Controlling the Quality of Laser Sintered Parts Along the Process Chain

The quality of laser sintered parts, in this work, manufactured by polymer laser sintering by using an EOSINT P395 Laser Sintering system, depends on several steps along the process chain. The first step is the characterization of the powder quality, whereas the rheological and physical investigations of nylon 12 powder are shown. By changing some important influencing factors, for example the powder ratio, the powder ageing and the moisture content, the influence on mechanical and physical properties, density and porosity, are investigated. The composition of the used powder is known. The previous process (storage conditions, etc.) as well as the laser sintering process (regarding energy density, temperature, etc.) is kept constant for the duration of this work. Regarding the post process in this work the cooling down phase is investigated as well. With an automatically blasting system it is possible to keep the post process parameters blasting distance and blasting time, constant. All of the tests will be performed using dry and conditioned test specimens. This work is showing the dependence on mechanical, rheological and physical parameters by varying important influencing factors along the laser sintering process quality chain.Mechanical Engineerin

X-ray computed tomography for additive manufacturing: a review

In this review, the use of x-ray computed tomography (XCT) is examined, identifying the requirement for volumetric dimensional measurements in industrial verification of additively manufactured (AM) parts. The XCT technology and AM processes are summarised, and their historical use is documented. The use of XCT and AM as tools for medical reverse engineering is discussed, and the transition of XCT from a tool used solely for imaging to a vital metrological instrument is documented. The current states of the combined technologies are then examined in detail, separated into porosity measurements and general dimensional measurements. In the conclusions of this review, the limitation of resolution on improvement of porosity measurements and the lack of research regarding the measurement of surface texture are identified as the primary barriers to ongoing adoption of XCT in AM. The limitations of both AM and XCT regarding slow speeds and high costs, when compared to other manufacturing and measurement techniques, are also noted as general barriers to continued adoption of XCT and AM

Mechanical and Physical Properties - A Way to Assess Quality of Laser Sintered Parts

The aim of this paper is the description and evaluation of physical properties like porosity and density and their influence on mechanical properties of laser sintered polyamide parts. For example, by reducing the porosity an increase of mechanical properties is possible. The correlation of laser parameters to these properties is investigated in detail. The energy density is an important parameter for the laser sintering process. By changing laser power, scan velocity and hatch distance an influence on manufactured components is given. A systematic variation of all three laser parameters is performed. A comparison of results obtained at constant energy densities obtained by varying these relevant parameters accordingly is shown as well.Mechanical Engineerin

How do generic quotas work? An analysis using HIV infection as an example.

BACKGROUND: Instruments controlling statutory healthcare medical supply have long been a topic of debate in health policy reform discussions. Over the years, a variety of tools have been developed, most of which are aimed at controlling drug expenditure. The instruments controlling regional prescriptions primarily focus on controlling behavioural patterns of the prescribing physicians. Important to note is the increased use of indication-directed quotas, primarily of drug leads and/or generics/biosimilars. These are now also available in the area of the human immunodeficiency virus (HIV), such as the generic quotas for HIV medications introduced in Bavaria and Berlin in 2020. OBJECTIVE: The aim of this article is to analyse the benefits and limitations of generic quota solutions in HIV care using statutory health insurance drug prescription data and to outline recommendations for action. RESULTS: It was observed that the quota potential for generics in the area of patent-free drugs in HIV care has already been largely exhausted. This can be explained by HIV prescribers supporting product exchange on the prescription. DISCUSSION: The best-case scenario in terms of regulation has almost been reached. This is due to a suitable set of instruments, including the framework agreement for medical supply as well as prescribing according to guidelines - in conjunction with the Pharmaceuticals Market Reorganisation Act (AMNOG) and reference prices for drugs. Conforming with guidelines and (existing) single-tablet regimens play an integral role in maintaining good quality of care