Product assembly and disassembly sequence optimization based on genetic algorithm and design for assembly methodologies

Product assembly and disassembly sequences are the most crucial operations in product lifecycle. In this paper, an Artificial Intelligence (AI) technique, namely Genetic Algorithm (GA) is proposed to optimize product components assembly and disassembly sequences.The proposed methodology is developed and tested on an industrial product made of plastics with no integrated assembly and permanent joint parts.GA method is applied to determine the accuracy and optimum results based on 20 assembly and disassembly sequence solutions that was generated by the Design for Assembly methodology.The results indicated that GA based approach is able to obtain a near optimal solution for assembly and disassembly sequences

STEP for e-manufacturing: Concepts and applications

The ISO standard, STandard for the Exchange Product Data Model or STEP is known as a standard data exchange format for design and manufacturing.STEP is intended to provide a complete representation of a product throughout the product lifecycle. More recently, with the idea of e-manufacturing is being put into great emphasis; this brings the consideration of implementing STEP into that new idea.This paper presents the concepts, applications, and perspectives of STEP in the e-manufacturing environment.The objective is to provide guidelines and references for future research and implementation related to this area

Product assembly sequence optimization based on genetic algorithm

Genetic algorithm (GA) is a search technique used in computing to find approximate solution to optimization and search problem based on the theory of natural selection. This study investigates the application of GA in optimizing product assembly sequences. The objective is to minimize the time taken for the parts to be assembled into a unit product. A single objective GA is used to obtain the optimal assembly sequence, exhibiting the minimum time taken. The assembly experiment is done using a case study product and results were compared with manual assembly sequences using the ‘Design for Assembly’(DFA) method. The results indicate that GA can be used to obtain a near optimal solution for minimizing the process time in sequence assembly. This shows that GA can be applied as a tool for assembly sequence planning that can be implemented at the design process to obtain faster result than the traditional methods

Experimental Analysis of Fabricated Synthetic Midthoracic Paediatric Spine as Compared to the Porcine Spine Based on Range of Motion (ROM)

The present study is aimed at investigating the mechanical behaviour of fabricated synthetic midthoracic paediatric spine based on range of motion (ROM) as compared to porcine spine as the biological specimen. The main interest was to ensure that the fabricated synthetic model could mimic the biological specimen behaviour. The synthetic paediatric spine was designed as a 200% scaled-up model to fit into the Bionix Servohydraulic spine simulator. Biomechanical tests were conducted to measure the ROM and nonlinearity of sigmoidal curves at six degrees of freedom (DOF) with moments at ±4 Nm before the specimens failed. Results were compared with the porcine spine (biological specimen). The differences found between the lateral bending and axial rotation of synthetic paediatric spine as compared to the porcine spine were 18% and 3%, respectively, but was still within the range. Flexion extension of the synthetic spine is a bit stiff in comparison of porcine spine with 45% different. The ROM curves of the synthetic paediatric spine exhibited nonlinearities for all motions as the measurements of neutral zone (NZ) and elastic zone (EZ) stiffness were below 1. Therefore, it showed that the proposed synthetic paediatric spine behaved similarly to the biological specimen, particularly on ROM

Reverse engineering of printed circuit boards: A conceptual idea

One of the backbones in electronic manufacturing industry is the printed circuit board (PCB).The recent rapid growth in electronics devices, results escalating in the production number of the PCBs.For electronic equipment and appliances which are PCB based, new generations of PCB's are produced to suit the requirements of new products.This development can lead to waste and inefficiency when perfectly serviceable electronic components and appliances have to be scrapped because of the unavailability of spare PCB's from the Original Equipment Manufacturer (OEM) or are already obsolete.This paper proposed a novel framework for reverse engineering of obsolete single layer PCB.Equivalent PCB's which can be used as spares will be reproduced utilizing this new framework.This framework involves several steps, such as Data Acquisition, Image Processing, CAD Editing, PCB Fabrication and Circuitry testing and Analysis.Each stage of the framework and the functionality evaluation of the reproduced PCB will be discussed in detail in following sections

Half pins stress shielding interaction behavior at implant-bone interface

External fixator (EF) is assembled by pin, ring, rods and locking devices. Pin implantation is used to provide stability for bone healing and osseointegration. Clinical failure of screw implant is reported to occur at the end of screw thread due to screw loosening and screw tightening. It is hypothesized that the same failure mechanism is occurred for pins. This paper presents the finite element (FE) analysis of EF implantation of different half pins on diaphysis of femur bone. Tapered conical half-pin and trocar-tip tapered half- pin were analysed using four types of materials (titanium alloy, stainless steel, magnesium alloy and carbon fiber) to determine the von-Mises stress and stress shielding. It is found that the pins were yielded at the thread of pin near to hard-soft tissue interface, which is agreed with the clinical screw implant fracture. However, magnesium alloy has the lower von- Mises and greater stress shielding (STP) transfer. Thus, trocar-tip tapered magnesium alloy half pin is predicted to be the best material for better stability of bone fixation

Reverse engineering for obsolete single layer printed circuit board (PCB)

One of the backbones in electronic manufacturing industry is the printed circuit board (PCB). The recent rapid growth in electronics devices, results escalating in the production number of the PCBs. For electronic equipment and appliances which are PCB based, new generations of PCB's are produced to suit the requirements of new products.This development can lead to waste and inefficiency when perfectly serviceable electronic components and appliances have to be scrapped because of the unavailability of spare PCB's from the Original Equipment Manufacturer (OEM) or are already obsolete. This paper proposed a novel framework for reverse engineering of obsolete single layer PCB.Equivalent PCB's which can be used as spares will be reproduced utilizing this new framework. This framework involves several steps, such as data acquisition, image processing, CAD editing, PCB fabrication and circuitry testing and analysis. Each stage of the framework and the functionality evaluation of the reproduced PCB will be discussed in detail in following sections

Morphological operation on printed circuit board (PCB) reverse engineering using MATLAB

Image segmentation has been an important and challenging issue in the Feld of computer vision over decades. It ploys a critical role for most image analysis tasks, such as object detection and recognition.The aim of this paper is to obtain segmented image of Printed Circuit Board (PCB)'s track using mathematical morphological operation. Morphological image analysis is based on the idea that images represent a collection ofspatial paiterns that can be analyzed based on some prened parterns called structuring elements. Most basic morphological operation, dilation and erosion have been employed in this research. Detail elaboration on this method will be discussed and experimental results are presented

Biomechanical analysis of patient-specific femur model of osteogenesis imperfecta with cortical and cancellous bone

Osteogenesis imperfecta (OI) is a fragile bone disease characterized by easy fractures. The femur consists of cortical and cancellous bone, each with different mechanical properties. Bone fractures often occur throughout patients’ lifetime. However, doctors still have no quantitative method to predict fractures. This project’s purpose is to investigate the mechanical behaviour of patient-specific OI femur from the finite element analysis. The fracture risk in daily activities (ADL) were examined. All the stress values were judged by the fracture criteria, assumed as 115 MPa. The exercises that exerted force more than 6 times of body weight could cause fractures. Cancellous bone was not affected in any case of ADL. The effects of force and stress on cancellous bone and its impact on fracture risk are negligible