scholarly journals A Feedrate-Constraint Method for Continuous Small Line Segments in CNC Machining Based on Nominal Acceleration

2021 ◽  
Vol 11 (19) ◽  
pp. 8837
Author(s):  
Peng Guo ◽  
Ronghua Wang ◽  
Zhebin Shen ◽  
Haorong Zhang ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Machine Tool ◽  
High Speed ◽  
Cnc Machining ◽  
Machining Process ◽  
Free Form ◽  
Cnc Machine ◽  
Line Segments ◽  
Machining Quality ◽  
Adjacent Line ◽  
Constraint Method

When the CNC machining of continuous small line segments is performed, the direction of the machine tool movement will change abruptly at the corner of adjacent line segments. Therefore, a reasonable constraint on the feedrate at the corner is the prerequisite for achieving high-speed and high-precision machining. To achieve this goal, a feedrate-constraint method based on the nominal acceleration was proposed. The proposed method obtains the predicted value of acceleration during the machining process by the machining trajectory prediction and acceleration filtering. Then, the feedrate at the corner is constrained, according to the predicted acceleration. Specifically, for any corner of adjacent line segments, the proposed method assumes that the CNC machining of a short path centered on the corner is carried out at a constant feedrate. First, the actual machining trajectory is predicted according to the transfer function of the servo system. Then, the nominal acceleration, when the CNC machining is carried out to the corner, is calculated and processed by a low-pass FIR filter. Last, the feedrate-constraint value at the corner is obtained according to the nominal acceleration and the preset normal acceleration. The advantage of the proposed method is that it can be used for different machining paths consisting of long segments or continuous small segments and it has no special requirement for the accuracy of the machining path. As a result, the feedrate-constraint value obtained is reasonable and the smooth machining process can be ensured. The simulation results in both 2D and 3D machining paths show that the proposed method is insensitive to the length of the line segment and the angle of the corner, and the calculated feedrate-constraint value is close to the theoretical value, which has good stability and versatility. In contrast, the feedrate-constraint values obtained by conventional methods change abruptly along the machining path, especially in the 3D simulation, which will damage the machining quality. The experiment was performed on a three-axis CNC machine tool controlled by a self-developed controller, and a free-form surface workpiece was machined by a conventional feedrate-constraint method and the proposed method, respectively. The experimental results showed that the proposed method can make the feedrate of the machining process higher and more stable. Then, machining defects such as overcutting and undercutting can be avoided and the machining quality can be improved. Therefore, the article proposes a new method to constrain the feedrate at the corner of continuous small line segments, which can improve the machining efficiency and quality of the CNC machining.

Research on Machining Simulation of Ultra High-Speed Grinding Machine Tool Based on Web

2010 ◽  
Vol 126-128 ◽  
pp. 77-81
Author(s):  
Wan Shan Wang ◽  
Peng Guan ◽  
Tian Biao Yu
Keyword(s):  
Machine Tool ◽  
Geometric Modeling ◽  
High Speed ◽  
Cnc Machining ◽  
Machining Process ◽  
Machining Simulation ◽  
Ultra High Speed ◽  
Cad Cam ◽  
High Speed Grinding ◽  
Grinding Machine

The future development of the manufacturing is using VR technology to make the machining simulation before the actual machining process made. The machining simulation of Ultra High-speed Grinding Machine Tool is researched in this paper. Firstly, using UG/NX software and VRML, the geometric modeling of machine tool is modeled. Secondly, through using Java and Javascript language, the operation and display of machining process of ultra high-speed grinding are realized. The main technologies include NC codes compiling, collision detection and material removal. Thirdly, the example of machining simulation using virtual ultra high-speed grinding machine tool can be obtained in the paper. Compared to other CNC machining simulation methods, the method in the paper has reality display, rich features, a good man-machine interaction, etc., and it does not rely on expensive CAD/CAM software. The system files generated by the machining simulation have the small size and can be transferred on the network easily.

scholarly journals Tool-Path Planning Method For Kinematics Optimization of Blade Machining On Five-Axis Machine Tool

2022 ◽  
Author(s):  
Zhongyang Lu ◽  
Xu Yang ◽  
Ji Zhao
Keyword(s):  
Path Planning ◽  
Machine Tool ◽  
Tool Path ◽  
Machining Process ◽  
Free Form ◽  
Traditional Methods ◽  
Machining Quality ◽  
Blade Machining ◽  
Kinematic Performance ◽  
Five Axis

Abstract Planning tool-paths on free-form surfaces is a widely discussed issue. However, traditional methods of generating paths capable of meeting all the requirements of blade machining remain challenging. In this study, a new iso-parametric path-planning strategy based on a novel parameterization method combined with the conformal transformation theory was proposed. The proposed method could adapt to the curvature characteristics of the blade surface, improving the kinematic performance of the machining process, reducing multi-axis coordinated motion control complexity, and improving machining quality. The proposed method was then compared with three traditional methods. The influence of the tool-path on the kinematic performance of the machine tool was quantitatively examined based on the kinematics models of two different machine tools. A large cutting depth milling experiment was conducted to verify that kinematics optimization could improve machining quality. The proposed method provides a more reasonable path-planning approach for blade machining on a five-axis machine tool, which is of great significance in reducing the cost of blade machining and the risks of blade failure. Moreover, it is of great significance for the large-scale automated production of blades.

Research on Motion Profile Smooth Control Algorithm Based on Continuous Jerk

2010 ◽  
Vol 29-32 ◽  
pp. 2002-2007 ◽  
Author(s):  
Guo Yong Zhao ◽  
Yu Gang Zhao ◽  
Rong Guo Hou
Keyword(s):  
Machine Tool ◽  
High Speed ◽  
Control Algorithm ◽  
Linear Acceleration ◽  
High Accuracy ◽  
Cnc Machining ◽  
Cnc Machine ◽  
Maximum Acceleration ◽  
Smooth Control ◽  
Motion Profile

Motion profile smooth control is significant to reduce the obvious impact on machine tool in high speed and high accuracy CNC machining. However, the jerk is discontinuous and brings about flexible impact on machine tool in the linear Acceleration/Deceleration (ab. Acc/Dec), exponent Acc/Dec and S curve Acc/Dec approach. In the paper, the CNC machine tool dynamic model is built up to analyze the cause of machine impact, to describe the mathematics and physics meanings of jerk. Then a new Acc/Dec approach in which the jerk is continuous is put forward. And the motion profile smooth control algorithm based on continuous jerk is developed in details according to the permissible maximum acceleration, the permissible maximum jerk, the machining program segment displacement and the instruction feedrate. The motion profile smooth control algorithm can achieve continuous jerk, reduce impact on machine tool effectively, and be important to high speed and high accuracy CNC machining.

scholarly journals Automatic Data Collecting and Application of the Touch Probing System on the CNC Machine Tool

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Zhi Tang ◽  
Xinyu Jiang ◽  
Wenliang Zi ◽  
Xin Shen ◽  
Die Zhang
Keyword(s):  
Big Data ◽  
Machine Tool ◽  
Cnc Machining ◽  
Machining Process ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Automatic Data ◽  
Data Collecting ◽  
Siemens 840D ◽  
Big Data Technology

For realizing automatic data collecting of the touch probing system on the CNC machine tool and practicing the application technology of big data from the CNC machining process, a special NC program was developed on the Siemens 840D SL controller to record data with a defined text format, and they were uploaded onto the host computer automatically. With the help of DB management software in the host PC, data obtained were sent into the MES database regularly, and then automatic data collecting of manufacturing process information was realized. With the big data technology, three applications based on big data technology have been listed. They are duo active error detection on the probing system, geometrical accuracy monitoring, and management of the cutting parameter and tool life. Tests of cutting on the platen of an injection molding machine with a PAMA SR3000 floor-type CNC boring-milling machine proved that the new technology achieves its design objectives.

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.

CNC Machine Tools

2009 ◽  
pp. 165-187 ◽  
Author(s):  
Xun Xu
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Manufacturing Industry ◽  
Human Action ◽  
Cnc Machining ◽  
Cnc Machine Tools ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Cnc Machines ◽  
Time Required

The introduction of CNC machines has radically changed the manufacturing industry. Curves are as easy to cut as straight lines, complex 3-D structures are relatively easy to produce, and the number of machining steps that required human action has dramatically reduced. With the increased automation of manufacturing processes with CNC machining, considerable improvements in consistency and quality can be achieved. CNC automation reduced the frequency of errors and provided CNC operators with time to perform additional tasks. CNC automation also allows for more flexibility in the way parts are held in the manufacturing process and the time required to change the machine to produce different components. In a production environment, a series of CNC machines may be combined into one station, commonly called a “cell”, to progressively machine a part requiring several operations. CNC controller is the “brain” of a CNC machine, whereas the physical configuration of the machine tool is the “skeleton”. A thorough understanding of the physical configuration of a machine tool is always a priority for a CNC programmer as well as the CNC machine tool manufacturers. This chapter starts with a historical perspective of CNC machine tools. Two typical types of CNC machine tools (i.e. vertical and horizontal machining centres) are first discussed. Tooling systems for a CNC machine tool are integral part of a CNC system and are therefore elaborated. Also discussed are the four principal elements of a CNC machine tool. They are machine base, machine spindle, spindle drive, and slide drive. What letter should be assigned to a linear or rotary axis and what if a machine tool has two sets of linear axes? These questions are answered later in the chapter. In order for readers to better comprehend the axis and motion designations, a number of machine tool schematics are given.

scholarly journals Design and Evaluation of Uniform LED Illumination Based on Double Linear Fresnel Lenses

2020 ◽  
Vol 10 (9) ◽  
pp. 3257
Author(s):  
Hoang Vu ◽  
Ngoc Minh Kieu ◽  
Do Thi Gam ◽  
Seoyong Shin ◽  
Tran Quoc Tien ◽  
...  
Keyword(s):  
High Speed ◽  
Field Experiments ◽  
Numerical Control ◽  
Free Form ◽  
Light Sources ◽  
Cnc Machine ◽  
Led Lighting ◽  
Positive Effects ◽  
Fresnel Lenses ◽  
Linear Fresnel Lenses

Redistribution of LED radiation in lighting is necessary in many applications. In this article, we propose a new optical component design for LED lighting to achieve a higher performance. The design consists of a commercial collimator and two linear Fresnel lenses. The LED radiation is collimated by a collimator and redistributed by double linear Fresnel lenses to create a square-shaped, uniform distribution. The linear Fresnel lenses design is based on Snell’s law and the “edge-ray principle”. The optical devices are made from poly methyl methacrylate (PMMA) using a high-speed computer numerical control (CNC) machine. The LED prototypes with complementary optics were measured, and the optical intensity distribution was evaluated. The numerical results showed we obtained a free-form lens that produced an illumination uniformity of 78% with an efficiency of 77%. We used the developed LED light sources for field experiments in agricultural lighting. The figures of these tests showed positive effects with control flowering criteria and advantages of harvested products in comparison with the conventional LED sources. This allows our approach in this paper to be considered as an alternative candidate for highly efficient and energy-saving LED lighting applications.

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.

Adaptive Tool Path Planning Strategy for 5-Axis CNC Machining of Free Form Surfaces

2019 ◽  
Author(s):  
Hrishikesh Mane ◽  
S. S. Pande
Keyword(s):  
Tool Path ◽  
Cnc Machining ◽  
Memory Storage ◽  
Free Form ◽  
Cnc Machine ◽  
Planning Strategy ◽  
Part Quality ◽  
Tool Paths ◽  
Path Topology ◽  
Free Form Surfaces

Abstract This paper presents a curvature based adaptive iso-parametric strategy for the efficient machining of free form surfaces on 5-axis CNC machine using the flat end mill tool. One iso-parametric boundary of the surface is selected as the initial tool path. Set of cutter contact (CC) points are chosen adaptively on the initial tool path considering desired profile tolerance. Adjacent iso-parametric tool paths are computed adaptively based on the scallop height constraint unlike the traditional iso-parametric approach. The path topology is post-processed to generate the part program for 5-axis CNC machine in ISO format. The system was rigorously tested for various case studies by comparing the results with the traditional 5-axis iso-parametric tool path strategy, iso-scallop strategy and iso-planar strategy of a commercial software. Our system was found to generate efficient tool paths in terms of part quality, productivity and memory storage compared to the conventional strategies.

Sign in / Sign up

Export Citation Format

Share Document