Investigation on the Effects of Acetone Vapor-Polishing to Fracture Behavior of ABS Printed Materials at Different Operating Temperature

Fused Deposition Modelling (FDM) technology is one of most common technique used in 3D printing as of today for several reasons such as it is low cost and high speed printing capacity. However, common characteristic of FDM 3D printed materials are poor layer adhesion strength and rough surface finish which requires post-processing to improve it. Heat treatment and vapor-polishing are post-processing techniques used to address the poor layer adhesion and rough surface finish of 3D printed materials, respectively. This study will combine these two post-processing techniques and investigate its effect on the mechanical properties of 3D printed materials. The present study describes the effect of acetone vapor-polishing to facture behavior of ABS 3D printed material at higher operating temperatures. The study will compare the fracture behavior of ABS 3D-printed material when polished using acetone vapor bath and tested at high operating temperature to unpolished material. Five replications for each test condition were conducted. All experiment was carried out using ASTM Izod Type E tests with a 2.75J pendulum. The results showed that acetone vapor polishing strongly affects the fracture behavior of ABS 3D printed materials when operating at high temperature.

The Effect of Surface Finish on Zinc Whisker Growth

To understand the relationship between surface finish and zinc whisker growth, this study investigated the growth of whiskers on two mild steel substrates of different surface finish by Field Emission Gun Scanning Electron Microscope (FEG SEM). Results show that, under the same experimental conditions, deposits on substrates with a mirror finish grew less whiskers and nodules than substrates with a rough surface finish.

Representing and Recognizing Features in Mechanical Designs

When experts view an object, they perceive it in terms of their own expertise. For example, manufacturers see features that affect the processes used to fabricate a part, while structural engineers see sources of stresses and other features that tend to reduce the life of a part. Features can be geometric, such as slots or chamfers; they can be quantitative, such as distances between holes; they can be functional, such as alignment; or they can be qualitative, such as a rough surface finish. Research in feature-based design systems for mechanical designers has been motivated by the realization that geometric models represent the design in greater detail than can be utilized by designers, process planners, assembly planners, or by systems that emulate these activities. Features provide abstractions to facilitate the creation, representation, and analysis of designs. Our goal is to enable designers to compose mechanical designs from high-level features that embody functional and geometric properties. In addition, we want to provide designers with feedback on the manufacturability, assemblability, functionality, cost, etc. of the design as it evolves. To support this process in an intelligent CAD environment requires the integration of geometric models, analysis tools, and synthesis tools so that all aspects of the design can be considered while it is in progress. We are developing a design environment based on a shared representation of the design in which we can extract and reason about features of the design from different perspectives. Our approach is to represent both the design and the features using graph grammars. By representing the features using the same grammar as the design, we can recognize features by parsing a feature against the graph that represents the design. We are exploring grammars for behavior as well as geometry in order to provide a link between behavioral and geometric representations. In this paper, we focus on the representation and recognition of features.

The Effect of Rotor Blade Thickness and Surface Finish on the Performance of a Small Axial Flow Turbine

An experimental investigation was conducted to determine the effect of blade profile inaccuracies and surface finish on the aerodynamic performance of a 11.15-cm tip dia turbine. The as-received cast rotor blades had a significantly thicker profile than the design intent and a fairly rough surface finish. Stage test results showed an increase of one point in efficiency by smoothing the surface finish and another three points by thinning the blade profiles to near the design profile. Most of the performance gain between the as-cast thick and the thinned rotor blades, both with the same surface finish, was attributed to reduced trailing edge losses of the recontoured blades.