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Article
Publication date: 1 October 1996

Joris S.M. Vergeest and Johan W.H. Tangelder

Describes the application of an industrial robot to the rapid prototyping of 3D CAD‐defined products. Outlines the equipment and the major software issues of the fully automatic…

401

Abstract

Describes the application of an industrial robot to the rapid prototyping of 3D CAD‐defined products. Outlines the equipment and the major software issues of the fully automatic offline generation of the robot instructions. Presents performance, limitations and practical results.

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Industrial Robot: An International Journal, vol. 23 no. 5
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 1 September 1997

P.J. de Jager, J.J. Broek and J.S.M. Vergeest

The third part of a comprehensive six‐part series on a promising and growing approach to mechanical attachment amenable to automation. Integral snap‐fit attachment design has…

253

Abstract

The third part of a comprehensive six‐part series on a promising and growing approach to mechanical attachment amenable to automation. Integral snap‐fit attachment design has traditionally focused almost exclusively on the individual features that actually accomplish locking between parts of an assembly (e.g. cantilever hooks, bayonet‐fingers, compressive hooks, traps, and others). The placement and orientation of features that facilitate or enhance engagement or eliminate unwanted translation, rotation or vibration, i.e. locating features and enhancements, are rarely considered. Here, describes integral features classified as locks, locators or enhancements. More importantly, presents a systematic six‐step approach or methodology to guide designers at the higher, attachment or conceptual design level (as opposed to lower, feature or detail design level).

Details

Assembly Automation, vol. 17 no. 3
Type: Research Article
ISSN: 0144-5154

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Article
Publication date: 1 December 1997

P.J. de Jager, J.J. Broek and J.S.M. Vergeest

Current rapid prototyping processes are mainly based on layered manufacturing techniques using 2.5D slices. Defines manufacturing by means of 2.5D slices as a zero order…

590

Abstract

Current rapid prototyping processes are mainly based on layered manufacturing techniques using 2.5D slices. Defines manufacturing by means of 2.5D slices as a zero order approximation. A disadvantage of this approximation is the staircase effect, requiring thin layers to be used. If the outer surfaces of the slices can be inclined, speaks of a first order approximation. This approximation is achieved by linear interpolation between adjacent contours, resulting in ruled slices. Describes a method to approximate a given model geometry in a layered fashion not exceeding a user‐defined error δ using either a zero or a first order approximation and an adaptive layer thickness. Analyses the model geometry for curvature and inclination in order to determine the adaptive layer thickness. Provides a method for matching corresponding contours from adjacent slices. Several test objects have been processed using both zero and first order approximation. Shows that the first order approximation significantly reduces the number of required layers for a given δ when compared to the zero order approximation.

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Rapid Prototyping Journal, vol. 3 no. 4
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 11 January 2008

William Owen, Elizabeth Croft and Beno Benhabib

Recent research has considered robotic machining as a dextrous alternative to traditional CNC machine tools for complex sculptured surfaces. One challenge in using robotic…

883

Abstract

Purpose

Recent research has considered robotic machining as a dextrous alternative to traditional CNC machine tools for complex sculptured surfaces. One challenge in using robotic machining is that the stiffness is lower than traditional machine tools, due to the cantilever design of the links and low‐torsional stiffness of the actuators. This paper seeks to examine this limitation, using optimization algorithms to determine the best trajectories for the manipulators such that the stiffness is maximized.

Design/methodology/approach

The issue of low stiffness is addressed with an integrated off‐line planner and real‐time re‐planner. The available manipulator stiffness is maximized during off‐line planning through a trajectory resolution method that exploits the nullspace of the robot machining system. In response to unmodeled disturbances, a real‐time trajectory re‐planner utilizes a time‐scaling method to reduce the tool speed, thereby reducing the demand on the actuator torques, increasing the robot's dynamic stiffness capabilities. During real‐time re‐planning, priorities are assigned to conflicting performance criteria such as stiffness, collision avoidance, and joint limits.

Findings

The algorithms developed were able to generate trajectories with stiffer configurations, which resulted in a reduction in the actuator torques. The real‐time re‐planner successfully allowed the process plan to continue when disturbances were encountered.

Research limitations/implications

Simulations are presented to demonstrate the effectiveness of the approach.

Practical implications

Addressing the limitation of stiffness in serial‐link manipulators will enable robots to become more suitable for machining tasks. The real‐time re‐planning approach will allow robots to become more autonomous during the execution of a given task.

Originality/value

An integrated off‐line and real‐time planning approach has been applied to robotic machining.

Details

Industrial Robot: An International Journal, vol. 35 no. 1
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 1 December 2000

Walter Schaaf

This article describes new approaches in rapid prototyping large sand moulds using industrial robots. In contrast to state of the art processes, the new approaches work…

978

Abstract

This article describes new approaches in rapid prototyping large sand moulds using industrial robots. In contrast to state of the art processes, the new approaches work three‐dimensionally taking advantage of the large working area of industrial robots.

Details

Assembly Automation, vol. 20 no. 4
Type: Research Article
ISSN: 0144-5154

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Article
Publication date: 16 August 2013

Jie Liu

Refurbishing may be the most practical approach under the low volume production. This effort aims to achieve robotic laser cladding with the main purpose of achieving maximum…

2080

Abstract

Purpose

Refurbishing may be the most practical approach under the low volume production. This effort aims to achieve robotic laser cladding with the main purpose of achieving maximum processing flexibility, predictably high quality, lower maintenance and operating costs. This study aims to focus on online measurement and cladding path generation toward automatic laser cladding.

Design/methodology/approach

Based on the specific requirements of automatic laser cladding, an approach was proposed toward an automatic laser cladding with powder injection for the refurbishment of components with free‐form surfaces. This study assessed the feasibility of integrating a non‐contact free‐form surface measurement system, an industrial robot, and an algorithm for generating cladding tool paths seamlessly.

Findings

3D laser scanning and laser cladding systems can be embedded into an existing robot motion control system. Online measurement based 3D surface reconstruction is a practical approach toward cladding tool path generation for on‐site refurbishment.

Practical implications

Robotic laser cladding may be a potential application by integrating other measurement devices, such as temperature sensor based monitoring system.

Originality/value

Refurbishing worn‐out components could have significant economic benefits. This study indicates that robotic laser cladding may potentially facilitate improved refurbishment of oversized components.

Details

Industrial Robot: An International Journal, vol. 40 no. 5
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 14 June 2013

Jie Liu

The purpose of this paper is to develop a robotic tooth brushing simulator mimicking realistic tooth brushing motions, thereby facilitating greater understanding of the generation…

271

Abstract

Purpose

The purpose of this paper is to develop a robotic tooth brushing simulator mimicking realistic tooth brushing motions, thereby facilitating greater understanding of the generation of realistic tooth brushing motion for optimal design of toothbrushes.

Design/methodology/approach

Tooth brushing motions were measured via a motion capture system. Different motion patterns of brushing were analysed. A series of elliptical motion segments were generated by interpolating ellipse‐like trajectories. Furthermore, a path generation algorithm for brushing simulation was proposed. A path planning system incorporating robot motion control was developed to simulate realistic tooth brushing. The generality and efficiency of the proposed algorithm was demonstrated through simulation and experimental results.

Findings

The interpolation of ellipse‐like trajectories can generate elliptical motion segments. Furthermore, realistic tooth brushing can be achieved by integrating the elliptical motion segments into the path generated from the surfaces of teeth. The brushing simulator demonstrated good reproducibility of clinically standardized tooth brushing.

Practical implications

A robotic toothbrush assessment system is a potential application to the robotic tooth brushing simulator by incorporating control of brushing variables, including brushing pressure, speed and temperature.

Originality/value

This study demonstrates the feasibility of using robotic simulation techniques towards improved realistic human tooth brushing motions simulation for optimal design of tooth brushes.

Details

Industrial Robot: An International Journal, vol. 40 no. 4
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 3 August 2010

Hadley Brooks and David Aitchison

Current additive rapid prototyping (RP) technologies fail to efficiently produce objects greater than 0.5 m3 due to restrictions in build size, build time and cost. A need exists…

1643

Abstract

Purpose

Current additive rapid prototyping (RP) technologies fail to efficiently produce objects greater than 0.5 m3 due to restrictions in build size, build time and cost. A need exists to develop RP and manufacturing technologies capable of producing large objects in a rapid manner directly from computer‐aided design data. Foam cutting RP is a relatively new technology capable of producing large complex objects using inexpensive materials. The purpose of this paper is to describe nine such technologies that have been developed or are currently being developed at institutions around the world. The relative merits of each system are discussed. Recommendations are given with the aim of enhancing the performance of existing and future foam cutting RP systems.

Design/methodology/approach

The review is based on an extensive literature review covering academic publications, company documents and web site information.

Findings

The paper provides insights into the different machine configurations and cutting strategies. The most successful machines and cutting strategies are identified.

Research limitations/implications

Most of the foam cutting RP systems described have not been developed to the commercial level, thus a benchmark study directly comparing the nine systems was not possible.

Originality/value

This paper provides the first overview of foam cutting RP technology, a field which is over a decade old. The information contained in this paper will help improve future developments in foam cutting RP systems.

Details

Rapid Prototyping Journal, vol. 16 no. 5
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 9 March 2010

Xiaoming Luo and Matthew C. Frank

The purpose of this paper is to present an algorithm for an additive/subtractive rapid pattern manufacturing (RPM) process where thick slabs of material are sequentially stacked…

1507

Abstract

Purpose

The purpose of this paper is to present an algorithm for an additive/subtractive rapid pattern manufacturing (RPM) process where thick slabs of material are sequentially stacked and then cut to 3D shapes. Unlike traditional rapid prototyping processes where layer thickness is typically uniform, this process is able to vary the layer thickness in order to most effectively generate feature shapes.

Design/methodology/approach

This paper discusses the factors affecting layer thickness decisions and then presents an algorithm to determine layer thicknesses for a given part model. The system is designed to import a computer‐aided design file and use the algorithm to automatically generate the set of layers based on the slab height, material and bonding properties and the process parameters used in the system.

Findings

The layer thickness algorithm is implemented and tested using an additive/subtractive manufacturing system developed in the laboratory. The algorithm has proved effective in determining appropriate layer heights for thick slab machining, taking into account a variety of geometries. Several sand casting patterns have been successfully created using the proposed system, which could significantly improve traditional sand casting pattern manufacturing.

Originality/value

The proposed RPM process is a new process presented by the authors, developed for rapid sand castings. The layer thickness algorithm is an original contribution that enables automatic process planning for this new process.

Details

Rapid Prototyping Journal, vol. 16 no. 2
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 1 July 2005

Chandan Kumar and A. Roy Choudhury

To calculate the volume deviation between a CAD model and built‐up part in 5‐axis laminated object manufacturing employing direct slicing with first‐order approximation.

1064

Abstract

Purpose

To calculate the volume deviation between a CAD model and built‐up part in 5‐axis laminated object manufacturing employing direct slicing with first‐order approximation.

Design/methodology/approach

It is proposed here that the deviation between the CAD model and the built‐up part, which is normally calculated as a linear dimension in specific 2D sections of the CAD model, be treated as a volume (as it actually is), for higher accuracy in subsequent calculations. An algorithm has been developed and implemented for identification and calculation of volume deviation, considering all possibilities.

Findings

It has been conclusively shown that volume deviation consideration results in improved feature recognition and less approximation.

Research limitations/implications

Increase in complexity of the CAD model leads to a considerable increase in the volume deviation computation time. Future research in this area would focus on optimization and calculation of the slice heights based on volume deviation.

Practical implications

Calculation of volume deviation would help eliminate the loss of intricate features in a complex surface and thus improve feature recognition. Slice height calculations based on volume deviation would reduce the deviation between the actual model and the built‐up part.

Originality/value

A new method has been developed for the calculation of volume deviation that could be implemented in the rapid prototyping software packages so as to build prototypes with higher accuracy.

Details

Rapid Prototyping Journal, vol. 11 no. 3
Type: Research Article
ISSN: 1355-2546

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