sintered part
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Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7873
Author(s):  
Cho-Pei Jiang ◽  
M Fahrur Rozy Hentihu ◽  
Yung-Chang Cheng ◽  
Tzu-Yi Lei ◽  
Richard Lin ◽  
...  

This study proposes an innovative three-dimensional printing technology with submersion-light apparatus. A zirconia powder with an average particle size of 0.5 µm is mixed with 1,6-Hexanediol diacrylate (HDDA) and photo-initiator to form a slurry. The weight percentage of zirconia powder to HDDA is 70:30 wt.%. A light engine box is submerged in a slurry and emits a layered pattern to induce photopolymerization and transform a slurry into a printed green body. Green body sintering parameters for the first and second stages are 380 °C with a holding time of 1.5 h and 1550 °C with a holding time of 2 h. The sintered parts’ length, width, and height shrinkage ratios are 29.9%, 29.7%, and 30.6%. The ball milling decreases the powder particle size to 158 ± 16 nm and the mean grain size of the sintered part is 423 ± 25 nm. The sintered part has an average hardness of 1224 (HV), a density of 5.45 g/cm3, and a flexural strength of 641.04 MPa. A three-unit zirconia dental bridge also has been fabricated with a clinically acceptable marginal gap.


2019 ◽  
Vol 30 ◽  
pp. 100840
Author(s):  
Ryuichi Kobayashi ◽  
Yuki Yamauchi ◽  
Seiji Koganei ◽  
Takashi Kigure
Keyword(s):  

2017 ◽  
Author(s):  
M. Azmirruddin Ahmad ◽  
M. Jabir ◽  
N. Johari ◽  
R. Ibrahim ◽  
N. Hamidi

2016 ◽  
Vol 12 ◽  
pp. 189-196 ◽  
Author(s):  
Stefan Josupeit ◽  
Lavish Ordia ◽  
Hans-Joachim Schmid
Keyword(s):  

2016 ◽  
Vol 22 (5) ◽  
pp. 788-793 ◽  
Author(s):  
Stefan Josupeit ◽  
Hans-Joachim Schmid

Purpose The temperature distribution and history within laser sintered part cakes is an important aspect regarding the process quality and reproducibility of the polymer laser sintering process. This paper aims to an analysis of the temperature history during the build and cooling phase, which is decisive for powder ageing effects and the development of part quality characteristics. Design/methodology/approach A measurement system for three-dimensional in-process temperature measurements is set up and the influence of different parameters on the inner part cake temperature distribution and history is analyzed. In addition, position dependent temperature histories are finally correlated with powder ageing effects. Findings The main parameters influencing the part cake temperature history are figured out. Temperature inhomogeneities on the powder bed surface are detectable within the part cake, but only for a specific time or additional build height. Heat flux through the build frame results in different cooling rates dependent on z height. A combination of process parameters and build job layout results in individual, position-dependent temperature histories. As a consequence, completely different ageing intensities are found within one part cake. Research limitations/implications Temperature measurements are limited to part-free powder cakes so far. To transfer the results to other boundary conditions and machine types, simulation tools have to be developed and validated. Originality/value For the first time, the inner part cake temperature distribution and history have been measured during all build phases and with a high sensor density. The results of this work help to understand the temperature history dependency of powder and part properties and can therefore be used to develop optimized process controls.


2012 ◽  
Vol 727-728 ◽  
pp. 404-411 ◽  
Author(s):  
Gian R.C. Silva ◽  
Thomas Philips ◽  
John J. Dwyer ◽  
Zbigniew Zurecki

The quality of the atmosphere inside a sintering furnace plays a key role in the final properties of the sintered part. Properties such as the hardness, ductility, dimensions, carbon content, microstructure and magnetic properties among others are influenced not only by time and temperature, but also by the composition, flow rate and stability of the atmosphere within the furnace. The different physical zones within the furnace require different degrees of oxidizing or reducing power to develop the optimum properties in the final sintered part. Presented in this paper are practical techniques and technologies developed over the last 30 years of experiences with production sintering furnaces. The concept of distributed atmosphere introduction, combined with the use of directional atmosphere injectors, flame curtains, and gas curtains are used to stabilize and maintain the atmosphere profile within the furnace. Optimum and proven designs for atmosphere injectors, flame curtains, gas curtains and exhaust systems are presented.


2012 ◽  
Vol 445 ◽  
pp. 357-361
Author(s):  
Khairur Rijal Jamaludin ◽  
Norhamidi Muhamad ◽  
Sufizar Ahmad ◽  
Mohd Halim Irwan Ibrahim ◽  
Nor Hafiez Mohd Nor ◽  
...  

Sintering is a key step in the metal injection molding (MIM) process, which affects the mechanical properties of the sintered part. The mechanical properties of the sintered compacts are resulted from tremendous sintered part densification. This work utilizes robust engineering technique in optimizing sintering parameters of metal injection molding compacts. Three quality characteristics; shrinkage, density and flexure strength is optimized using Taguchi method-based grey analysis. The modified algorithm adopted here was successfully used for both detraining the optimum setting of the process parameters and for combining multiple quality characteristics into one integrated numerical value called grey relational grade. The sintering parameters investigated are: sintering temperature, sintering time, and heating rate. The result concluded that sintering time is the most significant for the combination of the quality characteristics.


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