Machine Tool Bed Research Articles

Research on the Optimization of Porosity in Resin Mineral Composite

With good vibration alleviating properties, resin mineral composite (RMC) has been used to produce precision machine tool beds to satisfy the requirements of machining accuracy. Aggregate is one of the key components in RMC to bear loads, its gradation design determines the overall mechanical properties of the composite directly. In this article, an optimal method to determine critical dimension of screen holes is proposed based on Euclidean geometry and Particle interference theory, and the corresponding proportion of each component is adjusted on the basis of fractal theory. Variation tendency of porosity corresponding to different fractal dimension is obtained by using simulation method. On this basis, image processing technology is used to validate the aforementioned assumptions. Experimental results show that the optimal design has smaller porosity performance, which is consistent with the simulation results.

The Static and Dynamic Characteristics Analysis of a CNC Grinding Machine Bed Made from Artificial Granite

The machine tool bed is an important fundamental unit of the Machine tool, and its static and dynamic characteristics directly influence the precision of the Machine tool’s process. The precise composite B2-K3000 CNC grinding machine bed is made from artificial granite. Through entity modeling, adding the boundary conditions and stress conditions to the bed, this article analyses the static stiffness, natural frequency, vibration mode and harmonic response of the grinding machine bed, and masters the natural characteristics and preponderant natural frequency.On the basic of the bed’s structure characteristics and stiffness requirements, the original bed’s structure gets partial improvements. By increasing the number of ribs and using the cross-shaped ribs, the improved result indicates that the bed’s static stiffness can be enhanced obviously and the bed’s static and dynamic characteristics can be more excellent.

Optimal Design of Machine Tool Bed by Load Bearing Topology Identification with Weight Distribution Criterion

This paper attempts to develop a simple and practical procedure for the optimal design of machine tool bed. In this research, a simplified model is first defined to characterize the bed structure. The load bearing topology of the bed structure is then identified to represent the optimal layout of the inner stiffener plates. Subsequently, detailed sizing optimization is conducted by using a novel criterion which describes the best solution in terms of weight distribution of both the outer supporting panels and inner stiffener plates. Finally, calculation results are elaborated to demonstrate the effectiveness of the proposed method.

Structural Analysis and Weight-Losing Optimization for the Five-Axis Grinding Machine Tool Bed

With the five-axis grinding machine tool bed as the research object, the maximum deformation region can be found after analyzing the static characteristics in the use of the grinder limit positions. Through free modal analysis and constraint modal analysis, the vibration characteristics of each order of the bed can be seen and a point in the maximum deformation region is selected to carry out the harmonic response analysis to predict the sustainable dynamic characteristic. According to the results of analysis, find out the weak areas in the bed and conduct the weight-lowing optimization on the condition of no reduction of static and dynamic characteristic of the bed. This paper draws the conclusion of reduction of weight of 143.42kg and materials of 7.73%.

Finite Element Analysis of Machine Tool Bed

Taking machine tool bed as example,the modal analysis and harmonic response analysis were done by means of finite element method. Find out its characteristics of vibration modal. The analysis is conducive to the design of the machine tool bed. It makes a base for optimized design and remanufacturing.

Structure Analysis and Optimum Design of NC Grinding Machine Tool Bed

The modern design method based on the finite element theory has become the essential means of present machine design. In this paper, dynamics finite element model of NC grinding machine tool’s bed has been established with the finite element analytic technique. Dynamic characteristic of processing has been studied. The optimization program of structure to lower the vibratory response has been designed. This advances the dynamic stiffness of bed. This research provides an essential theory and technology support for achieving the advanced level of the international similar machine tool on the aspect of machining precision, reliability and security.

Static and Dynamic Performance Improvement of Conventional Computer Numerical Control Machine Tool Bed with Hybrid Welded Steel

Problem statement: The advancements in machine tools to maximize the production by increasing spindle speeds have caused vibration in machine tools. The two functional requirements of machine tool bed for machine tools are high structural stiffness and high damping, which cannot be satisfied simultaneously if conventional metallic materials such as cast iron are employed. Hence there is a need to replace cast iron with alternate materials. Approach: The objective of this study is to improve the stiffness, natural frequency and damping capability of machine tool bed using a composite material containing welded steel and polymer concrete. Welded steel material has high stiffness but low damping and polymer concrete has high damping but low stiffness. So in this study, a machine tool bed made of sandwich structures of welded steel and polymer concrete is designed and manufactured. Modal and static analyses were conducted numerically and experimentally to determine the modal frequencies, damping ratio, deformation and strain. Results: The results at first mode showed that the natural frequency improved by 24.7% and damping ratio was 2.7 times higher than cast iron. The comparison of strain and deformation also showed significant improvement. Conclusion: This study proposed a hybrid welded steel bed as a replacement for cast iron as a machine tool bed material and the results showed that the static and dynamic characteristics were superior to cast iron.

Study on Performances and its Structural Designing of the High-Speed CNC Lathe Epoxy Resin Concrete Bed

The epoxy resin concrete is one of high performance composite materials used to the basic parts of machine tool and measuring instruments. Based on the study of related technologies at home and abroad, technical route and manufacturing process on the development of machine tool bed have been proposed. The epoxy resin concrete material self developed and results of its performances testing are introduced, and they are contrasted with cast iron material. The high-speed CNC lathe was taken as example which characteristic of the epoxy resin concrete bed structural design has been explained in this paper. The cast iron bed and epoxy resin concrete bed of the high-speed CNC lathe has respectively been analyzed and contrasted by finite element method. At last, the performances of epoxy resin concrete bed exceeding to cast iron bed have been educed.

Numerical Simulation of Solidification Process for a Machine Tool Bed

In this paper, the flow, heat transfer and stress during solidification process of the machine tool bed weighed about 2.5ton that has been optimized by structural topologymethod, was calculated with ProCAST software, and the causes of the crack forming in the casting of the machine tool bed was analysed. According to the calculation results, the structural design of the local part where cracks tends to form has been improved, and the heat transfer and the stress are calculated again. By comparing the temperature field with filling of molten cast iron and without filling, it has been found that there was little effect of filling on the results of temperature distribution of the cast, therefore the effect of filling can be ignored in the following temperature field calculation to save computation time. The model has been simplified in the stress field calculation with considering the complexity of the machine tool bed and the cost of computation. Then, the merits and demerits of the original design and the improved design are compared and analyzed depending on the calculated temperature and stress results. It is suggested that the improved one could get a more uniform temperature distribution and then the trend of the crack occurring can be greatly reduced. These results could provide a guide for the actual casting production, achieving the scientific control of the production of castings, ensuring the quality of the castings.

Theoretical Modeling and Verifications of Unit Structure Method

Unit structure method is broadly used in structure analysis,but its theoretical modeling research is rarely found in literature.Lumped parameter method is used to analyze the unit structure and the whole structure made up by repeating it.Theoretical models of the unit structure method are established based on the relationship between the vibration frequencies of the unit structure and the whole structure.The model which doesn't consider the mass of the spring is called simple model,with relatively large error.The error of the Rayleigh model which considers the mass of the spring using Rayleigh method is less than that of the simple model.The calculation and design of the whole structure can be realized by using theoretical models of the unit structure method,when the vibration frequency of the unit structure and the dimensions of the whole structure are known.In the first simulation example,the fact is verified that the error of Rayleigh model(5.7%) is less than that of the the simple model(15.6%).In the second simulation example,a machine tool bed is designed by using the unit structure method.In an experiment example,the vibration frequency of a casting is calculated and designed by using the unit structure method.These examples show that the unit structure method is an effective way to deduce the performance of the whole from the part,which can reduce the simulation modeling work in finite element method and prototype construction cost.

Structural Dynamic Analysis and Optimization of Precision NC Machine Tool Bed Based on the Unit Structure

The theory of structural dynamic analysis is put forward in this paper. The dynamic performance of a precision machine tool bed is analyzed by means of finite element method, and the analysis result shows that the natural frequency is too low is the main reason of the vibration of the bed. In order to improve the dynamic performance of the bed, the dynamic performance of the unit structure of the precision machine tool bed is analyzed. Based on the analysis of the unit structure, two structural optimization schemes for the machine tool bed are obtained. Furthermore, two optimization schemes are analyzed by means of finite element method too. Compared to the original machine tool bed, the dynamic performance of two structural optimization schemes is significantly improved.

Optimal design approach for eco-efficient machine tool bed

An optimal design approach of machine tool bed with the aim of obtaining an eco-efficient machine structure is studied. The suggested method includes three phases. The first is the layout design optimization of stiffener plates inside bed. In order to improve the design efficiency, a simplified design model called fiber model is suggested, and the layout of the stiffener plates inside bed is optimized by changing a 3-dimensional topology design optimization problem to a 2-dimensional problem. The second is the detailed sizing optimization of stiffener plates and supporting blocks under the structure based on the initial optimal model resulted from phase one. Finally, a topology design optimization process is implemented to obtain a reasonable distribution of manufacturing holes in bed structure. By considering the manufacturing requirement, an optimal bed structure is obtained. The validity of the suggested method is confirmed by a typical cylindrical grinding machine tool bed, and the result shows that the suggested method is effective, and the optimal structure has much better mechanical and economical performance by comparing with the original structures.

Manufacturing and Green Estimation of Composite Concrete Machine Tool Bed

This paper presents a new manufacturing technology for machine tool beds, which is composed of high stiffness epoxy concrete structure faces and lower cost steel fiber cement concrete core. After steel fiber cement concrete core is poured, epoxy concrete structure faces are poured. The technology is first applied in manufacturing of CKA6150 CNC lathe bed. Through comparing with cast iron machine tool bed and epoxy concrete machine tool bed, it is estimated by five elements value green estimate theory. The result demonstrates that composite concrete machine tool bed not only has high characteristic and lower energy cost but also meets requirements of green manufacturing.

Research and Design on Green Reconfigurable NC Machine Tool

The thesis researched the relationship between green design and reconfigurable on NC machine tool, and expatiated that the development of the reconfigurable machine tools is essential. This article has carried on the analysis from the deep hole components classification and the formed movement craft two aspects to the deep hole components race. The reconfigurable deep hole machine tool was to carry on the modular design based two aspects for the module partition and reconstructable analyze, solved the key technologies the machine tool modulation design. From the machine tool bed module, the head of machine tool module, the cutting tool auxiliary system and the numerical control system four aspects, to design and research on reconfigurable machine tool, solved the difficult design problem which the part reconfigurable designed.

Research on steel-fibber polymer concrete machine tool structure

Researched on the design and manufacturing of machine tool bed made by Steel-fibber Polymer Concrete(SFPC), which analyzed the static, dynamic and thermal performances of the bed. The results of study prove that machine tool bed made with SFPC is much more superiority than made in cast iron in dynamic and thermal performances, and is more superiority then made in Polymer Concrete (PC) in static performances. It can be concluded that the static, dynamic and thermal properties of machine tool can be improved by manufacturing machine tool bed with SFPC. Also SFPC machine tool bed posses some other advantages in the following: short development time, simple production process, reducing cost cost, saving energy, iron and steel.

Design and manufacture of hybrid polymer concrete bed for high-speed CNC milling machine

To maximize the productivity of precision products such as molds and dies, machine tools should be operated at high speeds without vibration. As the operation speeds of machine tools are increased, the vibration problem has become a major constraint of manufacturing of precision products. The two important functional requirements of machine tool bed for precision machine tools are high structural stiffness and high damping, which cannot be satisfied simultaneously if conventional metallic materials are used for bed structure because conventional high stiffness metals have low damping and vice versa. This paper presents the application of hybrid polymer concrete for precision machine tool beds. The hybrid polymer concrete bed composed of welded steel structure faces and polymer concrete core was designed and manufactured for a high-speed gantry type milling machine through static and dynamic analyses using finite element method. The developed hybrid machine tool bed showed good damping characteristics over wide range of frequency (η = 2.93–5.69%) and was stable during high speed machining process when the spindle angular speed and acceleration of slide were 35,000 rpm and 30 m/s2, respectively.

Parametric study on design of composite–foam–resin concrete sandwich structures for precision machine tool structures

In this paper, sandwich structures for micro-EDM machines are optimized by using parametric study varying composite geometries and parameters like stacking sequence, thickness and rib geometry. The structures are composed of fibre reinforced composites for skin material and resin concrete and PVC foam (Closed cell, Divinycell) for core materials. Column structure was designed by a beam with cruciform rib and performance indices such as static bending stiffness ( EI) and specific bending stiffness ( EI/ ρ) for dynamic stability are examined by controlling the thickness and stacking sequence of composites. For the machine tool bed, which usually has a plate shape, was designed to have high stiffness in two directions at the same time controlling stacking sequence and rib geometry; that is, rib thickness and number of ribs. The sensitivity of design parameters like rib thickness and composite skin thickness was examined and the optimal condition for high stiffness structure was suggested. Finite element analysis was also performed to verify the static and dynamic robustness of the machine structure. L-shaped joint for combining bed and column of the micro-EDM machine was proposed and fabricated using adhesive bonding. The dynamic performance such as damping characteristics was investigated by vibration tests. From the results optimal configuration and materials for high precision micro-EDM machines are proposed.

Residual Stress Computation and Analysis of Machine Tool Bed Casting

Residual Stress Computation and Analysis of Machine Tool Bed Casting

A study on the epoxy resin concrete for the ultra-precision machine tool bed

Since the resin concrete has many beneficial properties for the machine tool bed, in this work, several experiments were performed to obtain its best properties of resin concrete. The modulus, compressive strength, flexural strength, coefficient of thermal expansion, specific heat, thermal conductivity, and damping factor were measured by varying the compaction ratio, sizes and the contents of the ingredients to assess the effect of the processing parameters on the properties of the material. Based on the measured properties, the bed of the ultra-precision CNC grinding machine for mirror surface machining of brittle materials such as ceramics and composite materials was manufactured with epoxy resin concrete material.

Thermal Deformation of Machine Tool Structures Using Resin Concrete : Thermal Behaviour of Concrete Bed of Machine Tool in Fluctuating Ambient Temperature

The thermal inertia of a machine tool bed made from concrete material is generally much larger than that of conventional ones such as cast iron or steel. Hence, it is considered that the thermal response of a concrete bed depends strongly on the period of fluctuation of the ambient temperature. In this paper, the thermal behaviour of a concrete bed in fluctuating ambient temperature is discussed, comparing it with that of a conventional cast-iron bed. It is verified that a concrete bed has a great advantage from the viewpoint of thermal deformation when the period of ambient temperature fluctuation is relatively short.