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There is abnormal wear and fracture of the retainer in the faulty piston pump. To investigate the early failure mechanism of the fractured retainer, a model for the calculation of the transient contact between the overturning retainer and the slipper is presented. The equations of the trajectory between the overturning retainer and the slipper are established based on the transformation matrix and the operating mechanism of the slipper in the oil sucking and discharging areas. The trajectory of the push points between the overturning retainer and the slipper is solved. The failure mechanism of the retainer extrusion wear is determined. The results show that with the increase of the degree of overturning, the degree and range of extrusion and wear between the failure retainer and the slipper is increased. The research elucidates the failure mechanism of the retainer and lays the foundation for the dynamics modeling and coupling vibration analysis of the overturning retainer.

In order to optimize and analyze the cogging torque of hybrid stator motor, a hybrid stator motor is taken as the research project. The axial distribution of air gap magnetic flux density was analyzed, and the analytical formula of the cogging torque of the hybrid stator motor was derived. Combined with the cogging torque analytical formula, the superposition calculation method of cogging torque of hybrid stator motor was proposed, and the correctness of the superposition calculation method was verified by simulation analysis. The silicon steel segment and the amorphous alloy segment of hybrid stator core were optimized by using the uneven air gap structure, and the optimized results of the silicon steel segment and the amorphous alloy segment were obtained by two-dimensional simulation. Based on the results of two-dimensional simulation analysis, a three-dimensional model was built for simulation analysis. After optimization, the cogging torque of the motor was weakened by 48.1% and the torque ripple was reduced by 1.32%, while the loss and output torque remained basically unchanged.

The quality of rolled products and consumption of rolls are greatly influenced by the oxidation behavior of work roll surface in hot rolling. It is of great significance to improve the quality of rolled products and reduce the consumption of rolls to monitor and evaluate the oxidation states of work rolls in service by non-contact nondestructive inspection technology. In this study, a self-developed test apparatus simulated the high-speed steel (HSS) work roll oxidation in real hot rolling conditions. The interaction mechanism between oxidation and wear of HSS work roll under different conditions was revealed. Furthermore, a set of pulsed eddy current (PEC) nondestructive inspection system was designed and built to evaluate different oxidation states of HSS work roll in service. Variational mode decomposition (VMD) Hilbert transformation was proposed to overcome the problem of mode mixing in mode decomposition of oxidation monitoring signals. At last, the Hilbert marginal spectrum centroid was presented as a characteristic for quantifying the surface oxidation state of work rolls in service.

Considering the cost and performance of the remanufactured motor, a motor remanufacturing method with a hybrid stator core structure was proposed, a prototype of the remanufacturing motor was made and the experiment was carried out. The modified magnetic circuit model of the hybrid stator motor was established by fitting the B–H curves of the two materials to consider the influence of the stator material. The errors for silicon steel and amorphous alloy were approximately 4.9 and 4.3%, respectively. The variation in no-load air-gap magnetic density along the axial direction was studied via simulation, and the air-gap flux density decreases gradually from the centre of silicon steel segment to the centre of amorphous alloy segment. A deflection occurs in the distribution of the air-gap magnetic field, which is in connection with the saturation degree of the materials. The method for calculating the air-gap magnetic density of the hybrid laminated stator from the magnetic density of the two materials was proposed. Compared with the stator composed of only one material, the calculation result obtained by the proposed method is in good agreement with the simulation result, with an error of

The present study analyzed the recovery mechanism of the thermosetting phenolic resin waste, optimizing the recovery process parameters, based on the mechanochemical recovery method. The physical and chemical structure of the ultrapulverized phenolic resin powder was characterized by the low-field NMR (nuclear magnetic resonance), IR (infrared spectroscopy), and SEM (scanning electron microscopy). The recovery process parameters were designed by using the response surface analysis method, and the multiple quadratic regression model was established and the multiobjective process parameter was optimized. The results show that the body network structure of the material is destroyed during the crushing process. The intensity of the internal cross-linking signal is reduced and tends to be stable at about 60%, when the particle size exceeds 120 mesh. The cross-linking bonds methylene (-CH2-) in the main chain of the molecular chain and the C-O bond in the methylol group on the branch are broken. The tensile strength of the recycled sheet made of the phenolic resin powder is 8.27 MPa, and the bending strength is 17.76 Mpa through the mechanical properties test. The influences on the change rate of the cross-linking signal intensity and the yield of the recycled powder are in the following order: rotation speed, feed size, time, and feed volume. The best recovery parameters are as follows: rotation speed of 2820 r/min, time of 80 min, feed particle diameter of 0.43 mm, and feed volume of 60 g.

Sheet metal forming that consists of discrete flow processes, is employed in a wide range of applications in industry. Aiming at supporting energy efficient manufacturing in sheet metal forming, an integrated framework is proposed. The framework comprises two layers, namely, operation management and data acquisition. Operation management is performed by three procedures, i.e., energy consumption modeling, energy performance evaluation, and production optimization. Through the operation management, suggestions for saving energy and improving production efficiency are proposed and implemented. Data acquisition is employed to provide useful information. Demonstration analysis in a stamping shop floor validates the feasibility of the proposed framework.

In recent years, mobile payments have gradually replaced cash payments, resulting in a gradual decline in the number of automatic teller machines (ATMs) demanded by banks. Through investigation and analysis, we determine four means to deal with decommissioned ATMs, and construct thereafter an ATM reverse logistics (RL_ATMs) network model, which includes suppliers, producers, warehouses, operators, maintenance centers, collection and inspection centers, disposal centers, remanufacturing centers, and recycling centers. This model is further expressed as a mixed integer linear programming (MILP) model. Given that an ATM recycling network has planned and batched characteristics, a percentage diversion method is proposed to transform a real multi-cycle problem to a single-cycle problem. The RL_ATMs network constructed in this study presents the two forms of ATMs, functional modules and the entire machine. We used the actual situations of the related companies and enterprises in Anhui Province and its surrounding areas, as well as major banks’ ATMs, as bases in using the LINGO software to solve the proposed MILP model with the objective function of minimizing costs and environmental emissions, and obtain the relevant companies’ launch operations. Lastly, we analyzed the relationship between coefficients in the percentage diversion method and calculation results, cost, and carbon emissions. Accordingly, we find that the number of remanufacturing and maintenance centers has no evident impact on the objective function, transportation costs account for a large proportion of the total cost, and emissions tax is small.

Due to the variable end-of-life timing of remanufacturing cores, the failure condition of products’ remanufacturing is uncertainty, with low efficient processes and high cost in remanufacturing procedure. With presenting the definition and content of the predecisional remanufacturing, timing matching method of decision-making in predecisional remanufacturing are proposed. Firstly, based on whole life cycle theory, considering the performance as the characteristic variable, which is influenced by the failure condition of key components, the multiple indicators of timing decision-making in remanufacturing are analysed, and the decion-maing method in predecisonal remanufacturing is proposed. Then with presenting principle of time matching, the timing matching method for the key parts is presented. Finally, with the instance of engine, the timing of predecisional remanufacturing for the key parts in engine is analysed and determined to verify the feasibility and effectiveness of the proposed method.

Since the electric vehicle battery (EVB) is wildly recycled in industry, the disassembly procedures of variable EVBs is so important that can influence the efficiency and environmental impacts in remanufacturing. To improve disassembly efficiency in EVB remanufacturing, a disassembly sequence planning method based on frame-subgroup structure is proposed in this paper. Firstly, the improved disassembly relation hybrid graph and disassembly relation matrix are proposed to identify the disassembly precedence relationship and connection relationship between the components in EVB. Secondly, the frame - subgroup structure is given, and the method for solving disassembly sequence planning with frame-subgroup structure and genetic algorithm is introduced. In this method, to simplify the series of processes such as encoding, decoding, crossover and mutation, the solution space composed of all disassembly sequences is transformed into the positive integer sequence for the disassembly efficiency in battery remanufacturing. Finally, the case study of EVB disassembly sequence planning is presented to validate the feasibility of this proposed method. Comparing with other traditional methods, the advantage and application of this proposed method are introduced.

Nowadays, the uncertainty of the remanufacturing cores increased the cost and difficulty in remanufacturing, and the mechanical and electrical products are rarely designed for remanufacturing. To solve these issues, the optimization design method based on structure similarity model is presented. With identifying the timing in predecisional remanufacturing, the design demands are presented. Since the concept of structural similarity is given, the quantitative mapping relationship between the structure parameters and its performance is analyzed. And the optimization design method for predecisional remanufacturing is given. Finally, the experiment on a typical shaft structure is given to validate the feasibility of this method.

Ultra-high pressure water jet is proposed for recycling of vulcanized waste rubber, and cavitation desulfurization in the recycling process is analyzed. The chemical effects of mechanical shearing, pyrolysis, free radical oxidation, and supercritical oxidation produced by bubble collapse are considered the main causes of desulfurization. Scanning electron microscopy, Fourier transform infrared spectrometry, differential scanning calorimetry, nuclear magnetic resonance test, and X-ray photoelectron spectroscopy are used to determine the performance of rubber powder. Gel fraction of rubber powder is measured to analyze the effect of jet pressure on desulfurization. Results indicate that the vulcanized rubber could achieve partial desulfurization. The glass transition temperature of the rubber powder slightly increases after crushing. With the increase of jet pressure, the gel fraction of rubber powder initially decreases and then increases, as well as achieves a minimum value at the jet pressure of nearly 220 MPa, which is ideal for desulfurization.

Generally, the economic profits in product using are considered as the main factor in decision-making in remanufacturing. Since used key components are identified as the core in remanufacturing, each component and its own condition should be considered in decision-making. Thus, with mapping the relationship between product performance and its key components failure condition, a timing decision-making method in proactive remanufacturing is presented to conduct the remanufacturing with low consuming per year. Moreover, the remanufacturability of key components at the time with low consumption per year is evaluated. Finally, a diesel engine is given as an instance to validate the method.

Nowadays, since the resources of remanufacturing are the ‘cores’, the uncertainty in quantity and quality of the ‘cores’ is an obstacle in remanufacturing engineering. To solve this problem, production management and design for remanufacturing have been discussed in the former studies. However, the current remanufacturing mode, which is carried out in the end of life cycle, is reactive. To delimit the uncertainty of ‘cores’, the concept of proactive remanufacturing is presented in this paper. And one issue is to identify the proactive remanufacturing timing. In the beginning, the reactive remanufacturing timing and proactive remanufacturing timing are introduced. Then, to characterise the remanufacturability of components, the concept of residual strength is proposed. To identify the proactive remanufacturing timing, the mathematical model is established based on the residual strength, remanufacturing value and technical feasibility. Based on this model, the timing determination method in proactive remanu...

Nowadays, since the resources of remanufacturing are the “cores”, the uncertainty in quantity and quality of the “cores” is an important issue in remanufacturing engineering. To meet with this issue, the concept of active remanufacturing is discussed and presented in this paper. It is elaborated from the aspects of product performance degradation and the failure state of key components, based on which the active remanufacturing timing determination mechanism is put forward. Finally, to validate the mechanism, the active remanufacturing timing of engines is determined by analyzing the crankshaft.

With the rapid development of modern industry, more and more electronic and electric products containing Printed Circuit Boards (PCBs) are produced, consumed, and discarded in our daily life. The disassembling and reuse of electronic components mounted on these discarded PCBs are meaningful to reuse the valuable electronic components, reduce the pollution to the environment, reuse the bare PCBs, and retrieve the materials of PCBs. Four evaluation principles of disassembling methods, components reutilization rate, reliability and uniformity, thermal energy consumption and environmental impact, are analyzed. Based on the analysis of the existing disassembling approach, a new method is presented, which adopts a kind of special liquor, methylphenyl silicone oil, as the medium to transmit heat to the PCBs. The ultrasonic is used in the liquor to accelerate the melting and dropping of soldering tin through ultrasonic vibrations. An experimental framework has been established. The experiment proves that the method has good performances such as high efficiency of energy utilization and high unsoldering proportion.

Currently, due to the uncertainty of operation loading and service time, sometimes the mechanical parts are difficultly or hardly to be remanufactured. On the otherwise, it is also wasteful to remanufacture these parts too early. In remanufacturing, a large number of inspections and evaluations of failure condition in the parts have to be done, which are uneconomical and inefficient. In this paper, the concept of proactive remanufacturing is given, with considering remanufacturability in the initial design stage of parts. Analyzing the performance deteriorating law, one main characteristic of proactive remanufacturing is the best timing point to be remanufactured. Informed by modular design theory, structural characteristics are extracted, and the mapping relationship of design parameters and remanufacturability of parts is established. Moreover, the proactive remanufacturing factor is hierarchically and qualitatively expressed as a comprehensive index to measure parts overall remanufacturability, which can implement the design parameters feedback to adjust the best timing point to avoid one-sided optimization of design parameters. Finally, an engine crankshaft is given as an instance to validate this method.