Optimizing the Sharpening Process of Hybrid-Bonded Diamond Grinding Wheels by Means of a Process Model

The grinding wheel topography influences the cutting performance and thus the economic efficiency of a grinding process. In contrary to conventional grinding wheels, super abrasive grinding wheels should undergo an additional sharpening process after the initial profiling process to obtain a suitable microstructure of the grinding wheel. Due to the lack of scientific knowledge, the sharpening process is mostly performed manually in industrial practice. A CNC-controlled sharpening process can not only improve the reproducibility of grinding processes but also decrease the secondary processing time and thereby increase the economic efficiency significantly. To optimize the sharpening process, experimental investigations were carried out to identify the significant sharpening parameters influencing the grinding wheel topography. The sharpening block width lSb, the grain size of the sharpening block dkSb and the area-related material removal in sharpening V’’Sb were identified as the most significant parameters. Additional experiments were performed to further quantify the influence of the significant sharpening parameters. Based on that, a process model was developed to predict the required sharpening parameters for certain target topographies. By using the process model, constant work results and improved process reliability can be obtained.

Investigating the Conditions of Automatic Assembly of Polyhedral Joints

Purpose – Providing the technological reliability of the robotic assembly of joints with RK-profile on the basis of adaptation devices and low-frequency oscillations. Design/methodology/approach – Ensuring the assembly conditions is achieved by the vibration device that provides oscillations relative to the two axes, perpendicular to the assembly direction and rotation about the assembly axis. Compensation of the linear error in the position of the parts is attained by an adaptive gripper with a flexible link. Findings – A mathematical model describing the assembly process of parts relative to the non-inertial coordinate system is developed. The technological modes of profile parts assembly are defined. Originality/value – The robotic assembly method of profile joints by the adaptation devices, namely a combination of elastic fixing of the installed profile part and the simultaneous rotation and vibration of the base part to improve the process reliability is developed. Experimental studies confirmed the adequacy of the created mathematical model. The patent for the assembly method of profile joints with a gap is received.

Reliability optimization of process parameters for marine diesel engine block hole system machining using improved PSO

The processing quality of the block hole system affects the working performance of the marine diesel engine block directly. Choosing an appropriate combination of process parameters is a prerequisite to improving the accuracy of the block hole system. Uncertain fluctuations of process parameters during the machining process would affect the process reliability of the block hole system, resulting in an ultra-poor accuracy. For this reason, the RBF method is used to establish the relationship between the verticality of the cylinder hole and process parameters, including cutting speed, depth of cut, and feed rate. The minimum cylinder hole verticality is taken as the goal and the process reliability constraints of the cylinder hole are set based on Monte Carlo, a reliability optimization model of processing parameters for cylinder hole is established in this paper. Meanwhile, an improved particle swarm algorithm was designed to solve the model, and eventually, the global optimal combination of process parameters for the cylinder hole processing of the diesel engine block in the reliability stable region was obtained.

Dry Fibre Placement: The Influence of Process Parameters on Mechanical Laminate Properties and Infusion Behaviour

Within the dry fibre placement (DFP) process, spread and pre-bindered carbon fibre rovings are automatically processed into dry textile preforms using 2-D and 3-D laying systems. The aim was to automate existing hand lay-up processes, reducing the complexity, increasing robustness, and facilitating the handling of the DFP technology. Process reliability, low waste rates, and flexible production are demonstrated. In this publication, the influences of the process parameters, 2 mm wide gaps and the percentage of 90° plies in the laminate, are investigated with regard to the mechanical properties, the permeability, and the infusion times in the preform z-direction (thickness). The effects on stiffness and strength are compared for several use cases. An approach to determine the infusion times as a function of the laminate thickness, the ply structure, and 2 mm wide gaps is demonstrated and analysed using vacuum-assisted process (VAP) infusion tests. The investigations are performed with carbon fibre tows (24 k), a reactive epoxy-based binder system, and a thermoset infusion resin system.

Transfer of Tactile Sensors Using Stiction Effect Temporary Handling

A novel method for transfer of tactile sensors using stiction effect temporary handling (SETH) is presented to simplify the microelectromechanical-system (MEMS)/CMOS integration process, improve the process reliability and electrical performance, and reduce material constriction. The structure of the tactile sensor and the reroute substrate were first manufactured separately. Following the release process, the stiction-contact structures, which are designed to protect the low-stress silicon nitride diaphragm of the tactile sensor and prevent the low-stress silicon nitride diaphragm from moving during the subsequent bonding process, are temporarily bonded to the substrate owing to the stiction effect. After the released tactile sensor is bonded to the reroute substrate by Au–Si eutectic flip-chip bonding, a pulling force perpendicular to the bonded die is applied to break away the temporary supported beam of the tactile sensor, and the tactile sensor is then successfully transferred to the reroute substrate. The size of the transferred tactile sensor is as small as 180 μm × 180 μm × 1.2 μm, and the force area of the tactile sensor is only 120 μm × 120 μm × 1.2 μm. The maximum misalignment of the flip-chip bonding process is approximately 1.5 μm. The tactile sensors are tested from 0 to 17.1 kPa when the power supply is 5 V, resulting in a sensitivity of 0.22 mV/V/kPa, 0.26 mV/V/kPa, 0.27 mV/V/kPa and 0.27 mV/V/kPa, separately. The stress caused by the Au–Si eutectic flip-chip bonding ranges from −5.83 to +5.54 kPa. The temporary bonding strength caused by stiction is calculated to be larger than 7.06 kPa and less than 22.31 kPa. The shear strength of the bonded test structure is approximately 30.74 MPa and the yield of the transferred tactile sensors is as high as 90%.

Development of a new joining technology for hybrid joints of sheet metal and continuous fiber-reinforced thermoplastics

Punctiform mechanical joining technologies, such as riveting, clinching, or screwing, which are widely used in sheet metal processing, are frequently applied because they have been established for many years. Depending on the process, they offer a variety of advantages such as one-sided accessibility, re-detachability, and no need for pre-punching operations or auxiliary joining elements. In addition, the processes often guarantee a high process reliability and extensive process monitoring. However, with thermoplastic composites, they lead to considerable stress concentrations at the joint due to the fibers. Undesirable fiber and inter-fiber breaks then result. With the development of the novel joining technology of joint stamp riveting, an improvement is achieved in this situation that has been described for hybrid joints on components made of thermoplastic composites and metal sheets. The joining principle is based on the formation of a form lock between the joining partners. The thermoplastic composite is thermomechanically formed by means of a joint stamp without using an auxiliary joining element. Within the scope of a research project, the joining process was characterized with regard to the structure of the joining spot, the geometry of the forming tools, and also the mechanical properties for purposes of analyzing and designing the joining process.

The Effect of Extrovert-Introvert Personality Types on Consumer Trust on Online Customer at Bekado Mart

This study examines the effect of extrovert-introvert personality types on consumer confidence in online customers at Bekado Mart Purwokerto. This research is a quantitative study with a population of online customers or members of Bekado Mart Purwokerto. The sample used in this study was 500 customers (according to the data of the Bekado Mart admin). The data collection method uses a consumer confidence scale and an extrovert-introvert personality type scale. The sampling system uses an accidental sampling technique carried out using Google Forms in the data collection process. Reliability test using Cronbach alpha. The consumer confidence scale is 38 items. Based on the results of the study, sig. P = 0.000 (p < 0.05) and the coefficient of determination Rsquare = .148. The proposed hypothesis is accepted, namely that the extrovert-introvert personality type influences consumer confidence in online customers at Bekado Mart Purwokerto. The regression results show a positive value, meaning that the extrovert-introvert personality type influences consumer confidence.

Health Monitoring Using Acoustic Emission Technique During Fused Filament Fabrication Printing Process

Fused Filament Fabrication (FFF) is one of the most popular additive manufacturing technologies for manufacturing prototypes with various complex geometries. However, current commercial FFF machines have limitations in terms of process reliability and product quality. In order to overcome these limitations and improve the accuracy and reliability of these machines, a real-time monitoring system is needed to make sure that any part defects can be detected during the printing process and printing parameters can be identified that can be modified to resolve the printing anomalies resulting in minimization of waste and improvement of efficiency. In this study, a method for in-situ monitoring of FFF machine conditions is proposed utilizing an acoustic emission (AE) technology. The AE sensor is used to monitor the vibration signals generated during the whole printing process in real-time. The AE signal is then analyzed and processed, and categorized according to the selected objective characteristics. The proposed method can be utilized to identify the abnormal states of machine conditions. The time-domain features of AE hits after post-processing are used as key indicators. Experimental results show that this method has the potential to be used as a non-invasive diagnostic and prognostic tool for FFF machine maintenance and process control.

Evaluation and Selection of the Quality Methods for Manufacturing Process Reliability Improvement—Intuitionistic Fuzzy Sets and Genetic Algorithm Approach

The aim of this research is to propose a hybrid decision-making model for evaluation and selection of quality methods whose application leads to improved reliability of manufacturing in the process industry. Evaluation of failures and determination of their priorities are based on failure mode and effect analysis (FMEA), which is a widely used framework in practice combining with triangular intuitionistic fuzzy numbers (TIFNs). The all-existing uncertainties in the relative importance of the risk factors (RFs), their values, applicability of the quality methods, as well as implementation costs are described by pre-defined linguistic terms which are modeled by the TIFNs. The selection of quality methods is stated as the rubber knapsack problem which is decomposed into subproblems with a certain number of solution elements. The solution of this problem is found by using genetic algorithm (GA). The model is verified through the case study with the real-life data originating from a significant number of organizations from one region. It is shown that the proposed model is highly suitable as a decision-making tool for improving the manufacturing process reliability in small and medium enterprises (SMEs) of process industry.

Machining-Reliability-based Optimization of Process Parameters for Marine Diesel Engine Block Hole System Using HJ-PSO

The processing quality of the block hole system affects the working performance of the marine diesel engine block directly. Choosing an appropriate combination of process parameters is a prerequisite to improve the accuracy of the block hole system. Uncertain fluctuations of process parameters during the machining process would affect the process reliability of the block hole system, resulting in an ultra-poor accuracy. For this reason, the RBF method is used to establish the relationship between the verticality of the cylinder hole and process parameters, including cutting speed, depth of cut, and feed rate. Taking the minimum cylinder hole verticality as the goal and setting the process reliability constraints of the cylinder hole based on Monte Carlo, a reliability optimization model of processing parameters for cylinder hole is established in this paper. Meanwhile, an improved particle swarm algorithm was designed to solve the model, and eventually, the global optimal combination of process parameters for the cylinder hole processing of the diesel engine block in the reliability stable region was obtained.