Binder Design for Fabricating Internal Crack-Free Injection-Molded Si3N4-Based Ceramics

1991 ◽  
Vol 249 ◽  
Author(s):  
Sophia R. Su
Keyword(s):  
Mass Transfer ◽  
Injection Molding ◽  
Cross Section ◽  
Decomposition Temperature ◽  
Internal Crack ◽  
Large Cross Section ◽  
Binder Removal ◽  
Ceramic Injection Molding ◽  
Injection Molded ◽  
The Right

ABSTRACTBinder design is an important issue in ceramic injection molding technology. The binder decomposition mechanism, which involves thermodynamics, kinetics, as well as heat and mass transfer, controls the binder removal process. This process, in turn, is governed by the thermal and physical characteristics of the organic waxes used, and is the most critical step in injection molding ceramics. In this paper, we present the binder design philosophy and the method of binder selection. A systematic binder removal study focusing on heating rate, setter powder, and sublimable materials was carried out with the selected compositions. As a result of this study, we concluded that the fluid wicking controls the binder removal at the molten temperature of the binder, and the diffusion and permeation-controlled mechanism dominate at the decomposition temperature range of the binder. With the right binder selection, it is feasible to produce internal and external crack-free large cross-section injection-molded ceramic parts.

scholarly journals Are We Able to Print Components as Strong as Injection Molded?—Comparing the Properties of 3D Printed and Injection Molded Components Made from ABS Thermoplastic

2021 ◽  
Vol 11 (15) ◽  
pp. 6946
Author(s):  
Bartłomiej Podsiadły ◽  
Andrzej Skalski ◽  
Wiktor Rozpiórski ◽  
Marcin Słoma
Keyword(s):  
Tensile Strength ◽  
Injection Molding ◽  
Mechanical Strength ◽  
Cross Section ◽  
Fused Deposition Modeling ◽  
High Strength ◽  
Large Cross Section ◽  
Fused Deposition ◽  
Injection Molded ◽  
The Cross

In this paper, we are focusing on comparing results obtained for polymer elements manufactured with injection molding and additive manufacturing techniques. The analysis was performed for fused deposition modeling (FDM) and single screw injection molding with regards to the standards used in thermoplastics processing technology. We argue that the cross-section structure of the sample obtained via FDM is the key factor in the fabrication of high-strength components and that the dimensions of the samples have a strong influence on the mechanical properties. Large cross-section samples, 4 × 10 mm2, with three perimeter layers and 50% infill, have lower mechanical strength than injection molded reference samples—less than 60% of the strength. However, if we reduce the cross-section dimensions down to 2 × 4 mm2, the samples will be more durable, reaching up to 110% of the tensile strength observed for the injection molded samples. In the case of large cross-section samples, strength increases with the number of contour layers, leading to an increase of up to 97% of the tensile strength value for 11 perimeter layer samples. The mechanical strength of the printed components can also be improved by using lower values of the thickness of the deposited layers.

scholarly journals S-Bend Silicon-On-Insulator (SOI) Large Cross-Section Rib Waveguide for Directional Coupler

2017 ◽  
Vol 7 (6) ◽  
pp. 3299
Author(s):  
Nurdiani Zamhari ◽  
Abang Annuar Ehsan ◽  
Mohd Syuhaimi Abdul Rahman
Keyword(s):  
Cross Section ◽  
Directional Coupler ◽  
Beam Propagation Method ◽  
Single Mode ◽  
Silicon On Insulator ◽  
Large Cross Section ◽  
Rib Waveguide ◽  
Passive Devices ◽  
The Right ◽  
Future Work

S-bend contributes the high losses in the silicon-on-insulator (SOI) large cross-section rib waveguide (LCRW). The objective of this work is to investigate S-bend SOI LCRW with two different single-mode dimensions named symmetrical and asymmetrical. The S-bend SOI LCRW has been simulating using beam propagation method in OptiBPM software. The asymmetrical waveguide with two different dimension arc given the best performance if compared to others dimension with 3 µm of waveguide spacing. It achieved 92.24% and 91.10% of normalized output power (NOP) for 1550 nm and 1480 nm wavelength respectively. Moreover, the minimum of S-bend spacing between the two cores is 0.9 µm for both 1550 nm and 1480 nm. Therefore, asymmetrical waveguide with two different dimension arc and 0.9 µm of S-bend spacing are chosen. This analysis is important to determine the right parameter in order to design the SOI passive devices. However, future work should be done to see the performance by designing the coupler and implement in the real system.

scholarly journals Experimental Investigation of Comparative Process Capabilities of Metal and Ceramic Injection Molding for Precision Applications

2016 ◽  
Vol 4 (3) ◽  
Author(s):  
Aminul Islam ◽  
Nikolaos Giannekas ◽  
David Marhöfer ◽  
Guido Tosello ◽  
Hans Hansen
Keyword(s):  
Experimental Investigation ◽  
Injection Molding ◽  
Comparative Study ◽  
State Of The Art ◽  
Ceramic Materials ◽  
Metal Injection Molding ◽  
Powder Injection ◽  
Ceramic Injection Molding ◽  
Metal Ceramic ◽  
The Right

The purpose of this paper is to make a comparative study on the process capabilities of the two branches of the powder injection molding (PIM) process—metal injection molding (MIM) and ceramic injection molding (CIM), for high-end precision applications. The state-of-the-art literature does not make a clear comparative picture of the process capabilities of MIM and CIM. The current paper systematically characterizes the MIM and CIM processes and presents the process capabilities in terms of part shrinkage, surface replication, tolerance capability, and morphological fidelity. The results and discussion presented in the paper will be useful for thorough understanding of the MIM and CIM processes and to select the right material and process for the right application or even to combine metal and ceramic materials by molding to produce metal–ceramic hybrid components.

Binder removal via a two-stage debinding process for ceramic injection molding parts

2014 ◽  
Vol 40 (2) ◽  
pp. 2819-2824 ◽  
Author(s):  
Sarizal Md Ani ◽  
Andanastuti Muchtar ◽  
Norhamidi Muhamad ◽  
Jaharah A. Ghani
Keyword(s):  
Injection Molding ◽  
Two Stage ◽  
Binder Removal ◽  
Ceramic Injection Molding ◽  
Debinding Process

Binder System Containing Polycarbosilane and Polysiiazane for Injection-Molded Si3N4 Parts

1991 ◽  
Vol 249 ◽  
Author(s):  
Sophia R. Su
Keyword(s):  
Thermal Decomposition ◽  
Injection Molding ◽  
Decomposition Rate ◽  
Gas Diffusion ◽  
Removal Mechanism ◽  
Binder System ◽  
Diffusion Effect ◽  
Binder Removal ◽  
Key Factor ◽  
Injection Molded

ABSTRACTPolycarbosilane and polysilazane, precursors of SiC and Si3N4, have been incorporated into the binder system for injection-molded Si3N4-based parts. Property requirements for these precursors as the injection-molding binder are briefly described. The binder removal mechanism is proposed and discussed based on the experimental results. Instead, the gas diffusion effect, rather than fluid wicking, is a key factor. Controlling the thermal decomposition rate of the binder is the key for achieving crack-free dense sintered parts.

The solidification of large sections in ceramic injection molding: Part II. Modulated pressure molding

1993 ◽  
Vol 8 (2) ◽  
pp. 345-351 ◽  
Author(s):  
T. Zhang ◽  
J.R.G. Evans
Keyword(s):  
Injection Molding ◽  
Residual Stresses ◽  
Volume Flow ◽  
Solidification Time ◽  
Ceramic Injection Molding ◽  
Injection Molded ◽  
Large Sections

Cylindrical moldings of 20 and 40 mm diameter were injection molded with the application of modulated hold pressure using a well-characterized alumina-polypropylene suspension. The effect of frequency on sprue solidification was explored. For the smaller moldings, very little extension to sprue solidification time was obtained with pressures up to 140 MPa, and this is attributed to the low reciprocating volume flow. For the larger moldings, pressures of 98 MPa were sufficient to produce moldings with neither voids nor cracks, and the sprue solidification time corresponded to the time needed for solidification of the molding. The use of higher pressures resulted in internal residual stresses which were qualitatively detected by the defomation on annealing of polished diametral sections.

scholarly journals Porosity distribution in metal injection molded parts

2021 ◽  
Vol 46 (1) ◽  
pp. 7-10
Author(s):  
Samir Butković ◽  
Emir Šarić ◽  
Muhamed Mehmedović
Keyword(s):  
Injection Molding ◽  
Cross Section ◽  
Density Variation ◽  
Residual Porosity ◽  
Metal Injection Molding ◽  
Green Density ◽  
Shaped Part ◽  
Molded Parts ◽  
Injection Molded ◽  
Complex Parts

Metal injection molding technology is commonly used in production of small and very complex parts. Residual porosity is unavoidable characteristic of P/M parts, affecting their final properties. During injection molding phase powder-binder separation can occur, causing green density variation through cross section of the part. This behaviour is particularly pronounced as complexity of the parts increases. As a consequence, zones with different density and residual porosity can be seen after sintering. In this regard, porosity and hardness distribution of the sintered ring-shaped part is analysed and presented in the paper.

Air exchange dynamics in the system of large cross-section blind roadways

2020 ◽  
Vol 2 ◽  
pp. 46-57
Author(s):  
S.V. Maltsev ◽  
◽  
B.P. Kazakov ◽  
A.G. Isaevich ◽  
M.A. Semin ◽  
...  
Keyword(s):  
Cross Section ◽  
Large Cross Section ◽  
Air Exchange

Longitudinal oscillation of a rod with a variable cross section

2019 ◽  
Vol 14 (2) ◽  
pp. 138-141
Author(s):  
I.M. Utyashev
Keyword(s):  
Cross Section ◽  
Natural Frequencies ◽  
Liouville Problem ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Independent Functions ◽  
The Cross ◽  
The Right

Variable cross-section rods are used in many parts and mechanisms. For example, conical rods are widely used in percussion mechanisms. The strength of such parts directly depends on the natural frequencies of longitudinal vibrations. The paper presents a method that allows numerically finding the natural frequencies of longitudinal vibrations of an elastic rod with a variable cross section. This method is based on representing the cross-sectional area as an exponential function of a polynomial of degree n. Based on this idea, it was possible to formulate the Sturm-Liouville problem with boundary conditions of the third kind. The linearly independent functions of the general solution have the form of a power series in the variables x and λ, as a result of which the order of the characteristic equation depends on the choice of the number of terms in the series. The presented approach differs from the works of other authors both in the formulation and in the solution method. In the work, a rod with a rigidly fixed left end is considered, fixing on the right end can be either free, or elastic or rigid. The first three natural frequencies for various cross-sectional profiles are given. From the analysis of the numerical results it follows that in a rigidly fixed rod with thinning in the middle part, the first natural frequency is noticeably higher than that of a conical rod. It is shown that with an increase in the rigidity of fixation at the right end, the natural frequencies increase for all cross section profiles. The results of the study can be used to solve inverse problems of restoring the cross-sectional profile from a finite set of natural frequencies.

Mass transfer into the liquid in turbulent flow at high Schmidt numbers. Dissolution of benzoic acid into aqueous solutions of glycerol from internal surface of the pipe

1981 ◽  
Vol 46 (7) ◽  
pp. 1566-1576
Author(s):  
František Vašák ◽  
Václav Kolář ◽  
Zdeněk Brož
Keyword(s):  
Mass Transfer ◽  
Benzoic Acid ◽  
Aqueous Solutions ◽  
Cross Section ◽  
Circular Cross Section ◽  
Internal Surface ◽  
Theoretical Relation ◽  
Acid Dissolution ◽  
Schmidt Numbers ◽  
Unified Description

Theoretical relation derived in the last study for calculation of the mass transfer coefficient in the region of not fully developed concentration profile at high Schmidt numbers has been verified experimentally. This experimental study has been devoted to measurements of the rate of benzoic acid dissolution into aqueous solutions of glycerol from the internal surface of the pipe of circular cross section in the range 933 ⪬ Sc ⪬ 225 000 and 5 000 ⪬ Re ⪬ 50 000. It has been possible to explain on basis of the theoretical model, the differences between the data of various authors and to obtain a unified description of the phenomena.

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