Tensile Properties of Inkjet 3D Printed Parts: Critical Process Parameters and Their Efficient Analysis

To design and optimize for capabilities of additive manufacturing processes it is also necessary to understand and model their variations in geometric and mechanical properties. In this paper, such variations of inkjet 3D printed parts are systematically investigated by analyzing parameters of the whole process, i.e. storage of the material, printing, testing, and storage of finished parts. The goal is to both understand the process and determine the parameters that lead to the best mechanical properties and the most accurate geometric properties. Using models based on this understanding, we can design and optimize parts, and fabricate and test them successfully, thus closing the loop. Since AM materials change rapidly and this process will have to be repeated, it is shown how to create a cost and time efficient experimental design with the one-factor-at-a-time and design of experiments methods, yielding high statistical accuracies for both main and interaction effects. The results show that the number of intersections between layers and nozzles along the load-direction has the strongest impact on the mechanical properties followed by the UV exposure time, which is investigated by part spacing, the position on the printing table and the expiry date of the material. Minor effects are found for the storage time and the surface roughness is not affected by any factor. Nozzle blockage, which leads to a smaller flow-rate of printing material, significantly affected the width and waviness of the printed product. Furthermore, the machine’s warm-up time is found to be an important factor.

Investigation on the Reaction of Refractories with 16MnRE Steel

When teeming rare earth treated steels the nozzle blockage occurred so frequently that seriously interferes the application of RE in steels. In this study we tried to investigate the relationship between the wettablility of 16MnRE steel and nozzle materials. The results showed that the weakest wettability of steel liquid was observed on fused silica among the six nozzle materials. Next came zircon and high-alumina nozzle. It has no obvious difference between the 16MnRE steels when final deoxidized containing and not containing Al addition. The wettability of 10Ti steel was weaker than 16MnRE steels on zircon nozzle. The clay nozzle was corroded by the precipitate from steel liquid.

Moisture and Humidity Effects on the ABS Used in Fused Deposition Modeling Machine

The environment seems to have an effect on Acrylonitrile-Butadiene-Styrene (ABS) which consequently causes physical, morphological and thermal stability changes to the polymer. Not only that, these changes may have caused nozzle blockage on the liquefier of the Fused Deposition Modeling (FDM) rapid prototyping machine. Experiments are conducted to support and verify whether ABS does affect the blockage. It has been observed that physical changes may have not caused nozzle clogging.

The MV Robert LeMeur Ice/Propeller Interaction Project: Full-Scale Data

An experimental program was conducted in which ice/propeller interaction data were collected on a twin-shaft shrouded controllable pitch propeller vessel with 3500 kW per shaft line. The tests were conducted in late June 1984 in the seasonal ice of the Canadian Beaufort Sea. Collected data illustrate the phenomena occurring in the Kort nozzle. A number of observations were made: interaction forces during nozzle blockage are of the same magnitude as during ice-blade impact; the maximum ice-induced blade force is not a function of ship speed; maximum ice-induced blade force occurs near relative radius 0.8. Ice interactions cause significant movement of the shaft relative to the shaft bearing; in ahead mode the blade is bent forward during ice interactions. Ice-induced shaft torque transients reached twice nominal and ice-induced shaft thrust transients reached four times nominal value. The largest blade impact forces are associated with the short-duration impacts.