Article
Refine
Year of publication
- 2024 (1)
- 2023 (6)
- 2022 (3)
- 2021 (4)
- 2020 (10)
- 2019 (8)
- 2018 (13)
- 2017 (11)
- 2016 (11)
- 2015 (9)
- 2014 (13)
- 2013 (3)
- 2012 (11)
- 2011 (10)
- 2010 (8)
- 2009 (8)
- 2008 (15)
- 2007 (9)
- 2006 (11)
- 2005 (15)
- 2004 (13)
- 2003 (17)
- 2002 (16)
- 2001 (16)
- 2000 (5)
- 1999 (15)
- 1998 (19)
- 1997 (16)
- 1996 (24)
- 1995 (21)
- 1994 (17)
- 1993 (12)
- 1992 (12)
- 1991 (9)
- 1990 (4)
- 1989 (7)
- 1988 (7)
- 1987 (8)
- 1986 (6)
- 1985 (11)
- 1984 (12)
- 1983 (11)
- 1982 (4)
- 1981 (7)
- 1979 (4)
- 1978 (2)
- 1977 (2)
- 1974 (4)
- 1973 (2)
- 1972 (4)
- 1971 (3)
- 1970 (1)
Institute
- Fachbereich Maschinenbau und Mechatronik (490) (remove)
Document Type
- Article (490) (remove)
Keywords
- Rapid prototyping (5)
- Rapid Prototyping (4)
- SLM (3)
- additive manufacturing (3)
- 3D-Printing (2)
- Brake set-up (2)
- Freight rail (2)
- Rapid Manufacturing (2)
- Stereolithographie (2)
- factory planning (2)
Mit der Digitalen Automatischen Kupplung beginnt ein neues Kapitel des Schienengüterverkehrs, in dem zusammengestellte Wagen sich automatisch in wenigen Minuten abfahrbereit machen, ohne dass der Mensch eingreifen muss. Eines des größten Hemmnisse der umweltfreundlichen Schiene wird dann entfallen. Notwendig ist jetzt eine Diskussion über den Umfang und die Systemgrenzen der Automatischen Bremsprobe.
Lokomotiven sind dank modernster Konzepte der Antriebstechnik heute energiesparend und umweltfreundlich. Eine Ausrüstung mit Telematik und Assistenzfunktionen ist Standard. Auf der Strecke zeigt sich moderne Technik in Form elektronischer Stellwerke und Zugsicherungssysteme und in Rangier- und Abstellanlagen als EOW-Technik. Am Güterwagen hingegen ist der technische Fortschritt komplett vorbeigegangen. Auch beim modernsten Wagen (Abb. 1) ist die einzige „Automatik“-Funktion die zentral über die Hauptluftleitung (HL) versorgte und betätigte Luftbremse.
The thermal conductivity of components manufactured using Laser Powder Bed Fusion (LPBF), also called Selective Laser Melting (SLM), plays an important role in their processing. Not only does a reduced thermal conductivity cause residual stresses during the process, but it also makes subsequent processes such as the welding of LPBF components more difficult. This article uses 316L stainless steel samples to investigate whether and to what extent the thermal conductivity of specimens can be influenced by different LPBF parameters. To this end, samples are set up using different parameters, orientations, and powder conditions and measured by a heat flow meter using stationary analysis. The heat flow meter set-up used in this study achieves good reproducibility and high measurement accuracy, so that comparative measurements between the various LPBF influencing factors to be tested are possible. In summary, the series of measurements show that the residual porosity of the components has the greatest influence on conductivity. The degradation of the powder due to increased recycling also appears to be detectable. The build-up direction shows no detectable effect in the measurement series.
In times of short product life cycles, additive manufacturing and rapid tooling are important methods to make tool development and manufacturing more efficient. High-performance polymers are the key to mold production for prototypes and small series. However, the high temperatures during vulcanization injection molding cause thermal aging and can impair service life. The extent to which the thermal stress over the entire process chain stresses the material and whether it leads to irreversible material aging is evaluated. To this end, a mold made of PEEK is fabricated using fused filament fabrication and examined for its potential application. The mold is heated to 200 ◦C, filled with rubber, and cured. A differential scanning calorimetry analysis of each process step illustrates the crystallization behavior and first indicates the material resistance. It shows distinct cold crystallization regions at a build chamber temperature of 90 ◦C. At an ambient temperature above Tg, crystallization of 30% is achieved, and cold crystallization no longer occurs. Additional tensile tests show a decrease in tensile strength after ten days of thermal aging. The steady decrease in recrystallization temperature indicates degradation of the additives. However, the tensile tests reveal steady embrittlement of the material due to increasing crosslinking.
Manufacturing companies across multiple industries face an increasingly dynamic and unpredictable environment. This development can be seen on both the market and supply side. To respond to these challenges, manufacturing companies must implement smart manufacturing systems and become more flexible and agile. The flexibility in operational planning regarding the scheduling and sequencing of customer orders needs to be increased and new structures must be implemented in manufacturing systems’ fundamental design as they constitute much of the operational flexibility available. To this end, smart and more flexible solutions for production planning and control (PPC) are developed. However, scheduling or sequencing is often only considered isolated in a predefined stable environment. Moreover, their orientation on the fundamental logic of the existing IT solutions and their applicability in a dynamic environment is limited. This paper presents a conceptual model for a task-based description logic that can be applied to factory planning, technology planning, and operational control. By using service-oriented architectures, the goal is to generate smart manufacturing systems. The logic is designed to allow for easy and automated maintenance. It is compatible with the existing resource and process allocation logic across operational and strategic factory and production planning.
Traditional vulcanization mold manufacturing is complex, costly, and under pressure due to shorter product lifecycles and diverse variations. Additive manufacturing using Fused Filament Fabrication and high-performance polymers like PEEK offer a promising future in this industry. This study assesses the compressive strength of various infill structures (honeycomb, grid, triangle, cubic, and gyroid) when considering two distinct build directions (Z, XY) to enhance PEEK’s economic and resource efficiency in rapid tooling. A comparison with PETG samples shows the behavior of the infill strategies. Additionally, a proof of concept illustrates the application of a PEEK mold in vulcanization. A peak compressive strength of 135.6 MPa was attained in specimens that were 100% solid and subjected to thermal post-treatment. This corresponds to a 20% strength improvement in the Z direction. In terms of time and mechanical properties, the anisotropic grid and isotropic cubic infill have emerged for use in rapid tooling. Furthermore, the study highlights that reducing the layer thickness from 0.15 mm to 0.1 mm can result in a 15% strength increase. The study unveils the successful utilization of a room-temperature FFF-printed PEEK mold in vulcanization injection molding. The parameters and infill strategies identified in this research enable the resource-efficient FFF printing of PEEK without compromising its strength properties. Using PEEK in rapid tooling allows a cost reduction of up to 70% in tool production.