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For many applications, including space applications, the usability and performance of a component is dependent on the surface topology of the additively manufactured part. The purpose of this paper is to present an investigation into minimizing the residual surface roughness of direct metal laser sintering (DMLS) samples by manipulating the input process parameters.

First, the ability to manipulate surface roughness by modifying processing parameters was explored. Next, the surface topography was characterized to quantify roughness. Finally, microthruster nozzles were created both additively and conventionally for flow testing and comparison.

Surface roughness of DMLS samples was found to be highly dependent on the laser power and scan speed. Because of unintended partially sintered particles adhering to the surface, a localized laser fluence mechanism was explored. Experimental results show that surface roughness is influenced by the varied parameters but is not a completely fluence driven process; therefore, a relationship between laser fluence and surface roughness can be incorporated but not completely assumed.

This paper serves as an aid in understanding the importance of surface roughness and the mechanisms associated with DMLS. Rather than exploring a more common global energy density, a localized laser fluence was initiated. Moreover, the methodology and conclusions can be used when optimizing parts via metal additive manufacturing.

This study aims to solve the problems of low flow rate and low efficiency of micropumps in high-frequency applications. This micropump system was proposed to meet the requirements of 1–5 ml/min for microthrusters or drug delivery devices.

In this paper, a comprehensive analysis indicator and numerical procedure were disclosed and used to demonstrate the fluid dynamic characteristics and performance of a micropump. Accordingly, the reliability of the two-way coupling calculation was ensured through mutual verification of the real structure and the numerical system.

The research results indicate that the Polydimethylsiloxane (PDMS) microchannel can realize the contraction and expansion mechanism, allowing the fluid to generate different levels of pressure gradient during the working stroke and also enhancing the characteristics of energy consumption and storage of the flow field.

The pressure gradient between the fluid and PDMS microchannel can facilitate the improvement of the fluid backflow in a micropump. Therefore, in terms of performance improvement, the PDMS micropump increased the maximum backflow and optimum efficiency by approximately 50 and 90%, respectively.

IN the two years since the last Farnborough Air Show was held by the Society of British Aerospace Companies the aircraft industry has achieved an almost complete metamorphosis from the body blows in the form of major programme cancellations that almost felled it in 1965 to the very healthy position that it holds today.

This paper aims to provide an overview of current and historical arcjet development. The reviewed arcjets are considered with respect to both design and thruster relevant parameters. Correspondingly, the paper enables the identification of adequate design criteria and of the probable thruster parameters.

The approach consists of a database for thruster relevant parameters in conjunction with relevant operational requirements (such as type of propellant) and specific design criteria (such as e.g. propellant injection systems).

The synopsis of both operational parameter and respectively assigned design allows for the derivation of development approaches for arcjets under given high level requirements such as power regime.

The paper is a general review. However, its strength is in the synthesis of the arcjet classification, the functional evidence of design criteria and the application scenario.

Not only basic but also specific design criteria are analyzed and evaluated leading to a recommendation feature of the paper with respect to the overall design of adequate arcjets.

Within the scope of the Clean Space initiative, new applications and scenarios from the operation of arcjets arise enabling EOL phases of spacecraft that fulfill respective levels of debris mitigation and, in addition, the requirements concerning the adequately adapted re-entry of spacecrafts that are at end of life.

The paper is a general review. However, its strength is in the synthesis of the arcjet classification, the functional evidence of design criteria and the application scenario.