Capability of measurement with a touch probe on CNC machine tools

Purpose: This paper presents a multi-criteria assessment methodology to evaluate the remanufacturability of converting conventional surface grinding machines into CNC machine tools. Methodology: Conventional surface grinding machines remanufactured into CNC machine tools were analyzed and classified into five remanufacturing alternatives. A multi-criteria assessment model incorporating cost, time, accuracy, reliability, processing shape complexity, and ergonomics was developed. The importance of criteria and performance of alternatives were weighted through machine tool remanufacturing experience analysis and comparative literature review. Results: The Remanufacturability Index (RI) for remanufactured conventional surface grinding machines ranges from 0.637 to 0.999 based on the level of CNC upgrades from 2-axis to 5-axis configurations. Higher-axis remanufactured machines showed greater feasibility. Theoretical Contribution: This study provides a quantitative methodology to assess the technical, economic, and environmental feasibility of remanufacturing conventional machines into CNC machine tools. It extends the application of multi-criteria decision making to the field of machine tool remanufacturing. Practical Implications: The proposed methodology can guide small and medium-sized manufacturers in making decisions to upgrade their conventional machines to CNC through remanufacturing. It helps evaluate the benefits and risks of different upgrade configurations to support the implementation of machine tool remanufacturing in practice. Sustainable Development Goals (SDGs): SDG 9: Industry, Innovation and Infrastructure; SDG 12: Responsible Consumption and Production; SDG 8: Decent Work and Economic Growth; SDG 13: Climate Action; SDG 4: Quality Education

Estimation and analysis of energy consumption for machine tool is the basis of energy efficiency improvement. The existing researches of energy model focus on the static modelling of energy consumption, and a few study of dynamic energy consumption model focus on the dynamic characteristics of operating states of machine tool, the study of dynamic characteristics of energy sources, especially multi energy sources of a CNC machine tool is scarce. Based on the characteristics of CNC machine tool(e.g. multi-energy sources, dynamically changed machining tasks and process parameters), a method for modeling the dynamic energy characteristics of multi-energy sources in CNC machine tool is proposed. The dynamic characteristics of energy consumption process of machine tool are analyzed. On this basis, the colored timed object-oriented Petri net(CTOPN) integrated with virtual component method is applied to model the dynamic energy consumption of machine tool. The CTOPN model is used to describe the dynamic characteristics of operating states of machine tool and multi-energy sources. The virtual component method is used to describe the dynamic characteristics of multi energy sources which is influenced by process parameters. The virtual component model is driven by the information of activity transitions in CTOPN model. The case study shows that the proposed energy model is effective and can provide fundamental support for dynamic energy consumption forecasting, comprehensive depiction of the energy profile and quantitative analysis of influencing factors and so on during the operation of a CNC machine tool, which has significance in practice.

The CNC Machine Tools with high efficiency, high precision and high stability is the inevitable trend of the modern manufacturing industry development.This development trend puts forward the extremely high request to the CNC machine tool error compensation technology. However, the error of CNC machine tools have a variety of reasons, these errors affect each other, which leads to the inevitable error. At the high efficiency processing, we must ensure the high stability and high precision of the machine tool. Which requires the error compensation function to maintain high stability and high compensation accuracy, when the CNC machine tool is under the action of high speed and dynamic load. The rapid development of computer technology provides us with more possibilities to solve error compensation. CNC machine tool error compensation technology based on computer is an important means to improve the machining accuracy in the manufacturing industry, which reduce the error in the production process and increase the production efficiency. This paper firstly analysis the error classification and error source percentage of CNC machine tools. And then it analysis the movement error when the CNC machine tools is working. Finally, it puts forward the key technique and application of error compensation based on computer.

To cope with the increasingly competitive and demanding markets, CNC machine tool company needs a new form of development that focuses on two core competency factors: ‘process’ and ‘knowledge’. This study presents a knowledge-centric process management framework for the CNC machine tool design and development (D&D) with the integration of process and knowledge. Requirements for the framework are generated based primarily on the nature of the machine tool design practice. The proposed framework consists of process integration model, process simulation, process execution and knowledge objects management modules. Each of these modules is elaborated to support the knowledge-centric machine tool development process management. Finally, the prototype development is presented. Results of this study facilitate the knowledge integration in CNC machine tool D&D, and thus increase machine tool development capability, reduce development cycle time and cost, and ultimately speed up the effectiveness and ensure the excellent machine tool development.

Modular design is one of the modern design methods used for the development of CNC machine tools, which can shorten the product design and manufacturing cycle, and improve the product quality and reliability. Module coding is one of the important steps in carrying out the modular design. Aiming at the effective application and management of the module codes in the enterprise informatization, this paper studied and developed the module coding system oriented on CNC machine tools. First, this paper analyzed the purpose of the module coding and put forward the basic rules of the module coding. Then, considering the characteristics of the modular design for CNC machine tools, this paper determined the coding scheme fit to the requirements of the machine tools enterprise. Next, based on the popular B/S structure and J2EE platform, this paper completed the function design and software development of the module coding system. At last, the development environment and example interface were introduced. The application of this module coding system in one machine tools enterprise proved that it was powerful to promote the application of modular design and the realization of the enterprise informatization.

In the process of thermal error modeling of machine tools, the error information is not transparent and the data characteristics are not comprehensive. The Dijkstra algorithm provides an optimization for the classical algorithm, and improving the accuracy of machine tools is an important issue in advanced manufacturing technologies. In this paper we study two methods of error avoidance and error compensation. For CNC machine tools, computer real-time error compensation technology is an economical and effective basic approach. The application of the folded Dijkstra algorithm to realize the compensation technology of the full error model of geometrical machine tool including geometric error and thermal error is put forward. The practical results show the geometric error and thermal error are compensated on 3-axis and 4-axis CNC machine tools, and the accuracy of the error model and the practicality of the compensation method.

With the continuous development and application of digital technology, CNC machine tools have become the main production equipment in the manufacturing industry. CNC machine tools are developed on the basis of the theory of CNC technology, but it is necessary to design the system with some computer-aided design to achieve automatic management. This paper analyzes the computer aided technology and numerical control technology applied in the numerical control machine tool error analysis of the practical application of, and by using multiple regression analysis method for the computation of the efficiency and quality of application of computer aided technology and numerical control technology of CNC machine tool error analysis on the efficiency and quality of data with 15% and 45% respectively than traditional CNC machine analysis, proves that computer aided technology and numerical control technology for numerical control machine tool error analysis plays an important role.

In CNC machine tools, transient temperature variation in the headstock assembly is the major contributors for spindle thermal error. The compensation of thermal error is critical for ensuring the accuracy of machine tool. The performance of an error compensation system depends largely on the accuracy and robustness of the thermal error model. In the present work, a robust thermal error model is developed for minimizing the error in lateral direction of the spindle which significantly influences the geometrical accuracy of the workpiece. Analysis-of-variance (ANOVA) is applied to the results of the experiments in determining the percentage contribution of each individual temperature key point against a stated level of confidence. Based on the analysis of existing approaches for thermal error modeling of machine tools, an approach of LASSO (least absolute shrinkage and selection operator) is proposed in order to avoid the multi collinearity problem. The proposed method is an innovative variable selection method to remove redundant or unimportant temperature key points in the linear thermal error model and minimize the residual sum of squares. The predictive error model is found to have better robustness and accuracy in comparison to the combination of grey correlation and step wise linear regression for error compensation of CNC lathe. Keywords: Analysis Of Variance (ANOVA), CNC Machine Tool, Grey Correlation Analysis (GCA), Headstock Assembly, LASSO Regression, Mean Absolute Deviation (MAD), Mean Square Error (MSE), Robustness, Standard Deviation (SD), Thermal Error.

With the rapid development of modern industry and industrial upgrading, machine tool performances such as high machining speed, high machining accuracy, and high reliability have gradually become the development trend of high-end CNC machine tools. The vibration characteristics of the machine structure become an important factor affecting the machining quality and processing efficiency of the machine tool. Since the movable parts of the CNC machine tool will impact the machine structure itself during the acceleration and deceleration process, by identifying the structural vibration response signal, the modal parameters of the machine tool in the running state can be obtained, called active excitation mode analysis. However, this method still has certain defects in theory and experiment. For example, the excitation principle is not theoretically explained, and the excitation energy and the frequency band of the method are limited. To solve these problems, this paper conducts more comprehensive research on the modal analysis method of CNC machine tools based on operational impact excitation. The main research contents are as follows: considering the rigid body motion of the table and the elastic collision of the screw nut pair, the impact excitation is modeled and analyzed. We have introduced a response-based modal identification algorithm. The influence factors of impact excitation energy and frequency band were studied from both theoretical and experimental aspects. Design three excitation sequences for workbench excitation and spindle excitation, respectively, analyze the vibration response and modal identification of the machine tool structure under different excitation sequences. It is verified that the method does not depend on the specific excitation sequence, as long as it satisfies the random characteristics. Aiming at the problem of insufficient excitation energy of the machine tool structure for single-component impact excitation, a multi-component joint impact excitation method based on the principle of multi-point excitation technology is proposed. The design experiment is carried out to verify the impact excitation method, which shows that the joint excitation has better excitation effect than single-axis excitation.

An approach to identify and select optimal temperature-sensitive measuring points for thermal error compensation modeling in CNC machines: A case study using cantilever beam

The quality of the workpiece produced by CNC machine tool is primarily due to the degree of precision and stability of the machines themselves. In general, the quality measures the degree of conformity of a part with predefined dimensions and geometric specifications. However, a simple measure does not identify the contribution of each source of error affecting the room. It is therefore important to analyze the technological aspects of machine tools, numerical control and the influence of the process. In order to give the issues of precision machine tools a conceptual dimension, it is preferable to classify the affecting factors. Errors can be classified according to the working phase during which the sources that generate them are active. During the preparation phase, errors can be associated with setting procedures, errors in the programming, and machining programs converted into machine language. During the machining phase, the sources of error which affect the accuracy are much more varied. Their effects can be considered as the combination of the individual contributions of all the elements constituting the system machine tool cutter, as well as the interaction of this system with the process. The purpose of this article is to present a study on the evaluation of the geometrical errors of a machine tool EMCO PC MILL 155 that exists within our laboratory, which are due to cut efforts.

Slide level impacts the CNC machine tool performance. The deterioration of slide level will result in the torsional vibration of a feed-axis control system and lower the CNC machine tool control precision. It is necessary to investigate the rapid evaluation technology for the slide level of a CNC machine tool. In this paper, a new type of rapid evaluation method for machine tool slide level is proposed, which uses the linear scale, motor encoder, and AC servo motor current/output torque. To acquire level information, the built-in sensors test principle is profoundly investigated, and the mathematical model between the slide level and the measured data is established. In addition, two different level identification methods are comparatively analyzed. The analysis results of experiments show that it is simple, rapid, feasible, and reliable to use built-in sensors information for evaluating slide level.

Big data technology has strongly promoted the development of social productive forces, and commercial applications are continuously expanding in all walks of life. It also uses the power of Internet technology to provide strong technical support for the development of the entire industry. In terms of the production of CNC machine tools, due to the use of big data technology, CNC machine tools have been rapidly produced on a large scale, which has played an important role in the upgrading of the entire CNC machine tools and the improvement of quality and efficiency. This article takes the technology of big data acquisition bus for CNC machine tools as the topic, through researching and discussing its concept, meaning and related strategies, in order to effectively improve the production scale and reference.Chinese Library Classification number : TP23 Document Identification code : A

As a typical manufacturing equipment, CNC machine tool (CNCMT), which is the mother machine of industry, plays an important role in the new trend of smart manufacturing. As the requirement of smart manufacturing, the abilities of its self-sensing, self-prediction and self-maintenance are necessary. In order to make CNCMT become more intelligent, a research about Digital twin (DT) for CNCMT is conducted. In this research, a multi-domain unified modeling method of DT is established, a mapping strategy between physical space and digital space is explored, and an autonomous strategy of DT is proposed. These methods can optimize the running mode, reduce the sudden failure probability and improve the stability of CNCMT. Finally, this paper provides a demonstration of DT model building and using strategy in fault prediction and diagnosis for CNC milling machine tool.

Uncertainty assessment for on-machine tool measurement: An alternative approach to the ISO 15530-3 technical specification