Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture

Halicioglu, Recep; Dulger, L Canan; Bozdana, A Tolga

2016 Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture

doi: 10.1177/0954405415600013

Servo presses have recently come into prominence for sheet metal forming operations due to their flexibility, controllability, and simplicity. Minimum energy consumption and maximum tool life are their significant characteristics, leading to considerable reductions in manufacturing costs. This article presents technological review on design and applications of servo presses. The characteristics of servo presses are described and compared to conventional and hydraulic presses. Mechanisms used in servo presses and their motion concepts are evaluated with design features. The industrial background of mechanisms is reported with typical examples from leading press manufacturers. A new classification of the servo presses is presented according to mechanisms and drivers. Besides, ranking of press types according to power control and mechanisms is determined. Servo presses with slider-crank mechanism design are preferred due to their distinctive characteristics.

Lin, Xiaohui; Liu, Jianchun; Ke, Xiaolong; Guo, Yinbiao

2016 Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture

doi: 10.1177/0954405415624638

Waviness error is one of the most critical errors in the large aspheric lenses grinding and one that has a strong impact on the performance of the optical system. In this article, the waviness error of large axisymmetric aspheric lenses for X-axis direction as well as Z-axis direction is analyzed by employing grate parallel grinding method. The grinding wheel vibration and Z-axis interpolation pace are regarded as the main causes of the surface waviness error. Furthermore, to reduce the waviness error, the influence of grinding parameters on waviness error is investigated. The waviness errors measured during grinding experiments are in good agreement with the theoretical results and the appropriate grinding parameters are recommended.

Ashrafi, Amir; Khalili, Khalil

2016 Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture

doi: 10.1177/0954405415597831

Tube hydroforming is a process that uses internal pressure and axial feeding simultaneously to form a tube into a desired shape. The internal pressure provides the stress required to yield the material while axial feeding eases metal flow helping to produce a part without wrinkles and with even wall thickness. Pulsating pressure hydroforming applies loading path with fluctuating pressures. In this study, pulsating pressure hydroforming of T-joint part was examined experimentally. Six process parameters in pulsating pressure loading path were selected. Using Taguchi design of experiments with six parameters and two levels for each parameter, 12 experiments were conducted to study the effects of pulsating pressure parameters on the parts’ defects and shape accuracy. Signal-to-noise ratio and analysis of variance were employed to determine the important process parameters affecting the final part in terms of wrinkling, bulge height and wall thickness. Three linear regressions without any interaction between the parameters were extracted for three quality responses and were evaluated through three extra experiments that show the best levels for three responses. The results show reasonable agreement between the experiments and linear regression models.

Gao, Jicheng; Shen, Yifu; Xu, Haisheng

2016 Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture

doi: 10.1177/0954405415572663

In this article, the lap joint of acrylonitrile butadiene styrene and polycarbonate is produced by submerged friction stir welding. The objective of this research work is to investigate the effect of welding parameters (rotational speed, traverse speed and plunge depth) on tensile strength. Maximization of weld strength (19.2 MPa) is achieved at a rotational speed of 1500 r/min, traverse speed of 40 mm/min and plunge depth of 1.0 mm. The macrostructure morphology and microstructure are analyzed using the optical microscope and scanning electron microscope. The major defects of the joints are cracks, pores and voids, which are the main reasons for decreasing the tensile strength.

Chen, Yujie; Bunget, Cristina; Mears, Laine; Kurfess, Thomas R

2016 Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture

doi: 10.1177/0954405415577055

γ′-strengthened nickel-based superalloys are developed for high-performance systems such as jet engines, internal combustion engines, and gas turbines. Their excellent properties are given by specifically designed microstructure. Unfortunately, the structure is deformed during machining. Too much deformation generated results in components with low mechanical integrity and reduced in-service life. Experimental investigations indicated that the machining affected zone or subsurface damage formation for nickel-based superalloys is an atypical phenomenon; its dependence on the process parameters is fundamentally different from the conventional materials. This research investigates subsurface damage formation in orthogonal cutting tests performed on nickel-based superalloys, followed by empirical and numerical modeling. The simulations are used to estimate the depth of the subsurface damage and are compared with the experimental results. The knowledge can then be applied to select optimum cutting parameters for an acceptable depth of subsurface damage.

Elyasi, Majid; Aghajani Derazkola, Hamed; Hosseinzadeh, Morteza

2016 Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture

doi: 10.1177/0954405416645986

The aim of this article is the investigation of the effects of tool tilt angle on the friction stir welding of aluminium to the steel butt joint. For this purpose, 1°, 2° and 3° tilt angles are selected to friction stir welding of AA1100 to A441 AISI, while the other process parameters (i.e. tool rotational speed, travelling speed, tool offset and plunge depth) kept constant. The results showed that with increasing tool tilt angle, the interaction between two metals and axial force increased. The increasing tool tilt angle caused more surfaces to mingle, internal mixing and frictional heat generation. The results of the microstructure of joints revealed that the AA1100 microstructure is more thermo-mechanically affected than A441 AISI. The AA1100 average grain sizes at stir zone were 1.2, 1.6 and 2 µm and at A441 AISI were 6, 7 and 9 µm at 1°, 2° and 3° tilt angles, respectively. The maximum tensile strength of joints was 75% of the aluminium base metal, which was produced at 2° tilt angle. The higher heat generation and axial force at upper tilt angle cause separation of the steel fragments on the aluminium matrix and formation of Al-Fe intermetallic compound. These phenomena lead to increase in the micro-hardness of the joint at the upper tool tilt angle.

Shaikh, Javed Habib; Jain, Neelesh Kumar; Pathak, Sunil

2016 Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture

doi: 10.1177/0954405415584899

Electrochemical honing is a hybrid finishing process combining advantages and simultaneously overcoming the individual limitations of electrochemical machining and mechanical honing. Finishing of conical gears by electrochemical honing is very complicated due their complex geometry. This article reports on the development of an innovative experimental setup and investigations on improving surface finish of straight bevel gears by electrochemical honing and its process productivity. A novel idea of using twin-complementary cathode gears was envisaged to ensure simultaneous fine finishing of all the teeth of straight bevel gear made of 20MnCr5 alloy steel. Effects of five important electrochemical honing parameters, namely, concentration, temperature and flow rate of electrolyte, rotary speed of workpiece gear, voltage on surface finish and material removal rate of the bevel gear were investigated. Improvement in the microstructure of electrochemical honing finished gear was studied using scanning electron microscopic images. To prove importance of hybridization in improving finishing capabilities of electrochemical honing, a comparative study of surface quality of a bevel gear finished by mechanical honing, electrochemical machining and electrochemical honing was done. The results revealed considerable improvements in the surface quality of the bevel gears finished by electrochemical honing. Electrolyte concentration of 7.5%, temperature of 32 °C, flow rate of 30 L/min, 8 V as voltage and speed of 40 r/min of the workpiece gear yielded the best combination of percentage improvements in average surface roughness (i.e. 58.5%), maximum surface roughness (i.e. 44.4%) and volumetric material removal rate (0.21 mm3/s). This work helps to establish electrochemical honing as a viable alternative bevel gear finishing process which has potential to overcome the limitations of conventional bevel gear finishing processes.

Wang, Jianjian; Feng, Pingfa; Zhang, Jianfu

2016 Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture

doi: 10.1177/0954405416654426

The edge chipping of holes, which is induced by mechanical machining, restricts the applications of brittle materials. Rotary ultrasonic machining is considered a suitable approach to machine holes in brittle materials with a smaller edge-chipping size. However, obvious edge chipping at the hole exit in rotary ultrasonic machining remains observable. In this study, conical diamond core drills with various characteristic angles (θ) were designed to further reduce the edge-chipping size for rotary ultrasonic machining. Machining tests on quartz glass were conducted to evaluate the effectiveness of this new type of drill. Experimental results show that the conical drill can obviously reduce the edge-chipping size only when certain conditions are satisfied. The mechanism of edge-chipping reduction using a conical drill was revealed by the theoretical analysis and detailed observation of the thrust force and obtained cylinder. To guarantee the feasibility of the conical drill, its characteristic angle should exceed a critical value at a certain feed rate. A higher feed rate requires a higher critical characteristic angle. The other advantage of the conical drill is its ability to suppress the bad effects of increasing the feed rate on the stability of ultrasonic vibration.

Xie, Jun; Liu, Fei; Huang, Jing; Qiu, Hang

2016 Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture

doi: 10.1177/0954405415623488

The machining systems that mainly consist of machine tools are numerous and are used in a wide range in industries. The total amount of energy consumption by machining systems in the world is extremely high. The loading loss energy is one of the most important and complicated parts of the energy consumption of machine tool in machining processes. The key of acquiring the loading loss energy is the acquisition of the loading loss coefficient, which is indispensable for machine tools’ energy efficiency on-line monitoring, energy prediction and energy quota customization. Up to now, the loading loss coefficient is mainly obtained by the experimental method which needs to conduct a large amount of experiments and a comprehensive on-line measurement to obtain the input power, idle power and cutting power beforehand. On the other hand, in many cases, it is unavailable to install the dynamometers on the machine tool’s worktable to measure the parameters on-line. This article provides a mapping method to acquire the loading loss coefficient of main driving system of machine tools. First, choose a standard machine tool, cutter and workpiece to construct the standard machining circumstance. Second, carry out the experiments with a series of given cutting parameters under the standard circumstance and record the cutting power accordingly. Third, construct the overall cutting power model which can be used to calculate the cutting power of any other target machine tools under the standard machining circumstance. Fourth, establish the air-cutting power database of the target machine tools. Then, carry out the experiments on the target machine tool with the parameters which is as close as possible to the standard parameters and record the input power of the main driving system respectively. Finally, substitute the input power, air-cutting power and cutting power into the acquisition model to calculate the loading loss coefficient. The case study indicates that this method with high accuracy, on the other hand, can simplify the procedure of the acquisition of the loading loss coefficient to a great degree and shows that the method is practical and promising.

Jin, Liangliang; Zhang, Chaoyong; Shao, Xinyu; Tian, Guangdong

2016 Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture

doi: 10.1177/0954405415625916

The integration of process planning and scheduling is important for an efficient utilization of manufacturing resources. However, the focus of existing works is mainly on deterministic constraints of jobs. This article proposes a novel memetic algorithm for the integrated process planning and scheduling problem with processing time uncertainty based on processing time scenarios. First, a mathematical model for the stochastic integrated process planning and scheduling problem based on the network graph is established. Due to the nonlinearity in the model and the complexity of the problem, a memetic algorithm is then suggested for this problem. A novel local search (variable neighborhood search) algorithm is incorporated into the memetic algorithm. Two effective neighborhood structures are employed in the variable neighborhood search algorithm to improve the overall performance of the population. Furthermore, for the uncertainty in processing times, a set of scenarios have been generated to evaluate each individual. Finally, two performance measures—the expected performance measure and the worst-case deviation measure—are introduced and compared. In the experimental studies, the proposed memetic algorithm is tested on typical benchmark instances. Computational results show that the expected makespan measure performs better than the worst-case deviation measure and the proposed method exhibits high performance especially for large-scale instances. In addition, the results obtained by the proposed memetic algorithm are more satisfactory than those obtained by the algorithm that considers deterministic processing times only.