete paver, mathematical models of the technological process have been developed. The analysis of the obtained results shows that accelerating additives signifi cantly reduce the duration of the concrete reaching its critical strength, in other words, it reduces the duration of the curing of the concrete under the formwork. The study of the obtained surface of the cladding on the stand shows that it contains some irregularities due to the absence of a smoothing strip. Therefore, under production conditions, concrete pavers must be equipped with smoothing devices, and the concrete mixture must be placed through a special hopper that regulates the height of the concrete mixture supply. For the construction of concrete linings on mobile concrete mixtures, it is recommended to use accelerating additives or their preliminary heating to a temperature of 50 … 60°C.

Dynamics of the processes in metal machining

1998 ◽  
Vol 2 ◽  
pp. 115-122
Author(s):  
Donatas Švitra ◽  
Jolanta Janutėnienė
Keyword(s):  
High Frequency ◽  
Machine Tools ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Low Frequency ◽  
Metal Cutting Machine ◽  
Cutting Machine ◽  
Metal Machining

In the practice of processing of metals by cutting it is necessary to overcome the vibration of the cutting tool, the processed detail and units of the machine tool. These vibrations in many cases are an obstacle to increase the productivity and quality of treatment of details on metal-cutting machine tools. Vibration at cutting of metals is a very diverse phenomenon due to both it’s nature and the form of oscillatory motion. The most general classification of vibrations at cutting is a division them into forced vibration and autovibrations. The most difficult to remove and poorly investigated are the autovibrations, i.e. vibrations arising at the absence of external periodic forces. The autovibrations, stipulated by the process of cutting on metalcutting machine are of two types: the low-frequency autovibrations and high-frequency autovibrations. When the low-frequency autovibration there appear, the cutting process ought to be terminated and the cause of the vibrations eliminated. Otherwise, there is a danger of a break of both machine and tool. In the case of high-frequency vibration the machine operates apparently quiently, but the processed surface feature small-sized roughness. The frequency of autovibrations can reach 5000 Hz and more.

scholarly journals A Feedrate Planning Method for the NURBS Curve in CNC Machining Based on the Critical Constraint Curve

2021 ◽  
Vol 11 (11) ◽  
pp. 4959
Author(s):  
Peng Guo ◽  
Yijie Wu ◽  
Guang Yang ◽  
Zhebin Shen ◽  
Haorong Zhang ◽  
...  
Keyword(s):  
Planning Method ◽  
Cnc Machining ◽  
Arc Length ◽  
Kinematic Constraint ◽  
Nurbs Curve ◽  
Planning Strategy ◽  
Feedrate Planning ◽  
Curvature Constraint ◽  
Planning Methods ◽  
The Relationship

The curvature of the NURBS curve varies along its trajectory, therefore, the commonly used feedrate-planning method, which based on the acceleration/deceleration (Acc/Dec) model, is difficult to be directly applied in CNC machining of a NURBS curve. To address this problem, a feedrate-planning method based on the critical constraint curve of the feedrate (CCC) is proposed. Firstly, the problems of existing feedrate-planning methods and their causes are analyzed. Secondly, by considering both the curvature constraint and the kinematic constraint during the Acc/Dec process, the concept of CCC which represents the relationship between the critical feedrate-constraint value and the arc length is proposed. Then the CCC of a NURBS curve is constructed, and it has a concise expression conforming to the Acc/Dec model. Finally, a feedrate-planning method of a NURBS curve based on CCC and the Acc/Dec model is established. In the simulation, a comparison between the proposed method and the conventional feedrate-planning method is performed, and the results show that, the proposed method can reduce the Acc/Dec time by over 40%, while little computational burden being added. The machining experimental results validate the real-time performance and stability of the proposed method, and also the machining quality is verified. The proposed method offers an effective feedrate-planning strategy for a NURBS curve in CNC machining.

Design and development of automatic sheet metal cutting machine

2020 ◽  
Author(s):  
R. Muthu Siva Bharath ◽  
Arunkumar Gopal ◽  
I. Maria James ◽  
S. Lakshmi Sankar
Keyword(s):  
Sheet Metal ◽  
Metal Cutting ◽  
Metal Cutting Machine ◽  
Design And Development ◽  
Cutting Machine ◽  
Sheet Metal Cutting
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