A Reuse-Oriented Redesign Method of used Machine Tool based on Matter-Element Theory

Huajun Cao,Xiang Chen,Lei Xu,Enxu Ma 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

Aiming at the remanufacturing of used machine tool, a reuse-oriented redesign method was presented. The function tree of machinetool was established on the basis of machine tool’s characteristics of the function and structure in the method. The matter-elementmodel of sub-function was built with the matter-element theory, and then the redesign alternatives of sub-functions were made byfinding and removing the differences between the corresponding matter-element of sub-functions. The redesign alternatives of machinetool were built by combining the redesign alternatives of every sub-function together organically. For obtaining the best alternative,a comprehensive evaluation method was proposed based on the correlation function, the Analytic Hierarchy Process (AHP) and theremanufacturing knowledge of used machine tool. The evaluation method includes four indexes, such as the cost (C), the time (T),the rate of reuse (R) and the overall performance (P). Finally, this reuse-oriented redesign method was applied in one floor-typemilling & boring machine’s remanufacturing in an enterprise, and its effectiveness was verified.

An adaptive parameter optimization model and system for sustainable gear dry hobbing in batch production

Ying Zhang,Huajun Cao,Peng Chen,Li-Bin Zhu,Xiao Yang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6

Gear hobbing technology is one of the most widely used forming processes of gear teeth. And the development of dry hobbing technologyprovides a solution for realizing productive, economical, and ecological gear production. Since there is no cutting oil for coolingand lubrication in dry hobbing process, the hob tool life, thermal deformation errors of machine tool, and quality of workpiece are sensitiveto the cutting parameters, especially the cutting speed and tip chip thickness. Considering this situation, a dry hobbing parametersoptimization model with the hobbing efficiency as our objective, and the hobbing cost per piece, gear quality, tact time as constraints wasestablished, in which the cutting speed and tip chip thickness were considered as optimal variables and the material of workpiece, coatingof hob, and feed rate were considered comprehensively. An iterative test method is proposed to solve this model. And for the applicationin automated production line, an online adaptive application system was also developed based on SINUMERIK 840D NC system. Theparameters of five different kinds of material gear were optimized by applying this model and system, and the result showed the modeland the system were practical.

An Analytical Model of Chip Heat-Carrying Capacity for High-Speed Dry Hobbing Based on 3D Chip Geometry

Xiao Yang,Huajun Cao,Yong-peng Chen,Li-Bin Zhu,Ben-jie Li 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.2

High-speed dry hobbing is the dominating green technique for gear hobbing owing to its high productivity and environmental friendliness. However, a large amount of cutting heat is generated during the machining process due to the absence of metalworking fluids and the adoption of high cutting speed. A better understanding of chip heat-carrying capacity for high-speed dry hobbing is quite necessary when aiming to reduce the influence of cutting heat on machining precision. In this paper, an analytical model is established to quantitatively determine the chip heat-carrying capacity of high-speed dry hobbing. According to the progressive heat transfer characteristic of high-speed dry hobbing, cutting heat generation and transmission are analyzed. 3D chip geometry is numerically calculated by modeling the complex hob geometry and the interrelated kinematic relations of high-speed dry hobbing. Based on the 3D chip geometry and the specific cutting energy, chip heat-carrying capacity model is developed considering three heat sources. In this model, chip heat partition is experimentally determined by calorimetric method. With the help of the developed model, chip heat-carrying quantity and chip heat-carrying efficiency are discussed by investigating their influence factors (hob rotation speed, axial feed, feed method, chip removal time and hob geometry).

Energy Dissipation Characteristics Modelling for Hot Extrusion Forming of Aluminum-Alloy Components

Hongcheng Li,Yuanjie Wu,Huajun Cao,Feng Lu,Congbo Li 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.6

The hot extrusion forming process is widely used to process aluminum-alloy components in both the automobile and aircraft manufacturing industries. Since it involves pushing the material through the die at increased temperature, it is very energy-intensive despite requiring less blank material allowance. During hot extrusion forming, the multi-stage dynamic conversion of electricity, mechanical energy, and hydraulic energy to heat results in high energy dissipation. In order to improve the power and energy conversion efficiency of hot extrusion forming process, it is necessary to identify the energy dissipation characteristics. The transfer and conversion paths of the electrical, mechanical, and hydraulic energy from the motor to the hydraulic cylinder were firstly depicted based on the motion cycle of the extruder. A bond graph-based energy dissipation model was then proposed for dynamically identifying the energy-saving potentials. The energy dissipation model integrated the power bond graph sub-model of energy conversion elements such as motor, pump, hydraulic valve group, and hydraulic cylinder. These power bond graph sub-models were separately developed to find the energy dissipation state equations of energy conversion elements. An experiment was carried out using data obtained from the energy management system to validate the bond graph-based energy dissipation model. The results have shown that the power and energy conversion efficiency of hot extrusion forming is primarily controlled by the parameters such as extrusion velocity and extrusion force. Both the higher extrusion velocity and lower extrusion force will reduce the power and energy conversion efficiency. An optimal combination of extrusion velocity and pressure can achieve the lowest energy consumption per unit product.

Exergy-based Energy Efficiency Evaluation Model for Machine Tools Considering Thermal Stability

Ben-jie Li,Huajun Cao,Bernard Hon,Lei Liu,Xi Gao 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.2

Machine tools, as the extensively used basic equipment of manufacturing industry, are characterized by intensive and inefficient energy consumption. With the launch and implementation of ISO 14955-1, energy efficiency has become an important criterion for machine tool evaluation. However, most ongoing research on energy efficiency evaluation of machine tools emphasizes on workpiece material removal energy efficiency and rarely considers energy consumption needed to ensure machining accuracy and accuracy consistency, especially energy consumption for thermal stability control of machine tools. In light of this, an exergy analysis based approach is presented to assess the comprehensive energy efficiency of machine tools, including energy consumption for material removal and thermal stability control. The key performance indexes of exergy efficiency, exergy destruction, and specific exergy consumption are analyzed. The feasibility of the proposed approach was demonstrated by a case study, in which the comprehensive energy efficiency of a machine tool was found to be 21.57% instead of 14.38% of material removal energy efficiency. The proposed method is more effective to evaluate the comprehensive energy efficiency, to support designers to design high-efficient machine tool and users to operate machine tool for green and precision machining.

Reliability Allocation Method for Remanufactured Machine Tools Based on Fuzzy Evaluation Importance and Failure Influence

Yan-bin Du,Guoao Wu,Ying Tang,Huajun Cao,Shihao Liu 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.6

Reliability is the key performance indicator for remanufactured machine tools to be approved by customers. Reliability allocation is an important task that needs to be done in the design phase of remanufactured machine tools to ensure that remanufactured products meet the reliability target requirements. A reliability allocation method for remanufactured machine tools is proposed based on fuzzy evaluation importance and failure influence of each component. The importance of each component is evaluated by five indicators such as complexity of structure, maturity of technology, criticality of fault, difficulty of maintenance, and severity of service condition, in which their weights are determined by the method of analytic hierarchy process (AHP). Failure influence is determined by the proportion of downtime caused by each component in total downtime of machine tools. Finally, the proposed method is illustrated in a numerical case study of NC lathe remanufacturing.

Cutting fluid corrosion inhibitors from inorganic to organic: Progress and applications

Haogang Li,Yanbin Zhang,Changhe Li,Zongming Zhou,Xiaolin Nie,Yun Chen,Huajun Cao,Bo Liu,Naiqing Zhang,Zafar Said,Sujan Debnath,Muhammad Jamil,Hafiz Muhammad Ali,Shubham Sharma 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.5

Water-based cutting fluid has a broad application area and a hundred year history, but its poor corrosioninhibition and anti-rust ability limit its further promotion. Adding corrosion inhibitors can effectively solve the aboveproblems. However, no review papers are available on cutting fluid corrosion inhibitors, and their mechanism, suitability,and performance influencing factors have not been revealed. This article discusses cutting fluid corrosion inhibitorsto fill the gaps in theoretical research and industrial applications. Inorganic matters are initially used in corrosion inhibitiondue to their strong oxidizing properties. Therefore, the film formation mechanism of inorganic corrosion inhibitoroxide and precipitation film is first analyzed, and the applications in corrosive medium are summarized. Given thatinorganic corrosion inhibitors are not environmentally friendly and expensive, organic corrosion inhibitors are currentlyused as replacement. Thus, the film formation mechanism of different organic corrosion inhibitors adsorptionfilm is analyzed, and their suitability with metals is determined. The influence of molecular structure and temperatureon their corrosion inhibition effect is also studied, and the performance of inorganic and organic corrosion inhibitors iscompared. However, single organic corrosion inhibitors are greatly affected by metal surface state, temperature, andimmersion time. Therefore, the synergistic film formation after the compounding of organic and inorganic corrosioninhibitors is analyzed. In addition, the influence rate of concentration, molecular structure, and temperature on corrosioninhibition performance is revealed, and a matching database of corrosion inhibitor type and metal type in cuttingis established. Finally, in view of the limitations of cutting fluid corrosion inhibitors, the establishment of a moleculardynamics model of corrosion inhibitor failure and accelerates corrosion and the development of general-purpose greenadditives based on the molecular design and physical and chemical analysis of the suitability of corrosion inhibitor andbase liquid are prospected.

Convective Heat Transfer Coeicient Model Under Nanoluid Minimum Quantity Lubrication Coupled with Cryogenic Air Grinding Ti–6Al–4V

Jianchao Zhang,Wentao Wu,Changhe Li,Min Yang,Yanbin Zhang,Dongzhou Jia,Yali Hou,Runze Li,Huajun Cao,Hafiz Muhammad Ali 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.4

Under the threat of serious environmental pollution and resource waste, sustainable development and green manufacturing have gradually become a new development trend. A new environmentally sustainable approach, namely, cryogenic air nanofluid minimum quantity lubrication (CNMQL), is proposed considering the unfavorable lubricating characteristic of cryogenic air (CA) and the deficient cooling performance of minimum quantity lubrication (MQL). However, the heat transfer mechanism of vortex tube cold air fraction by CNMQL remains unclear. The cold air fraction of vortex tubes influences the boiling heat transfer state and cooling heat transfer performance of nanofluids during the grinding process. Thus, a convective heat transfer coefficient model was established based on the theory of boiling heat transfer and conduction, and the numerical simulation of finite difference and temperature field in the grinding zone under different vortex tube cold air fractions was conducted. Simulation results demonstrated that the highest temperature initially declines and then rises with increasing cold air fraction. Afterward, this temperature reaches the lowest peak (192.7 °C) when the cold air fraction is 0.35. Experimental verification was conducted with Ti–6Al–4V to verify the convective heat transfer coefficient model. The results concluded that the low specific grinding energy (66.03 J/mm 3 ), high viscosity (267.8 cP), and large contact angle (54.01°) of nanofluids were obtained when the cold air fraction was 0.35. Meanwhile, the lowest temperature of the grinding zone was obtained (183.9 °C). Furthermore, the experimental results were consistent with the theoretical analysis, thereby verifying the reliability of the simulation model.