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Functional dimensioning has a clear mission: to choose the correct dimension and tolerance in order to optimise the parts in the definition of the mechanical assembly for their functional purpose. The current development of computer systems allows us to introduce intelligent help in CAD systems, which makes the complex task of functional dimensioning a lot easier. The international technical literature offers a number of investigation projects that contribute to establishing the bases for implementing intelligent help for functional dimensioning in the design phase. The main aim of this study is to define a system of computer‐aided dimensioning, using graphic design (CAD) systems and the necessary programming language.

The task of defining the parts in mechanical assembly based on their functional purpose is done by the functional dimensioning and tolerancing which tries to optimise its dimensions and tolerances. This work is very hard and complex to do. The actual development of CAD systems, which allows us to introduce intelligent help, seems to be the indicate tool to do the work easier. The international technical literature offers a number of investigation projects that contribute to establish the bases for implementing this intelligent help, in order to help the functional dimensioning in the design phase. The main aim of this study is to define and programme a computer application to aid the unidirectional dimensioning and tolerancing synthesis using graphic design (CAD).

Nowadays there is a trend in industry to optimize processes through computerization. In the field of machining, computer assistance is available to design and describe the product, analyze and simulate its behaviour, describe the manufacturing conditions and generate the corresponding orders. These are the CAD, CAM and computer aided process planning systems. However, there are no computer applications for machining processes that offer assistance to determine the characteristics of the blank. This task is usually done by workshop operators, numerical control programmers, process planners or other professionals whose knowledge and, especially, experience allow them to carry it out. This paper aims to present a computer application that provides assistance to select the characteristics of the blanks used in machining processes.

The methodology applied consists of studying the methods experts use to choose blanks, analyzing the variety of parts that are currently machined in the workshops, designing the application and then implementing and validating it.

The system developed calculates the characteristics of the blank and optimizes the decision according to the experience, knowledge and methods of the experts. This application can carry out calculations for any of the parts that are usually manufactured in a workshop. The solutions that the programme offers can be developed using current‐cutting techniques or the profiles that suppliers sell in the market. The paper includes a case study to demonstrate how the tool is used. Implementation of this computer application brings the present industry closer to production optimization and computerization of the processes (computer integrated manufacturing).

This is the first time the knowledge and the reasoning methods of experts have been analyzed and implemented in a computer tool that gives assistance to determine the characteristics of the blank.

The traditional precision design only takes the influence of geometric tolerance of the parts and does not involve the load deformation in the assembly process. This paper aims to analyze the influence mechanism of flexible parts deformation on the geometric precision, and then to ensure the reliability and stability of the mechanical system.

Firstly, this paper adopts the N-GPS to analyze the influence mechanism of flexible parts deformation on the geometric precision and constructs a coupling 3D tolerance mathematical model of the geometric tolerance and the load deformation deviation based on the SDT theory, homogeneous coordinate transformation theory and surface authentication idea. Secondly, the least square method is used to fit the deformation surface of the mating surface under load so as to complete the conversion from the non-ideal element to the ideal element.

This paper takes the horizontal machining center as a case to obtain the deformation information of the mating surface under the self-weight load. The results show that the deformation deviation of the parts has the trend of transmission and accumulation under the load. The terminal deformation cumulative amount of the system is up to –0.0249 mm, which indicated that the influence of parts deformation on the mechanical system precision cannot be ignored.

This paper establishes a comprehensive 3D tolerance mathematical model, which comprehensively considers the effect of the dimensional tolerance, geometric tolerance and load deformation deviation. By this way, the assembly precision of mechanical system can be accurately predicted.

This study aims to develop an optimal tolerance allocation strategy involves integrating the unique transfer (UT) approach and the difficulty coefficient evaluation (DCE) routine in an interactive hybrid method. This method combines the strengths of both UT and DCE, ensuring simultaneous utilization for enhanced performance. The proposed tolerancing model manifests an integrated computer-aided design (CAD) tool.

By combining UT and DCE based on failure mode, effects and criticality analysis (FMECA) tool and the Ishikawa diagram, the proposed collaborative hybrid tool ensures an efficient and optimal tolerance allocation approach. The integration of these methodologies not only addresses specific transfer challenges through UT but also conducts a thorough evaluation of difficulty coefficients via DCE routine using reliability analysis tools as FMECA tool and the Ishikawa diagram. This comprehensive framework contributes to a robust and informed decision-making process in tolerance allocation, ultimately optimizing the design and manufacturing processes.

The presented methodology is implemented with the aim of generating allocated tolerances that align with specific difficulty requirements, facilitating the creation of a mechanical assembly characterized by high quality and low cost. To substantiate and validate the conceptual framework and methods, an integrated tool has been developed, featuring a graphical user interface (GUI) designed in MATLAB. This interface serves as a platform to showcase various interactive and integrated tolerance allocation approaches that adhere to both functional and manufacturing prerequisites. The proposed integrated tool, designed with a GUI in MATLAB, offers the capability to execute various examples that effectively demonstrate the benefits of the developed tolerance transfer and allocation methodology.

The originality of the proposed approach is the twining between the UT and DCE simultaneous in an integrated and concurrent tolerance transfer and allocation model. Therefore, the proposed approach is named an integrated CAD/tolerance model based on the manufacturing difficulty tool. The obtained results underscore the tangible advantages stemming from the integration of this innovative tolerance transfer and allocation approach. These benefits include a notable reduction in total cost and a concurrent enhancement in product quality.

The purpose of this paper is to provide a new method to estimate the reliability of series system by using a discrete bivariate distribution. This problem is of great interest in industrial and engineering applications.

The authors considered the Basu–Dhar bivariate geometric distribution and a Bayesian approach with application to a simulated data set and an engineering data set.

From the obtained results of this study, the authors observe that the discrete Basu–Dhar bivariate probability distribution could be a good alternative in the analysis of series system structures with accurate inference results for the reliability of the system under a Bayesian approach.

System reliability studies usually assume independent lifetimes for the components (series, parallel or complex system structures) in the estimation of the reliability of the system. This assumption in general is not reasonable in many engineering applications, since it is possible that the presence of some dependence structure between the lifetimes of the components could affect the evaluation of the reliability of the system.

There are calls for greater regulation of online content related to self-harm and suicide, particularly that which is user-generated. However, the online space is a source of support and advice, including an important sharing of experiences. This study aims to explore what it is about such online content, and how people interact with it, that may confer harm or offer benefit.

The authors undertook a systematic review of the published evidence, using customised searches up to February 2021 in seven databases. The authors included empirical research on the internet or online use and self-harm or suicide content that had been indexed since 2015. The authors undertook a theoretically driven narrative synthesis.

From 4,493 unique records, 87 met our inclusion criteria. The literature is rapidly expanding and not all the evidence is high quality, with very few longitudinal or intervention studies so little evidence to understand possible causal links. Very little content online is classifiable as explicitly harmful or definitively helpful, with responses varying by the individual and immediate context. The authors present a framework that seeks to represent the interplay in online use between the person, the medium, the content and the outcome.

This review highlights that content should not be considered separately to the person accessing it, so online safety means thinking about all users. Blanket removal or unthinking regulation may be more harmful than helpful. A focus on safe browsing is important and tools that limit time and diversify content would support this.