Gianni Caligiana

A CAD-augmented reality integrated environment for assembly sequence check and interactive validation

An integrated environment based on CAD assembly software and on an Augmented Reality wearable system is used to improve the overall integration between engineering design and real prototypes manufacturing. The environment following called – Personal Active Assistant (PAA) – exploits a CAD tool connection to remarkably improve object recognition, best assembly sequence optimization, and operator instructions generation. PAA is real-time and wirelessly linked to a remote server or designer workstation where project geometric database is stored. The PAA head-mounted camera is also able to acquire the human-driven assembly sequence and check the efficiency and correctness via object recognition: an incremental sub-assembly detection algorithm has been developed in order to achieve complex dataset monitoring. On the other hand, the Augmented Reality-based assembly evaluation tool allows engineers to interact directly with the assembly operator while manipulating the real and virtual prototype components. Information from the assembly planner can be displayed, directly superimposed, on the real scene by using a see-through head-mounted display. Thus the new combined software and hardware equipment may be considered a step ahead in the support of true concurrent engineering and remote collaboration, strongly improving this latter through a better heterogeneous task integration. Several tests have been performed also to achieve personnel training and warehouse part seeking.

Tablet-based 3D sketching and curve reverse modelling

This paper describes the development of an innovative hardware and software tool useful to sketch planar shapes in computer aided industrial design and computer aided design systems. The proposed system is based upon a tracked touch screen hand-held by the designer. The whole system is composed by a portable hand-held small touch screen (tablet size), a fixed LCD display and an optical tracking equipment. The touch screen is added by a simple camera for mixed reality optional functionality and its 6° of freedom movements are tracked. A custom software has been implemented for optimal exploitation and 3D sketching. The system acts as a free sketching device, a 3D mouse, as a realtime virtual and physical sketching plane or an external shape remodelling tool. The results obtained confirm the benefits of the virtual tablet in design, modelling and reverse engineering of industrial products.

Multiobjective wing design using genetic algorithms and fuzzy logic

Abstract The designer frequently faces problems in which the project depends on many parameters and the final solution must be evaluated according to several optimization objectives. This may be the case for the aeroelastic and aeromechanical design of lifting surfaces. The aim of the present paper is to show how the combined techniques of genetic algorithms (GAs) and fuzzy logic can be useful in these situations. The leading idea is the development of a tool to assist the designer in the preliminary phase of activity by assigning a genetic code to every possible solution and assessing its performance by means of a fuzzy controller in order to handle simultaneously different design criteria. Examples are given for some typical problems in aeronautical design.

CAD-CAM integration for 3D Hybrid Manufacturing

Hybrid Manufacturing (HM) is oriented to combine the advantages of additive manufacturing, such as few limits in shape reproduction, good customization of parts, distributive production, minimization of production costs and minimization of waste materials, with the advantages of subtractive manufacturing, in terms of finishing properties and accuracy of dimensional tolerances. In this context, our research group presents a design technique that aims to data processing that switches between additive and subtractive procedures, to the costs and time of product-manufacturing optimization. The component prototyping may be performed combining different stages (addiction, gross milling, fine milling, deposition…) with different parameters and head/nozzles and is able to work with different materials either in addictive, either in milling. The present paper is dedicated to introduce different strategies, or in other terms, different combinations of machining features (addictive or deductive) and different materials to complete a prototype model or mold. The optimization/analysis piece of software is fully integrated in classic CAD/CAM environment for better supporting the design and engineering processes.

From spline to Class-A curves through multi-scale analysis filtering

This paper reports the work on a novel wavelet-based multi-scale filtering application used to generate very smooth subset of profiles known as Class-A curves. The multi-scale representation, based on B-spline wavelets, allows to split a spline curves in terms of a coarser least-square approximation and details coefficients. It raises that non-Class-A curves are determined by geometric imperfections strongly connected to the details coefficients. The extraction and manipulation of details with multi-scale filtering allows to select and evaluate geometric imperfections. Finally, an efficient algorithm devoted to improve a given non-Class-A profile to a Class-A curve has been implemented and tested with several examples in order to check and visualize the results.

Sustainable design of open molds with QFD and TRIZ combination

Abstract The planning activity relative to physical items, environment, and services that adapts to optimize social, economic, and ecological impact is the target of sustainable design. Quality Function Deployment (QFD) achieves product design by choosing and defining factors that can be qualitatively argued. The aim of design is to match needs in new and innovative ways. In this perspective, the QFD aims to evaluate the quality of a design process. TRIZ is a design methodology that aims at defining and overcoming some critical issues that can affect the development of a product, by means of potential innovative solutions. In this paper, QFD and TRIZ analysis were adopted in order to validate a design method for direct open molds by means of a new strategy: hybrid manufacturing can reduce production time, use of material, and energy and waste consumption, employing subtractive and additive techniques efficiently combined.

Strain gauge analysis of implant-supported, screw-retained metal frameworks: Comparison between different manufacturing technologies

Over the past decades, the technological development in the medical field, coupled with the ongoing scientific research, has led to the development and improvement of dental prostheses supported by screw-retained metal frameworks. A key point in the manufacture of the framework is the achievement of a passive fit, intended as the capability of an implant-supported reconstruction to transmit minimum strain to implant components as well as to the surrounding bone, when subject to any load. The fitting of four different kinds of screw-retained metal frameworks was tested in this article. They differ both in materials and manufacturing process: two frameworks are made by casting, one framework is made by computer-aided design and computer-aided manufacturing and one framework is made by electric resistance spot welding (WeldONE, DENTSPLY Implants Manufacturing GmbH, Mannheim, Germany). The passivity of the frameworks was evaluated on the entire system, composed of a resin master cast, the implant analogues embedded in the cast and the frameworks. Strains were recorded by means of an electrical strain gauge connected to a control unit for strain gauge measurements. The experimental tests were carried out in the laboratories of the Department of INdustrial engineering at the University of Bologna. The results of the test campaigns, which compared three samples for each technological process, showed that no significant differences exist between the four framework types. In particular, the frameworks made by the resistance welding approach led to a mechanical response that is well comparable to that of the other tested frameworks.

TRIZ method for innovation applied to an hoverboard

Abstract The aim of this work is to complete the QFD analysis carried out in a previous work that aimed to identify the main features that contribute to the success of a modern urban transport means: the hoverboard. Starting from this analysis, through the TRIZ methodology, resolutive principles have been identified for the realization of innovative solutions of the said urban transport means. In practice this analysis aims to manage the next phase of conceptual design realized with the QFD methodology and tries to guide the design process in its next phase. In this work was used the hill model, a characteristic model of the TRIZ methodology, and the technical innovative problems encountered were reformulated in terms of technical contradictions. Subsequently, general principles of inventive solutions were obtained using one of the tools of TRIZ: the matrix of contradiction. Finally, starting from these general principles of solution, innovative constructive solutions have been developed to be applied to the design of an innovative hoverboard.

QFD and TRIZ to Sustain the Design of Direct Open Moulds

Sustainable design aims at the creation of physical objects, environment and services that complies to optimize social, economic, and ecological impact. QFD is able to assess the product design by the choice and definition of parameters that can be qualitatively discussed. The purpose of design is to meet a need in new ways and in innovative ways. In this context, the QFD aims at evaluating the quality of a design process. TRIZ is a design method that aim at defining and overcome some critical issue that can affect the development of a product, by means of potential innovative solutions. In this paper QDF and TRIZ analysis have been adopted in order to validate a design method for direct open moulds, by a new strategy: hybrid manufacturing can reduce the production time, the use of material, the energy and the waste consumption, employing subtractive and addictive techniques efficiently combined.