The accuracy of 12 impression materials of six different types were studied by using complete-arch FPD impressions. Sixty impressions were made of a Columbia dentoform maxillary model with complete cast crown abutment preparations on the canines and the second molars. A one-piece casting was constructed by connecting the four individual castings made for the four abutment teeth. The master pros...

The present paper aims to investigate the solidification behavior and the forgeability of Aluminum alloy (LM6)-SiCp composites at different section of three-stepped composite castings. The temperature of the cast composites during solidification has measured by putting K-type thermocouples at the center of the each step/section, from which the solidification curves were constructed. The forgeab...

For steel castings produced in sand moulds, the expansion of the sand and have a significant impact on the final size and shape of the casting. Experiments are conducted using a cylindrical casting to study this effect for different sands (silica and zircon) and different sand binder systems (phenolic urethane and sodium silicate). The type of sand has a significant effect on the final casting ...

This paper gives an overview of the problem of heat treatment stress and distortion and a review of literature surrounding it. Software developed to predict heat treat distortion is also reviewed. Simulations are presented for a quenched cylinder to demonstrate the capabilities of software available for predicting heat treatment stress and distortion. The software package DANTE was identified a...

introduction: the aim of this study was to evaluate the effect of bridge orientation in casting machine on castability and quality of base metal castings. methods: three groups of patterns with different direction and lengths in casting machine were casted and then studied qualitatively and quantitatively using mean and standard deviation in table of frequency. results: larger nodules and poros...

One way to ensure the required technical characteristics of castings is the strict control of production parameters affecting the quality of the finished products. If the production process is improperly configured, the resulting defects in castings lead to huge losses. Therefore, from the point of view of economics, it is advisable to use the methods of computational intelligence in the field ...

A method is presented to use a dimensionless form of the well-known Niyama criterion to directly predict the amount of shrinkage porosity that forms during solidification of metal alloy castings. The main advancement offered by this method is that it avoids the need to know the threshold Niyama value below which shrinkage porosity forms; such threshold values are generally unknown and alloy dep...

BACKGROUND & OBJECTIVES To evaluate the retention of complete cast crowns in teeth with adequate and inadequate crown height and to evaluate the effects of auxiliary retentive features on retention form complete cast crowns. MATERIALS AND METHODS Sixty freshly extracted human premolars. They were divided into 2 major groups depending upon the height of the teeth after the preparation. Group1 ...

This paper presents a new method to inspect aluminum castings automatically from a sequence of radioscopic images taken at different positions of the casting. The classic image processing methods for flaw detection of aluminum castings use a bank of filters to generate an error-free reference image. This reference image is compared with the real radioscopic image, and flaws are detected at the ...

Purpose – Castings defects are usually easy to characterize, but to eradicate them can be a difficult task. In many cases, defects are caused by the combined effect of different factors, whose identification is often difficult. Besides, the real non-quality costs are usually unknown, and even neglected. This paper aims to describe the development of a modular tool for quality improvement in fou...