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This paper aims to provide an assembly method to improve cylindrical components assembly quality. The proposed method not only could be applied to tolerance allocation, but also could guide the assembly of cylindrical components.

The paper claims to provide a stack-build assembly method using a connective assembly model to take the location and orientation tolerances of a rotor stage into account. Through the separate analysis of the location and orientation tolerances propagation process in the assembly, the quality of the final assembly of the rotationally symmetric cylindrical components assembly could be improved by properly selecting component orientations to minimize the eccentric deviation in the assembly.

The effectiveness of the proposed stack-build assembly technique in improving the tolerance propagation in the assembly of cylindrical components was verified through experiments run with a measuring machine. A real aero-engine rotor was assembly using the proposed method; compared to the direct-build assembly technique, which had the component orientations without consideration, the stack-build assembly technique could be used to reduce the eccentric deviation in cylindrical components assembly by nearly 50 per cent.

Different with the old methods, the new method defined the tolerances in detail, such as perpendicularity and angle of the lowest point, and could guide the assembly by the features of surfaces on different components. Through measuring the special tolerances of surfaces on the components, the best assembly angle for each component could be obtained.

Addresses the need for a unified product information model and presents a new representation scheme for mechanical component modelling using shells as its principal geometric primitives for modelling form features. The representation scheme was implemented using the ACIS geometric modeller and C++ on a SUN SPARC/10 station. The advantage of using shells is that both surface and volume information of a form feature can be derived from a shell. Different levels of product data representation can be integrated into a single model. Therefore, it allows the user to model the geometry effectively and form features of a mechanical part on one system.

The purpose of this paper is to propose a methodology to estimate manufacturing complexity for both machining and layered manufacturing. The goal is to take into account manufacturing constraints at design stage in order to realize tools (dies and molds) by a combination of a subtractive process (high‐speed machining) and an additive process (selective laser sintering).

Manufacturability indexes are defined and calculated from the tool computer‐aided design (CAD) model, according to geometric, material and specification information. The indexes are divided into two categories: global and local. For local indexes, a decomposition of the tool CAD model is used, based on an octree decomposition algorithm and a map of manufacturing complexity is obtained.

The manufacturability indexes values provide a well‐detailed view of which areas of the tool may advantageously be machined or manufactured by an additive process.

Nowadays, layered manufacturing processes are coming to maturity, but there is still no way to compare these new processes with traditional ones (like machining) at the early design stage. In this paper, a new methodology is proposed to combine additive and subtractive processes, for tooling design and manufacturing. A manufacturability analysis is based on an octree decomposition, with calculation of manufacturing complexity indexes from the tool CAD model.

To develop, test and implement a sampling strategy for equipment auditing for a Fortune 100 company.

Regression analysis is applied to auditing of equipment for a large US corporation. Empirical data and test data sets are used to evaluate the efficacy of using regression for auditing and to determine reasonable and efficient sample sizes to be employed across more than 5,000 locations.

Regression is a viable and useful method for equipment auditing when there is anticipated high correlation between pre‐ and post‐audit equipment value. Recommended sample size is dependent upon the size of the location as measured by total pieces of equipment. Decision rules combining acceptable tolerance limits, desired confidence level and sample size are provided.

The method, recommended sample sizes and decision rules are particularly applicable to instances where high correlation is expected between pre‐ and post‐audit equipment values. Standard regression assumptions are not all met in all instances, especially with small sample sizes.

The regression approach and model, sample size recommendations and decision rules for passing or failing an equipment audit described herein have been implemented at a Fortune 100 company, and are generally applicable to equipment and inventory auditing when high correlation between pre‐ and post‐audit equipment is expected.

This paper provides a practical and useful regression‐based approach to sampling for equipment auditing. Recommended sample sizes and decision rules for passing or failing the audit are explicitly defined.

The purpose of this paper is to model how geometric errors of a machined surface (or manufacturing errors) are related to locators’ error, workpiece form error and machine tool volumetric error. A kinematic model is presented that puts into relationship the locator error, the workpiece form deviations and the machine tool volumetric error.

The paper presents a general and systematic approach for geometric error modelling in drilling because of the geometric errors of locators positioning, of workpiece datum surface and of machine tool. The model can be implemented in four steps: (1) calculation of the deviation in the workpiece reference frame because of deviations of locator positions; (2) evaluation of the deviation in the workpiece reference frame owing to form deviations in the datum surfaces of the workpiece; (3) formulation of the volumetric error of the machine tool; and (4) combination of those three models.

The advantage of this approach lies in that it enables the source errors affecting the drilling accuracy to be explicitly separated, thereby providing designers and/or field engineers with an informative guideline for accuracy improvement through suitable measures, i.e. component tolerancing in design, machining and so on. Two typical drilling operations are taken as examples to illustrate the generality and effectiveness of this approach.

Some source errors, such as the dynamic behaviour of the machine tool, are not taken into consideration, which will be modelled in practical applications.

The proposed kinematic model may be set by means of experimental tests, concerning the industrial specific application, to identify the values of the model parameters, such as standard deviation of the machine tool axes positioning and rotational errors. Then, it may be easily used to foresee the location deviation of a single or a pattern of holes.

The approaches present in the literature aim to model only one or at most two sources of machining error, such as fixturing, machine tool or workpiece datum. This paper goes beyond the state of the art because it considers the locator errors together with the form deviation on the datum surface into contact with the locators and, then, the volumetric error of the machine tool.

The surface mount technology (SMT) assembly process for 0.4 mm pitch chip scale package (CSP) components was studied in this work. For the screen printing process, the printing performance of different solder pastes, aperture shapes and sizes was investigated. Square apertures and a fine particle size in the solder paste provided a better paste release. Besides optimising the printing process capability and minimizing the printing defects such as bridging and missing paste, the total volume of solder consisting of the paste and the solder ball has to be considered in order to maximize the final process yield. For the pick & place process, the accuracy required for the placement equipment was determined by studying the self‐alignment of the lead‐free CSPs (with Sn/4.0Ag/0.5Cu balls) during the reflow process using lead‐free Sn/3.9Ag/0.6Cu paste. The components were intentionally misplaced up to ∼50percent off‐pad. After reflow, x‐ray inspection showed that the components had aligned to the pad. By considering the stack‐up of the printed circuit board pad location and size tolerances, the solder paste printing tolerances and the placement tolerances, the required alignment accuracy for the pick & place equipment was established to meet the total process capability requirement.

The purpose of this paper is to present a state‐of‐the‐art review of dimensional tolerance synthesis and to demonstrate the evolution of tolerance synthesis from product to process‐oriented strategy, as well as to compare the same for single stage and multistage manufacturing systems (MMS). The main focus is in delineating the different approaches, methods and techniques used with critical appraisal of their uses, applicability and limitations, based on which future research directions and a generic methodology are proposed.

Starting with issues in tolerancing research, the review demonstrates the critical aspects of product and process‐oriented tolerance synthesis. The aspects considered are: construction of tolerance design functions; construction of optimization functions; and use of optimization methods. In describing the issues of process‐oriented tolerance synthesis, a comparative study of single and multistage manufacturing has been provided.

This study critically reviews: the relationship between the tolerance variables and the variations created through manufacturing operations; objective functions for tolerance synthesis; and suitable optimization methods based upon the nature of the tolerance variables and the design functions created.

This study is limited to dimensional tolerance synthesis problems and evolution of process‐oriented tolerance synthesis to counteract dimensional variation problems in assembly manufacturing.

The paper provides a comprehensive and step‐by‐step approach of review of dimensional tolerance synthesis.

The purpose of this paper is to compare two different tools for tolerance analysis. Tolerance analysis is an important task to design and manufacture high-precision mechanical assemblies; it has received considerable attention in the literature. Many are the tools required to carry out a tolerance analysis, and may be divided into two categories: the analytical models and the statistical software packages. No comparison exists in the literature among these two categories.

This work presents a comparison between two different approaches to tolerance analysis: an analytical method, the variational model, and a statistical software, eM-Tolmate. The comparison has been developed on the same aeronautical case study that constitutes an actual product.

The proposed approach has been applied to an aeronautical case study. The results of the case study show how, when 2D tolerance analysis problems need to be solved, the two adopted tools give the same results. When the complexity of the tolerance analysis problems increases, the statistical software becomes the only choice to use. The new findings of the present paper are related to the fact that computer-aided tolerance analysis software packages remain the only choice to approach actual complex industrial products despite the extensive development of theoretical research.

This paper deals with a unique case study. However, the two adopted approaches and the obtained results are general, that is, they may be applied to any assembly.

Tolerance analysis is a valid tool to foresee geometric interferences among the components of an assembly, before getting the physical assembly. It involves a decrease of the manufacturing costs.

Many are the tools for tolerance analysis, such as different analytical models and different commercial software packages. Some are the comparisons among the different tools in the literature, but they are not exhaustive. Therefore, when a user has to solve an assembly problem to foresee the geometric interferences during the design stage, he/she does not know what to choose. The original contribution of the paper is to address the user’s choice through a comparison between an analytical model and a statistical software to solve the tolerance analysis problems of an actual aeronautical assembly.

The purpose of this paper is to create an assembly verification system that is capable of verifying complete assembly and torque for each individual fastener.

The 3D position of the tool used to torque the fastener and the assembly pallet will be tracked using an infrared (IR) tracking system. A set of retro‐reflective markers are attached to the tool and assembly while being tracked by multiple IR cameras. Software is used to triangulate the relative position of the tool in order to identify the fastener being torqued. The torque value is obtained from the tool controller device. By combining the location of the tool and the torque value from the tool controller, assembly of each individual fastener can be verified and its achieved torque recorded.

The IR tracking is capable of tracking within 2‐3 mm for each tracking ball, with a resulting practical resolution of 24 mm distance between fasteners while maintaining 99.9999 per cent reliability without false positive fastener identification.

This experiment was run under simulated assembly line lighting conditions.

By being able to verify assembly reliably, the need for manual torque check is eliminate and hence yield significant cost savings. This will also allow programming electric tools according in real time based on the fastener in proximity identification.

Currently, assembly verification is only done using the torque values. In automated assembly line, each process might involve fastening multiple fasteners. Using this system, a new level of assembly verification is achieved by recording the assembled fastener and its associated torque.

The aim of the research was to evaluate the concept that utilizes structured planar substrates based on low temperature co‐fired ceramics (LTCC) as a precision platform for the passive alignment of a multimode fiber and wide‐stripe diode laser.

Presents the manufacturing process for realisation of 3D precision structures, heat dissipation structures and a cooling channel into the LTCC substrate. The developed methodology for 3D modelling and simulation of the system was used to optimize structures, materials and components in order to achieve optimal performance for the final product and still maintain reasonably low fabrication costs. The simulated optical coupling efficiency and alignment tolerances were verified by prototype realization and characterization.

The achieved passive alignment accuracy allows high coupling efficiency realisations of multimode fiber pigtailed laser modules and is suitable for mass production.

Provides guidance in the design of LTCC precision platforms for passive alignment and presents a hybrid simulation method for photonics module concept analysis.

The three‐dimensional shape of the laminated and fired ceramic substrate provides the necessary alignment structures including holes, grooves and cavities for the laser to fiber coupling. Thick‐film printing and via punching can be incorporated in order to integrate electronic assemblies directly into the opto‐mechanical platform.

Introduces the LTCC 3D precision structures for photonics modules enabling passive alignment of multimode fiber pigtailed laser with high efficiency optical coupling. Demonstrates the hybrid simulation methodology for concept analysis.