Top-Down Decomposition of Multi-Product Requirements Onto Locator Tolerances

2007 ◽  
Author(s):  
Johan Lo¨o¨f ◽  
Rikard So¨derberg
Keyword(s):  
The Body ◽  
Allocation Problem ◽  
Tolerance Allocation ◽  
Manufacturing Cost ◽  
Top Down ◽  
Complex Assembly ◽  
Optimal State ◽  
Selection Of ◽  
Rear Lamp

The tolerance allocation problem consists of choosing tolerances on dimensions of a complex assembly so that they combine into an ‘optimal state’ while fulfilling certain requirements on an allowed variation. This optimal state often coincides with the minimum manufacturing cost of the product. Sometimes it is balanced with an artificial cost that the deviation from target induces on the quality of the product. This paper suggests a multiobjective formulation of the tolerance allocation problem to automatically decompose requirements for an allowed variation on a set of critical product dimensions. This formulation is demonstrated using a rear lamp on a car with multiple requirements on allowed variation. In this case only the tolerances on locators that locates the lamp on the body are considered. The paper also reviews a selection of work that has been made on solving tolerance allocation problems.

The Reduced Tolerance Allocation Problem

2016 ◽  
Author(s):  
David Sh. L. Shoukr ◽  
Mohamed H. Gadallah ◽  
Sayed M. Metwalli
Keyword(s):  
Genetic Algorithm ◽  
Optimization Problem ◽  
Computational Effort ◽  
Allocation Problem ◽  
Tolerance Allocation ◽  
Benchmark Problems ◽  
Manufacturing Processes ◽  
Manufacturing Cost ◽  
Functional Requirements ◽  
Different Dimensions

Tolerance allocation is a necessary and important step in product design and development. It involves the assignment of tolerances to different dimensions such that the manufacturing cost is minimum, while maintaining the tolerance stack-up conditions satisfied. Considering the design functional requirements, manufacturing processes, and dimensional and/or geometrical tolerances, the tolerance allocation problem requires intensive computational effort and time. An approach is proposed to reduce the size of the tolerance allocation problem using design of experiments (DOE). Instead of solving the optimization problem for all dimensional tolerances, it is solved for the significant dimensions only and the insignificant dimensional tolerances are set at lower control levels. A Genetic Algorithm is developed and employed to optimize the synthesis problem. A set of benchmark problems are used to test the proposed approach, and results are compared with some standard problems in literature.

An Immune Algorithm for Least Cost Advanced Tolerance Design Problem

2006 ◽  
Vol 505-507 ◽  
pp. 511-516
Author(s):  
Ta Cheng Chen ◽  
Tung-Chou Hsu
Keyword(s):  
Immune Algorithm ◽  
Allocation Problem ◽  
Tolerance Allocation ◽  
Mixed Integer ◽  
Manufacturing Cost ◽  
Process Selection ◽  
Artificial Immune ◽  
Artificial Immune Algorithm ◽  
Allocation Problems ◽  
Artificial Immune Algorithms

This paper considers nonlinearly mixed integer tolerance allocation problems in which both tolerance and process selection are to be decided simultaneously so as to minimize the manufacturing cost. The tolerance allocation problem has been studied in the literature for decades, usually using mathematical programming or heuristic/metaheuristic optimization approaches. The difficulties encountered for both methodologies are the number of constraints and the difficulty of satisfying the constraints. A penalty-guided artificial immune algorithm is presented for solving such mixed integer tolerance allocation problems. Numerical examples indicate that the proposed artificial immune algorithms perform well for the tolerance allocation problem considered in this paper. In particular, as reported, solutions obtained by artificial immune algorithm are as well as or better than the previously best-known solutions.

scholarly journals MICROSCOPIC EXAMINATION OF WOOL FIBERS IN PRAMENKA FOR THE QUALITY CLASSIFICATION OF RAW WOOL

2020 ◽  
Vol 19 (2) ◽  
Author(s):  
Nadžida MLAĆO ◽  
Amela KATICA ◽  
Velija KATICA ◽  
Almira SOFTIĆ ◽  
Vedad ŠAKIĆ ◽  
...  
Keyword(s):  
Textile Industry ◽  
Organic Waste ◽  
Environmental Problem ◽  
The Body ◽  
Raw Material ◽  
Wool Fibers ◽  
Quality Classification ◽  
Selection Of

In Bosnia and Herzegovina, Montenegro, as well as in most Balkan countries, wool is a major environmental problem. After sheep shearing, farmers usually leave the wool at the shear sites, providing poorly degradable organic waste. The purchase price of such untreated wool is as low as its quality. By this research, we have tried to draw attention, from another aspect, to the quality of wool fibers of certain parts of the body, which is ultimately very important in the textile industry and in the selection of wool for further processing. The cuticle is made from cornfied cells, flakes, located on the surface of wool fibers. One of the significant roles of the cuticle is the protective. Namely, the cuticle protects the wool fibers from various external factors, whether mechanical or physic-chemical (such as ammonia evaporation in poorly maintained facilities, etc.), which can damage the fleece and thus make it less quality. We have found some differences in the flakes position and shape in the wool fibers we investigated, depending on part of the body from which they were sampled. However, by microscopic analyses of samples taken from the root of the tail, we have found that the flakes were much smaller and finer in structure than the arrangement and appearance of the cornified flakes from the rump. In this study, we have compared the appearance and arrangement of flakes of cuticle, which is very important in assessing the quality of wool and its further use as a raw material.

Simultaneous Tolerance Synthesis for Manufacturing and Quality using Evolutionary Algorithms

2011 ◽  
Vol 2 (2) ◽  
pp. 1-20 ◽  
Author(s):  
Y. S. Rao ◽  
C. S. P. Rao ◽  
G. Ranga Janardhana ◽  
Pandu R. Vundavilli
Keyword(s):  
Evolutionary Algorithms ◽  
Product Design ◽  
Manufacturing Industry ◽  
Tolerance Allocation ◽  
Manufacturing Cost ◽  
Quality Loss ◽  
Mechanical Assembly ◽  
Swarm Optimization ◽  
Single Objective

Tolerance plays a major role in the manufacturing industry, as it affects product design, manufacturing, and quality of the product. This paper considers product design, manufacturing, and quality simultaneously, and introduces a concurrent approach for tolerance allocation using evolutionary algorithms. A non-linear model that minimizes the combination of manufacturing cost and quality loss simultaneously, in a single objective function has been considered. In the proposed work, evolutionary algorithms (that is, Genetic Algorithms (GA), Differential Evolution (DE), and Particle Swarm Optimization (PSO)) have been used to determine the optimal tolerances at the minimum manufacturing and quality loss cost. The application of the proposed methodology has been demonstrated on a simple mechanical assembly.

A Closed-Form Approach for Optimum Tolerance Allocation of Assemblies with General Tolerance-Cost Function

2011 ◽  
Vol 201-203 ◽  
pp. 1272-1278
Author(s):  
Kuo Ming Cheng ◽  
Jhy Cherng Tsai
Keyword(s):  
Closed Form ◽  
Closed Form Solution ◽  
Form Solution ◽  
Equality Constraints ◽  
Allocation Problem ◽  
Tolerance Allocation ◽  
Lambert W Function ◽  
Manufacturing Cost ◽  
Worst Case ◽  
Constrained Minimization Problems

Tolerancing is one of the most crucial foundations for industry development and an index of product quality and cost. As tolerance allocation is based on manufacturing costs, this paper proposes a comprehensive method for optimal tolerance allocation with minimum manufacturing cost subject to constraints on dimensional chains and machining capabilities. The general reciprocal power and exponential cost-tolerance models with equality constraints as well as the worst-case and statistical tolerancings are employed in this method. A closed-form solution for the optimization problem by applying Lagrange multipliers is derived. The optimal tolerance allocation problem for reciprocal exponential cost-tolerance model by introducing Lambert W function is demonstrated. For constrained minimization problems with only equality constraints, the optimum design can be obtained by solving simultaneous equations without differentiating. An example is illustrated to demonstrate this approach. The result also shows that tolerance can be allocated economically and accurately using this method. The contribution of this paper is to solve the optimal tolerancing allocation problem by an efficient and robust method with simultaneous active constraints.

Optimum tolerance synthesis of simple assemblies with nominal dimension selection using genetic algorithm

2016 ◽  
Vol 230 (19) ◽  
pp. 3488-3508 ◽  
Author(s):  
D Vignesh Kumar ◽  
D Ravindran ◽  
M Siva Kumar ◽  
MN Islam
Keyword(s):  
Genetic Algorithm ◽  
Vital Role ◽  
Tolerance Allocation ◽  
Manufacturing Cost ◽  
Test Results ◽  
Manufacturing Costs ◽  
Critical Dimensions ◽  
Optimal Adjustment ◽  
Selection Of ◽  
Nominal Dimension

Optimum tolerance allocation plays a vital role in minimization of the direct manufacturing cost, and it is sensitive to tolerances related to variations in manufacturing processes. However, optimal adjustment of both nominal dimensions and selection of tolerances may further reduce assembly manufacturing cost and wastage of materials during processing. Most studies in existing literature focus on optimum tolerance allocation for the assemblies without considering nominal dimension selection. The method proposed in this work uses genetic algorithm techniques to allocate tolerances to assembly components, thereby minimizing costs. The component alternate nominal dimensions are predicted based on critical dimensions and its tolerances. The effectiveness of the developed algorithms demonstrated using randomly generated problems as well as sample problems taken from the literature. Test results are compared with those obtained using the Lagrange multiplier method. It is shown that by adjusting the nominal dimensions, the proposed method yields considerable savings in manufacturing costs.

scholarly journals From a Tactile Epistemology to the Ontology of Affect: Two Readings of Deleuze’s Time-Image in Film and New Media Theory

2013 ◽  
Vol 6 (1) ◽  
pp. 19-33
Author(s):  
Árpád Bak
Keyword(s):  
New Media ◽  
Video Art ◽  
The Body ◽  
Experimental Film ◽  
Media Arts ◽  
Contemporary Media ◽  
The One ◽  
Time Image ◽  
Selection Of

Abstract The paper compares how two theorists of media arts, Mark B. N. Hansen and Laura U. Marks, interpret the relation of Deleuze’s time-image to corporeality. Both argue that some novel types of images - in film and media art - engage the body in new and also more intensive ways than traditional cinema did. While they remain committed to Bergson’s theory of perception, their works offer different readings of how the Bergsonian concepts of Deleuze’s film philosophy can be applied to new media: on the one hand, to the non-signifying, affective properties of Hansen’s digital image in contemporary media arts, and on the other, to Marks’s - in the last instance, memory-signifying - haptic image, which she discussed initially in connection with video art and experimental film. In New Philosophy for New Media (2004), Hansen asserts that “Deleuze’s neo-Bergsonist account of the cinema carries out the progressive disembodying of the [body]”, which “reaches its culmination in […] what he calls the ‘time-image,’” and calls for “a rehabilitation of Bergson’s embodied concept of affection.” While Marks also offers some criticism on Deleuze, she suggests that his “theory of timeimage cinema permits a discussion of the multisensory quality of cinema,” and undertakes to examine “how the body may be involved in the inauguration of time-image cinema.” Besides arguing that both tendencies are present in Deleuze to varying degrees, I attempt to contextualize the divergences in their lines of thought by looking at the types of media and selection of works they examine, as well as the possible theoretical commitments that might guide these selective strategies

scholarly journals Selection of Sport- and Racehorses

2005 ◽  
pp. 3-10
Author(s):  
Sándor Mihók
Keyword(s):  
High Performance ◽  
Decisive Role ◽  
Active Role ◽  
The Body ◽  
Second Phase ◽  
Human Needs ◽  
Equestrian Sports ◽  
The Moment ◽  
Selection Of

The utilisation of the horse has changed from time to time in response to human needs. For a few decades, it has been serving in several equestrian sports more intensively. It has also been proved that the standards for this kind of performance cannot be established in the way certain characteristics, such as the weight gain or milk production of other animal breeds can. Breeding horses for sporting comprises highly complex selection criteria.Some of these (e.g. external features, temperament, manageability and intelligence) do not put the breeder in a difficult position, but finding the traits that establishes the safety of sporting achievements poses a genetic problem.The performance of a horse for sports is a highly complex feature, which cannot easily be assessed or put down in figures. In addition, man plays a decisive role in shaping all kinds of performance of a horse at any given time by not only creating conditions for a better performance, but also by playing an active role in increasing it.The performance of the horse is mostly defined by its general aptitude to movement, ie., the regularity, clear rhythm and springiness of basic types of strides, as well as the ability to move in a naturally balanced way. Training and riding principles are based on these traits. These two together will determine about 70% of the value of the horse and its adequacy for high performance equestrian sports. In order to avoid subjectivity in determining the above variables and to increase the degree of objectivity, competent expert teams (trainers, judges, other riders) are employed to form an opinion on an individual animal.Assessing horse performance outside races does not seem to be efficient, as owing to the dominant effects of the environment, the indicator of inheritability is hardly above 0.1.Free jumping is an especially appropriate means for assessing a horse’s readiness and ability to move in an environment free of disturbing factors. In free jumping, it is especially important to judge the style of the jump. The first phase of jumping – as a sequence of movements – lasts from the moment the fore-feet touch the ground until the moment the hind-feet push off, while the second phase lasts from this moment until touching the ground. The most important task in the first phase is to make the angle of the dip of the body by the supporting fore-feet that is necessary for the jump. The quality of the jump is determined by the jumping and adequately expanded hind-legs. The intensity of pushing off and jumping done by the hind-legs can be inferred, and differences between individuals can be discerned from the shaping of the curve by the hocks and the paths of the pasterns in relation to the withers.

Robust Design by Tolerance Allocation Considering Quality and Manufacturing Cost

1994 ◽  
Author(s):  
Rikard Söderberg
Keyword(s):  
Critical Parameter ◽  
Point Of View ◽  
Total Loss ◽  
Tolerance Allocation ◽  
Manufacturing Cost ◽  
Total Quality ◽  
Tolerance Limits ◽  
Component Price ◽  
Customer Values

Abstract Involving customer values in the design process is necessary to improve the total quality of a product. The purpose of this work is to establish a theoretical base for tolerance allocation which allows both quality and manufacturing cost to be considered. The paper addresses functional tolerance chains, i.e. tolerance chains that involve a dimension important for the function of the product or component. The total loss to customer is determined as the sum of two tolerance dependent properties; the functionality loss and the component price. The functionality loss represents the customer’s economical loss due to poor functionality. The optimal tolerance limits are found by minimizing the total loss to customer. These are the limits that represent the best trade-off between cost and quality, from the customer’s point of view. This work specially emphasizes a method for treating asymmetrical functionality loss, i.e. when the design is more sensitive to a deviation of a critical parameter in one direction than in the other. By moving the manufacturing target in a direction away from the most sensitive part, the total loss to customer can be reduced. This paper describes how the optimal manufacturing target and corresponding symmetrical tolerance band are found. This method thus increases the robustness of the design. The method may be used for single tolerances or any resulting tolerance of a tolerance chain.

Simultaneous Tolerance Synthesis for Manufacturing and Quality using Evolutionary Algorithms

2013 ◽  
pp. 54-72
Author(s):  
Y. S. Rao ◽  
C. S. P. Rao ◽  
G. Ranga Janardhana ◽  
Pandu R. Vundavilli
Keyword(s):  
Evolutionary Algorithms ◽  
Product Design ◽  
Manufacturing Industry ◽  
Tolerance Allocation ◽  
Manufacturing Cost ◽  
Quality Loss ◽  
Mechanical Assembly ◽  
Swarm Optimization ◽  
Single Objective

Tolerance plays a major role in the manufacturing industry, as it affects product design, manufacturing, and quality of the product. This paper considers product design, manufacturing, and quality simultaneously, and introduces a concurrent approach for tolerance allocation using evolutionary algorithms. A non-linear model that minimizes the combination of manufacturing cost and quality loss simultaneously, in a single objective function has been considered. In the proposed work, evolutionary algorithms (that is, Genetic Algorithms (GA), Differential Evolution (DE), and Particle Swarm Optimization (PSO)) have been used to determine the optimal tolerances at the minimum manufacturing and quality loss cost. The application of the proposed methodology has been demonstrated on a simple mechanical assembly.

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