Thermal transfer simulations, computed fluid dynamic solutions and finite element methods in general are vital sources of information about behavior of machine parts with heat loading. All these methods have common disadvantages, which include the requirements of a skilled engineer, hardware and software, and generally the high cost of computation. These problems are solved in this article. The reduction of costs is solved by a new tool, which uses simple macro-elements with predefined, parametric properties. These elements are able to describe cooling channels, heat transfers in bodies or identify the temperatures of heat sources. Computation by macro-element method takes a significantly shorter time with suitable accuracy. The macro-element method is suitable for customizing in a wide spectrum of thermal transfer cases. The article defines macro-elements, describes their implementation and the verification of the method.

The article summarizes basic research into thermal transfer simulations. Problems of thermal influence in mechanical systems are solved there. The first steps focus on matching simple heat-transfer samples with CAE software. Simple cases are performed in a real environment. Thermal values are measured. Cases are also solved using CAE software tools. Solutions are compared. CAE solutions are matched to real values. CAE results are verified or refuted. There are many differences between the options in the solvers, there are steady states and transient-run possibilities, etc. Software tools like Nastran, etc. need many coefficients to solve the problem. This procedure is able to identify specific conditions, fits the solver to the specific sample and performs CAE simulations to get real, verified results. For example, passive radiators heated by an induction heater are used for real tests. Temperature fields are measured by thermal camera and structural deformations by measuring displacement. These values are used in simulations and solved by finite elements method. Simulations are performed in Siemens NX10 software, supported by solvers Nastran, MAYA, and NX Multiphysics. Results are compared and matched in the simulation to acquire a more precise solution in the following steps All these steps are processed to get characteristics of thermal transfer simulation which will be useful in difficult examples of simulation machines, machine tools etc.Keywords: heat load; thermal flow simulation; FEM Verifying of thermal loadA simple simulation of the heat load was performed in the first part of the research. A small iron cylinder was heated by a high frequency induction heater. The cylinder was heated from 25°C to nearly 250°C as you can see on the Fig.1. The heat load was turned on for 60 seconds, and then it was cooled by radiation and natural convection. The temperature of the cylinder was logged by a thermocouple. The temperature was monitored in relation to time. Thermal fields were monitored by a thermal camera. The thermal camera was used to verify the optimum homogeneous warming. Four measurements were made. Three measurements of a cylinder with diameter 25 mm and 30 mm high are performed. Effective emissivity was guaranteed by paint with guaranteed emissivity (e = 0.95). This effect was simulated. Derivation of the measured curve provided the loading characteristic. The same loading characteristic is used in the simulation. That obtains two views, measured and simulated, as you can see in the Fig. 1. The results of the experiments are shown in the graphs Figs. 2. Heat load was measured in the experiment. Measuring determined heat load 219 W. For equivalent simulation was estimated heat load 220 W. Then was computed convection heat exchange. Measured exchange was 16.3 W and simulated heat exchange less, about 14 W. Cooling losses were calculated by derivation of curves in Fig. 2. -0578 -

Displacements of milling centres caused by thermal load is a vital issue of a present research. The Final element analysis, the computed fluid dynamic and other predicting tools are strong sources of information about thermo-mechanical behaviour of a machine. Validation and verification of a solution is required as many factors and coefficients influence the solution. The presented study describes the thermo-mechanical behaviour of a spindle of a milling centre. There is demonstrated the thermo-mechanical model and the verification is shown. Simulated data are compared with the measurement. Data generated by simulated options are processed. The goal of this processing is a sensitivity analysis of a thermo-mechanical system. Compensation of thermal displacements of machining spindles is currently a requested issue. Presented sensitivity analysis might help with identification of a critical area of a heat load. Improvements in these areas increase symmetry of warming-up, cooling and other heat distribution parameters. These thermal parameters influence structural displacements. Improvements decrease negative effects of heat loading, such as thermal dilatations and angular deviations. This approach leads to increase the quality and the performance of machining.

Many mechatronic systems operate with parts made of polymers. This cost-effective solution is also easy to design. Manufacturing is trivial for producers who produce millions of parts. The solution is more complicated when the fatigue and loading is a significant factor. The paper describes the development of polymer parts that are loaded by cyclic operation. The number of cycles in a specific application can be around 1 million. The specific case also deals with a corrosion environment around these components. Gasses in the environment cause degradation of material and failure of parts made of specific polymers. This interaction limits the choice of suitable materials. The mechanism operates in two directions which define the opening of a valve and free turn. Two variants of elastic valves were analysed. Loading states were simulated by final element methods. Internal stresses and contact stresses were analysed. Results were compared with long-term test results. The material creep and other material properties define the function of elastic parts after thousands of cycles. The technology of mould fabrication was analysed considering simplification and general effectivity of production. Prototype valves were printed by FDM 3D printer and tested. Prototype moulds were printed by SLA 3D printer, which produces high-temperature stable polymer. This procedure shows cost-effective prototype development and test procedures.

This paper deals with the simulation of CNC machine tools. The main focus is to develop a Case Study for a new virtual concept of Horizontal CNC Machine Tool. A virtual Machine Tool uses the main properties of a real machine. The goal is to simulate the functionality of the machine in virtual phases. This method is intended for complex and very expensive machines like Milling and Boring Machine Tools with numerous accessories. The current trend is to sell Machine Tools and equipment with complete technology of machining. Customers prefer a virtual Case Study of CNC technology. The idea of virtual prototyping is realized if the behaviour of the virtual Machine Tool is in compliance with real machine.