Tolerance modelling and robust design for concurrent engineering

2007 ◽  
Vol 221 (4) ◽  
pp. 455-465 ◽  
Author(s):  
J Hu ◽  
Y Peng
Keyword(s):  
Robust Design ◽  
Concurrent Engineering ◽  
Manufacturing Cost ◽  
Functional Requirements ◽  
Manufacturing Costs ◽  
Tolerance Optimization ◽  
Geometric Tolerances ◽  
Genetic Arithmetic ◽  
Tolerance Modelling ◽  
Tolerance Model

This article presents a tolerance modelling and robust design approach to support concurrent engineering. This method allows the designer to synthetically specify dimensional and geometric tolerance, considering assembly functional requirements (AFRs) and manufacturing costs. First, features of ISO/TC 213 are used as the basis for the construction of tolerance network and tolerance model for assembly. Second, the manufacturing cost-tolerance model for cylindrical and planar features is established. This model addresses not only dimensional tolerances but also geometric tolerances and nominal parameters. Finally, the robust tolerance optimization model is established, and genetic arithmetic is used to obtain robust tolerance values. The proposed approach is consistent with the philosophy of concurrent engineering, in which AFRs are satisfied and manufacturing cost is reduced. A design instance is introduced to show the validity of this method.

Efficient Gradient-Based Tolerance Optimization Using Monte Carlo Simulation

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
R. Alan Bowman
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Manufacturing Cost ◽  
Optimization Approach ◽  
Functional Requirements ◽  
Mechanical Assembly ◽  
New Approach ◽  
Tolerance Optimization ◽  
Gradient Based ◽  
Derivatives Of

A gradient-based optimization approach is employed to select design tolerances for the component dimensions of a mechanical assembly to minimize manufacturing cost while achieving a desired probability of meeting functional requirements, known as the yield. Key to the feasibility of such an approach is to be able to use Monte Carlo simulation to make estimates of the derivatives of the yield with respect to the design tolerances quickly and accurately. A new approach for making these estimates is presented and is shown to be far faster and more accurate than previous approaches. Gradient-based optimization using the new approach for estimating the derivatives is applied to example problems from the literature. The solutions are superior to all previously published solutions and are obtained with very reasonable computer run times. Additional advantages of a gradient-based approach are described.

Process Signature Modeling for Tolerance Analysis

2010 ◽  
Vol 10 (2) ◽  
Author(s):  
R. Ascione ◽  
W. Polini ◽  
Q. Semeraro
Keyword(s):  
Concurrent Engineering ◽  
Manufacturing Process ◽  
Tolerance Analysis ◽  
Actual Surface ◽  
Contact Points ◽  
Geometric Tolerances ◽  
Systematic Pattern ◽  
Process Signature ◽  
Nominal Surface

Many well-known approaches exist in the literature for tolerance analysis. All the methods proposed in the literature consider the dimensional and the geometric tolerances applied to some critical points (contact points among profiles belonging to couples of parts) on the surface of the assembly components. These points are generally considered uncorrelated since the nominal surface is considered. Therefore, the methods proposed in the literature do not consider the actual surface due to a manufacturing process. Every manufacturing process leaves on the surface a signature, i.e., a systematic pattern that characterizes all the features machined with that process. The aim of the present work is to investigate the effects of considering the manufacturing signature in solving a tolerance stack-up function. A case study involving three parts has been defined and solved by means of a method of the literature, the variational method, with and without considering the correlation among the points of the same surface due to the manufacturing signature. This work represents a first step toward the integration of the design and the manufacturing in a concurrent engineering approach.

Upper-Extremity Prostheses: A Renewed Approach

2009 ◽  
Author(s):  
Alwyn P. Johnson ◽  
Bradley Veatch
Keyword(s):  
Upper Extremity ◽  
Galvanic Corrosion ◽  
The United States ◽  
Manufacturing Cost ◽  
Heavy Duty ◽  
Axial Loads ◽  
Manufacturing Costs ◽  
Ongoing Development ◽  
Universal Interface ◽  
And Function

Upper-extremity (UE) prostheses are increasingly more functional and proportionately more costly, rendering them largely unattainable for impoverished amputees in the United States (US) and abroad. Recognizing the increasing need for appropriate devices, PhysioNetics, LLC is developing a heavy-duty, transradial body-powered (BP) UE prosthesis which can be prescribed with minimal instruction. The design of the key components, the split-hook terminal device [TD] and universal adjustable interface is presented in this paper. The TD is primarily fabricated from plastics to eliminate galvanic corrosion in saltwater environments, weighs 5.4 oz (153 g) and uses inexpensive rubber bands to generate pinch force. Unique gripping contours provide versatile grasp and replicate five (5) prehension patterns while six (6) discrete force settings provide 2 – 17 lbf (8.9 – 76 N) of pinch. Three (3) universal interface sizes (small, medium, and large) accommodate most amputees and comfortably support axial loads up to 40 lbf (178 N). Estimated manufacturing cost for a complete unit is less than US$250. Field testers report lower but comparable comfort to their individually custom-fabricated interfaces, and are highly satisfied with fit and function of the prosthesis overall. Ongoing development includes reduction of manufacturing costs, increasing interface comfort and implementing task-specific variant designs.

scholarly journals Early Robust Design—Its Effect on Parameter and Tolerance Optimization

2021 ◽  
Vol 11 (20) ◽  
pp. 9407
Author(s):  
Stefan Goetz ◽  
Martin Roth ◽  
Benjamin Schleich
Keyword(s):  
Product Development ◽  
Robust Design ◽  
Product Development Process ◽  
Design Parameters ◽  
Concept Design ◽  
Design Decisions ◽  
Dynamic Markets ◽  
Tolerance Optimization ◽  
Qualitative Approaches ◽  
Design Activities

The development of complex products with high quality in dynamic markets requires appropriate robust design and tolerancing workflows supporting the entire product development process. Despite the large number of methods and tools available for designers and tolerance engineers, there are hardly any consistent approaches that are applicable throughout all development stages. This is mainly due to the break between the primarily qualitative approaches for the concept stage and the quantitative parameter and tolerance design activities in subsequent stages. Motivated by this, this paper bridges the gap between these two different views by contrasting the used terminology and methods. Moreover, it studies the effects of early robust design decisions with a focus on Suh’s Axiomatic Design axioms on later parameter and tolerance optimization. Since most robust design activities in concept design can be ascribed to these axioms, this allows reliable statements about the specific benefits of early robust design decisions on the entire process considering variation in product development for the first time. The presented effects on the optimization of nominal design parameters and their tolerance values are shown by means of a case study based on ski bindings.

Architectures of Concurrent Engineering System for Composites

1996 ◽  
Author(s):  
Jian Zhang ◽  
H. Thomas Hahn
Keyword(s):  
Concurrent Engineering ◽  
Life Cycle Cost ◽  
Engineering System ◽  
Functional Requirements ◽  
System Architectures ◽  
Composite Manufacturing ◽  
Manufacturing Enterprises ◽  
System Requirements ◽  
Points Of View ◽  
Process Productivity

Abstract The demand for the better quality products with shorter lead-time and lower life-cycle cost forces the manufacturing enterprises all around the world to optimize their production strategies from both enterprise engineering and enterprise operation respectively. This paper addresses the architectural issue of applying the Concurrent Engineering (CE) approach in the composite manufacturing area. It first discussed briefly the characteristics of composite manufacturing process to examine the feasibility and possibility of applying the CE approach to improve its process productivity and product quality. Then the functional requirements for a concurrent engineering system for composites (CESC) were defined from both operational and architectural points of view. Finally, the integrated infrastructure based system architectures for the CESC were presented in accordance with the physical system requirements, and so were the associated and currently conducted R&D focuses for the system.

scholarly journals Length-scale effect in stability problems for thin biperiodic cylindrical shells: extended tolerance modelling

2020 ◽  
Author(s):  
B. Tomczyk ◽  
M. Gołąbczak ◽  
A. Litawska ◽  
A. Gołąbczak
Keyword(s):  
Scale Effect ◽  
Cylindrical Shells ◽  
Length Scale ◽  
Stability Problems ◽  
Constant Coefficients ◽  
A Cell ◽  
Circular Cylindrical Shells ◽  
Tolerance Modelling ◽  
Tolerance Model ◽  
Shell Equations

Abstract Thin linearly elastic Kirchhoff–Love-type circular cylindrical shells of periodically micro-inhomogeneous structure in circumferential and axial directions (biperiodic shells) are investigated. The aim of this contribution is to formulate and discuss a new averaged nonasymptotic model for the analysis of selected stability problems for these shells. This, so-called, general nonasymptotic tolerance model is derived by applying a certain extended version of the known tolerance modelling procedure. Contrary to the starting exact shell equations with highly oscillating, noncontinuous and periodic coefficients, governing equations of the tolerance model have constant coefficients depending also on a cell size. Hence, the model makes it possible to investigate the effect of a microstructure size on the global shell stability (the length-scale effect).

scholarly journals Simultaneous Robust Design and Tolerancing of Compressor Blades

2014 ◽  
Author(s):  
Eric A. Dow ◽  
Qiqi Wang
Keyword(s):  
Robust Design ◽  
Gaussian Random Field ◽  
Compressor Blade ◽  
Optimization Techniques ◽  
Manufacturing Cost ◽  
Compressor Blades ◽  
Manufacturing Tolerances ◽  
The Mean ◽  
The Impact ◽  
Blade Geometry

The manufacturing processes used to create compressor blades inevitably introduce geometric variability to the blade surface. In addition to increasing the performance variability, it has been observed that introducing geometric variability tends to reduce the mean performance of compressor blades. For example, the mean adiabatic efficiency observed in compressor blades with geometric variability is typically lower than the efficiency in the absence of variability. This “mean-shift” in performance leads to increased operating costs over the life of the compressor blade. These detrimental effects can be reduced by using robust optimization techniques to optimize the blade geometry. The impact of geometric variability can also be reduced by imposing stricter tolerances, thereby directly reducing the allowable level of variability. However, imposing stricter manufacturing tolerances increases the cost of manufacturing. Thus, the blade design and tolerances must be chosen with both performance and manufacturing cost in mind. This paper presents a computational framework for performing simultaneous robust design and tolerancing of compressor blades subject to manufacturing variability. The manufacturing variability is modelled as a Gaussian random field with non-stationary variance to simulate the effects of spatially varying manufacturing tolerances. The statistical performance of the compressor blade system is evaluated using the Monte Carlo method. A gradient based optimization scheme is used to determine the optimal blade geometry and distribution of manufacturing tolerances.

Tolerance Modeling and Optimization of XY-Table for LED Die Bonder Based on Multi-Body Systems

2011 ◽  
Vol 201-203 ◽  
pp. 2922-2926
Author(s):  
Mei Fa Huang ◽  
Jiang Tai Huang ◽  
Xiong Cheng ◽  
Jing Zhang ◽  
Hui Jing
Keyword(s):  
Optimization Model ◽  
High Speed ◽  
High Performance ◽  
Geometric Error ◽  
Structure Design ◽  
Manufacturing Costs ◽  
Tolerance Optimization ◽  
Performance Requirements ◽  
Multi Body ◽  
Geometry Error

High performance XY-table is commonly used in packaging equipments which needs rational tolerance to ensure its high performance requirements and low manufacturing costs. The related studies mainly focus on high speed motion control algorithms and high precision structure design. The proper tolerance is essential in the development process of new products. In this paper, a new method for tolerance optimization based on Multi-body systems is presented. The volumetric error model for XY-table is established based on Multi-body systems. And then, by identifying the basic geometric error components, the relationships between the final output precision of the XY-table and the geometry error sources are established. The tolerance optimization model of XY-table using the above relationships is presented. In this model, objective function is the total manufacturing costs and the constraints are the above relationships. By solving the optimization model, the optimal tolerances are obtained. Finally, a tolerance design example of LED die bonder is given to illustrate the proposed method.

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.

scholarly journals Modifikasi Alat Pemintal Benang Sutera Untuk Industri Rumah Tangga

2019 ◽  
Vol 17 (1) ◽  
pp. 101
Author(s):  
Abdul Salam ◽  
Muh Iswar ◽  
Bensar Pali ◽  
Agustinus Anggai ◽  
Janchristo Rantemangnga
Keyword(s):  
Data Collection ◽  
Performance Testing ◽  
Design Tool ◽  
Manufacturing Cost ◽  
Basic Design ◽  
Manufacturing Costs ◽  
Testing Tools ◽  
Manufacturing Performance ◽  
Equipment Manufacturing ◽  
Silk Yarn

This study aims to determine the yarn spinning time, spinning equipment manufacturing costs, and haspel shaft spinning. Basic design is done by data collection, direct visits to the silk farmers' groups, tool design, tool manufacturing, performance testing tools, analysis, calculating costs and tool manufacturing. In accordance with the testing of the spinning machine, the total working time is 8 hours / day for 3.36 kg of silk yarn, the spinning equipment manufacturing cost is Rp. 5,102,534.71. Whereas BEP is achieved when the sale of spinning machines is at least 1 unit / month or when income is Rp. 5,621,064. 

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