Milling Machining Center Research Articles

Structure Improvement and Optimization of Gantry Milling System for Complex Boring and Milling Machining Center

To enhance the efficiency and machining precision of the TX1600G complex boring and milling machining center, a study was conducted on the structure of its gantry milling system. This study aimed to mitigate the influence of factors such as structural quality, natural frequency, and stiffness. The approach employed for this investigation involved mechanism topology optimization. To initiate this process, a finite element model of the gantry milling system structure was established. Subsequently, an objective function, comprising strain energy and modal eigenvalues, was synthesized. This objective function was optimized through multi-objective topology optimization, taking into account certain mass fraction constraints and considering various factors, including processing technology. The ultimate goal of this optimization was to create a gantry milling structure that exhibited high levels of dynamic and static stiffness, a superior natural frequency, and reduced mass. To validate the effectiveness of these topology optimization results, a comparison was made between the new and previous structures. The findings of this study serve as a valuable reference for optimizing the structure of other components within the machining center.

Topology Optimization and Analysis of the Compound Boring and Milling Machining Center TX1600g Bed Structure

The overall performance of the machine tool bed of the boring and milling center has an important impact on the accuracy of the overall machining, in order to improve the machining accuracy and structural performance of the overall machine tool, the structure optimization design of the machine bed is carried out for the TX1600g composite boring and milling center. The maximum static displacement and mass of the bed were used as the evaluation index to optimize the topology and structure of the bed. An orthogonal test of 5 factors and 5 levels was designed, the maximum displacement generated by different positions in work was analyzed, the frequency under this working condition was explored, and modal analysis was conducted. The Hyperwork selective variable density method is used to optimize the beam structure with multiple objective topologies. By comparing and optimizing the performance parameters of the front and rear beams, the total static displacement is reduced by 9%, which proves the effectiveness of this method to solve the multi-objective optimization problem.

МОДЕРНИЗАЦИЯ ТЕХНОЛОГИЧЕСКОГО ПРОЦЕССА ИЗГОТОВЛЕНИЯ ТОНКОСТЕННОЙ ЗАТВОРНОЙ РАМЫ ИЗ ЛИСТОШТАМПОВАННОЙ ЗАГОТОВКИ

A comparative analysis of the technological processes of machining a part from a stamped workpiece using universal equipment and a CNC milling machining center is considered. Route technological processes have been developed. A diagram of a special fixture for machining on a CNC milling center Tongtai TMV-1050QII is presented. Comparative analysis of labor input is made.

Identification of the self-oscillating mode in metal-cutting machines in the production of agricultural machinery

The production of modern agricultural machinery includes various technological chains machining workshops, consisting mostly of turning and milling machining centers. The influence of self-oscillations on the dynamic characteristics of mechanisms for various purposes is due to the increased requirements for the quality and reliability of products of modern machines and units. Timely detection and reduction of the impact of oscillatory processes makes it possible to qualitatively optimize the design of mechanisms. A special role in the process of operation is exerted by self-oscillations on metal-cutting machines in the processing of materials. The consequence of the self-oscillatory process is a violation of the performance of a metal-cutting machine, expressed in a parametric (accuracy) failure. In this paper, the possibility of using parametric spectral analysis for the early identification of a self-oscillating process in hexapod machine tools was evaluated, for which the objective function was determined, i.e. the value of the damping coefficient of the dynamic system.

Cutting Performance of Multicomponent AlTiZrN-Coated Cemented Carbide (YG8) Tools during Milling of High-Chromium Cast Iron

In order to improve the cutting performance of cemented-carbide (YG8) tools during the milling of high-chromium cast iron, AlTiZrN coating was deposited on the surface of YG8 samples and milling tools by physical vapor deposition (PVD) technology. The micromorphology and mechanical properties of the coating were studied by the experimental method, and the cutting performance of the coated tools was tested by a milling machining center. The results show that the AlTiZrN coating presents the face-centered cubic (fcc) structure of TiN. The average microhardness is 3887 HV0.05. The bonding strength between the coating and the substrate meets the standard HF3 and is up to the requirements. The coefficient of friction (COF) of the coating is about 0.32. AlTiZrN coating can significantly improve the life of cemented-carbide tools. At cutting speeds of 85, 105, and 125 mm/min, the lives of the AlTiZrN-coated tools increased by 20.7%, 22.4%, and 35.2%, respectively, compared with the uncoated tools. Under the same cutting condition, AlTiZrN-coated tools have better cutting and chip-breaking performance than uncoated tools. With the increase in cutting speed, the workpiece chips produced by AlTiZrN-coated tools are smaller and more uniform, and the scratches on the machined surface are smoother. Therefore, at higher cutting speeds, AlTiZrN-coated tools have more advantages in life and cutting performance than that of uncoated tools. During the cutting process, the wear mechanisms of the AlTiZrN-coated tools mainly included friction, oxidation, and bonding, while oxidation and bonding wear were the main wear mechanisms in the later stage of wear.

Investigation of Hadfield Steel Machinability in Milling Operations

Hadfield steel is widely used in the manufacture of machines and mechanisms operating in harsh conditions. When machining Hadfield steel parts, problems are due to the strain hardening. The article studies the influence of cutting modes on steel hardness, tool thrust and surface roughness when milling Hadfield steel using cutters with replaceable inserts. The experiments were conducted on a milling machining center using high-productivity cutting tools. The optical roughness measuring method was applied. Hardness was measured with a portable hardness tester before and after milling. The article describes experimental results that show the dependence of the output machining parameters on the cutting speed and feed per tooth. The influence of cutting data on tool life in a finish milling operation was identified. The results will help to improve the quality and productivity and increase the tool life in roughing and finishing Hadfield steel parts.

Modelling of machining center vibration stability by the D-partitions method

The stability of operation, vibration-free processing of products various types at high-speed machining centers suggests the improvement of research in the field of the dynamics of machine tools and their main forming units. The three-dimensional models of the forming spindle node and the corner table of the machining center for the drilling-milling-boring type in the CAD environment KOMPAS-3D have been developed. An algorithm for analyzing the dynamic quality of the machine elastic parts based on the constructed static and frequency formular in the mathematical environment MAPLE is proposed. Programs have been developed and graphs of the main frequency characteristics and the hodograph of the transfer function for the spindle node in the specialized Signal Processing module have been obtained. The method of D-partitions using to estimate the vibration stability of the forming units on an example of 4 coordinate milling machining centers is introduced. Experiments on two variants of technological adjustments with different dimensions of the tool block (the cantilever part of the spindle assembly) were carried out. The analysis of stability in the plane of the cutting process optimized parameter (specific cutting force) was carried out. The region and the boundary of the stable functioning of the machine and, on this basis, the optimum modes of machining by the criterion of vibration stability are revealed.

Digital twin control of multi-axis wood CNC machining center based on LinuxCNC

This paper presents an application of an open architecture control system implemented on a multi-axis wood computer numerical control milling machining center, as a digital twin control. The development of the digital twin control system was motivated by research and educational requirements, especially in the field of configuring a new control system by “virtual commissioning”, enabling the validation of the developed controls, program verification, and analysis of the machining process and monitoring. The considered wood computer numerical control (CNC) machining system is supported by an equivalent virtual machine in a computer-aided design and computer-aided manufacturing (CAD/CAM) environment, as well as in the control system, as a digital twin. The configured virtual machines are used for the verification of the machining program and programming system via machining simulation, which is extremely important in multi-axis machining. Several test wood workpieces were machined to validate the effectiveness of the developed control system based on LinuxCNC.

Layout Design of Stiffened Plates for Large-Scale Box Structure under Moving Loads Based on Topology Optimization

As the main load-bearing structure of heavy machine tools, cranes, and other high-end equipment, the large-scale box structures usually bear moving loads, and the results of direct topology optimization usually have some problems: the load transfer skeleton is difficult to identify and all working conditions are difficult to consider comprehensively. In this paper, a layout design method of stiffened plates for the large-scale box structures under moving loads based on multiworking-condition topology optimization is proposed. Based on the equivalent principle of force, the box structures are simplified into the main bending functional section, main torsional functional section, and auxiliary functional section by the magnitude of loads and moments, which can reduce the structural dimension and complexity in topology optimization. Then, the moving loads are simplified to some multiple position loads, and the comprehensive evaluation function is constructed by the compromise programming method. The mathematical model of multiworking-condition topology optimization is established to optimize the functional sections. Taking a crossbeam of superheavy turning and milling machining center as an example, optimization results show that the stiffness and strength of the crossbeam are increased by 17.39% and 19.9%, respectively, while the weight is reduced by 12.57%. It shows that the method proposed in this paper has better practicability and effectiveness for large-scale box structures.

Synthesis of a deforming-cutting mill design

The article is devoted to the synthesis of a new threading tool used to form internal threads in products made of aluminum alloys. As a rule, when machining internal threads in complex parts, the manufacture of which is carried out at milling machining centers, thread mills are used. This is due to low reliability of threading operations where classic marking tools are used, which are unacceptable for parts that have high cost at this time. In addition, when processing products made of aluminum alloys, there are features related to the presence of porosity in the material and ‘tears’ on the treated surface, the nature of which is associated with the cutting process. This degrades such an operational parameter of threaded joints as tightness. To solve these problems, the design of a new tool, a deforming-cutting mill, was proposed on basis of morphological analysis and synthesis, and the combined machining principle was taken as a basis for its creation.

Study on Mechanical and Electrical Coupling characteristics of Milling system based on CMAC-PID Compound Control

Taking boring and milling machining center as the research object, analyze and optimize the dynamic characteristics of milling control system. Use Simulink software to create mathematical model and simulate the dynamic characteristics of milling control system. Based on the theory of CMAC, consider the theory of the CMAC-PID compound control in the way of M function in Simulink Control language. Apply the theory, calculate the relevant parameters of milling system and model its transfer function, and all the parameters are solved by CMAC-PID compound control in Simulink. Verify the optimization of milling control system, and obtains the method of optimizing the mechanical and electrical coupling characteristics based on the CMAC-PID compound control theory.

Badania efektywności ekonomicznej oprzyrządowania technologicznego wydłużającego łańcuchy kinematyczne obrabiarek sterowanych numerycznie

The article describes the selection of machining holders included in the so called special machining fixture-tools. The equipment presented in the work is readily used by technologists as a solution extending the kinematic chain of the machine tool. It enables multi-axis machining (from many sides) using one item clamping. This paper presents the calculation of productivity and its growth through the use of special equipment. The research was carried out for medium-volume production, which is quite a difficult area in the design of technologies and the study of production costs. In the technical development of tooling and modeling of its usage costs, it was assumed to maintain the required level of dimensional and shape accuracy with a simultaneous significant reduction of operating costs. As part of the work, a model was also developed for determining the break-even point of investment in special machining tools that are used on triaxial milling machining centers.

Reducing the Risks during the Purchase of Five-Axis CNC Machining Centers Using AHP Method and Fuzzy Systems

Nowadays, companies are in the process of renewing their manufacturing lines by equipping them with modern five-axis CNC (computer numerical control) machining centers. The decision to select between different five-axis CNC machining centers, with similar technological capabilities is a difficult process, so the main goal of this work was to develop a method for assisting it. The proposed approach relies on seven technical criteria, four quantitative ones (traverse speed, thrust, spindle power, and spindle speed) which can be expressed by crisp numerical values, while the other three (flexibility, operation easiness, and setup time) are qualitative ones. The analytic hierarchy process (AHP) was used for ordering four variants of five-axis CNC milling machining centers. The qualitative criteria were processed using fuzzy systems to be expressed by crisp numerical values, suitable for AHP. Finally, the four variants of five-axis CNC milling machining centers were hierarchized and the best one was chosen. A sensitivity analysis was also unfolded to certify the robustness of the AHP.

Approach to the construction of specialized portable terminals for monitoring and controlling technological equipment

The work deals with the features of construction of human-computer interaction to manage the complex process equipment. The mechanism for creating additional portable terminals for monitoring and controlling complex machine tools is presented. A practical example of using the mechanism for creating additional terminal solutions for monitoring and controlling the Quaser MV184P milling machining center is given.

Study on Construction Method of Geometry Simulation Environment of Eight-axis with Five-axis Linkage Machining Center

In order to solve the machining geometry simulation of an eight-axis with five-axis linkage boring and milling machining center produced by JOBS company in Italy, in this paper, the structure of geometry simulation environment was designed based on the analysis of functional requirements, the geometric constraint relations and motion relations of machine tool was analysed, the machine model, control model and measurement analysis model was built, and the machining geometry simulation environment was established that had the same all functions, characteristics and behaviours with real machine tool. The practical application shows that the simulation environment can factually reflect the static and dynamic characteristics of machine tool; the measurement analysis function can effectively ensure the quality of processing products and the safety of machine tool. The construction method of geometry simulation environment can provide a technology and method reference for constructing numerical control machining geometry simulation environment of other types multi-axis machine tool.

Design of adaptable product platform for heavy-duty gantry milling machines based on sensitivity design structure matrix

Development of complex customized machine tools with low manufacturing costs is a challenging problem for many machine tool manufacturers in today’s competitive marketplace. In this research, a novel design method based on axiomatic design and sensitivity design structure matrix is introduced for identification of adaptable product platform. In order to identify the adaptable product platform, customer requirements are first classified into different groups based on K-means clustering method through genetic algorithm. axiomatic design is used to build the mathematical model for identification of the non-adaptable platform parameters, and sensitivity design structure matrix is employed to separate non-adaptable parameters in non-adaptable platform modules and adaptable parameters in adaptable platform modules. A bridge-type double-gantry boring–milling machining center, XXX-2890, is developed based on the existing heavy-duty gantry milling machines to demonstrate the effectiveness of the developed method.

PRECISE ROTARY TABLE INDEXING SYSTEM USED ON MILLING MACHINING CENTRES

Growing performance demands in the mechanical manufacturing field have lead to a great development of the machine tools domain, regarding especially the productivity and the manufacturing precision. When equipping a machine tool with an automatic tool changer and an automatic pallet mechanism, the obtained result is a machining center. For small series products, milling machining centers fulfill the precision and productivity requirements, through the advantages of a reduced auxiliary time and reduced operating errors. This paper presents a new technical solution of the rotary table indexing mechanism used on milling machining centers, which offers a very high positioning precision, by using a curvic coupling and a hydraulically driven table clamp/unclamp mechanism.

复合镗铣加工中心双刀库可视化设计界面

复合式镗铣加工中心是一种功能较为齐全的数控加工机床，其加工效率为普通机床的5~10倍，现在已经普遍应用于各机械加工行业，但是传统的数控加工中心只有一个刀库，换刀时间较长。本文复合式镗铣加工中心采用的是双刀库的自动换刀设计思想，即固定换刀刀库和随机换刀刀库主要是为方便镗床和铣床在机加工过程换刀效率从而提高机床的加工精度并且提高机床的加工效率从而提高整个加工中心的工作效率。一般加工中心的刀库都是封闭的，但是在加床加工的过程中尤其是随机换刀刀库看不刀机床中主轴和刀库中各个刀座上具体是存放的哪种刀具，本文针对此问题使用vb6.0编程语言研究设计了复合镗铣加工中心双刀库可视化的人机界面，实现机床随机换刀刀库的可视化控制，实时监控机床随机换刀的运行状态，通过实验运行证明，该运行系统具有有效稳定性，精确性，实时性。 Composite boring milling machining center which has complete function is the NC machine. The processing efficiency is 5 to 10 times than the ordinary machine tool. So far, it has been widely used in the machining industry, but the traditional CNC machining center with only a Knife Bank spends longer time of changing knife. In this paper, automatic changing tool thought of double tool bank was applied in composite boring milling machining center. Namely, fixed knife bank and random changing knife bank were used to improve the efficiency of changing knife in the machining process. At the same time, machining efficiency and machining precision were improved. Generally, the knife bank of machining center was sealed. But for the random knife bank, the knife type on the knife seat which was installed on the spindle and knife bank couldn’t be identified in the machining process. According to above problems, by means of VB6.0 programming language, the visual human computer-interface of double knife bank was designed in the machining center. And the visual control of random changing knife bank was accomplished. At the same time, running state of random changing knife was controlled in the real time. The experiment showed that the system was stable, accurate and real-time.

Simulating The Technological Movements Of The Equipment Used For Manufacturing Prosthetic Devices Using 3D Models

Abstract The paper presents the process of building geometric and kinematic models of a technological equipment used in the process of manufacturing devices. First, the process of building the model for a six axes industrial robot is presented. In the second part of the paper, the process of building the model for a five-axis CNC milling machining center is also shown. Both models can be used for accurate cutting processes simulation of complex parts, such as prosthetic devices.

Geometrical feature analysis of Co-Cr-Mo single tracks after selective laser melting processing

Purpose – Therefore, the purpose of this study is to understand the relationships between the processing parameters and the geometric form of the produced single tracks, in order to control dimensional quality in future experimentations. The quality of the deposited single track and layer is of prime importance in the selective laser melting (SLM) process, as it affects the product quality in terms of dimensional precision and product performance. Design/methodology/approach – In this paper, a vertical milling machining center equipped with an Ytterbium-fiber laser was used in the SLM experimentation to form single cobalt-chromium-molybdenum (CoCrMo) tracks. The different geometric features and the influence of the scanning parameters on these morphologic characteristics were studied statistically by means of ANOVA. Findings – Evidently, track height (h1) inaccuracy reduced in layer thicknesses between 100 and 200 μm. The re-melt depth (h2) was determined by the energy parameters, with laser power of 325-350 W and scanning speed (SS) of 66.6-83.3 mm/s being the most favorable parameters to obtain the required anchoring. Moreover, a contact angle of 117° was proposed as optimal, as it permitted an adequate overlapping region and a full densification, and, finally, an SS of 50 mm/s and a layer thickness of 250 were suggested for its development. Originality/value – The comprehension of the phenomena inherent to the process is related to the single track geometrical characteristics, which allow the definition of an optimal value for each factor for a further proposal of processing conditions that can finally derive a higher precision, wetting, density and mechanical properties.