A Multi-Objective Optimization Approach for Multi-Head Beam-Type Placement Machines

This paper addresses a highly challenging scheduling problem in the field of printed circuit board (PCB) assembly systems using Surface Mounting Devices (SMD). After describing some challenging optimization sub-problems relating to the heads of multi-head surface mounting placement machines, we formulate an integrated multi-objective mathematical model considering of two main sub-problems simultaneously. The proposed model is a mixed integer nonlinear programming one which is very complex to be solved optimally. Therefore, it is first converted into a linearized model and then solved using an efficient multi-objective approach, i.e., the augmented epsilon constraint method. An illustrative example is also provided to show the usefulness and applicability of the proposed model and solution method.PCB assembly. Multi-head beam-type placement machine. Multi-objective mathematical programming. Augmented epsilon-constraint method

An Aggregated Optimization Model for Multi-Head SMD Placements

In this article we propose an aggregate optimization approach by formulating the multi-head SMD placement optimization problem into a mixed integer program (MIP) with the variables based on batches of components. This MIP is tractable and effective in balancing workload among placement heads, minimizing the number of nozzle exchanges, and improving handling class. The handling class which specifies the traveling speed of the robot arm, to the best of our knowledge, has been for the first time incorporated in an optimization model. While the MIP produces an optimal planning for batches of components, a new sequencing heuristics is developed in order to determine the final sequence of component placements based on the outputs of the MIP. This two-stage approach guarantees a good feasible solution to the multi-head SMD placement optimization problem. The computational performance is examined using real industrial data.Multi-head surface mounting device;Component placement;Variable placement speed

Spray automated balancing of rotors: Methods and materials

The work described consists of two parts. In the first part, a survey is performed to assess the state of the art in rotor balancing technology as it applies to Army gas turbine engines and associated power transmission hardware. The second part evaluates thermal spray processes for balancing weight addition in an automated balancing procedure. The industry survey reveals that: (1) computerized balancing equipment is valuable to reduce errors, improve balance quality, and provide documentation; (2) slow-speed balancing is used exclusively, with no forseeable need for production high-speed balancing; (3) automated procedures are desired; and (4) thermal spray balancing is viewed with cautious optimism whereas laser balancing is viewed with concern for flight propulsion hardware. The FARE method (Fuel/Air Repetitive Explosion) was selected for experimental evaluation of bond strength and fatigue strength. Material combinations tested were tungsten carbide on stainless steel (17-4), Inconel 718 on Inconel 718, and Triballoy 800 on Inconel 718. Bond strengths were entirely adequate for use in balancing. Material combinations have been identified for use in hot and cold sections of an engine, with fatigue strengths equivalent to those for hand-ground materials

AN INVESTIGATION INTO PRODUCT DESIGN AND PRODUCTION TECHNIQUES WITHIN A JUST-IN-TIME MANUFACTURING ENVIRONMENT

This thesis describes the implementation of a Just-in-Time (JIT) cell on a greenfield site. It concentrates on a before and after implementation situation. Various production parameters are analysed to compare flowline performance before and after the implementation of JIT. The study is primarily concerned with the philosophies behind the Japanese management style of JIT and the practical use of JIT in a relatively small production line. Each area of JIT and its associated components are studied and, where practical, executed into practice within the production line. The study includes an investigation of the present manufacturing system and recommends improvements to aid manufacturing output. Total Quality Control, Set-up Reduction, Group Technology, Kanban, Failure Mode and Effects Analysis and Value Analysis are tools used to assist the formation of the JIT cell. Results taken after implementation revealed that stock levels reduced by 25%. Shop floor area was reduced by 205 square metres and lead time reduced by 33%. Large arrears in orders were virtually eliminated six weeks after implementation. Warranty claims were greatly reduced. Quality Management greatly enhanced the product and cross-training of operatives was achieved.Tecalemit Systems Limite

Time-study of Rotary-Screen-Printing Operation

Improving operations-efficiency is an on-going-need, for all-industries, including textile-manufacturing. Time-study is essential, for-both; planning and control, of industrial-operations. This-research used Time- study, of observational-design-type, and of element-scope-level. Classical-stopwatch-technique was-used, to-ascertain the-standard-time, for the-printing-operaton, on the Octrooi-Aangevraagd Rotary-Screen printing-machine, for 3 cycles. Performance-rating was obtained using the-speed-rating-technique. The-machine-operation was-divided into 4 distinct and repetitive machine-elements: machine set-up; color-impression; drying; and pick-up. This-time-study established Standard-Second-Value of 18, 725.41, giving machine-utilization of 65%. The-most time-consuming elements, requiring constant-operators’ attention, were found to-be color-impression, and pick-up/curing. Hawthorne-Effect was also-observed, where machine-operators noticeably-changed their-behavior, when they know that their-work being-measured. The-study made several-recommendations for future-more broader and deeper-research. Keywords: textile finishing, Hawthorne Effect, equipment, operator, allowances, standard time

Development of automatic manipulators for plastic injection machines

The automotive industry is a competitive sector, always asking for improvements in productivity, efficiency and quality. This is the reason why the demand for automation of processes arises, resulting in relying less on manpower. Bowden cables are mechanical elements that allow the transmission of motion between two or more systems. They are most of the time not visible for the user. Some examples of applications inside the car are opening doors, windows, seat’s adjustment, among many others. At present, the production of Bowden cables is done by multiple working stations with multiple operators. This work is focused on the workstation where the end of the conduit is injected. At the moment, there are injection machines with a capacity of 8 conduits at the same time and one operator at every injection machine. These injection machines need a lot of space, spend a lot of energy and usually present persistent breakdown problems, needing maintenance. The future outlook of the company is, to have smaller injection machines with a capacity of 4 conduits at a time and one operator for 2 injection machines. These injection machines are easier in maintenance and also occupy less space, consuming less energy as well. The main goal for this project is to make it possible to have 1 operator at 2 injection machines. The possibility to fully automate was rejected as it is really hard to automate the feeding of the conduits in the injection machines due to low stiffness of the conduits, becoming hard to align them in the mould. The proposed solution to make this happens is to design a manipulator to take out the 4 conduits and the scrap out of the mould. The scrap and the conduits then need to be separated, scrap to a recycling box and the conduits to a production/supply chain box. The manipulator has been successfully designed, after a thorough comparison of a variety of possibilities. All the components that were needed for this concept have successfully been defined, calculated, selected and integrated into the design. After the designing process, a budget and payback calculation has been done, as well as a return of investment. Lastly, a maintenance manual and an assembly manual has been elaborated in order to ease the assembly of all the components. The results after implementing the designed solutions are a reduction in energy consumption of the injection peocess (79,8%) and an improvement in productivity (12,0%).A indústria automóvel é um setor competitivo, mas sempre ávido por melhorias de produtividade, eficiência e qualidade. É por esse motivo que surge a procura pela automação de processos, resultando na necessidade de menos recursos humanos. Os cabos de comando são elementos mecânicos que permitem a transmissão de movimento entre dois ou mais sistemas. Na maioria das vezes, eles não são visíveis para o utilizador. Alguns exemplos de aplicações dentro do carro são abrir portas, janelas, ajuste de assentos, entre muitos outros. Atualmente, a produção de cabos de comando é feita em várias estações de trabalho através de vários operadores. Este trabalho está focado na estação de trabalho onde a espiral é sujeita à injeção de terminais. Atualmente, existem máquinas de injeção com capacidade para 8 espirais ao mesmo tempo e um operador em cada máquina de injeção. Essas máquinas de injeção ocupam muito espaço e apresentam problemas constantes de manutenção. A perspectiva futura da empresa é ter máquinas de injeção com menor volume e capacidade para injetar em 4 espirais de cada vez e necessitando apenas de um operador para cada duas máquinas de injeção. Essas máquinas de injeção são mais fáceis de gerir em termos de manutenção e também ocupam menos espaço. O principal objetivo deste projeto é tornar possível um operador em duas máquinas de injeção. A possibilidade de automatizar completamente o processo foi rejeitada, pois é realmente difícil automatizar a alimentação das espirais nas máquinas de injeção. A razão por detrás disso é o alinhamento de alguns tipos de espiral. A solução proposta para fazer isso acontecer é projetar um manipulador para retirar as 4 espirais e os canais de alimentação/gitos do molde. A sucata e as espirais precisam ser separadas, sendo a sucata encaminhada para uma caixa para reciclagem e as espirais para uma caixa de produção/logística interna. Os resultados após a implementação das soluções projetadas são uma redução no consumo de energia do processo de injeção (79,8%) e uma melhoria na produtividade (12,0%)

Algorithms and Methods for Designing and Scheduling Smart Manufacturing Systems

This book, as a Special Issue, is a collection of some of the latest advancements in designing and scheduling smart manufacturing systems. The smart manufacturing concept is undoubtedly considered a paradigm shift in manufacturing technology. This conception is part of the Industry 4.0 strategy, or equivalent national policies, and brings new challenges and opportunities for the companies that are facing tough global competition. Industry 4.0 should not only be perceived as one of many possible strategies for manufacturing companies, but also as an important practice within organizations. The main focus of Industry 4.0 implementation is to combine production, information technology, and the internet. The presented Special Issue consists of ten research papers presenting the latest works in the field. The papers include various topics, which can be divided into three categories—(i) designing and scheduling manufacturing systems (seven articles), (ii) machining process optimization (two articles), (iii) digital insurance platforms (one article). Most of the mentioned research problems are solved in these articles by using genetic algorithms, the harmony search algorithm, the hybrid bat algorithm, the combined whale optimization algorithm, and other optimization and decision-making methods. The above-mentioned groups of articles are briefly described in this order in this book