Matti Pajula Utilization of model-based definition within mechanical design and manufacturing
of master's thesis
Will Model-based Definition replace engineering drawings throughout the product lifecycle? A global perspective from aerospace industry
The Model-based Definition (MBD) approach is gaining popularity in various industries. MBD represents a trend in Computer-aided Design (CAD) that promises reduced time-to-market and improved product quality. Its main goal is to improve and accelerate the design, manufacturing and inspection processes by integrating drawing annotations directly onto a 3D model, therefore obviating the need to generate engineering drawings. However, its implementation throughout the whole product lifecycle has not yet been fully adopted. Traditional engineering drawings still play an essential part in the capture and distribution of non-geometric information. Based on thirty-four interviews conducted within the Engineering, Drafting, Configuration Management, Airworthiness and Certification, Manufacturing, Inspection and Knowledge Management departments from two Canadian Aerospace companies, the objective of this paper is to report on the main barriers that need to be overcome in order to fully implement the MBD initiative. In addition, the necessary elements and specific requirements needed to evaluate the capacities of emergent tools are proposed.
Microstructure of the solder-casting zone in bridges of dental gold alloys.
The composition and structure were studied in the cast and in the solder of bridges which had failed clinically. Both materials were gold alloys but with different contents of Pt, Ag and Zn. The metallographic investigation revealed defects mostly in the solder, situated in the subsurface layer. SEM studied of the fracture surface revealed large porosites and a structure of dense parallel lines--striations--, indicating that the material had failed from fatigue. The materials in the fractured bridges were identified by micro-probe measurements. It was stated that cast material and solder material used together, were of different composition.