Journal articles: 'Tolerance'

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Burszta, Wojciech. "Wędrująca idea tolerancji." Slavia Meridionalis 14 (November 27, 2014): 33–47. http://dx.doi.org/10.11649/sm.2014.002.

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The travelling idea of toleranceAs an idea, “tolerance” belongs to a category of notions that can be seen as a subjective phenomenon in the sense that the underlying semantics of its assumptions are greatly varied and variable. Tolerance is a travelling idea exactly because of this primary reason, for which the practice of verbalising tolerance influences the way it is being understood. Tolerance always forms a relation with a wide palette of similar notions, which decide on its particular semantic understanding. These include for example the notions of universality, relativity and cosmopolitism. Against this background, the difference between tolerance in theory (subjective) and tolerance in practice (objective, pragmatic) also becomes evident.The paper presents several important episodes from the specific journey of tolerance-as-an-idea in the history of European culture – beginning with the Ottoman Empire and ending with modern disputes on the status of tolerance in liberal democracies. Wędrująca idea tolerancjiTolerancja należy do tych idei, które można traktować jako zjawisko podmiotowe w tym sensie, że semantyka założeń, leżąca u podstaw jego rozumienia, jest bardzo zróżnicowana i zmienna. Tolerancja jest ideą podróżującą w czasie i przestrzeni właśnie z tego podstawowego powodu, że sposób jej werbalizacji decyduje każdorazowo o sposobie, w jaki rozumie się to pojęcie. Tolerancja zawsze wchodzi w związki z całą paletą pokrewnych pojęć, w ramach których tworzy się konkretna semantyka tej idei. To m.in. pojęcia uniwersalności, relatywności i kosmopolityzmu. Na tym tle dobrze widać także różnicę między tolerancją w sensie teoretycznym (podmiotową) a tolerancją praktyczną (przedmiotową, pragmatyczną).Artykuł przedstawia kilka najważniejszych epizodów wędrówki tolerancji-jako-idei w historii kultury europejskiej – począwszy od Imperium Osmańskiego, a skończywszy na dzisiejszych sporach o status tolerancji w demokracjach liberalnych.

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Lustig, R., R. Hochmuth, and H. Meerkamm. "Tolerance Analysis of Sheet Metal Assemblies with Focus on Non-Rigid Geometry." Advanced Materials Research 6-8 (May 2005): 249–54. http://dx.doi.org/10.4028/www.scientific.net/amr.6-8.249.

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Tolerance analysis is nowadays a modern and efficient tool to simulate toleranced assemblies. As a result the designer gets the closing tolerance as well as to the priority of influencing tolerances. The closing tolerance can be calculated in worst-case or in statistical manner. These methods and tools have in common that only rigid, non-deformable geometry can be integrated. Many application cases in industry have tolerances as well as the influence of elastic deformations of components to be considered. Effects as spring-back of deformed components for assembly are reality. In this paper a method will be presented which allows a tolerance analysis of non-rigid geometry, especially for sheet metal assemblies.

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Polini, Wilma, Andrea Corrado, and Costanzo Cavaliere. "Tolerance Analysis Supports Tolerance Assignment." International Journal of Manufacturing, Materials, and Mechanical Engineering 8, no. 1 (January 2018): 1–20. http://dx.doi.org/10.4018/ijmmme.2018010101.

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This work presents a method to support product design, since it shows how to use together tolerance assignment and analysis for choosing among different set of tolerances assigned to the same product. It starts from tolerance assignment that produces different sets of tolerances for the product components which are all acceptable from a functional point of view. It translates each assigned set of tolerances into one or more groups of tolerances that are recognized by the software used for tolerance analysis. Therefore, the software for tolerance analysis is applied to each group of tolerances by means of a Monte Carlo simulation approach. Finally, the obtained results are intersected or compounded to obtain the trend of product functional requirements that allows to identify the best set of tolerances assigned to the product components. The developed method was applied to a skillet, a platform of an industrial plant that is made of five parts connected by screws. The obtained results show how the developed new method is a valid tool to support design for industrial application.

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Mihail, Rarița. "POLITICAL TOLERANCE VERSUS MORAL TOLERANCE." International Multidisciplinary Scientific Conference on the Dialogue between Sciences & Arts, Religion & Education 3, no. 1 (August 25, 2019): 167–73. http://dx.doi.org/10.26520/mcdsare.2019.3.167-173.

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Pereira Menaut, Antonio Carlos, and Carolina Pereira Sáez. "Mera Tolerancia // Simple Tolerance." Revista de Derecho Político 1, no. 96 (August 3, 2016): 49. http://dx.doi.org/10.5944/rdp.96.2016.17054.

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Pondělíček, Bedřich. "Tolerance distributive and tolerance Boolean varieties of semigroups." Czechoslovak Mathematical Journal 36, no. 4 (1986): 617–22. http://dx.doi.org/10.21136/cmj.1986.102120.

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Cheng, Kuo Ming, and Jhy Cherng Tsai. "Graph-Based Process Planning for Rotational Part Machined with Tolerancing." Applied Mechanics and Materials 52-54 (March 2011): 1824–29. http://dx.doi.org/10.4028/www.scientific.net/amm.52-54.1824.

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This paper investigates a methodology and corresponding graph modeling of process planning for cylindrical machined parts with tolerancing. Methods and techniques for representing possible process plans, reducing the complexity and eliminating over-toleranced plans are developed. The method first maps each feature of a part into feasible finishing processes that are capable to achieve the specified tolerances associated with the feature. All possible process plans are then developed by expanding preceding processes of each finishing process. The expanded processes form a graph, or a forest, with processes as nodes and process sequence as links. Processes with same specifications can be further merged and pruned to reduce the complexity of the graph. Tolerance stack-up of each possible plan for simplified results is also further computed by tolerance chart such that over-toleranced plans are eliminated. As there are often many feasible plans for machining a part, the qualified plan that satisfies design specifications is achieved by traversal through the graph imposing tolerance chart. An example is also demonstrated to illustrate the approach and the model. The merit of this method is to employ a unified graph model for representing and reasoning.

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Pondělíček, Bedřich. "Tolerance distributive and tolerance modular varieties of commutative semigroups." Czechoslovak Mathematical Journal 36, no. 3 (1986): 485–88. http://dx.doi.org/10.21136/cmj.1986.102108.

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Moroni, G., and W. Polini. "Tolerance-based Variations in Solid Modeling." Journal of Computing and Information Science in Engineering 3, no. 4 (December 1, 2003): 345–52. http://dx.doi.org/10.1115/1.1631581.

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Information on tolerances and attributes of mechanical parts and assemblies is crucial for many activities in a product’s life cycle. Tolerance design is a complex task because many factors (functional, technological and economical) should be considered. It is an iterative process, starting from a first tolerances assignment and ending with the definition of their optimal values. Once all tolerances have been assigned to each part of an assembly, tolerance analysis is performed. This stage aim is to evaluate if the combined effects of the assigned tolerances let the design requirements be met. Then, feasible and economical aspects are considered on the basis of both available processes and cost evaluations. The whole tolerance design stage is usually defined as tolerance synthesis. The focus of this work is the discussion of the algorithms to model the geometrical variations, of each part of an assembly, allowed by geometric tolerances. This involves the change of the boundary nominal representation of a part face on the basis of the assigned dimensional and geometric tolerances. At present, the developed algorithms are able to simulate flatness, location and orientation. The modified parts, generated by tolerance simulation, may be used to evaluate the overall assemblability and, then, to verify the assembly functional requirements.

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Davidson, J. K., and J. J. Shah. "Geometric tolerances: A new application for line geometry and screws." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 216, no. 1 (January 1, 2002): 95–103. http://dx.doi.org/10.1243/0954406021524837.

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A new mathematical model is introduced for the tolerances of cylindrical surfaces. The model is compatible with the ISO/ANSI/ASME standard for geometric tolerances. Central to the new model is a Tolerance-Map®†, a hypothetical volume of points that corresponds to all possible locations and variations of a segment of a line (the axis) that can arise from tolerances on size, location and orientation of the cylindrical surface. Each axis in a tolerance zone will be represented with the six Plücker coordinates. Cylindrical surfaces in a tolerance zone for the same hole can then be treated by attaching a size tolerance to each of the lines, thereby forming a screw. Relationships for the content of line solids for a tolerance zone are developed to correspond to the variations of locations. These are then used to obtain a measure for the increment in cost when a more refined tolerance is specified. This model is one part of a bilevel model that is under development for geometric tolerances.

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Hu, J., and Y. Peng. "Tolerance modelling and robust design for concurrent engineering." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 221, no. 4 (April 1, 2007): 455–65. http://dx.doi.org/10.1243/0954406jmes438.

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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.

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Feng, Chang-Xue (Jack), and Andrew Kusiak. "Robust Tolerance Synthesis With the Design of Experiments Approach." Journal of Manufacturing Science and Engineering 122, no. 3 (May 1, 1999): 520–28. http://dx.doi.org/10.1115/1.1285860.

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Design of tolerances impacts quality, cost, and cycle time of a product. Most literature on deterministic tolerance design has focused on developing exact and heuristic algorithms to minimize manufacturing cost. Some research has been published on probabilistic tolerance synthesis and optimization. This paper presents the design of experiments (DOE) approach for concurrent selection of component tolerances and the corresponding manufacturing processes. The objective is to minimize the variation of tolerance stackups. Numerical examples illustrate the methodology. The Monte Carlo simulation approach is used to obtain component tolerances and tolerance stackups. Process shift, the worst case and root sum square tolerance stackup constraints, and setup reduction constraints have been incorporated into the proposed methodology. Benefits of the proposed DOE approach over exact algorithms are discussed. [S1087-1357(00)00202-1]

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G V, Madhavi Reddy, and Sreenivasulu Reddy A. "Assembly Gap Tolerance Calculation Using ANFIS and Cost Function Optimization." International Journal for Research in Applied Science and Engineering Technology 10, no. 2 (February 28, 2022): 1111–17. http://dx.doi.org/10.22214/ijraset.2022.40460.

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Abstract: Tolerance plays a crucial role in the quality of a product. When different parts of an assembly are assembled, gap arises due to variation in dimensions. The tolerance for the gap is calculated using two methodologies: ANFIS and cost function optimization. In ANFIS the network is trained using mean dimensions, standard deviations as inputs and tolerances as output. The tolerances are predicted from the trained network. In cost function optimization, a cost function is formulated. The machinability of a part is calculated using Fuzzy Comprehensive Evaluation method. The tolerances are calculated by optimizing the cost function. The tolerances calculated using the two methods are compared and optimal tolerance is considered for manufacturing. Keywords: Tolerance, ANFIS, Assembly gap, Cost function, Optimization.

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Liu, Ting, Yan-Long Cao, Qijian Zhao, Jiangxin Yang, and Lujun Cui. "Assembly tolerance analysis based on the Jacobian model and skin model shapes." Assembly Automation 39, no. 2 (April 1, 2019): 245–53. http://dx.doi.org/10.1108/aa-10-2017-128.

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Purpose The purpose of this paper is to carry out an assembly tolerance analysis by means of a combined Jacobian model and skin model shape. The former is based on small displacements modeling of points using 6 × 6 transformation matrices of open kinematic chains in robotics. The latter easily models toleranced features with all kinds of geometric deviations. Design/methodology/approach This paper presents the procedure of performing tolerance analysis by means of the Jacobian model and skin model shape for assemblies. The point cloud-based discrete representative is able to model the actual toleranced surfaces instead of the ideal or associated ones in an assembly, which brings the simulation tools closer to reality. Findings The proposed method has the advantage of skin model shape which is suitable for geometric tolerances management along the product life cycle and contact analysis of kinematic small variations, as well as, with the Jacobian, enabling transformation of locally expressed parts deviations to globally expressed functional requirements. The result of the case study shows the accuracy of the method. Research limitations/implications The proposed approach has not been developed fully; other functional features such as the pyramid are still ongoing challenges. Practical implications It is an effective method for supporting design, manufacturing and inspection by providing a quantitative analysis of the effects of multi-tolerances on the final functional key characteristics and for predicting the quality level. Originality/value The paper is original in taking advantages of both Jacobian model and skin model shape to consider all geometric tolerances in assembly.

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Panneer, R., and A. M. Jackson. "Comparative Analysis of Chosen Tolerance Stackup Methods and Development of an Improved Tolerance Analysis Method." Applied Mechanics and Materials 813-814 (November 2015): 954–58. http://dx.doi.org/10.4028/www.scientific.net/amm.813-814.954.

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The perception of Tolerance Analysis (TA)/Tolerance Stackup is imperative for every Design and Manufacturing Engineer because Tolerance is the criterion that should be compromised between the cost and function of a product. The literatures relevant to 15 methods of TA which are being used to determine Assembly Tolerance from Component Tolerances are collected and critically analyzed to gain an insight into the existing methods. Out of these methods, four major methods viz., Simulation Based Stack-Up Analysis, Second Order Tolerance Analysis, OpTol - Spatial Tolerance Analysis and Tolerance Analysis of 2D and 3D Assemblies are chosen for further study and comparative analysis. Based on the analysis and based on the identified merits and demerits of these methods, a framework for a new TA Method is developed. Based on the developed framework, a new TA Method using Artificial Neural Network (ANN) is developed and trained which can predict the value of Assembly Tolerance for the known Component Tolerances.

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Dao, Son Duy, and Kazem Abhary. "Determination of the Significance of Tolerance Parameters on Robot Performance Using Taguchi’s Tolerance Design Experiment." Applied Mechanics and Materials 229-231 (November 2012): 2100–2105. http://dx.doi.org/10.4028/www.scientific.net/amm.229-231.2100.

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Tolerance parameters have different effects on robot accuracy. Therefore, it is better to tighten the tolerances of the factors that have statistically significant effect on robot accuracy and widen the tolerances of insignificant ones. By doing so, one not only achieves the given robot accuracy but also reduces manufacturing costs. Objective of this paper is to present an approach used to determine statistical significance of each tolerance parameter of robot manipulator on robot accuracy which can assist robot designers in making decisions regarding tolerance design. In this paper, a comprehensive model of industrial robot manipulator capable of carrying out various applications is developed and computer simulated. Then Taguchi’s Tolerance Design Experiment is applied to determine the statistical significances of the tolerances on robot accuracy. The approach is illustrated by a case study dealing with 6-DOF PUMA 560 robot manipulator.

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Li, Hai, Yun Feng Leng, Hai Ping Zhu, and Pei Gen Li. "A Parameterized Method for Assembly Tolerance Analysis Based on Deviation Propagation Theory." Applied Mechanics and Materials 475-476 (December 2013): 1449–53. http://dx.doi.org/10.4028/www.scientific.net/amm.475-476.1449.

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The paper proposed a new tolerance analysis method: a unified tolerance and deviation model is adopted to synthesize different kinds of tolerances; an integrated tolerance propagation model is designed to construct the functional relationship between the tolerances and quality requirements. The method is simpler and more widely applicable than the traditional linearization analysis method. A case study is provided to illustrate the proposed method.

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Li, Guo Wei, Wei Min Zhang, Peng Zhong Li, and Yi Zhou Zhu. "Computer Aided Geometric Tolerance Specification in 3D-CAD System." Applied Mechanics and Materials 34-35 (October 2010): 1238–42. http://dx.doi.org/10.4028/www.scientific.net/amm.34-35.1238.

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Tolerance specification is the activity of specifying tolerances. In current 3D-CAD system, tolerance types and tolerance values are specified by designer manully, and the validity checking of tolerance is no available. To achieve semi-automatic tolerance specification, geometric feature in the next-generation Geometrical Product Specifications and Verification (GPS) was introduced, the corresponding rules between geometric features and tolerance types were presented; The recommended values for tolerance were stored in a database system and constrainted by tolerance principles. Additionally, the implementation of computer aided geometric tolerance specification was proposed. Finally, the initial prototype system was developed to demonstrate the proposed scheme, which aides designer to define reasonable tolerance types and tolerance values in 3D-CAD system.

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Rupal, Baltej Singh, Tegbir Singh, Tonya Wolfe, Marc Secanell, and Ahmed Jawad Qureshi. "Tri-Planar Geometric Dimensioning and Tolerancing Characteristics of SS 316L Laser Powder Bed Fusion Process Test Artifacts and Effect of Base Plate Removal." Materials 14, no. 13 (June 26, 2021): 3575. http://dx.doi.org/10.3390/ma14133575.

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The precision of LPBF manufactured parts is quantified by characterizing the geometric tolerances based on the ISO 1101 standard. However, there are research gaps in the characterization of geometric tolerance of LPBF parts. A literature survey reveals three significant research gaps: (1) systematic design of benchmarks for geometric tolerance characterization with minimum experimentation; (2) holistic geometric tolerance characterization in different orientations and with varying feature sizes; and (3) a comparison of results, with and without the base plate. This research article focuses on addressing these issues by systematically designing a benchmark that can characterize geometric tolerances in three principal planar directions. The designed benchmark was simulated using the finite element method, manufactured using a commercial LPBF process using stainless steel (SS 316L) powder, and the geometric tolerances were characterized. The effect of base plate removal on the geometric tolerances was quantified. Simulation and experimental results were compared to understand tolerance variations using process variations such as base plate removal, orientation, and size. The tolerance zone variations not only validate the need for systematically designed benchmarks, but also for tri-planar characterization. Simulation and experimental result comparisons provide quantitative information about the applicability of numerical simulation for geometric tolerance prediction for the LPBF process.

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Sa, Guodong, Zhenyu Liu, Chan Qiu, and Jianrong Tan. "A Hybrid Tolerance Design Method for the Active Phased-Array Antenna." Applied Sciences 10, no. 4 (February 20, 2020): 1435. http://dx.doi.org/10.3390/app10041435.

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With the increase of the working frequency of the array antenna, tolerance design has become increasingly important. The state-of-art tolerance design methods mainly deal with the position tolerance of the discrete elements. However, the geometric errors of the whole array have resulted from two aspects: (1) the position errors of the discrete elements and (2) the form errors of the continuous reflection plate. To optimize the position tolerance and flatness simultaneously, a hybrid tolerance design method is proposed. First, the relation between the performance of the array antenna and hybrid tolerances was determined based on the second order Taylor expansion. Then the expectation and variance of the performance were derived. Finally, the hybrid tolerances were optimized and the performance of the antenna was improved. Simulation results proved the effectiveness and efficiency of the proposed hybrid tolerance design method.

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Chiesi, Francesco, and Lapo Governi. "Tolerance Analysis with eM-TolMate." Journal of Computing and Information Science in Engineering 3, no. 1 (March 1, 2003): 100–105. http://dx.doi.org/10.1115/1.1574064.

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This article presents a review of a commercial computer-aided tolerance analysis tool, eM-TolMate, which is embedded in four major CAD systems (Catia [1], UG [2], Pro/E [3], SDRC [4]). eM-TolMate combines the Monte Carlo statistical simulation techniques with an internal tolerance management system and identifies the key characteristics (i.e. dimensions/clearances of interest) of nominal component models that are critical to proper assembly. Features and tolerances are directly created in CAD models and both single component or multi component analyses are available. For assemblies, eM-TolMate offers the capability to apply user-defined assembling rules or to automatically detect mating conditions. Actual features are varied within the specified tolerance range, and standard or user-defined statistical distributions are used in simulation runs to determine variations of key characteristics. It also offers the capability to rank tolerances based on contribution to the variation, so the user can identify where tolerances need to be tightened or can be loosened. eM-TolMate [5] represents a useful tool in tolerance analysis of mechanical assemblies.

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Loganathan, M. "On tolerance relations." Czechoslovak Mathematical Journal 36, no. 4 (1986): 662–67. http://dx.doi.org/10.21136/cmj.1986.102123.

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Cao, Shu Kun, Zhao Qian Li, Qing Gao, and Jing Xu. "Tolerance Optimal Design System Development and Application Based on UG Quick Stack Module." Applied Mechanics and Materials 10-12 (December 2007): 801–5. http://dx.doi.org/10.4028/www.scientific.net/amm.10-12.801.

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Computer-aided design tolerances (CADT) technology got far behind the CAD, CAPP, CAM etc, although there are many commercial tolerance software, but the tolerance optimal design still can’t be completed, which seriously affects the CAX technology's integral roles. Based on the tolerance computation function of the UG Quick Stack module, this paper accomplishes the product assembly relation modeling, tolerance distribution, locked circle calculation and so on, achieves the optimal design tolerance of whole product.

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G V, Madhavi Reddy, Vani S, and Sreenivasulu Reddy A. "Selection of Optimum Assembly Gap Tolerance for Motor Assembly." International Journal for Research in Applied Science and Engineering Technology 10, no. 4 (April 30, 2022): 107–12. http://dx.doi.org/10.22214/ijraset.2022.41180.

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Abstract: The parts in the motor assembly are divided into two types: fixed and variable. The tolerances of the fixed parts cannot be changed and the tolerances of the variable parts are calculated using three methodologies such as ME boost, ANFIS, and Cost function optimization.ME boost is an Excel add in used to calculate the tolerances of the variable parts. ANFIS is a neural network based optimization tool in matlab. Cost function is formulated for the variable parts in the assembly and optimized to calculate the tolerances. Then the tolerance for the assembly gap is calculated. The tolerances for the gap from the three methodologies are compared and optimum tolerance is considered for manufacturing. Keywords: Motor assembly, Tolerance, Assembly gap, ME boost, ANFIS, Cost function Optimization.

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Ting, Kwun-Lon, and Yufeng Long. "Performance Quality and Tolerance Sensitivity of Mechanisms." Journal of Mechanical Design 118, no. 1 (March 1, 1996): 144–50. http://dx.doi.org/10.1115/1.2826846.

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This paper presents a general theory to determine the sensitivity of tolerances to the performance quality of mechanisms and a technique to identify a robust design, which is the least sensitive to the tolerances. The method is demonstrated in position synthesis of linkages. The sensitivity Jacobian is first introduced to relate the performance tolerances and the dimensional tolerances. The Rayleigh quotient of the sensitivity Jacobian, which is equivalent to Taguchi’s signal to noise ratio, is then used to define the performance quality and a sensitivity index is introduced to measure the sensitivity of the performance quality to the dimensional tolerances for the whole system. The ideal tolerance distribution is obtained in closed form. It shows how the tolerance specification affects the performance quality and that the performance quality can be significantly improved by tightening a key tolerance while loosening the others. The theory is general and the technique can be adapted easily for other mechanical systems, including multiple-loop linkages.

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Kobayashi, Yuriko, Takashi Ikka, Kazuhiko Kimura, Orito Yasuda, and Hiroyuki Koyama. "Characterisation of lanthanum toxicity for root growth of Arabidopsis thaliana from the aspect of natural genetic variation." Functional Plant Biology 34, no. 11 (2007): 984. http://dx.doi.org/10.1071/fp07133.

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The mechanism of lanthanum (La3+) toxicity on root growth of Arabidopsis was studied by physiological and genetic approaches using Landsberg erecta (Ler) × Columbia (Col) recombinant inbred lines (RILs) and other natural accessions. Quantitative trait locus (QTL) analyses revealed regulation of La3+ tolerance of the Ler × Col RILs by multiple genetic factors consisted of three significant QTLs and seven epistatic interacting loci pairs. The La content in the root tip was not correlated with La3+ tolerance in the RILs, indicating that the observed La3+ rhizotoxicity was not related to direct toxicity of La3+ in the symplast. The La3+ tolerance of root growth in the RILs was not correlated with Al3+ and Cu2+ tolerances, but was correlated with tolerances for other rare earth elements, including Gd3+, a known Ca2+ channel antagonist, and verapamil, a Ca2+ channel blocker. The genetic architecture of verapamil tolerance in root growth, which was identified by QTL analysis, was closely related to that of La3+ tolerance. La3+ tolerance and verapamil tolerance or Gd3+ tolerance in natural accessions of Arabidopsis also showed a positive correlation. These results indicate that the major La3+ toxicity on the root growth of Arabidopsis may involve its action as a Ca2+ channel antagonist.

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Stanasel, I., F. S. Blaga, P. D. Tocut, M. D. Groza, and C. M. Stanasel. "Influence of workpiece tolerances on the fixtures design. Case study." IOP Conference Series: Materials Science and Engineering 1256, no. 1 (October 1, 2022): 012003. http://dx.doi.org/10.1088/1757-899x/1256/1/012003.

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Abstract The tolerances of a part influence both the operation of the assembly of which it is part and the technological manufacturing process. High tolerances can lead to an assembly that does not work at the designed parameters, and low tolerances require additional machining operations that increase the cost of the part. The manufacturing series is another factor that influences the technological process. Large series production requires special facilities in terms of processing and control equipment which are needed in the manufacturing process. The paper presents a case study on the influence of tolerances of a part being produced in large series on the construction of the orientation and clamping device used in machining. Starting from the dimensions indicated in the design drawing, a first version of the fixture is proposed in which the parts are fixed and the tolerance of the closing dimension of the assembly of parts is analysed using the Worst Case and Root-Sum-Square methods. Since the closure size tolerance is outside the recommended range, another variant of orientation and fixture is proposed. By re-analysing, the closing dimension tolerance by the two methods mentioned above it was confirmed the necessity of modifying the part width tolerance. The analysis of the tolerance of the closing quota is resumed by the two methods mentioned above and the result confirms that it is necessary to change the tolerance to the width of the piece. The tolerance verification of the closure dimension of the assembly formed by the parts fixed in the device is performed by Monte Carlo simulation.

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Wang, Bingxiang, Xianzhen Huang, and Miaoxin Chang. "Reliability-based tolerance redesign of mechanical assemblies using Jacobian-Torsor model." Science Progress 104, no. 2 (April 2021): 003685042110132. http://dx.doi.org/10.1177/00368504211013227.

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The purpose of this paper is to present a new method to redesign dimensional and geometric tolerances of mechanical assemblies at a lower cost and with higher reliability. A parametric Jacobian-Torsor model is proposed to conduct tolerance analysis of mechanical assembly. A reliability-based tolerance optimization model is established. Differing from previous studies of fixed process parameters, this research determines the optimal process variances of tolerances, which provide basis for the subsequent assembly tolerance redesign. By using the Lambert W function and the Lagrange multiplier method, the analytical solution of the parametric tolerance optimization model is obtained. A numerical example is presented to demonstrate the effectiveness of the model, while the results indicate that the total cost is reduced by 10.93% and assembly reliability improves by 2.12%. This study presents an efficient reliability-based tolerance optimization model. The proposed model of tolerance redesign can be used for mechanical assembly with a better economic effect and higher reliability.

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Walters, Annika W., Caitlin P. Mandeville, and Frank J. Rahel. "The interaction of exposure and warming tolerance determines fish species vulnerability to warming stream temperatures." Biology Letters 14, no. 9 (September 2018): 20180342. http://dx.doi.org/10.1098/rsbl.2018.0342.

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Species vulnerability to climate change involves an interaction between the magnitude of change (exposure) and a species's tolerance to change. We evaluated fish species vulnerability to predicted stream temperature increases by examining warming tolerances across the Wyoming fish assemblage. Warming tolerance combines stream temperature with a thermal tolerance metric to estimate how much warming beyond current conditions a species can withstand. Brown trout, rainbow trout and burbot had the lowest warming tolerances and the highest proportion of currently occupied sites that will become unsuitable under predicted temperature increases. These most vulnerable species were coldwater species, but had neither the lowest thermal tolerances nor would they experience the greatest temperature increases. Our results highlight the importance of considering the interaction of exposure and warming tolerance when predicting climate change vulnerability and demonstrate an approach that can be applied broadly.

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Greenwood, W. H., and K. W. Chase. "Worst Case Tolerance Analysis with Nonlinear Problems." Journal of Engineering for Industry 110, no. 3 (August 1, 1988): 232–35. http://dx.doi.org/10.1115/1.3187874.

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When designers assign tolerances on engineering drawings, they have a significant influence on the resulting cost and producibility of manufactured products. A rational basis for assigning tolerances involves constructing mathematical models of tolerance accumulation in assemblies of parts. However, tolerance stacks in two or three-dimensional problems or other nonlinear assembly functions may distort the resultant assembly tolerances, altering the range and symmetry. An iterative method is described for adjusting the nominal dimensions of the component parts such that the specified assembly limits are not violated.

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Banciu, Felicia Veronica, Ion Grozav, and Cristian Gheorge Turc. "Tolerance Allocation Using Design of Experiments." Applied Mechanics and Materials 760 (May 2015): 45–50. http://dx.doi.org/10.4028/www.scientific.net/amm.760.45.

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Tolerance design plays a very important in any manufacturing process because this activity directly influences products cost and quality. In design activity the designer solve the quality problems selecting tight tolerances for components but this generates cost increasing. The practical problem is to assure the high quality characteristics using the maximum tolerances for components that influence them. The paper’s aim is to find optimal parameters setting which assure the desire value of quality characteristics using the DoE (Design of Experiments), and to find a mathematical model and a respective quality characteristic function of the parameters that it was influenced. Using the mathematical function, by imposing the desired tolerance for quality characteristic, it will be allocated the optimal tolerance for components. This tolerance allocation will be verified using Monte-Carlo method.

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Kethara Pasupathy, T. M., Edward P. Morse, and Robert G. Wilhelm. "A Survey of Mathematical Methods for the Construction of Geometric Tolerance Zones." Journal of Computing and Information Science in Engineering 3, no. 1 (March 1, 2003): 64–75. http://dx.doi.org/10.1115/1.1572519.

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The physical realization of any part always yields imperfect forms with respect to the ideal geometry specified in the engineering design. To describe and preserve functional requirements of design, the allowable variation is specified using modern geometric tolerances via tolerance zones. Specification using geometric tolerances is intended for unambiguous communication. Mathematically unambiguous specification is required for the application of computing machinery across manufacturing enterprises to lower costs and improve efficiency. Several computer-based tools have been developed to aid in tolerance specification and also in subsequent processing, or applications that utilize tolerance specification information, such as analysis, synthesis, manufacture and measurement. In order to execute these activities, the tolerance zones have to be unambiguously captured by computer programs. The geometric tolerance specification is complex and not completely free of ambiguities. These difficulties pose as challenges in realizing the tolerance zones and limit the applicability of any particular method developed so far. This paper presents a survey of the current computer based methods available to capture tolerance zones of parts. The limitations of the methods are analyzed based on the following criteria: the range of applicability, compatibility with standards, ease in realization and the effects of singularities in shapes that are application specific. Various assembly analysis techniques that utilize the tolerance zone construction and other recent approaches for tolerance design are also reported.

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Humienny, Zbigniew. "Can ISO GPS and ASME Tolerancing Systems Define the Same Functional Requirements?" Applied Sciences 11, no. 17 (September 6, 2021): 8269. http://dx.doi.org/10.3390/app11178269.

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Geometrical tolerances are defined in the ISO Geometrical Product Specification system that is used worldwide, but on the other hand, the ASME Y14.5 standard is used in American companies to define how far actual parts may be away from their nominal geometry. This paper aimed to investigate whether specifications defining acceptable geometrical deviations in one system can be transformed to specifications in the other system. Twelve selected cases are discussed in the paper. Particularly, two cases of size tolerance, three cases of form tolerances, one case of orientation tolerance, four cases of position tolerance (including position tolerance with MMR for the pattern of five holes) and, finally, two cases of surface profile tolerance (unequally disposed tolerance zone and dynamic profile tolerance). The issue is not only in the several different symbols and a set of different defaults, but also in the different meanings and different application contexts of some symbols that have the same graphical form. The answer to the question raised in the paper title is yes for the majority of indications specified according to ASME Y14.5 when new tools from the 2017 edition of ISO 1101 are applied.

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Yang, Zhaohui, Wenrong Yang, Tianshi Gao, and Yu Zhang. "Tolerance analysis method considering multifactor coupling based on the Jacobian–torsor model." Advances in Mechanical Engineering 14, no. 12 (December 2022): 168781322211402. http://dx.doi.org/10.1177/16878132221140215.

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Assembly quality affects the performance of mechanical products and reasonable tolerance designs are central to assembly quality. Unreasonable tolerance design leads to the mechanical equipment performance degradation under complex operating conditions. This study developed a novel tolerance analysis method that considers the influence of temperature, load, and other environmental factors based on the Jacobian–torsor and skin models. First, the deformation caused by multifactor coupling was analyzed using the finite element method, and the feature surface of deformation is extracted. Second, the deformation extraction and tolerance conversion based on the new generation geometrical product specification theory was used to convert the deformation of the feature into the dimension, orientation, and form tolerance. Third, the modified Jacobian–torsor model considering multifactor coupling was constructed by superimposing the converted tolerance with the design tolerances. Finally, the abrasion problem of the airborne actuator was considered as an example to verify the effectiveness and accuracy of the novel method. Through the accurate calculation of tolerances, it accurately analyzes the assembly state of the product under the influence of environmental factors, and provides more accurate guidance for the design and optimization of product tolerance in complex working conditions.

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Cazals, F., and G. D. Ramkumar. "Algorithms for computing intersection and union of toleranced polygons with applications." Artificial Intelligence for Engineering Design, Analysis and Manufacturing 11, no. 4 (September 1997): 263–72. http://dx.doi.org/10.1017/s0890060400003218.

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AbstractBecause mechanical operations are performed only up to a certain precision, the geometry of parts involved in real-life products is never known precisely. But if tolerance models for specifying acceptable variations have received a substantial attention, operations on toleranced objects have not been studied extensively. That is the reason why we address in this paper the computation of the union and the intersection of toleranced simple polygons, under a simple and already known tolerance model. First, we provide a practical and efficient algorithm that stores in an implicit data structure the information necessary to answer a request for specific values of the tolerances without performing a computation from scratch. If the polygons are of sizes m and n, and s is the number of intersections between edges occurring for all the combinations of tolerance values, the preprocessed data structure takes O(s) space and the algorithm that computes a union/intersection from it takes O((n + m)log s + k' + k log k) time, where k is the number of vertices of the union/intersection and k ≤ k' ≤ s. Although the algorithm is not output sensitive, we show that the expectations of k and k' remain within a constant factor τ, a function of the input geometry. Second, we define and study the stability of union or intersection features. Third, we list interesting applications of the algorithms related to feasibility of assembly and assembly sequencing of real assemblies.

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Kusiak, A., and Chang-Xue Feng. "Robust Tolerance Design for Quality." Journal of Engineering for Industry 118, no. 1 (February 1, 1996): 166–69. http://dx.doi.org/10.1115/1.2803639.

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Design of a product (process) includes system design, parameter design, and tolerance design. Robust design is closely applicable to parameter design and tolerance design. The current literature on robust design has focused on parameter design while the problem of tolerance design has not been adequately covered. The tolerance design literature emphasizes the use of optimization to minimize cost while little attention has been paid to minimizing the sensitivity of tolerances to the variation of manufacturing processes. This paper discusses the application of the design of experiments (DOE) approach to tolerance synthesis to minimize manufacturing variations in a probabilistic case. The DOE approach is illustrated with an example.

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Li, Wei Qi, Jun Hong, Yun Long Li, Yi Zhang, and Zong Bin Li. "A Method on the Decision of Tolerance Grade Based on Cost and Lifetime." Advanced Materials Research 308-310 (August 2011): 568–73. http://dx.doi.org/10.4028/www.scientific.net/amr.308-310.568.

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Product tolerance is one of the important factors which affect the quality and cost of product. However, influenced by many complicated factors, there are still many problems which need to be resolved compared with other research works in CAD field. How to determine tolerances of product effectively is still a big problem. Based on exponent model of tolerance-cost, the relationships between tolerance and other characteristics influencing processing cost are studied in this paper. A relational model of tolerance-cost is come up with based on the above relationships. And then, internal relation between tolerance and lifetime is discussed. Meanwhile, along with the lifetime converted into the cost, the compensated relational model of tolerance-lifetime is presented. Finally, the method on the decision of tolerance grade is analyzed. This paper realizes the organic combination of tolerance, lifetime and cost, and effectively decides how to generate tolerance grades.

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Khanna, J. M., H. Kalant, J. Weiner, and G. Shah. "Rapid tolerance and cross-tolerance as predictors of chronic tolerance and cross-tolerance." Pharmacology Biochemistry and Behavior 41, no. 2 (February 1992): 355–60. http://dx.doi.org/10.1016/0091-3057(92)90110-2.

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Zhang, Li, Hong Nie, and Xiaohui Wei. "Kinematic Accuracy Method of Mechanisms Based on Tolerance Theories." Mathematical Problems in Engineering 2020 (October 14, 2020): 1–18. http://dx.doi.org/10.1155/2020/5023092.

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Traditional tolerance analysis is mostly restricted to static analysis. However, tolerances of different components also affect the movement accuracy in a mechanism. In this paper, the idea of kinematic tolerance analysis is advanced. In the interest of achieving movement precision considering tolerance, a kinematic Jacobian model is established on the basis of a traditional dimensional chain and an original Jacobian model. The tolerances of functional element (FE) pairs are expressed as small-displacement screws. In addition, joint clearances resulting from tolerance design also influence the kinematic accuracy, and they are modeled by FE pairs. Two examples are presented to illustrate the rationality and the validity of the kinematic tolerance model. The results of the two examples are shown, and the discussion is presented. A physical model of the 2D example is also built up in 3DCS software. Based on the discussion, a comparison between the statistical and physical models is carried out, and the merits and demerits of both are listed.

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Ji, P., J. Y. H. Fuh, and R. S. Ahluwalia. "A Digraphic Approach for Dimensional Chain Identification in Design and Manufacturing." Journal of Manufacturing Science and Engineering 118, no. 4 (November 1, 1996): 539–44. http://dx.doi.org/10.1115/1.2831065.

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In order to determine working dimensions and tolerances of a process plan, a tolerance chart is often employed. Dimensional chain identification is a necessary step in the tolerance charting procedures. This paper presents a digraphic representation for the tolerance chart. Two directed trees are generated from working dimensions, blueprint dimensions and stock removals of the tolerance chart. These trees are then used to identify dimensional chains in order to find the relationships among the design and manufacturing dimensions. Furthermore, the concept of a reverse dimensional chain is introduced. The reverse dimensional chains can also be identified from the directed trees. The relationship between the forward and reverse dimensional chains is also discussed. Finally, the applications of dimensional chains to the determination of the working dimensions and tolerances are briefly described.

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Budiwantoro, Bagus, Indra Djodikusumo, and Ade Ramdan. "ANALYSIS OF GEOMETRICAL SPECIFICATION IN DECANTER CENTRIFUGE MACHINE." ASEAN Engineering Journal 8, no. 2 (December 1, 2018): 29–47. http://dx.doi.org/10.11113/aej.v8.15501.

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A decanter centrifuge machine has been developed and currently at a complete stage of a preliminary 3D design layout. The next phase is a production phase. In the production phase, an ideal component that is identical with the 3D model will never be realized. Every manufacturing process has unavoidable variations. If they are accumulated, they can be immense and may cause serious problems. The machine may fail. Thus, the analysis of geometry specification is necessary to be conducted. The main objective of this study is to design the geometry specification which includes their tolerance to assure that the machine will work and achieve its performance, considering variation in manufacturing process. The study consists of four stages, they are: (1) reviewing the 3D design layout, (2) identifying functional key characteristics, (3) analyzing each requirement to determine the geometric dimensioning and tolerancing schemes and (4) allocating tolerances. Every scheme was built through six steps, establish the performance requirements, draw a loop diagram, converting dimension to mean dimension, calculate mean value with stack tolerance, determine the method of tolerance analysis and calculate the variation of performance requirements. The tolerance analysis uses the worst case and statistical methods. They involve 45 fixed tolerances and 38 variable tolerances. The calculated variation data output of every requirement is elaborated to finalize tolerance value that will meet all requirements. Finally, the final tolerance values are allocated and set to component geometry. This analysis concludes that every final tolerance of variable tolerance values must be tighter for the worst case method, and only 42% for statistical method. Probability of machine will work and achieve its performance is 100% for the worst case method and 99.73% for the statistical method.

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Desrochers, Alain. "A CAD/CAM Representation Model Applied to Tolerance Transfer Methods." Journal of Mechanical Design 125, no. 1 (March 1, 2003): 14–22. http://dx.doi.org/10.1115/1.1543974.

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This paper presents the adaptation of tolerance transfer techniques to a model called TTRS for Technologically and Topologically Related Surfaces. According to this model, any three-dimensional part can be represented as a succession of surface associations forming a tree. Additional tolerancing information can be associated to each surface association represented as a node on the tree. This information includes dimensional tolerances as well as tolerance chart values. Rules are then established to infer tolerance chains or stack up along with tolerance charts directly from the graph. This way it becomes possible to combine traditional one dimensional tolerance transfer techniques with a powerful three-dimensional representation model providing high technological contents.

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Turner, J. U. "A Feasibility Space Approach for Automated Tolerancing." Journal of Engineering for Industry 115, no. 3 (August 1, 1993): 341–46. http://dx.doi.org/10.1115/1.2901670.

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This paper develops a mathematical theory of tolerances in which tolerance specifications are interpreted as constraints that define a feasible region of a Cartesian space of model variations. Specific examples demonstrate the application of the feasibility space approach to the mathematical interpretation of tolerances of location, orientation, and form. We conclude with the description of an approach to worst-case tolerance analysis, using the feasibility space approach.

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Punch, Maurice. "Zero tolerance of zero tolerance." Criminal Justice Matters 75, no. 1 (March 2009): 45–46. http://dx.doi.org/10.1080/09627250802699848.

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The Lancet. "Losing tolerance with zero tolerance." Lancet 365, no. 9460 (February 2005): 629–30. http://dx.doi.org/10.1016/s0140-6736(05)17955-0.

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CHEN, GUANGMING, and KAILASH C. KAPUR. "TOLERANCE DESIGN BY BREAK-EVEN ANALYSIS FOR REDUCING VARIATION AND COST." International Journal of Reliability, Quality and Safety Engineering 01, no. 04 (December 1994): 445–57. http://dx.doi.org/10.1142/s0218539394000313.

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Tolerance design technique balances the expected quality loss due to variations of the system performance and the cost due to controlling these variations. Measures of quality are discussed and quality loss function is used for tolerance design. The goal is to minimize the total loss that consists of the quality loss to the customer and the cost increase to the producer. The design methodologies are presented for the tolerances of products before shipping to the customer and the tolerances of lower-level characteristics. The approaches to tolerance design for components and subsystems are also demonstrated using the variation transfer function. Examples are given as illustrations of the methodology.

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Farooq, S., and F. Azam. "Salinity tolerance in Triticeae." Czech Journal of Genetics and Plant Breeding 41, Special Issue (July 31, 2012): 252–62. http://dx.doi.org/10.17221/6187-cjgpb.

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Kondić, Živko, Đuro Tunjić, Leon Maglić, and Amalija Horvatić Novak. "Tolerance Analysis of Mechanical Parts." Tehnički glasnik 14, no. 3 (September 14, 2020): 265–72. http://dx.doi.org/10.31803/tg-20200504092314.

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The determination of tolerances has a huge impact on the price and quality of products. The objective of tolerance analysis is to provide the widest possible tolerance range of parts, without disturbing the functionality of the assembly. Tolerance analysis should be performed during the design process because then there is still the possibility for change. For the purpose of carrying out the analysis, three methods will be used: Worst Case method, Root Sum Square method and Monte Carlo Simulation. Methods are explained through simple examples and applied on the one-way clutch.

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Liu, Shao Gang, and Qiu Jin. "Closed-Form Optimal Tolerance for Minimum Manufacturing Cost and Quality Loss Cost." Advanced Materials Research 655-657 (January 2013): 2084–87. http://dx.doi.org/10.4028/www.scientific.net/amr.655-657.2084.

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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.

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Li, Chun Li, Jian Xin Yang, and Rui Li. "Functional Tolerance Analysis of a Complex Mechanism Based on Analysis Line Method." Applied Mechanics and Materials 373-375 (August 2013): 2078–81. http://dx.doi.org/10.4028/www.scientific.net/amm.373-375.2078.

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Tolerance analysis plays an important role at the stage of product design and has great influences on the assembly quality and manufacturing costs. For each ending point on the functional feature, the displacement transfer relationship is influenced by the clearance between the two parts and the tolerances of each part. With regard to functional tolerance accumulation for the simple assembly, the tolerance analysis of a complex mechanism with three parts is conducted based on the analysis line method. The rules for the functional tolerance analysis process will be summarized in this paper.

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Journal articles on the topic 'Tolerance'

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