Jerry Y. H. Fuh

Collaborative computer-aided design-research and development status

In order to facilitate product design and realization processes, presently, research is actively carried out for developing methodologies and technologies of collaborative computer-aided design systems to support design teams geographically dispersed based on the quickly evolving information technologies. In this paper, the developed collaborative systems, methodologies and technologies, which are organized as a horizontal or a hierarchical manner, are reviewed. Meanwhile, a 3D streaming technology, which can effectively transmit visualization information across networks for Web applications, is highlighted and the algorithms behind it are disclosed.

Fabrication of 3D chitosan–hydroxyapatite scaffolds using a robotic dispensing system

Abstract A new robotic desktop rapid prototyping (RP) system was designed to fabricate scaffolds for tissue engineering applications. The experimental setup consists of a computer-guided desktop robot and a one-component pneumatic dispenser. The dispensing material (chitosan and chitosan–hydroxyapatite (HA) dissolved in acetic acid) was stored in a 30-ml barrel and forced out through a small Teflon-lined nozzle into a dispensing medium (sodium hydroxide–ethanol in ratio of 7:3). Layer-by-layer, the chitosan was fabricated with a preprogramed lay-down pattern. Neutralization of the chitosan forms a gel-like precipitate, and the hydrostatic pressure in the sodium hydroxide (NaOH) solution keeps the cuboid scaffold in shape. Comparison of the freeze-dried scaffold to the wet one showed linear and volumetric shrinkage of about 31% and 62%, respectively. A good attachment between layers allowed the chitosan matrix to form a fully interconnected channel architecture. Results of in vitro cell culture studies revealed the scaffold biocompatibility. The results of this preliminary study using the rapid prototyping robotic dispensing (RPBOD) system demonstrated its potential in fabricating three-dimensional (3D) scaffolds with regular and reproducible macropore architecture.

Advances in collaborative CAD: the-state-of-the art

In collaborative design and distributed manufacturing, the need to co-develop parts by designers at different geographical locations often arises. For designing a promising product, there is always a need for collaboration among the design, marketing, finance and procurement departments, and the top management. Global manufacturing makes it difficult to frequently gather all the departments in a meeting room to discuss, because of geographical constraints. In order to address this issue, recently, a number of software tools and research works have arisen to provide collaborative solutions. In this paper, some important works in Web-based visualization and 3D concise representations, 3D streaming technology and co-design systems and feature-/assembly-based representation are elaborated. Meanwhile, previous works done by a project led by the authors towards this direction are also highlighted.

Feature-based design in a distributed and collaborative environment

Abstract In this paper, a client/server framework has been developed to enable a dispersed team to accomplish a feature-based design task collaboratively. A manipulation client+modelling server infrastructure has been proposed to facilitate consistent primary information modelling for multiple users and adaptability of the system. Based on feature-to-feature relationships, a distributed feature manipulation mechanism has been proposed to filter the varied information of a working part during a co-design activity to avoid unnecessary re-transferring of the complete large-size CAD files each time when any interactive operation is imposed on the model by a client. In the distributed environment, a design task and the engaged clients are organised and connected through working sessions generated and maintained dynamically with a collaborative server. The environment is open to downstream manufacturing analysis modules to achieve distributed concurrent engineering.

Selective Laser Sintering

For a given material system, the laser energy density, E s is a key factor which affects quality of the laser sintered structure. A laser energy density is defined by the laser power, laser scan speed and laser beam spot size:

An internet-enabled integrated system for co-design and concurrent engineering

{E_s} = \frac{P}{{v\delta }}\left( {J/c{m^2}} \right)

Effect of TiC in copper–tungsten electrodes on EDM performance

(5.1) where P is the incident laser power (Watts), v, the laser scan speed (cm/s) and δ, the laser beam spot diameter (cm).

An Overview of 3D Printing Technologies for Food Fabrication

In the design of plastic injection moulds, the presence of undercut features would affect mould cost and structure. In this paper, the definition, classification of undercut features and the related notions to identify them are presented. Based on the proposed undercut feature definition and taxonomy, the relationships between the undercut features and their mouldability are described. The definition of undercut feature parameters and the computational methodologies to determine them are proposed. The undercut feature draw range and directions are introduced based on the V-maps of undercut features. The recognition criteria from which the undercut features can be identified are presented. In consideration of blending surfaces, two pairs of notions, viz. actual and virtual first adjacent surfaces, actual and virtual edges are proposed. As undercut features can be consistently recognized, the identification criteria for undercut features are given. The industrial case studies show that the methodologies developed are efficient in recognition and extraction of undercut features in complex injection moulded parts.