Advances in Manufacturing

3D bare-hand interactions enabling ubiquitous interactions with smart objects

S. K. Ong, X. Wang, A. Y. C. Nee

2020, 8(2): 133-143. doi:10.1007/s40436-020-00295-1

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Ubiquitous augmented reality (UAR) implementation can benefit smart shop floor operations significantly. UAR from a user's first-person view can support and provide the user with suitable and comprehensive information without him/her being distracted from ongoing tasks. A natural hand-based interaction interface, namely, a mobile bare-hand interface (MBHI), is proposed to assist a user in exploring and navigating a large amount of information for a task in the user's first-person view. The integration of a smart shop floor and UAR-based MBHI is particularly challenging. A real shop floor environment is composed of challenging conditions for the implementation of UAR, e.g., messy backgrounds and significant changes in illumination conditions. Meanwhile, the MBHI is required to provide precise and quick responses to minimize the difficulty of a user's task. In this study, a wearable UAR system integrated with an MBHI is proposed to augment the shop floor environment with smart information. A case study is implemented to demonstrate the practicality and effectiveness of the proposed UAR and MBHI system.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-020-00295-1

Numerical study via total Lagrangian smoothed particle hydrodynamics on chip formation in micro cutting

Jin-Shi Wang, Xiao-Dong Zhang, Feng-Zhou Fang

2020, 8(2): 144-159. doi:10.1007/s40436-020-00297-z

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Numerical simulation is an effective approach in studying cutting mechanism. The widely used methods for cutting simulation include finite element analysis and molecular dynamics. However, there exist some intrinsic shortcomings when using a mesh-based formulation, and the capable scale of molecular dynamics is extremely small. In contrast, smoothed particle hydrodynamics (SPH) is a candidate to combine the advantages of them. It is a particle method which is suitable for simulating the large deformation process, and is formulated based on continuum mechanics so that large scale problems can be handled in principle. As a result, SPH has also become a main way for the cutting simulation. Since some issues arise while using conventional SPH to handle solid materials, the total Lagrangian smoothed particle hydrodynamics (TLSPH) is developed. But instabilities would still occur during the cutting, which is a critical issue to resolve. This paper studies the effects of TLSPH settings and cutting model parameters on the numerical instability, as well as the chip formation process. Plastic deformation, stress field and cutting forces are analyzed as well. It shows that the hourglass coefficient, critical pairwise deformation and time step are three important parameters to control the stability of the simulation, and a strategy on how to adjust them is provided.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-020-00297-z

An investigation on machined surface quality and tool wear during creep feed grinding of powder metallurgy nickel-based superalloy FGH96 with alumina abrasive wheels

Ben-Kai Li, Qing Miao, Min Li, Xi Zhang, Wen-Feng Ding

2020, 8(2): 160-176. doi:10.1007/s40436-020-00305-2

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In this study, the machined surface quality of powder metallurgy nickel-based superalloy FGH96 (similar to Rene88DT) and the grinding characteristics of brown alumina (BA) and microcrystalline alumina (MA) abrasive wheels were comparatively analyzed during creep feed grinding. The influences of the grinding parameters (abrasive wheel speed, workpiece infeed speed, and depth of cut) on the grinding force, grinding temperature, surface roughness, surface morphology, tool wear, and grinding ratio were analyzed comprehensively. The experimental results showed that there was no significant difference in terms of the machined surface quality and grinding characteristics of FGH96 during grinding with the two types of abrasive wheels. This was mainly because the grinding advantages of the MA wheel were weakened for the difficult-to-cut FGH96 material. Moreover, both the BA and MA abrasive wheels exhibited severe tool wear in the form of wheel clogging and workpiece material adhesion. Finally, an analytical model for prediction of the grinding ratio was established by combining the tool wear volume, grinding force, and grinding length. The acceptable errors between the predicted and experimental grinding ratios (ranging from 0.6 to 1.8) were 7.56% and 6.31% for the BA and MA abrasive wheels, respectively. This model can be used to evaluate quantitatively the grinding performance of an alumina abrasive wheel, and is therefore helpful for optimizing the grinding parameters in the creep feed grinding process.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-020-00305-2

Experimental and numerical investigations of the mechanical behavior of half sandwich laminate in the context of blanking

Sheng Cai, Lin Chen

2020, 8(2): 177-188. doi:10.1007/s40436-020-00308-z

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In this study, the complex mechanical behavior of an aluminum/low-density polyethylene (LDPE) half sandwich structure was investigated during the blanking process. Mechanical tests were conducted for the polymer and metal layer and the delamination behavior of the adhesive between the two layers. A new testing device was designed for detecting the delamination under tensile mode. Corresponding finite element models were established for the mechanical tests of the metal layer and the delamination of both layers for inverse parameter identification. Material parameters for Lemaitre-type damage, Drucker-Prager, and cohesive zone models were identified for the metal, polymer, and adhesive, respectively. A finiteelement (FE) model was established for the blanking process of the sandwich structures. The experimental forcedisplacement curves, obtained in the blanking process of the half sandwich sheet, were compared with the predicted results of the FE model. The results showed that the predicted force-displacement curves and the experimental results were in good agreement. Additionally, the correlation between cutting clearance and changes in the forcedisplacement curves was obtained. Three feature values quantitatively described the imperfection of the experimental cutting edge. The effect of punch clearance on these values was studied numerically and experimentally. The results indicated that a smaller clearance generated a better cutting-edge quality. The stress state of the half sandwich structure during blanking was analyzed using the established FE model.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-020-00308-z

Marginal-restraint mandrel-free spinning process for thin-walled ellipsoidal heads

Yong-Cheng Lin, Jia-Yang Chen, Dao-Guang He, Xin-He Li, Jian Yang

2020, 8(2): 189-203. doi:10.1007/s40436-020-00296-0

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Metal sheet spinning is an advanced near-net forming technology for the manufacture of thin-walled ellipsoidal heads. The exact control of dimensional accuracy, however, is a considerable problem for spinning thinwalled parts with large diameter-to-thickness ratios. In this work, a marginal-restraint mandrel-free spinning process with two passes is proposed for the fabrication of thinwalled ellipsoidal heads without wrinkling. A finite element model is established and verified to study the influences of spinning parameters on the dimensional precision of thin-walled ellipsoidal heads. It is found that the spinning parameters considerably influence the deviations of wall thickness and contour characteristics. A small forming angle or small roller fillet radius during the first pass spinning, as well as the small angle between passes or high feed ratio during the second pass spinning, can improve the wall thickness precision. Meanwhile, as the forming angle or feed ratio is increased during the first pass spinning, the contour precision initially increases and then decreases. During the second pass spinning, the contour precision can be improved at a small angle between passes, whereas it deteriorates at a larger roller installation angle. The optimized spinning parameters are obtained and verified by experiments.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-020-00296-0

A cortical bone milling force model based on orthogonal cutting distribution method

Qi-Sen Chen, Li Dai, Yu Liu, Qiu-Xiang Shi

2020, 8(2): 204-215. doi:10.1007/s40436-020-00300-7

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In orthopedic surgery, the bone milling force has attracted attention owing to its significant influence on bone cracks and the breaking of tools. It is necessary to build a milling force model to improve the process of bone milling. This paper proposes a cortical bone milling force model based on the orthogonal cutting distribution method (OCDM), explaining the effect of anisotropic bone materials on milling force. According to the model, the bone milling force could be represented by the equivalent effect of a transient cutting force in a rotating period, and the transient milling force could be calculated by the transient milling force coefficients, cutting thickness, and cutting width. Based on the OCDM, the change in transient cutting force coefficients during slotting can be described by using a quadratic polynomial. Subsequently, the force model is updated for robotic bone milling, considering the low stiffness of the robot arm. Next, an experimental platform for robotic bone milling is built to simulate the milling process in clinical operation, and the machining signal is employed to calculate the milling force. Finally, according to the experimental result, the rationality of the force model is verified by the contrast between the measured and predicted forces. The milling force model can satisfy the accuracy requirement for predicting the milling force in the different processing directions, and it could promote the development of force control in orthopedic surgery.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-020-00300-7

Robot programming by demonstration: a novel system for robot trajectory programming based on robot operating system

Hong-Da Zhang, Shou-Bin Liu, Qu-Jiang Lei, Yue He, Yang Yang, Yang Bai

2020, 8(2): 216-229. doi:10.1007/s40436-020-00303-4

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In this article, a new trajectory programming system that allows non-expert users to intuitively and efficiently program trajectories for robots is proposed. The system tracks a pen-shaped marker and obtains its position and orientation by processing the point cloud data of the workspace. A graphical user interface, which enables users to save and execute the acquired trajectory immediately after performing trajectory demonstration, is designed and developed for the system. The performance of the developed system is experimentally evaluated by using it to program trajectories for a UR5 robot. The results indicate that compared with traditional kinesthetic programming, the developed system has the potential of significantly reducing the ergonomic stress and workload of users. The system is developed based on the robot operating system, which facilitates its integration with different robot control systems.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-020-00303-4

Experimental study on the meso-scale milling of tungsten carbide WC-17.5Co with PCD end mills

Wei Zhao, Asif Iqbal, Ding Fang, Ning He, Qi Yang

2020, 8(2): 230-241. doi:10.1007/s40436-020-00298-y

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Tungsten carbide is a material that is very difficult to cut, mainly owing to its extreme wear resistance. Its high value of yield strength, accompanied by extreme brittleness, renders its machinability extremely poor, with most tools failing. Even when cutting with tool materials of the highest quality, its mode of cutting is mainly brittle and marred by material cracking. The ductile mode of cutting is possible only at micro levels of depth of cut and feed rate. This study aims to investigate the possibility of milling the carbide material at a meso-scale using polycrystalline diamond (PCD) end mills. A series of end milling experiments were performed to study the effects of cutting speed, feed per tooth, and axial depth of cut on performance measures such as cutting forces, surface roughness, and tool wear. To characterize the wear of PCD tools, a new approach to measuring the level of damage sustained by the faces of the cutter's teeth is presented. Analyses of the experimental data show that the effects of all the cutting parameters on the three performance measures are significant. The major damage mode of the PCD end mills is found to be the intermittent micro-chipping. The progress of tool damage saw a long, stable, and steady period sandwiched between two short, abrupt, and intermittent periods. Cutting forces and surface roughness are found to rise with increments in the three cutting parameters, although the latter shows signs of reduction during the initial increase in cutting speed only. The results of this study find that an acceptable surface quality (average roughness R_a<0.2 μm) and tool life (cutting length L>600 mm) can be obtained under the conditions of the given cutting parameters. It indicates that milling with PCD tools at a meso-scale is a suitable machining method for tungsten carbides.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-020-00298-y

Prediction model for determining the optimum operational parameters in laser forming of fiber-reinforced composites

Annamaria Gisario, Mehrshad Mehrpouya, Atabak Rahimzadeh, Andrea De Bartolomeis, Massimiliano Barletta

2020, 8(2): 242-251. doi:10.1007/s40436-020-00304-3

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Composite materials are widely employed in various industries, such as aerospace, automobile, and sports equipment, owing to their lightweight and strong structure in comparison with conventional materials. Laser material processing is a rapid technique for performing the various processes on composite materials. In particular, laser forming is a flexible and reliable approach for shaping fiber-metal laminates (FMLs), which are widely used in the aerospace industry due to several advantages, such as high strength and light weight. In this study, a prediction model was developed for determining the optimal laser parameters (power and speed) when forming FML composites. Artificial neural networks (ANNs) were applied to estimate the process outputs (temperature and bending angle) as a result of the modeling process. For this purpose, several ANN models were developed using various strategies. Finally, the achieved results demonstrated the advantage of the models for predicting the optimal operational parameters.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-020-00304-3

Tool wear mechanisms in axial ultrasonic vibration assisted milling in-situ TiB₂/7050Al metal matrix composites

Xiao-Fen Liu, Wen-Hu Wang, Rui-Song Jiang, Yi-Feng Xiong, Kun-Yang Lin

2020, 8(2): 252-264. doi:10.1007/s40436-020-00294-2

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The in-situ TiB₂ particle reinforced aluminum matrix composites are materials that are difficult to machine, owing to hard ceramic particles in the matrix. In the milling process, the polycrystalline diamond (PCD) tools are used for machining these materials instead of carbide cutting tools, which significantly increase the machining cost. In this study, ultrasonic vibration method was applied for milling in-situ TiB₂/7050Al metal matrix composites using a TiAlN coated carbide end milling tool. To completely understand the tool wear mechanism in ultrasonic-vibration assisted milling (UAM), the relative motion of the cutting tool and interaction of workpiecetool-chip contact interface was analyzed in detail. Additionally, a comparative experimental study with and without ultrasonic vibration was carried out to investigate the influences of ultrasonic vibration and cutting parameters on the cutting force, tool life and tool wear mechanism. The results show that the motion of the cutting tool relative to the chip changes periodically in the helical direction and the separation of tool and chip occurs in the transverse direction in one vibration period, in ultrasonic vibration assisted cutting. Large instantaneous acceleration can be obtained in axial ultrasonic vibration milling. The cutting force in axial direction is significantly reduced by 42%-57%, 40%-57% and 44%-54%, at different cutting speeds, feed rates and cutting depths, respectively, compared with that in conventional milling. Additionally, the tool life is prolonged approximately 2-5 times when the ultrasonic vibration method is applied. The tool wear pattern microcracks are only found in UAM. These might be of great importance for future research in order to understand the cutting mechanisms in UAM of in-situ TiB₂/7050Al metal matrix composites.

The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-020-00294-2

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