Non-Contact Device for Measuring Frequency Response Functions of CNC Machine Tools

Manufacturing ◽  
2003 ◽  
Author(s):  
Donald Esterling ◽  
F. Donald Caulfield ◽  
Aaron Kiefer ◽  
Gregory Buckner ◽  
Pavan Jaju

The frequency response function (FRF) of a CNC machine tool is composed of tool/toolholder/spindle dynamics, and plays an important role in determining the stability of high speed machining processes. This paper details the design, development and operational verification of a non-contacting, controllable, electromechanical actuator (EMA) for measuring the FRFs of tools mounted in CNC milling machines. Although standard modal testing methods are available and provide similarly accurate results, these test procedures are difficult to perform in machine shop environments and can require expensive equipment. The EMA developed as part of this research extends the capabilities of the NIST “best speeds device” to provide controllable, non-contacting excitation for modal tests on machine tools. This EMA device offers the advantages of being accurate, easy to use, and applicable to a wide variety of tools and operating conditions.

Author(s):  
Sepehr Zarifmansour ◽  
Rudolf Seethaler

Growing industrial demand for faster machine tools, makes feed-rate and trajectory optimization a challenging problem in machining processes. One of the most challenging machining operations for computer numerically controlled (CNC) machine tools is corner tracking. In this scenario, most of the conventional feed-rate optimization approaches sacrifice speed for accuracy. This paper, proposes a new feed-rate and trajectory optimization algorithm for CNC machines. At each corner of the trajectory, the presented algorithm regenerates the trajectory, using a circular move within a desired tolerance limit. Then, a new feed rate optimization method is employed, which enables the machine tool to travel at the maximum feasible velocity through the corners, while taking acceleration constraints into account. Experimental results for different desired tolerances indicate that the new algorithm achieves significantly shorter travel times than the theoretical minimum time trajectory with zero tolerance.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2913
Author(s):  
Rafał Gołębski ◽  
Piotr Boral

Classic methods of machining cylindrical gears, such as hobbing or circumferential chiseling, require the use of expensive special machine tools and dedicated tools, which makes production unprofitable, especially in small and medium series. Today, special attention is paid to the technology of making gears using universal CNC (computer numerical control) machine tools with standard cheap tools. On the basis of the presented mathematical model, a software was developed to generate a code that controls a machine tool for machining cylindrical gears with straight and modified tooth line using the multipass method. Made of steel 16MnCr5, gear wheels with a straight tooth line and with a longitudinally modified convex-convex tooth line were machined on a five-axis CNC milling machine DMG MORI CMX50U, using solid carbide milling cutters (cylindrical and ball end) for processing. The manufactured gears were inspected on a ZEISS coordinate measuring machine, using the software Gear Pro Involute. The conformity of the outline, the tooth line, and the gear pitch were assessed. The side surfaces of the teeth after machining according to the planned strategy were also assessed; the tests were carried out using the optical microscope Alicona Infinite Focus G5 and the contact profilographometer Taylor Hobson, Talysurf 120. The presented method is able to provide a very good quality of machined gears in relation to competing methods. The great advantage of this method is the use of a tool that is not geometrically related to the shape of the machined gear profile, which allows the production of cylindrical gears with a tooth and profile line other than the standard.


Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4506 ◽  
Author(s):  
Hyungjung Kim ◽  
Woo-Kyun Jung ◽  
In-Gyu Choi ◽  
Sung-Hoon Ahn

In the new era of manufacturing with the Fourth Industrial Revolution, the smart factory is getting much attention as a solution for the factory of the future. Despite challenges in small and medium-sized enterprises (SMEs), such as short-term strategies and labor-intensive with limited resources, they have to improve productivity and stay competitive by adopting smart factory technologies. This study presents a novel monitoring approach for SMEs, KEM (keep an eye on your machine), and using a low-cost vision, such as a webcam and open-source technologies. Mainly, this idea focuses on collecting and processing operational data using cheaper and easy-to-use components. A prototype was tested with the typical 3-axis computer numerical control (CNC) milling machine. From the evaluation, availability of using a low-cost webcam and open-source technologies for monitoring of machine tools was confirmed. The results revealed that the proposed system is easy to integrate and can be conveniently applied to legacy machine tools on the shop floor without a significant change of equipment and cost barrier, which is less than $500 USD. These benefits could lead to a change of monitoring operations to reduce time in operation, energy consumption, and environmental impact for the sustainable production of SMEs.


2018 ◽  
Vol 224 ◽  
pp. 01020 ◽  
Author(s):  
Georgi M. Martinov ◽  
Akram Al Khoury ◽  
Ahed Issa

Nowadays, there is a big demand on using small sized CNC machine tools, which have low price tag, wide range of implementations, low manufacturing costs and can be used for educational purposes. These machines can achieve casual manufacturing routines, like milling and drilling in applications, where there is no need for high speed performances and super quality of products. In this work, we proposed a model of CNC for these machines and analysed its components and efficiency. The model consists of three main layers: CNC system (application layer), ARM based microcomputer as CAN master and controller (connecting layer) and Servo-Drive Step Motors (actuating layer).


2014 ◽  
Vol 556-562 ◽  
pp. 1413-1416 ◽  
Author(s):  
Tian Xiang Hu ◽  
Li Bing Zhang ◽  
Ting Wu ◽  
Feng Li Huang

To overcome some shortcomings of the linear Acc/Dec approach and the traditional S-curve Acc/Dec method, a novel velocity planning approach is proposed for CNC machine tools in this paper. The velocity planning model based on moving average technology is structured. The presented approach is used to make velocity planning for the CNC system. Comparing with the linear Acc/Dec algorithm, the presented method greatly improves motional smoothness of the linear Acc/Dec approach and reduces the complexity of the traditional S-curve Acc/Dec algorithm, which is more suitable for high-speed and high-precision CNC machine tools. The proposed approach is tested by simulation and experimentation. Simulation and experimental results have shown that the proposed method can significantly improve the motional smoothness and consumes less resource and shortens processing time for the CNC system.


2013 ◽  
Vol 690-693 ◽  
pp. 1983-1987
Author(s):  
Shui Sheng Chen ◽  
Shuang Qiang Li ◽  
Zhong Ping Hua ◽  
Chen Dai

Large heavy-duty CNC machine tools commonly used rolling bearing as Main bearing. This paper analyses the causes of Main bearing fever deeply, pointing out the mechanism of the bearing heating; combined with the practical application of the TK6926 landing CNC milling and borings main bearing, putting forward the main method to reduce the rolling bearing fever and achieved good results.


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