Small Production Line Research Articles

Design of online laser marking system by vision guided based on template matching

Industry 4.0 has put forward the requirements of improving the marking efficiency and accuracy of the laser marking industry, and manual placement has been unable to meet the production needs. In this paper, laser marking technology is combined with image recognition technology, and the automation of marking production process is realized by controlling the stepper motor to drive the conveyor belt, and accurate marking of arbitrarily placed workpiece is realized on the conveyor belt. The test results show that this marking system designed by us has high precision, and the yield of finished products reaches 99.5%, which provides a set of efficient and reliable solution for small and medium power laser marking production line to realize online positioning function.

A straightforward and low-cost pre-inspection measurement method for small gears

On-line or rapid inspection of parts is essential in streamlining manufacturing processes. A novel pre-inspection method for measuring small gears is proposed. This method requires little specialist equipment outside that normally found in a laboratory or on a shop floor. Gears are measured using a standard optical microscope. These are then processed using an image processing algorithm to give a percentage error in tooth profile. This allows only gears of sufficiently high quality to be “passed on” to more sophisticated inspection techniques. The technique is used to analyse sub-centimetre diameter gears produced using WEDM. It is found that the technique provides a simple but effective method of determining how close a gear is to the required geometry. While the result is basic, it is extremely quick and inexpensive to perform alongside the manufacturing process. This method provides a capability to small companies and production lines for pre-inspection of gears before detailed analysis without purchasing specialist equipment.

AN ANALYSIS ON INFLUENCE OF BEWILDERMENT PHENOMENON ON OPERATION TIME AND LEARNING PERIOD IN MULTI ASSEMBLY PROCESS

In recent years, more and more variety of products are produced also in manual assembly lines like white goods as customer needs become diversified. In response to this, there is a transition in the bases from a traditional mass production line to multiple small production lines for each kind of product. In the small production lines, the process tasks become more complicated than in the mass production lines because a lot of element tasks are involved with a process. As the result, there are some cases where the productivity deteriorates because the tasks which used to be completed in the mass production lines cannot be completed in time. One of the causes is assumed to be occurrence of a bewilderment phenomenon, the phenomenon where movements of human being are frozen or delayed by the freeze or blunting of thought when they handle a lot of tasks. This study, focusing on the bewilderment phenomenon, clarified the types of bewilderment phenomenon which may occur during manual assembly tasks. Then, the relationships between complexity of tasks and occurrence of bewilderment phenomenon were analyzed. Then, it was confirmed that the bewilderment phenomenon cause prolonged operation time and learning periods.

Production Systems Flow Modelling Using Decomposition Method and Required Buffers

This paper aims to provide an introduction to the analytical modelling and the discrete-events simulation for a manufacturing system. A general method of constructing a Markov chain and the simulation with discrete events using Delmia Quest software, are presented. In the present paper, those interested can find a real case study: modelling and simulation of the headrest support manufacturing line. The scientific contribution of this paper consists in the development of a theoretical model implemented in a real case study. The theoretical model estimates the production rate of the line and then, using this model we can establish how many parts in the buffers are required in order to achieve a production rate of X parts per minute. In the first phase, the manufacturing line is analyzed, then the Markov chains for subsystems with two machines and a buffer are constructed. As the Markov chains need more time to provide solutions in queues theory, they can be used only for small production lines. To find the production rate for all the system, it is necessary to apply the Markov chains and the decomposition method. Those methods are implemented in the C/C++ programming. To validate the analytical model, the discrete-event simulation with Delmia Quest software is used. The article presents some comparisons between modelling with Markov chains and simulation with Delmia Quest software and provides a method of optimization of the buffers for the case study.

Framework to decide for an expansion strategy of a small scale continuously operated modular multi-product plant

Continuously operated multi-product plants enable an efficient and flexible production of new products. As a future plant concept, a modular design allows the possibility of a stepwise capacity expansion when market demand is increasing. Choosing the right plant capacity combined with a suitable expansion strategy is a key challenge in this context. Therefore, additional costs for expansion have to be balanced against an achievable economic performance and a reduction of investment risk.In this work a framework to evaluate the production capacity of a continuously operated modular multi-product production line for a production line wise capacity expansion will be presented. As a result, a decision tree analysis integrating production planning by a capacitated lot sizing method is introduced to evaluate the economic performance of plants with different capacities in an uncertain market. The framework is applied for a case study considering a continuous production of a set of three different products. As a key result it can be said that the investment risk can be reduced by applying smaller scale modular production lines. However, the low scalability of investment costs of a small scale production line negatively affects an economic expansion strategy.

SPC Study of the Key Process of Varieties and Small Batch Production Line

According to the characteristics of variety and small batch production line and the existing problems, puts forward three layers of technology implementation framework workshop key procedure of dynamic SPC; And the use of combined with Hugh Hart control charts and cumulative sum control chart of statistical process control, to solve the Hugh Hart control chart on abnormal reaction of small offset insensitive question.

Layout Design for a Low Capacity Manufacturing Line: A Case Study

The layout re-arrangement of fashion production lines realizing many small batches is rarely deployed according to well-known engineering procedures. In fact, it would often appear too complex to call a plant engineer for the proper layout design of such small production lines. Rather, it is preferred to apply empirical methodologies when considering, generally, factory know-how, general business needs, safety requirements, and so on. In the present work, the results of a fashion manufacturing line re-layout were compared by analysing the current situation with the solutions provided by a “homemade” company design, both through a systematic layout planning approach and a broader lean reengineering activity. In order to evaluate the effectiveness of each solution, the different alternatives were compared with the help of a discrete event simulator, analysing productivity, transportation times and costs. The result of the case study showed a slight advantage with the lean approach in considering such efficiency indicators. In addition, the lean production methods allowed the designers to identify some inefficiencies that other approaches could not see, since the latter did not focus on production in a holistic way.

GASD Based Relayout Method in Mass Customization Manufacturing Quality Assurance

Mass Customization is the most advanced production mode. In Mass Customization Manufacturing (MCM), facility relayout is needed frequently in an instant, costless, seamless and frictionless mode. Three kinds of production line layouts are brought forward which are probably suitable for the MCM. These three types are the child production lines type, the C-shape lines type and the flower type, whose nature characteristics (the optimization of weak coupling relations) are also analyzed. Using a Genetic Algorithm with Sex Differentiation under the concept of quality loss, its model in MCM is built. Then a real small MCM production line in our lab and its digital model in e-Factory are described. Finally, the algorithm was integrated in the model and a petal type production line layout was implemented in a QUEST based simulation system.

Three-dimensional performance surfaces–a tool for analysing and estimation of production system performances

This paper presents a new method to describe, analyse and estimate production system performances. Work-in-process (units), lead time (number of time units spent in the production system for each unit) and throughput (number of produced units per time unit) are basic performance measures, also used in this article. It is essential for industry to know about relations between system parameters and system performances in existing systems, and in not yet implemented system alternatives. Different performances are achieved by adjusting system parameters. Trade-offs between system parameters and its different performances are necessary to stay efficient and competitive in today's market. Queuing theory and simulation can help the decision makers to estimate system performances of existing and not yet implemented systems. When the complexity increases queuing theory becomes cumbersome, very difficult and eventually impossible to use. A single simulation presents limited information. Multiple simulations are necessary to ensure that the best alternative is chosen. A high number of simulations demand a lot of computer time and resources. Reduction of runs is desirable even with cheaper computer equipment. Currently, traditional two-dimensional charts are the only tools to present and analyse system performances. This article presents a new surrogate model for easier estimation and presentation of system performances, their internal relations, and relations to the system parameters. With the new surrogate model, system performances based on simulations are presented as positions in a three-dimensional environment. Parametric curves and surfaces of Bezier type are generated and adapted to these positions. System performances of other system alternatives can then be estimated without explicit simulation. The number of simulation calculations can thereby be moderated. The method is illustrated with a small production line system.

TECHNOLOGY, INNOVATION AND COMPETITIVE ADVANTAGE: MAKING A BUSINESS PROCESS PERSPECTIVE PART OF INVESTMENT APPRAISAL

Investments in technology are an important focus for innovation but, like other forms of change, they also carry risk. The risk associated with a poor decision in part depends on the number of processes impacted by the technology, ranging from low with a small and reversible production line enhancement, to high with the irreversible implementation of an enterprise-wide information system. In terms of competitiveness, just as a local innovation can remove efficiency-sapping bottlenecks from a wide range of related business processes, so can the same business processes amplify any negative effects. This paper reports on an ESRC Innovation Programme funded project that has made a detailed study of investments in both the manufacturing and service sectors. Detailed maps of the business processes related to an investment have been recorded both before and after implementation to allow identification of where process versus technology benefits actually arise. These observations are used to construct a framework for investment appraisal that links local enhancements to process performance improvements experienced by the customer. In addition to providing a benchmark for future competitive enhancements of the technology/process, the standardised maps may also help the transfer of technologies across, and between, organisations.

Exploiting symmetry in the synthesis of supervisors for discrete event systems

We investigate a method to exploit the symmetry inherent to many discrete-event systems in order to reduce the computational complexity of the supervisory control problem (SCP). We characterize symmetry using notions of group theory and derive conditions under which there exists a quotient (reduced) automaton representation for a language with, in general, a much smaller state space than the original minimal (in number of states) automaton representation for the language. We then propose an algorithm to synthesize a solution to the SCP which is similar to the classical one, but performed on reduced automata. Special attention is given to the particular case of systems whose models contain similar components. The approach is illustrated by an example of control of a small production line.

2自由度制御理論を用いた押出し機の速度制御

In this paper, a new velocity control system with two degrees of freedom based on mathematical models for extrusion press has been presented. The feedforward controller is designed based on model matching method. In a small variety production line, the PI control system with two degrees of freedom has been developed. The PI parameters of the obtained controller are derived analytically from parameters of plant models. In a large variety small quantity production line, the H∞ control system with two degrees of freedom has been developed to cope with model errors. The effectiveness of the new system has been shown by application in an actual plant.

A simulation approach for adapting a production line balancing procedure to a probabilistic environment

Abstract Many of the line balancing procedures at present available have several limiting characteristics. First, they often tend to be based on approaches that encompass deterministic operating parameters when, in fact, realistic production systems have probabilistic operating parameters. Secondly, they are often applicable only to small noncomplex production lines. It is the purpose of this paper to demonstrate how Q-GERT network modelling and simulation can be employed to ascertain the effect of these realistic operating conditions on a line balancing procedure. Once such effects have been determined it will be shown how simulation can be used to adapt the line balancing procedure to realistic operating conditions.