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.

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.

Optimal Manufacturing Cost and Quality Loss by Reciprocal Exponential Cost-Tolerance Function

2015 ◽  
Vol 766-767 ◽  
pp. 1097-1102 ◽  
Author(s):  
L. Ramesh Kumar ◽  
K.P. Padmanaban
Keyword(s):  
Solution Method ◽  
Function Parameter ◽  
Design Stage ◽  
Manufacturing Cost ◽  
Quality Loss ◽  
Productivity Improvement ◽  
Proposed Model ◽  
And Function ◽  
Blue Print

Specific improvement of a quality of the product and its productivity improvement mainly depend on the designing and fixing of the tolerance of that product. This is done prior to the design stage of the product. Design of tolerance is based on its functional conditions only then its specification for each component in a mechanical system is developed. The finalized tolerance is printed as a drawing (blue print tolerance), inclusive of individual part details, fit and function parameter, critical parameter and design criteria.This paper reveals a new comprehensive and analytical method for fixing an optimal tolerance by worse case limit. This is done to reduce the manufacturing cost and to improve the quality loss of the product by using the expoentional cost function. An example illustrates the proposed model attached with solution method.

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.

Optimizing Tolerance Allocation Based on Manufacturing Cost and Quality Loss

1994 ◽  
Author(s):  
Mukund Krishnaswami ◽  
R. W. Mayne
Keyword(s):  
Product Quality ◽  
Numerical Optimization ◽  
Quantitative Measure ◽  
Tolerance Allocation ◽  
Manufacturing Cost ◽  
Quality Loss ◽  
Assembly Tolerance ◽  
Trade Offs ◽  
Nonlinear Programming Methods ◽  
Methods Numerical

Abstract This paper describes a procedure for optimizing the allocation of tolerances considering manufacturing cost and product quality in a constrained optimization process. The procedure can utilize various existing models for relating manufacturing costs to part tolerances. It also includes a relationship between part tolerances and assembly tolerance to provide a quantitative measure of product quality using the Taguchi concept of quality loss. The two cost relationships are combined in a formulation which is convenient for solving the optimal tolerance allocation problem by nonlinear programming methods. Numerical optimization can then be directly applied to balance manufacturing cost and product quality allowing trade-offs to be explored.

Use of a Quality Loss Function to Select Statistical Tolerances

1997 ◽  
Vol 119 (3) ◽  
pp. 410-416 ◽  
Author(s):  
H. Vasseur ◽  
T. R. Kurfess ◽  
J. Cagan
Keyword(s):  
Loss Function ◽  
A Priori ◽  
Manufacturing Cost ◽  
Quality Loss ◽  
Quality Loss Function ◽  
Component Assembly ◽  
The Impact ◽  
The Relationship ◽  
Selection Of

In this paper, we present a method for the selection of processes to manufacture various parts of an assembly by establishing a compromise between product quality and part manufacturing cost. We quantify the impact the precision of a part characteristic has on the overall quality of a product by using a standard Taguchi loss function. Part manufacturing cost is modeled as a function of process precision (i.e., standard deviation of the output characteristic) as opposed to previous models where manufacturing cost is a function of part tolerance. This approach is more realistic and does not assume, a priori, a relationship between conventional tolerance and process spread. Rather than allocating conventional tolerances on the assembly parts, we use statistical tolerances that are more pertinent when using a quality loss function. The model adopted makes it possible to investigate the relationship between optimum quality loss and tolerance variations. As expected, the optimum quality loss generally decreases when the tolerance increases. Exceptions may be encountered when changes of process occur. The manufacture of a simple three component assembly is studied to illustrate the findings.

Closed-Form Optimal Tolerance for Minimum Manufacturing Cost and Quality Loss Cost

2013 ◽  
Vol 655-657 ◽  
pp. 2084-2087 ◽  
Author(s):  
Shao Gang Liu ◽  
Qiu Jin
Keyword(s):  
Closed Form ◽  
Lagrange Multiplier ◽  
Significant Influence ◽  
Tolerance Allocation ◽  
Manufacturing Cost ◽  
Functional Requirement ◽  
Quality Loss ◽  
Functional Constraints ◽  
Power Cost ◽  
Tolerance Model

Tolerance allocation have significant influence on the manufacturing cost and quality loss cost. In order to obtain optimal tolerance, Lagrange multiplier method is used to minimize the summation of manufacturing cost and quality loss cost subject to constraints on product functional requirement. The reciprocal power cost-tolerance model with different functional constraints is considered, and closed-form optimal tolerances are obtained. Using the model proposed in this paper, the optimal tolerance can be obtained quickly and accurately. One example is used to illustrate the method proposed in this paper.

Tolerance Allocation Considering Customer and Manufacturer Objectives

1993 ◽  
Author(s):  
Rikard Söderberg
Keyword(s):  
Cost Function ◽  
Loss Function ◽  
Roller Bearing ◽  
Critical Dimension ◽  
Tolerance Allocation ◽  
Manufacturing Cost ◽  
Total Quality ◽  
Basic Ideas ◽  
Customer Values

Abstract Involving customer values in the design process is necessary for improving the total quality of a product This paper presents the basic ideas for a method that allows tolerances to be assigned to dimensions in a tolerance chain with regard to both customer and manufacturer objectives. The method uses an extended “quality loss function” to consider customer objectives. The total life of a component is here focused, representing one important aspect of quality. A minimum manufacturing cost function for the tolerance of a critical dimension, dependent on a number of manufactured components, is determined. This function is used to consider manufacturers’ objectives. Based on the customer’s total loss function and the minimum manufacturing cost function, the optimal tolerance limits of a critical dimension are determined. These are the tolerances that simultaneously satisfy the customer and the manufacturer as much as possible. The ideas behind the method are described using a roller bearing application as an example.

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