scholarly journals Fabrication of Micro-Patterned Surface for Pool-boiling Enhancement by Using Powder Injection Molding Process

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 507 ◽  
Author(s):  
Hanlyun Cho ◽  
Juan Godinez ◽  
Jun Sae Han ◽  
Dani Fadda ◽  
Seung Mun You ◽  
...  

In this study, two kinds of copper micro-patterned surfaces with different heights were fabricated by using a powder injection molding (PIM) process. The micro-pattern’s size was 100 μm, and the gap size was 50 μm. The short micro-pattern’s height was 100 μm, and the height of the tall one was 380 μm. A copper powder and wax-polymer-based binder system was used to fabricate the micro-patterned surfaces. The critical heat flux (CHF) and heat transfer coefficient (HTC) during pool-boiling tests were measured with the micro-patterned surfaces and a reference plain copper surface. The CHF of short and tall micro-patterned surfaces were 1434 and 1444 kW/m2, respectively, and the plain copper surface’s CHF was 1191 kW/m2. The HTC of the plain copper surface and the PIM surface with short and tall micro-patterned surfaces were similar in value up to a heat flux 1000 kW/m2. Beyond that value, the plain surface quickly reached its CHF, while the HTC of the short micro-patterned surface achieved higher values than that of the tall micro-patterned surface. At CHF, the maximum values of HTC for the short micro-pattern, tall micro-pattern, and the plain copper surface were 68, 58, and 57 kW/m2 K.

2018 ◽  
Vol 770 ◽  
pp. 189-194
Author(s):  
Dong Guo Lin ◽  
Jae Man Park ◽  
Tae Gon Kang ◽  
Seong Taek Chung ◽  
Young Sam Kwon ◽  
...  

In this work, powder injection molding (PIM) of Ti-6Al-4V alloy powder has been studied. Defect-free high performance Ti-6Al-4V parts with low carbon/oxygen contents have been successfully prepared by PIM. A pre-alloyed Ti-6Al-4V alloy powder and wax-polymer binder system have been mixed together to prepare the feedstock. In mixing stage, the solid loading percentage and mixing conditions have been optimized. Rheological and thermal debinding behaviors of prepared feedstock have been characterized and numerically expressed based on rheometry and thermal gravity experimental results. In addition, the injection molding process of Ti-6Al-4V parts has been numerically analyzed to optimize the injection molding conditions. Consequently, the defect-free Ti-6Al-4V parts with low carbon and oxygen contents have been successfully fabricated by PIM, which exhibits excellent physical and mechanical properties.


10.14311/1608 ◽  
2012 ◽  
Vol 52 (4) ◽  
Author(s):  
Pavel Petera

The PIM (powder injection molding) process consists of several steps in which faults can occur. The quality of the part that is produced usually cannot be seen until the end of the process. It is therefore necessary to find a way to discover the fault earlier in the process. The cause of defects is very often “phase separation” (inhomogeneity in powder distribution), which can also be influenced by the holding pressure. This paper evaluates the powder distribution with a new method based on density measurement. Measurements were made using various holding pressure values.


Author(s):  
Ali Keshavarz Panahi ◽  
Hossein Khoshkish

In this article, the fabrication steps of copper parts, using the powder injection molding method have been investigated. For the purpose of this study, first, several feedstocks were prepared by mixing copper powder (in volume percentages of 60, 64, 68, and 72%) and a thermoplastic binder. Due to the sensitivity of the mixing stage in the powder injection molding process, the Extrumixing method was utilized to appropriately mix the copper powder with the binder. Rheological characteristics of the different feedstocks were analyzed by means of a capillary rheometer. Based on this analysis, the feedstock having a 68 vol. % copper powder was selected as the optimum powder, out of which, samples shaped like tensile test specimens were successfully molded. These samples were later debinded by the solvent debinding method. Sintering of the pieces was carried out at different temperatures. Research showed that raising the sintering temperature leads to an increase of density and tensile strength of the specimens.


2020 ◽  
Vol 56 (12) ◽  
pp. 1-7
Author(s):  
U. Soupremanien ◽  
J.-S. Ngoua-Teu ◽  
P. Sallot ◽  
C. Delafosse ◽  
G. Delette

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