Novel Binder System Based on Paraffin-Wax for Low-Pressure Injection Molding of Metall–Ceramic Powder Mixtures

2001 ◽  
Vol 3 (12) ◽  
pp. 995 ◽  
Author(s):  
M. Leverkoehne ◽  
J. Coronel-Hernandez ◽  
R. Dirscherl ◽  
I. Gorlov ◽  
R. Janssen ◽  
...  
Keyword(s):  
Injection Molding ◽  
Ceramic Powder ◽  
Low Pressure ◽  
Paraffin Wax ◽  
Binder System ◽  
Powder Mixtures ◽  
Pressure Injection

A New Dewaxing Method and its Effect on the Properties of Low-Pressure Injection Molded Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 1012-1016
Author(s):  
Yin Wu ◽  
Wen Jie Si ◽  
He Zhuo Miao
Keyword(s):  
Carbon Dioxide ◽  
Injection Molding ◽  
Bending Strength ◽  
Low Pressure ◽  
Supercritical Extraction ◽  
Paraffin Wax ◽  
Organic Additives ◽  
Extraction Condition ◽  
Pressure Injection ◽  
Injection Molded

A new dewaxing method for low-pressure injection molded ceramics is presented. Supercritical extraction with carbon dioxide was used to remove paraffin wax from the ceramic green parts. The composition of organic additives for low-pressure injection molding feedstock and the extraction condition for the green parts were investigated. Moreover, the properties of sintered ceramic samples dewaxed by supercritical carbon dioxide were compared with those by thermal dewaxing. The results show that the new binder system containing 50wt% paraffin wax, 35% bee wax and 15% stearic acid fulfills the requirements of both low-pressure injection molding feedstocks and supercritical dewaxing, where the feedstock has high fluidity, low viscosity and quick solidification. The efficient extraction condition for supercritical dewaxing from the green parts is at 30MPa pressure and 45°C. Under this condition, defect free ceramic green parts can be obtained. Dewaxing methods have significant influence on the properties of sintered parts. The mechanical properties of the sintered sample can be improved by supercritical dewaxing. With this method, the bending strength of sintered samples (σ = 331.6 MPa) is higher than that obtained by thermal treatment (σ = 312.3MPa). The sintered samples dewaxed by supercritical CO2 have shown the property of higher density and less distortion compared to the thermal dewaxing method. Moreover, with supercritical extraction the dewaxing time can be reduced to about one tenth of the time required by thermal dewaxing.

Low-pressure injection molding processing of a 316-L stainless steel feedstock

2002 ◽  
Vol 52 (4-5) ◽  
pp. 360-365 ◽  
Author(s):  
M Rei ◽  
E.C Milke ◽  
R.M Gomes ◽  
L Schaeffer ◽  
J.P Souza
Keyword(s):  
Stainless Steel ◽  
Injection Molding ◽  
Low Pressure ◽  
Pressure Injection ◽  
316 L Stainless Steel

scholarly journals Preparation of Al2O3 ceramics by low pressure injection molding method.

1987 ◽  
Vol 34 (9) ◽  
pp. 378-382
Author(s):  
Kei Miyamoto ◽  
Yuzuru Takahashi ◽  
Suguru Inamura ◽  
Hiroki Miyamoto
Keyword(s):  
Injection Molding ◽  
Low Pressure ◽  
Molding Method ◽  
Pressure Injection

Preparation of Aluminum Feedstock for Green Part Specimen Using Metal Injection Molding

2013 ◽  
Vol 465-466 ◽  
pp. 1250-1254 ◽  
Author(s):  
Hafeiz Saidin ◽  
M. Azuddin
Keyword(s):  
Injection Molding ◽  
Paraffin Wax ◽  
Metal Injection Molding ◽  
Sudden Increase ◽  
Binder System ◽  
Molding Machine ◽  
Metal Composition ◽  
Binder Composition ◽  
Wax Content ◽  
Process Ability

In metal injection molding, to identify the homogenous aluminum based feedstock is a challenging issues. In this study, a metal injection molding of aluminum feedstock which contains of high density polyethylene, stearic acid and paraffin wax as binder system was performed. The feedstock are used to produce tensile and gear shape green specimens using injection molding machine. The process ability of the metal injection molding feedstock depends on different parameters such as their binder composition and amount of metal powder used. From this study, the percentage of volume shrinkage experienced a sudden increase at the metal composition more than 50%. It also shown that, the paraffin wax content, affects the feedstock performances.

Segregation Measurement of Inconel 718 Feedstocks Used in Low-Pressure Metal Injection Molding

2016 ◽  
Vol 857 ◽  
pp. 286-290 ◽  
Author(s):  
Faoud Fareh ◽  
V. Demers ◽  
S. Turenne ◽  
O. Scalzo
Keyword(s):  
Injection Molding ◽  
Inconel 718 ◽  
Volume Fraction ◽  
Phase Segregation ◽  
Ethylene Vinyl Acetate ◽  
Low Pressure ◽  
Paraffin Wax ◽  
Metal Injection Molding ◽  
Solid Loading ◽  
Molten State

Low-pressure metal injection molding (LP-MIM) is an advanced manufacturing technology where a wax-based feedstock is injected into a complex shape before densification heat treatments. Feedstock is generally designed to minimize segregation, maximize flowability, maximize the strength of the molded component, maximize the solid loading potential and ease of debinding. In this study, the emphasis is placed on the evaluation of the effect of segregation on different wax-based Inconel 718 superalloy feedstocks used in LP-MIM. In powder metallurgy, particle or phase segregation generates a fluctuation of the particle distribution in powder-binder mixtures from point to point. Such demixing generally occurs before or during the injection process, and can lead to the formation of defects such as cracks, distortions or heterogeneous shrinkage of the sintered parts. Different wax-based feedstocks were poured in cylindrical hot molds (95°C), maintained in molten state for 1 minutes or for 60 minutes, and rapidly cooled to room temperature. The specimens were then extracted from the top and bottom regions of each cylindrical part. A thermogravimetric analysis technique was used to measure the volume fraction of powder at these two locations in order to quantify the degree of segregation in green parts. The best candidate feedstocks minimizing segregation are the mixtures containing only paraffin wax, or those containing paraffin wax and ethylene vinyl acetate combined. An increase in the time spent in the molten state and the use of beeswax or stearic acid promote the powder-binder separation of feedstocks.

Manufacturing of Net-Shape Reaction-Bonded Ceramic Microparts by Low-Pressure Injection Molding

2009 ◽  
Vol 11 (5) ◽  
pp. 339-345 ◽  
Author(s):  
Nadja Schlechtriemen ◽  
Joachim R. Binder ◽  
Christina Hane ◽  
Marcus Müller ◽  
Hans-Joachim Ritzhaupt-Kleissl ◽  
...  
Keyword(s):  
Injection Molding ◽  
Low Pressure ◽  
Pressure Injection
Sign in / Sign up

Export Citation Format

Share Document