دانلود کتاب چهارمین کنفرانس بین‌المللی مسائل حرارتی در ابزارهای ماشین‌

Machining is energy conversion. All energy supplied to the machine tool ends in heat, also the intentionally provided energy to the process zone. The only exception is the tiny amount incorporated in the state change of the material as workpiece and chips. Understanding the heat conversion and flow in the process zone is of crucial importance for the correct setup of the respective process, for the wear of the tool, the process signature onto the material and for the operation of the machine tool. Machining processes therefore cannot be discussed, the process result not predicted without taking the energy conversion and the development of temperature as the most important state variable into account. Temperature and the temperature time profile on the material decide on the state and microstructure of the material and the properties and quality of the manufactured part. A significant effort in machining is therefore dedicated to the attempt to control the temperature in the process zone by cooling but still more efficient by correct process setup, which requires besides experience a good deal of simulation technology. From the energy release in the process zone but also from necessary drives and the environment, a manufacturing machine is influenced. Thermal distortion and thermal errors in machine tools are the most frequent reasons for defective parts. When the knowledge- and technology transfer organisation inspire AG started to grow in 2002 and IWF of ETH Zürich restarted, the most urgent whish of Swiss machine tool manufacturers according to an industry survey was to develop means against thermal distortions of machines. CIRP colleague Jim Brian stated “whatever you design, it becomes a thermometer”. The next milestone in this topic was the CIRP-keynote paper of 2012 on “thermal issues in machine tools” prepared by a large scientific group since 2009, collecting the relevant state of the art at that time and initiated a lot of research throughout the world. The International Conference on Thermal Issues in Machine Tools, ICTIMT, a conference series having taken place in Dresden, Prague, Dresden, and now in Zurich was launched out of the SFB TR 96 funded by the German research foundation (DFG) by the involved scientists and as a forum to discuss findings and developed methods both for the heat release in the process zone and the thermal influence on machine tools. As the physics of heat transfer and thermal elongation is invincible, three different approaches remain: thermo-energetically optimized design, tempering of shop floors and machine tools and thermal compensation using the axes of the machine and as required auxiliary compensation axes with small strokes. The first is generally recommended, whatever comes afterwards. Tempering is straightforward and therefore the most frequently applied method, but also the least sustainable one, as it consumes energy and/or requires startup time partly even with scrap production to reach the thermal equilibrium due to the inbuilt heat sources. Compensation especially while using the machine axes is the most elegant way for better accuracy. Thermal compensation replaces resource expenditure by a knowledge-based approach, which was the general guideline for the EU Horizon2020 program. Thermal compensation is one of the rare cases, where sustainability and increase of accuracy coincide. General outline of compensation methods is based on three different functions and can thus be described with a morphological box: information supply by sensors and the CNC-program, control system based on a machine model and actuation like machine axes or auxiliary heat sources and sinks. The measurement of thermal displacements is a challenge as such, as they are superposed with large strokes of the machine tool. But also the isolation and identification of individual errors are a task to be solved. An important topic today is the influence of fluidic media and thus of hollow spaces especially but not only the working area with the influences of process and process cooling. Modelling for compensation requires sufficient precise models that are capable to deliver correction data in real time. This then is the domain of meta models, which today are frequently based on artificial intelligence (AI) in terms of self-learning compensation models. Physics-supported AI in most cases provides the best tradeoff between effort and success. For both topical blocks machine and process CFD simulation becomes important and still suffers from the bad predictability of heat transfer coefficients to the machine body for the modelling of the machine and to tool, workpiece and fluid for the simulation of the process behavior. Careful measurements are crucial technologies and in most cases need to be supported by modelling and simulation because the accessibility of the process zone or the area of interaction is limited. With all efforts in compensation of manufacturing machines only deterministic errors can be compensated. This emphasizes that a design for compensation must generate machine tools with excellent repeatability as primary goal. Increasing the repeatability, increasing the predictability by enhancing models and simulation approaches and enhancing the measurability of thermal deviations as well as tracing them back to their origin are the tasks for future progress in the field to achieve still higher accuracy of machining results. A vital role plays the cooperation between industry and academia in this topic. Provide understanding and explore possible approaches is the domain of academia, implementation, integration of sensors and providing powerful interfaces to the control as well as long term experience under real industry conditions the one of the industry. To promote and deepen this collaboration are one of the most important goals of the ICTIMT 2025 conference We would like to sincerely thank all scientists and industrial partners, the CIRP conformance committee, the scientific committee, having all contributed to the ICTIMT2025 in Zurich.