A theory to support the high-speed computer numerical control machining of corner profiles

Author(s):  
M Loftus ◽  
D Wang

This paper presents a new mathematical model for the motion of a milling cutter as it generates an obtuse corner profile. The model describes the different phases of cutter contact and can be used to optimize the speed of machining and to protect the cutters from adverse loading conditions in high-speed milling applications.

2019 ◽  
Vol 26 (7-8) ◽  
pp. 387-398 ◽  
Author(s):  
Daxian Hao ◽  
Wei Wang ◽  
Zhaoheng Liu ◽  
Chao Yun

It has been fully demonstrated that the regenerative chatter theory is applicable for predicting chatter-free milling parameters for computer numerical control machine tools, but researchers are still arguing whether it is effective for robotic milling processes. The main reason is that the robot’s modes greatly shift, depending on its varying dynamic parameters and joint configurations. More experimental investigations are required to study and better understand the mechanism of vibration in robotic machining. The present paper is focusing on finding experimental support for chatter-free prediction in robot high-speed milling by the regenerative chatter theory. Modal tests are first conducted on a milling robot and used to predict stability lobes by zeroth order approximation. A number of high-speed slotting tests are then carried out to verify the prediction results. Thus, the regenerative chatter theory is proved to be also applicable to robotic high-speed milling. Furthermore, low-frequency modes of the robot structure are investigated by more modal experiments involving a laser tracker and a displacement sensor. The low-frequency modes are identified as the main part of the prediction error of the zeroth order approximation method, which could also be dominant in low-speed robotic milling processes. In addition, robots are different from computer numerical control machines in terms of stiffness, trajectory following error, forced vibration, and motion coupling. These long-period trend terms have to be carefully taken into account in the regenerative chatter theory for robotic high-speed milling.


2019 ◽  
Vol 17 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Wen-Bin Zhong ◽  
Xi-Chun Luo ◽  
Wen-Long Chang ◽  
Yu-Kui Cai ◽  
Fei Ding ◽  
...  

Abstract Driven by the ever increasing demand in function integration, more and more next generation high value-added products, such as head-up displays, solar concentrators and intra-ocular-lens, etc., are designed to possess freeform (i.e., non-rotational symmetric) surfaces. The toolpath, composed of high density of short linear and circular segments, is generally used in computer numerical control (CNC) systems to machine those products. However, the discontinuity between toolpath segments leads to high-frequency fluctuation of feedrate and acceleration, which will decrease the machining efficiency and product surface finish. Driven by the ever-increasing need for high-speed high-precision machining of those products, many novel toolpath interpolation and smoothing approaches have been proposed in both academia and industry, aiming to alleviate the issues caused by the conventional toolpath representation and interpolation methods. This paper provides a comprehensive review of the state-of-the-art toolpath interpolation and smoothing approaches with systematic classifications. The advantages and disadvantages of these approaches are discussed. Possible future research directions are also offered.


2011 ◽  
Vol 105-107 ◽  
pp. 2217-2220
Author(s):  
Mu Lan Wang ◽  
Jian Min Zuo ◽  
Kun Liu ◽  
Xing Hua Zhu

In order to meet the development demands for high-speed and high-precision of Computer Numerical Control (CNC) machine tools, the equipped CNC systems begin to employ the technical route of software hardening. Making full use of the advanced performance of Large Scale Integrated Circuits (LSIC), this paper puts forward using Field Programmable Gates Array (FPGA) for the functional modules of CNC system, which is called Intelligent Software Hardening Chip (ISHC). The CNC system architecture with high performance is constructed based on the open system thought and ISHCs. The corresponding programs can be designed with Very high speed integrate circuit Hardware Description Language (VHDL) and downloaded into the FPGA. These hardening modules, including the arithmetic module, contour interpolation module, position control module and so on, demonstrate that the proposed schemes are reasonable and feasibility.


2008 ◽  
Vol 392-394 ◽  
pp. 793-797
Author(s):  
Bin Jiang ◽  
Min Li Zheng ◽  
Fang Xu

Based on analyses of cutting heat and temperature in high speed milling, to construct a model of critical cutting speed for high speed milling cutter, find out influencing factor of critical cutting speed, and put forward optimization method of high speed milling cutter based on critical cutting speed. The results indicate that chip conducts a majority of cutting heat along with increase of cutting speed, feed speed and the rake of cutter. Cutting heat which workpiece conducts gradually diminishes when heat source accelerates. When cutting performance of cutter satisfies requirements of high speed milling, the proportion of cutting heat which workpiece conducts approaches its maximum as cutting speed comes to critical cutting speed. To optimize high speed face milling cutter for machining aluminum alloy according to critical cutting speed, the cutter takes on better cutting performance when cutting speed is 2040m/min~2350m/min.


2011 ◽  
Vol 291-294 ◽  
pp. 710-714
Author(s):  
Jun Min Xiao ◽  
Ying Xu

Mold steel 3Cr2Mo has been used widely in manufacturing of plastic mold formed parts, owing to fine mechanical properties. However, it is also very difficult to cut mold formed parts of steel 3Cr2Mo due to high hardness. Ordinary NC cutting method of steel 3Cr2Mo is unable to relate to modern mold manufacturing due to bad cutting property, so it is extremely significant for improving cutting property of steel 3Cr2Mo to study the high speed milling technology. On the basis of improving the traditional cutting force formula, the mathematical model of high speed milling force for steel 3Cr2Mo was derived and solved by using the experimental data and constructing matrix equation based on MATLAB software. Comparing with experimental data, the error of mathematical model of high speed milling force could be controlled within 6 percent. Due to high precision the model of high speed milling force can meet practical engineering requirement and has great value in the fields of CAD/CAM/CAE.


2012 ◽  
Vol 226-228 ◽  
pp. 98-101
Author(s):  
Hong Qing Lv ◽  
Wei Xiao Tang ◽  
Qing Hua Song ◽  
Shan Shan Sun

A review of research on the vibration control technology inspiration from the biological vibration damping mechanisms is described. First the important concept and background of the bionic vibration damping technology are briefly introduced. Then the basic theories and its applications in the engineering fields are elaborated from three aspects: vibration damping mechanisms of the creatures own the good ability to withstand the ambient vibrations, mechanical models of biological prototypes and its application progress in the practical occasions.


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