scholarly journals A Method to Characterize the Quality of a Polymer Laser Sintering Process

2014 ◽  
Vol 6 ◽  
pp. 185374 ◽  
Author(s):  
Stefan Rüsenberg ◽  
Stefan Josupeit ◽  
Hans-Joachim Schmid
Keyword(s):  
Layer Thickness ◽  
Laser Sintering ◽  
Thermal Ageing ◽  
Process Chain ◽  
Sintering Process ◽  
Data Set ◽  
Whole Process ◽  
Quality Aspects ◽  
Important Challenge

The reproducibility and reliability of quality aspects are an important challenge of the polymer laser sintering process. However, existing quality concepts and standardization activities considering influencing factors along the whole process chain have not been validated experimentally yet. In this work, these factors are analyzed and kept constant to obtain a reliable material data set for different layer thicknesses and testing temperatures. In addition, material qualities regarding powder ageing effects are analyzed using different build heights and layer thicknesses: while an increase of the layer thickness reduces mechanical part strength and density, it also results in a less intense thermal ageing of unmolten powder due to shorter build times.

The Impact of Employing Different Quality PA2200 Powder Grades to Shrinkage on Sintered Part in Selective Laser Sintering Process

2015 ◽  
Vol 789-790 ◽  
pp. 126-130
Author(s):  
W.A.Y. Yusoff ◽  
D.T. Pham ◽  
K.D. Dotchev
Keyword(s):  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Sintering Process ◽  
Melt Flow Rate ◽  
Input Material ◽  
Low Degree ◽  
Powder Properties ◽  
Plastic Parts ◽  
The Impact

One of the challenges which Laser Sintering faces is the Rapid Manufacturing of plastic parts with good consistent quality. This is due to the fact that plastic powder properties deteriorate during the long periods of time through the LS building and cooling cycles. This paper presents an experimental study of the deterioration or ageing of PA12 powder properties in the LS process. The influences of different grades of recycled PA12 powders are investigated. The main aim of this research is to develop a methodology of controlling the input material properties that will ensure consistent and good quality of the fabricated parts. From the experiment it was found that PA12 powder with high melt flow rate, low melting temperature, low glass transition temperature and low degree of crystallization temperature could improve the sintering process to produce a good Laser Sintering (LS) parts with lower shrinkage rate.

Effects of micro laser sintering process parameters on quality of nickel-titanium single tracks and thin walls

2015 ◽  
Vol 21 (6) ◽  
pp. 1081-1090 ◽  
Author(s):  
Saeed Khademzadeh ◽  
Nader Parvin ◽  
Paolo F. Bariani ◽  
Federico Mazzucato
Keyword(s):  
Process Parameters ◽  
Laser Sintering ◽  
Nickel Titanium ◽  
Sintering Process ◽  
Thin Walls

Study on the Microstructure and Morphology of Sintering Process of SiC-TiB2 Composite

2013 ◽  
Vol 544 ◽  
pp. 196-199
Author(s):  
Liang Jiang ◽  
Yi Wang Bao ◽  
Yu Hong Chen ◽  
Jie Wei
Keyword(s):  
Silicon Carbide ◽  
Titanium Diboride ◽  
Sintering Process ◽  
Composite Ceramics ◽  
Loss On Ignition ◽  
Whole Process ◽  
Solid Phases ◽  
The Impact ◽  
New Phase

This research employs pressureless sintering process to study the impact of different amount of titanium diboride on the performance of silicon carbide-titanium diboride composite. Results show that: no new phase was produced, and the whole process is a solid-phases sintering process. In this experiment, it has the smallest relative density and loss on ignition and porosity, and highest degree of densification of the silicon carbide-titanium diboride composite ceramics sintered body when the titanium diboride content is 50g, and the quality of SiC and TiB2 ratio is 1:1.

Influence of Layer-by-Layer Laser Sintering Modes on the Roughness and Thickness of Sintered Layer of Copper Powder

2015 ◽  
Vol 756 ◽  
pp. 214-219
Author(s):  
N.A. Saprykina ◽  
A.A. Saprykin ◽  
S.M. Emelyanenko
Keyword(s):  
Mathematical Model ◽  
Surface Layer ◽  
Copper Powder ◽  
Laser Sintering ◽  
Experimental Setup ◽  
Layer By Layer ◽  
Practical Recommendation ◽  
Sintering Process ◽  
Sintered Layer

Quality improvement problem has been considered for a laser sintered surface layer. Purposely built experimental setup was described together with a four-factor experiment design on laser sintering PMS-1 copper powder. A mathematical model describing the effect of laser sintering process parameters on the surface roughness has been proposed. Practical recommendation for improving the quality of the surface layer is given.

Heat Transfer in Laser Sintering of Thick-Film Microelectronics

2005 ◽  
Author(s):  
Edward C. Kinzel ◽  
Xianfan Xu ◽  
Hjalti H. Sigmarsson ◽  
William J. Chappell
Keyword(s):  
Heat Transfer ◽  
Thick Film ◽  
Selective Laser Sintering ◽  
Thermal Conditions ◽  
Processing Parameters ◽  
Laser Sintering ◽  
Heat Transfer Analysis ◽  
Sintering Process ◽  
Microwave Frequencies

This paper investigates fabrication of functional thick-film components using Selective Laser Sintering (SLS). We demonstrated that SLS has exciting potentials for thick-film metallization of low-temperature substrates. The DC conductivity of laser sintered components is measured for a range of laser scan speeds and powers. The quality of metallization at microwave frequencies is evaluated by comparing the measured Q to simulations. The effects of processing parameters on the quality of components are investigated through a heat transfer analysis of the laser sintering process. Optimum properties of the fabricated components are obtained when proper thermal conditions are achieved during laser heating.

Structure and Orientation of As Precipitates in LT-MBE Grown GaAs

1991 ◽  
Vol 49 ◽  
pp. 900-901 ◽  
Author(s):  
Alain Claverie ◽  
Zuzanna Liliental-Weber
Keyword(s):  
Transport Properties ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Low Temperatures ◽  
Lattice Parameter ◽  
Crystalline Quality ◽  
Insulating Properties ◽  
Lt Gaas

GaAs layers grown by MBE at low temperatures (in the 200°C range, LT-GaAs) have been reported to have very interesting electronic and transport properties. Previous studies have shown that, before annealing, the crystalline quality of the layers is related to the growth temperature. Lowering the temperature or increasing the layer thickness generally results in some columnar polycrystalline growth. For the best “temperature-thickness” combinations, the layers may be very As rich (up to 1.25%) resulting in an up to 0.15% increase of the lattice parameter, consistent with the excess As. Only after annealing are the technologically important semi-insulating properties of these layers observed. When annealed in As atmosphere at about 600°C a decrease of the lattice parameter to the substrate value is observed. TEM studies show formation of precipitates which are supposed to be As related since the average As concentration remains almost unchanged upon annealing.

Development and Application of Quality Control System for Highway Subgrade Construction

2019 ◽  
Vol 2 (5) ◽  
Author(s):  
Tong Wang
Keyword(s):  
Quality Control ◽  
Real Time ◽  
Detection Method ◽  
System Development ◽  
Effective Control ◽  
Construction Process ◽  
Development Mode ◽  
The Road ◽  
Whole Process

The compaction quality of the subgrade is directly related to the service life of the road. Effective control of the subgrade construction process is the key to ensuring the compaction quality of the subgrade. Therefore, real-time, comprehensive, rapid and accurate prediction of construction compaction quality through informatization detection method is an important guarantee for speeding up construction progress and ensuring subgrade compaction quality. Based on the function of the system, this paper puts forward the principle of system development and the development mode used in system development, and displays the development system in real-time to achieve the whole process control of subgrade construction quality.

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