scholarly journals Hazards That Can Affect CNC Machine Tools during Operation—An AHP Approach

Safety ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 10
Author(s):  
Sever-Gabriel Racz ◽  
Radu-Eugen Breaz ◽  
Lucian-Ionel Cioca
Keyword(s):  
Machine Tools ◽  
Metal Cutting ◽  
Machining Process ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Nc Code ◽  
Safety Features ◽  
Cutting Processes ◽  
Safety Systems ◽  
Five Axes

CNC (computer numerically controlled) machine tools are highly advanced technological systems, used to machine parts by means of metal cutting processes. Their structure and kinematics are very complex, involving accurate coordinated motions on three to five axes. Operating CNC machine tools is a complicated process, which can easily be affected by errors. Nowadays, safety systems and devices are developed in order to make this process safer and more user friendly. Modern CNC controllers are designed to deal with obvious sources of hazards, such as overloads (by means of various sensor systems) and collisions (by checking the NC code syntax and simulating it on the machine). However, despite of these safety systems, various unwanted events still occur during machining operations on CNC machine tools. These means that there are still certain hazards, not so obvious, which can severely affect the operation of CNC machine tools. This work tries to identify and hierarchize the above-mentioned hazards by using an AHP (analytic hierarchy process) approach. The results of the AHP emphasize which hazard has the biggest influence upon the CNC machine tools operation and consequently should be avoided. The results of this work could be used by the machine tools designers to develop new safety features for the existing CNC controllers. Also, the users of the machine tools could focus some of the safety measures during the machining process upon the most significant hazards pointed by the results of the research.

scholarly journals Evaluating Safety Systems for Machine Tools with Computer Numerical Control using Analytic Hierarchy Process

Safety ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 14 ◽  
Author(s):  
Sever-Gabriel Racz ◽  
Radu-Eugen Breaz ◽  
Lucian-Ionel Cioca
Keyword(s):  
Analytic Hierarchy Process ◽  
Machine Tools ◽  
Computer Numerical Control ◽  
Numerical Control ◽  
Machining Process ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Analytic Hierarchy ◽  
Safety Systems ◽  
Hierarchy Process

Computer numerical control (CNC) machine tools are complex production systems with fully automatic machine parts. Nowadays, high feed rates and machining speeds are used during the machining process. Human operators are still needed to set-up the machine, load/unload workpieces and parts, load the machining code, and supervise the machining process. The operators work in an environment where automated high-speed motions occur, and consequently, CNC machine tools have to be equipped with safety systems. The approach presented in this paper was to evaluate the main safety systems of CNC machine tools based upon the analytic hierarchy process (AHP). The analyzed systems were divided into six main categories and compared pairwise using five criteria proposed by the authors. The approach and the obtained results significantly relied upon the situation found at the industrial company used as a benchmark for the research. The analysis reveals that, among considered safety devices, manually operated controls are the most efficient ones. Finally, a sensitivity analysis was conducted to test the stability of the AHP solution.

Application of Tree Graph Method for Reducing the Total Time of Tool Changing in Milling and Boring Machine Tools

2013 ◽  
Vol 371 ◽  
pp. 431-435 ◽  
Author(s):  
Claudiu Obreja ◽  
Gheorghe Stan ◽  
Lucian Adrian Mihaila ◽  
Marius Pascu
Keyword(s):  
Machine Tools ◽  
Design Method ◽  
Machining Process ◽  
Cnc Machine Tools ◽  
Tree Graph ◽  
Cnc Machine ◽  
High Productivity ◽  
Automatic Tool Changer ◽  
Automatic Tool ◽  
Set Up

With a view of increasing the productivity on CNC machine tools one of the main solution is to reduce, as much as possible, the auxiliary time consumed with the set-up and replacement of the tools and work pieces engaged in the machining process. Reducing the total time of the tool changing process by the automatic tool changer system can be also achieved through minimizing the number of movements needed for the actual exchange of the tool, from the tool magazine to the machine spindle (the optimization of the tool changing sequences). This paper presents a new design method based on the tree-graph theory. We consider an existing automatic tool changing system, mounted on the milling and boring machining centre, and by applying the new method we obtain all the possible configurations to minimize the tool changing sequence of the automatic tool changer system. By making use of the method proposed we obtain the tool changing sequences with minimum necessary movements needed to exchange the tool. Reconfiguring an existing machine tool provided with an automatic tool changer system by making use of the proposed method leads to obtaining the smallest changing time and thus high productivity.

scholarly journals On the Application of Impeller in Multi Axis CNC Machine Tools

2021 ◽  
Vol 2066 (1) ◽  
pp. 012113
Author(s):  
Weiwen Ye
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Complex Surface ◽  
Machining Process ◽  
Cnc Machine Tools ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Surface Processing ◽  
The Third ◽  
Machining Characteristics

Abstract Multi axis CNC machine tool has good linkage processing effect. Through the application of integral impeller in CNC machine tools, to improve the adaptability of CNC machine tools to complex surface processing parts, to improve the accuracy of multi axis CNC machine tools. The first part of this paper introduces the integral impeller and its machining characteristics; the second part introduces the basic NC machining process of integral impeller; the third part discusses the application of impeller in multi axis CNC machine tools from the creation of guide track, the simulation of integral impeller, software processing and generation. The purpose is to provide some reference for the processing and production of integral impeller.

Mathematical Approach for Geometric Error Modeling of Three Axis CNC Vertical Milling Machine

2016 ◽  
Vol 842 ◽  
pp. 303-310 ◽  
Author(s):  
Widyanti Kwintarini ◽  
Agung Wibowo ◽  
Yatna Yuwana Martawirya
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Machining Process ◽  
Cnc Machine Tools ◽  
Milling Machine ◽  
Cnc Machine ◽  
Geometrical Errors ◽  
Vertical Milling ◽  
Vertical Milling Machine ◽  
Accuracy And Repeatability

The aim of this paper overviews about to find out the errors that come from three axis CNC vertical milling machine. The errors come from, the CNC milling machine can be modelled into mathematical models and later on these error models will be used to analyse the errors in the measured data. Many errors from CNC machine tools have given significant effects toward the accuracy and repeatability of manufacturing process. There are two error sources come from CNC machine tools such as tool deflection and thermal distortions of machine tool structure. These errors later on will contribute to result in the geometrical deviations of moving axis in CNC vertical milling machine. Geometrical deviations of moving axis such as linear positioning errors, roll, pitch and yaw can be designated as volumetric errors in three axis machine tool. Geometrical deviations of moving axises happen at every axis in three axis CNC vertical milling machine. Geometrical deviations of moving axises in linear and angular movement has the amount of errors up to twenty one errors. Moreover, this geometrical errors play the major role in the total amount of errors and for that particular reason extra attention towards the geometrical deviation errors will be needed along machining process. Each of geometrical error of three axes vertical machining center is modeled using a homogeneous transformation matrix (HTM). The developed mathematical model is used to calculate geometrical errors at each axis and to predict the resultant error vector at the interface of machine tool and workpiece for error compensation.

Optimization of Planar Honing Process for Surface Finish of Machine Tool Sliding Guideways

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Kory Chang ◽  
Masakazu Soshi
Keyword(s):  
Machine Tools ◽  
Cubic Boron Nitride ◽  
Three Dimensional ◽  
Numerical Control ◽  
Machining Process ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Manufacturing Method ◽  
Traditional Manufacturing ◽  
Sliding Guideways

Sliding guideways are often used as the foundation for linear motion in computer numerical control (CNC) machine tools due to their high damping capabilities especially for heavy duty machining applications. However, the traditional manufacturing process with grinding is time-consuming, and the product’s sliding performance has not been optimized nor clearly understood. In order to increase productivity, a machining center based manufacturing method with cubic boron nitride (CBN) milling tools was introduced and tested by researchers. While greatly reducing manufacturing time and cost, a rougher milled surface, in comparison to traditional grinding, is a possible concern for the performance as well as the life of sliding guideways. In this study, a novel planar honing process was proposed as a postprocess of CBN milling to create a finish surface on hardened cast iron sliding guideways used for CNC machine tools. A design of experiment (DOE) was conducted to statistically understand significant factors in the machining process and their relationship with surface topography. Effective planar honing conditions were discovered and analyzed with three-dimensional (3D) and two-dimensional surface parameters.

Research on Machining Method of Complex Surface Face Gears

2012 ◽  
Vol 163 ◽  
pp. 233-237
Author(s):  
Yan Zhong Wang ◽  
Liang Wei Hou ◽  
Yan Qiang Liu ◽  
Rong Shen ◽  
Can Hui Wu ◽  
...  
Keyword(s):  
Machine Tools ◽  
Surface Characteristics ◽  
Complex Surface ◽  
Transformation Process ◽  
Cnc Machining ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Face Gear ◽  
Five Axes ◽  
Complex Parts

This paper describes the machining method of complex surface face gear used CNC machine tools and hob cutter, Based on surface characteristics and gear hob principle. A coordinate transformation process is explained in detail in the five axes CNC machining of complex parts. A CNC hob method is proposed about surface orthogonal gear. An experiment is done for validating the method.

Study on Cutter Radius Compensation Methods for 5-Axis CNC Machining

2009 ◽  
Vol 628-629 ◽  
pp. 347-352 ◽  
Author(s):  
Yuan Liu ◽  
Yong Zhang Wang ◽  
Hong Ya Fu ◽  
Zhen Yu Han
Keyword(s):  
Machine Tools ◽  
Cnc Machining ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Nc Program ◽  
Compensation Methods ◽  
Radius Compensation ◽  
Five Axes ◽  
Discrimination Methods

The numerical control (NC) program files need re-generating if there is any tool dimension change or tool wear for multi-axis machining. If the tool is replaced to adapt this change there will be increased cost. To solute this problem, 3D cutter radius compensation method for 5-axis computer numerical control (CNC) machining is deeply researched. Taking five axes linkage machine tools of X, Y, Z, B, C form with rotary tables B and C as an example, coordinate transformation matrix (CTM) and the cutter compensation vector for 3D cutter radius compensation are derived. The discrimination methods for path joint pattern (PJP) are given. A controller with 3D cutter radius compensation function for 5-axis linkage CNC machine tools is developed based on this method. The controller is allocated to a 5-axis milling machine tool and experiments are done. The proposed algorithm is demonstrated using a practical example.

scholarly journals Investigation of ultrasonic-assisted CNC cutting of honeycomb cores

2021 ◽  
Author(s):  
Dongfang Mu ◽  
Xiaoping Hu ◽  
Haofeng Yu ◽  
Baohua Yu
Keyword(s):  
Processing Method ◽  
Machining Process ◽  
Cnc Machine Tools ◽  
Post Processing ◽  
Cnc Machine ◽  
Rough Machining ◽  
Straight Blade ◽  
Nc Code ◽  
Ultrasonic Assisted ◽  
Machining Process Planning

AbstractAs compared to traditional milling, ultrasonic-assisted cutting of honeycomb core materials has the advantages of small cutting force and superior surface quality. Currently, ultrasonic straight blade V-shaped machining is one of the most efficient roughing processes. The requirement of a processing path to be post-processed based on the processing characteristics of the straight blade cutter is one of the key issues faced while meeting the technological requirements of CNC machine tools for V-shaped machining. A post-processing method of NC code for V-shaped machining of straight blade cutter is proposed in this article. Initially, the V-shaped rough machining process planning is done, followed by the usage of Unigraphics (UG) to output the initial CNC code. Next, the CNC code is executed through the three key technologies of the second arrangement of cutter locations. Later, research is done on information planning of lifting and lowering cutter, along with research on planning of chip breaking toolpath. Eventually, the simulation cutting experiment is carried out through VERICUT. The results demonstrate that the post-processing method can meet the processing requirements.

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