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Abstract

Details

Journal of Documentation, vol. 63 no. 3
Type: Research Article
ISSN: 0022-0418

Keywords

Article
Publication date: 1 June 1994

Ryoichi Yoshida and Mikihisa Tajima

Outlines development work on the surfing hopper, a new parts feedingsystem where chain conveyors with free rollers are driven by avariable‐speed motor and a flexible belt…

169

Abstract

Outlines development work on the surfing hopper, a new parts feeding system where chain conveyors with free rollers are driven by a variable‐speed motor and a flexible belt is pushed up partly by the free rollers to generate a wave in the belt. Describes how the wave effect keeps the stacked parts level and how experiments were carried out using different parts materials such as small water‐filled bottles and nuts made of steel. Looks at studies carried out on feeding correctly orientated parts to the assembly station and experiments on surfing feeding system with regard to part separation on the belt. Concludes that the surfing hopper can supply heavy parts intermittently at a rough definite supply ratio, without jamming and entangling the parts and without damage to the belt.

Details

Assembly Automation, vol. 14 no. 2
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 21 September 2012

R. Usubamatov, S.A. Adam and A. Harun

The purpose of this paper is to investigate the process of jamming of the hollow parts on the shaft and to derive a mathematical model for jamming in an assembly process.

Abstract

Purpose

The purpose of this paper is to investigate the process of jamming of the hollow parts on the shaft and to derive a mathematical model for jamming in an assembly process.

Design/methodology/approach

The mathematical model for jamming of parts on the shaft in an assembly process is based on the sizes, geometry, angular declination of part and shaft axes, and the frictional factor.

Findings

The equation for angular positional tolerance of coaxial parts and shafts, based on their geometry and sizes and leading to jamming, was derived.

Research limitations/implications

A mathematical model of parts jamming on the shaft is developed for assembly mechanisms. This research does not consider flexible deformations of components in assembly mechanisms, which results in the axis concentricity of part and shaft in the assembly process.

Practical implications

The results presented in the form of angular positional tolerance for coaxial parts and shafts based on their geometry and sizes make it possible to avoid the jamming of the parts. The results allow for formulating the angular positional tolerance of the assembly mechanisms that clamp the parts.

Originality/value

The proposed method for calculating the angular positional tolerance of coaxial parts and shafts for the assembly process should allow for increasing the reliability of the assembly process in the manufacturing industry.

Details

Assembly Automation, vol. 32 no. 4
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 1 July 2014

Andrzej Gontarz and Anna Dziubińska

The purpose of this research is working out of a new forming technology of flat parts with ribs from magnesium alloys with the application of a three-slide forging press…

Abstract

Purpose

The purpose of this research is working out of a new forming technology of flat parts with ribs from magnesium alloys with the application of a three-slide forging press (TSFP) for the aircraft industry.

Design/methodology/approach

New possibilities of forming aviation parts with ribs gives the application of a prototype TSFP. This press consists of three moveable tools and has wider technological possibilities than typical forging machines. It was assumed that this machine (press) application would allow for obtaining ribbed flat forgings from magnesium alloys of good functional and resistance qualities. A characteristic feature of such forgings forming is the working movement of two side tools, which upset the billet in the form of a plate; the result of their action is forming of one or more ribs in the plane central part. It is possible to use the upper punch to form appropriate rib outline. Theoretical research works based on simulations by means of finite element method were conducted for three cases of the process: semi-free forging of parts with one rib, semi-free forming of forgings with two ribs and forging in closed impression of parts with one rib of triangular outline. The first experimental tests were made on a TSFP for the variant of semi-free forging of parts with one rib.

Findings

Research results show that there exists the possibility of realization of forming process of parts with ribs according to the conception assumed by the authors. Positive results of theoretical analyses justify the purposefulness of conducting experimental verification for the proposed theoretical solutions of the forging processes of parts with one rib of triangular outline and with two ribs.

Practical implications

Production of flat parts with ribs from magnesium alloys basing on the worked out by the authors’ technology will allow for improving functional and mechanical properties of parts and for lowering their manufacturing costs. At present, such aviation parts are imported to Poland in the form of casts, which are expensive and not always fulfill the requirements. Additionally, large amount of machining at manufacturing of this type of parts generate larger price at their production.

Originality/value

Forging technology of parts with ribs in a TSFP is unique on a world scale. The advantages of this technology are the process material savings and better resistance properties of the formed forgings with ribs than parts obtained in a traditional way.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 86 no. 4
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 1 September 1999

Dadi Gudmundsson and Ken Goldberg

We study a programmable robotic part feeder that relies on a sequence of three conveyor belts to singulate and re‐circulate parts. In industrial practice, belt speeds are…

Abstract

We study a programmable robotic part feeder that relies on a sequence of three conveyor belts to singulate and re‐circulate parts. In industrial practice, belt speeds are set in an ad hoc fashion. Experience with real feeders reveals that throughput can suffer owing to: starvation where no parts are visible to the camera; and saturation, where too many parts are visible, which prevents identifying part pose or grasping due to obstruction by nearby parts. This motivates our search for a systematic approach to setting belt speeds. Our goal is to optimize throughput, measured in terms of how many parts per second are delivered from the robotic feeder. We describe a 1D model of the belts with a Poisson arrival process to stochastically model how belt speeds affect throughput. Initially, we study the finite case where N parts are placed into the feeder and re‐circulated until they are all delivered by the robot. Our first insight is that the vision belt should be run at maximum achievable velocity. We run simulations to empirically determine optimal buffer belt velocity as a function of lot size. Finally, we develop a theoretical model for the case where N = ∞ which approximates common usage where the buffer is replenished before it becomes empty. From this model, we derive the optimal buffer belt velocity and show that it produces throughput five times greater than that achieved with ad hoc settings.

Details

Assembly Automation, vol. 19 no. 3
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 27 February 2007

Bronius Baksys and Nomeda Puodziuniene

The paper aims to investigate theoretically and experimentally vibrational alignment of parts in an assembly position under kinematical excitement of the movably based part.

Abstract

Purpose

The paper aims to investigate theoretically and experimentally vibrational alignment of parts in an assembly position under kinematical excitement of the movably based part.

Design/methodology/approach

Presents developed mathematical model for vibrational alignment when the kinematical excitement of movable part is applied along the insertion axis. Dependencies of alignment duration on stiffness of basing elements and excitation frequency were defined numerically solving the mobile‐based part alignment equations. Alignment experiments of rectangular cross‐section and cylindrical parts under kinematical excitement were carried out.

Findings

The mathematical model and the experiments have demonstrated that alignment of the parts being assembled happens due to directed displacement of the movable part resulted by certain parameters of the system and excitement. In the course of the displacement, mating surfaces are aligned and the final mutual orientation of the parts before insertion is realized. Experiments have proved validity of the developed mathematical model. This process reduces allowable axial non‐coincidence and angular misfit of the parts to be assembled.

Research limitations/implications

Impact and non‐impact regimes of the displacement exist depending on the excitement amplitude and initial contact force between the parts. Also, during the vibrational alignment it is possible to control dry friction force between parts by additional high frequency vibrations. Besides, the vibrational excitement can be not only harmonic, but also impulse, bi‐harmonic, etc. Only non‐impact regime of the motion without dry friction force control was investigated and presented in the paper.

Practical implications

The paper investigates the vibrational alignment method based on the directed vibrational displacement of the connecting part, which does not require high preciseness of the interdependent position of the parts in the assembly position.

Originality/value

Vibrational assembly devices of directional action enable compensation of errors of the parts' mutual positioning without use of sensors, feedback systems and control algorithms.

Details

Assembly Automation, vol. 27 no. 1
Type: Research Article
ISSN: 0144-5154

Keywords

Open Access
Article
Publication date: 16 September 2022

Jan Sher Akmal, Mika Salmi, Roy Björkstrand, Jouni Partanen and Jan Holmström

Introducing additive manufacturing (AM) in a multinational corporation with a global spare parts operation requires tools for a dynamic supplier selection, considering…

172

Abstract

Purpose

Introducing additive manufacturing (AM) in a multinational corporation with a global spare parts operation requires tools for a dynamic supplier selection, considering both cost and delivery performance. In the switchover to AM from conventional manufacturing, the objective of this study is to find situations and ways to improve the spare parts service to end customers.

Design/methodology/approach

In this explorative study, the authors develop a procedure – in collaboration with the spare parts operations managers of a case company – for dynamic operational decision-making for the selection of spare parts supply from multiple suppliers. The authors' design proposition is based on a field experiment for the procurement and delivery of 36 problematic spare parts.

Findings

The practice intervention verified the intended outcomes of increased cost and delivery performance, yielding improved customer service through a switchover to AM according to situational context. The successful operational integration of dynamic additive and static conventional supply was triggered by the generative mechanisms of highly interactive model-based supplier relationships and insignificant transaction costs.

Originality/value

The dynamic decision-making proposal extends the product-specific make-to-order practice to the general-purpose build-to-model that selects the mode of supply and supplier for individual spare parts at an operational level through model-based interactions with AM suppliers. The successful outcome of the experiment prompted the case company to begin the introduction of AM into the company's spare parts supply chain.

Details

International Journal of Operations & Production Management, vol. 42 no. 13
Type: Research Article
ISSN: 0144-3577

Keywords

Article
Publication date: 7 September 2022

Abdul Wahab Hashmi, Harlal Singh Mali and Anoj Meena

The purpose of this paper is to study the functionality of additively manufactured (AM) parts, mainly depending on their dimensional accuracy and surface finish. However…

Abstract

Purpose

The purpose of this paper is to study the functionality of additively manufactured (AM) parts, mainly depending on their dimensional accuracy and surface finish. However, the products manufactured using AM usually suffer from defects like roughness or uneven surfaces. This paper discusses the various surface quality improvement techniques, including how to reduce surface defects, surface roughness and dimensional accuracy of AM parts.

Design/methodology/approach

There are many different types of popular AM methods. Unfortunately, these AM methods are susceptible to different kinds of surface defects in the product. As a result, pre- and postprocessing efforts and control of various AM process parameters are needed to improve the surface quality and reduce surface roughness.

Findings

In this paper, the various surface quality improvement methods are categorized based on the type of materials, working principles of AM and types of finishing processes. They have been divided into chemical, thermal, mechanical and hybrid-based categories.

Research limitations/implications

The review has evaluated the possibility of various surface finishing methods for enhancing the surface quality of AM parts. It has also discussed the research perspective of these methods for surface finishing of AM parts at micro- to nanolevel surface roughness and better dimensional accuracy.

Originality/value

This paper represents a comprehensive review of surface quality improvement methods for both metals and polymer-based AM parts.

Graphical abstract of surface quality improvement methods

Details

Rapid Prototyping Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 30 June 2022

Miguel Ángel Caminero, Ana Romero Gutiérrez, Jesús Miguel Chacón, Eustaquio García-Plaza and Pedro José Núñez

The extrusion-based additive manufacturing method followed by debinding and sintering steps can produce metal parts efficiently at a relatively low cost and material…

Abstract

Purpose

The extrusion-based additive manufacturing method followed by debinding and sintering steps can produce metal parts efficiently at a relatively low cost and material wastage. In this study, 316L stainless-steel metal filled filaments were used to print metal parts using the extrusion-based fused filament fabrication (FFF) approach. The purpose of this study is to assess the effects of common FFF printing parameters on the geometric and mechanical performance of FFF manufactured 316L stainless-steel components.

Design/methodology/approach

The microstructural characteristics of the metal filled filament, three-dimensional (3D) printed green parts and final sintered parts were analysed. In addition, the dimensional accuracy of the green parts was evaluated, as well as the hardness, tensile properties, relative density, part shrinkage and the porosity of the sintered samples. Moreover, surface quality in terms of surface roughness after sintering was assessed. Predictive models based on artificial neural networks (ANNs) were used for characterizing dimensional accuracy, shrinkage, surface roughness and density. Additionally, the response surface method based on ANNs was applied to represent the behaviour of these parameters and to identify the optimum 3D printing conditions.

Findings

The effects of the FFF process parameters such as build orientation and nozzle diameter were significant. The pore distribution was strongly linked to the build orientation and printing strategy. Furthermore, porosity decreased with increased nozzle diameter, which increased mechanical performance. In contrast, lower nozzle diameters achieved lower roughness values and average deviations. Thus, it should be noted that the modification of process parameters to achieve greater geometrical accuracy weakened mechanical performance.

Originality/value

Near-dense 316L austenitic stainless-steel components using FFF technology were successfully manufactured. This study provides print guidelines and further information regarding the impact of FFF process parameters on the mechanical, microstructural and geometric performance of 3D printed 316L components.

Details

Rapid Prototyping Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 1 April 1991

Alan Redford

For many types of automated manufacturing equipment there is a requirement to supply the equipment with parts which invariably need to be presented in a single…

Abstract

For many types of automated manufacturing equipment there is a requirement to supply the equipment with parts which invariably need to be presented in a single orientation. For metal cutting and forming work there is limited applicability and invariably the parts to be presented are simple shapes. For assembly, many different and sometimes complex shapes need to be presented and it is in this activity that small parts feeding has its biggest application.

Details

Assembly Automation, vol. 11 no. 4
Type: Research Article
ISSN: 0144-5154

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