Precision casting by the ‘Lost wax’ process

Background: Uncemented implants are still associated with several major challenges, especially with regard to their manufacturing and their osseointegration. In this study, a novel manufacturing technique—an optimized form of precision casting—and a novel surface modification to promote osseointegration—calcium and phosphorus ion implantation into the implant surface—were tested in vivo. Methods: Cylindrical Ti6Al4V implants were inserted bilaterally into the tibia of 110 rats. We compared two generations of cast Ti6Al4V implants (CAST 1st GEN, n = 22, and CAST 2nd GEN, n = 22) as well as cast 2nd GEN Ti6Al4V implants with calcium (CAST + CA, n = 22) and phosphorus (CAST + P, n = 22) ion implantation to standard machined Ti6Al4V implants (control, n = 22). After 4 and 12 weeks, maximal pull-out force and bone-to-implant contact rate (BIC) were measured and compared between all five groups. Results: There was no significant difference between all five groups after 4 weeks or 12 weeks with regard to pull-out force (p > 0.05, Kruskal Wallis test). Histomorphometric analysis showed no significant difference of BIC after 4 weeks (p > 0.05, Kruskal–Wallis test), whereas there was a trend towards a higher BIC in the CAST + P group (54.8% ± 15.2%), especially compared to the control group (38.6% ± 12.8%) after 12 weeks (p = 0.053, Kruskal–Wallis test). Conclusion: In this study, we found no indication of inferiority of Ti6Al4V implants cast with the optimized centrifugal precision casting technique of the second generation compared to standard Ti6Al4V implants. As the employed manufacturing process holds considerable economic potential, mainly due to a significantly decreased material demand per implant by casting near net-shape instead of milling away most of the starting ingot, its application in manufacturing uncemented implants seems promising. However, no significant advantages of calcium or phosphorus ion implantation could be observed in this study. Due to the promising results of ion implantation in previous in vitro and in vivo studies, further in vivo studies with different ion implantation conditions should be considered.

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Polymer Binders of Ceramic Nanoparticles for Precision Casting of Nickel-Based Superalloys

Nanomaterials ◽

10.3390/nano11071714 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1714

Author(s):

Paweł Wiśniewski

Keyword(s):

Solid Phase ◽

Average Particle Size ◽

Water Soluble ◽

Ethyl Silicate ◽

Average Particle ◽

Precision Casting ◽

Polymer Binders ◽

Initial Stage ◽

Nano Alumina ◽

Solid Phase Content

This study presents the general characteristics of binders used in precision casting of Nickel-based superalloys. Three groups of binders were described: resins, organic compounds, and materials containing nanoparticles in alcohol or aqueous systems. This study also includes literature reports on materials commonly used and those recently replaced by water-soluble binders, i.e., ethyl silicate (ES) and hydrolysed ethyl silicate (HES). The appearance of new and interesting solutions containing nano-alumina is described, as well as other solutions at the initial stage of scientific research, such as those containing biopolymers, biodegradable polycaprolactone (PCL), or modified starch. Special attention is paid to four binders containing nano-SiO2 intended for the first layers (Ludox AM, Ludox SK) and structural layers (EHT, Remasol) of shell moulds. Their morphology, viscosity, density, reactions, and electrokinetic potential were investigated. The binders were characterized by a high solid-phase content (>28%), viscosity, and density close to that of water (1–2 mPa·s) and good electrokinetic stability. The nanoparticles contained in the binders were approximately spherically shaped with an average particle size of 16–25 nm.

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Dental Precision Casting of Ti-29Nb-13Ta-4.6Zr Using Calcia Mold

MATERIALS TRANSACTIONS ◽

10.2320/matertrans.m2009139 ◽

2009 ◽

Vol 50 (8) ◽

pp. 2057-2063 ◽

Cited By ~ 5

Author(s):

Harumi Tsutsumi ◽

Mitsuo Niinomi ◽

Toshikazu Akahori ◽

Masaaki Nakai ◽

Tsutomu Takeuchi ◽

...

Keyword(s):

Precision Casting

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The “Lost Wax” Process of Precision Casting

Proceedings of the Institution of Mechanical Engineers ◽

10.1243/pime_proc_1950_162_014_02 ◽

1950 ◽

Vol 162 (1) ◽

pp. 66-74 ◽

Cited By ~ 1

Author(s):

J. S. Turnbull

Keyword(s):

Gas Turbine ◽

Turbine Blades ◽

Casting Process ◽

Alternative Methods ◽

Casting Technique ◽

Gas Turbine Blades ◽

Precision Casting ◽

Good Surface ◽

Wax Pattern ◽

Good Surface Finish

The paper describes a casting process which differs from standard foundry practice in that it uses a wax pattern in a high refractory one-piece mould to produce metal castings with a good surface finish to an accuracy of ±0·002 inch. The process involves making a master pattern in either hard wood or metal, relating it to a soft metal die by precision casting technique, and then the production of wax patterns from the die on an injection machine. Finally, the wax patterns are invested in refractory moulds, the wax is melted out, the mould baked, and the metal component is cast. The “lost wax” process is advantageous in cases where ( a) the metal is unmachinable, or ( b) where the component is of an unmachinable shape, or ( c) where production by other methods takes too long. One of the most common applications is in the manufacture of gas-turbine blades. The tool costs are relatively low compared to the costs involved in alternative methods of manufacture, the die cost being a function of the number of castings required. The production of cheap castings is necessarily dependent on the scrap percentage being kept to a minimum; at present the scrap from the manufacture of gas-turbine blades is less than 30 per cent, and the author surmises that it would not be unreasonable to expect it to be less than 10 per cent in two years' time.

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3D Printing of Ceramic Shell Molds for Precision Casting of Turbine Blades

10.1115/gt2021-58796 ◽

2021 ◽

Author(s):

Liubov Magerramova ◽

Boris Kozlov ◽

Eugene Kratt

Keyword(s):

3D Printing ◽

Turbine Blades ◽

Shell Shape ◽

Ceramic Shell ◽

Labor Costs ◽

Precision Casting ◽

Design And Manufacturing ◽

Refractory Ceramic ◽

Internal Core ◽

Ceramic Shell Mold

Abstract Traditionally, the technology used in the production of gas turbine blade castings characterized by a large number of technological conversions, high labor costs with a large amount of manual labor and the need to produce various types of complex and expensive equipment at different stages of production. This work aims to reduce the time and money spent on the manufacturing of ceramic shell shapes — a form suitable for the standard methods of precision casting by traditional heat-resistant nickel alloys. The proposed approached involves obtaining a shell shape with an internal core as a single, non-assembled product, without lengthy and time-consuming design and manufacturing processes involved in forming equipment for the production of castings based on smelted models. The proposed method is based on the use of 3D printing with refractory ceramic pastes. Using both uncooled and cooled blades as examples, models of casting molds were designed, technological processes were developed, and ceramic shell molds were manufactured. Experimental casting into a manufactured ceramic shell mold for an uncooled blade with a bandage shelf was performed and showed satisfactory results.

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Evaluation of the Internal Structure of the Multilayer Ceramic Mould for Precision Casting Critical Parts of Aircraft Engines by X-ray Computed Tomography

Journal of Powder Metallurgy and Mining ◽

10.4172/2168-9806.1000189 ◽

2018 ◽

Vol 07 (01) ◽

Author(s):

Tchorz A ◽

Ksiazek M ◽

Krzak I ◽

Szczepaniak-Lalewicz K ◽

Zaba K ◽

...

Keyword(s):

Computed Tomography ◽

Internal Structure ◽

Aircraft Engines ◽

X Ray ◽

Precision Casting ◽

X Ray Computed ◽

Multilayer Ceramic

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USE OF FUSED DEPOSITION MODELING PROCESS IN INVESTMENT PRECISION CASTING AND RISK OF USING SELECTIVE LASER SINTERING PROCESS

International Journal of Applied Research in Mechanical Engineering ◽

10.47893/ijarme.2012.1041 ◽

2012 ◽

pp. 226-230

Author(s):

SIVADASAN M ◽

N.K SINGH ◽

ANOOP KUMAR SOOD

Keyword(s):

Fused Deposition Modeling ◽

Selective Laser Sintering ◽

Thermal Response ◽

Acrylonitrile Butadiene Styrene ◽

Laser Sintering ◽

Precision Casting ◽

Fused Deposition ◽

Rp Process ◽

Deposition Modeling ◽

Metallic Parts

Investment Castings (IC) is one of the most economical ways to produce intricate metallic parts when forging, forming and other casting processes tend to fail. However, high tooling cost and long lead time associated with the fabrication of metal moulds for producing IC wax (sacrificial) patterns result in cost justification problems for customized single casting or small-lot production. Generating pattern using rapid prototyping (RP) process may be one of the feasible alternatives. For this purpose present study assessed the suitability of the fused deposition modeling (FDM) process for creating sacrificial IC patterns by studying FDM fabricated part thermal response at various temperatures. A series of experiments with RP patterns are conducted and a set of test castings are also made in steel for establishing feasibility. The build material used is acrylonitrile butadiene styrene (ABS). As an annexe to this work a concurrent attempt is also made to quantify the risk in using Selective Laser Sintering patterns for Investment Castings. Authors hope this work might establish applicability of ABS in IC and also lead the investigations to theoretically tone down the shell cracking tendency with Selective Laser Sintering patterns when Proprietary Duraform is used as the build material.

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Study on Rapid Casting for Complex Parts

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.121-126.433 ◽

2011 ◽

Vol 121-126 ◽

pp. 433-437

Author(s):

Feng Zeng ◽

Shan Yao ◽

Zhong Fei Jiao ◽

Shu Ming Zhao ◽

Tong Yang

Keyword(s):

Centrifugal Casting ◽

Casting Method ◽

Cloud Data ◽

Coordinate Measurement ◽

Rapid Casting ◽

Precision Casting ◽

Complex Cavity ◽

Simple Technology ◽

Five Axis ◽

Complex Parts

A rapid casting method for complex parts is presented. In this method, casting moulds with complex cavity are manufactured by self-created rapid prototyping approach which called Selected Laser Partitioning for Prototyping. After surface coating treatment for moulds, complex parts are obtained by centrifugal casting. As application cases, metal impeller was casted by this method. A self-developed five-axis coordinate measurement machine was used to process the surface measuring of impeller. The Dimension accuracy grade of impeller is CT-3 and the surface roughness is Ra 6.3µm through making comparisons directly between CAD model and point cloud data of impeller surface. The result shows that this rapid casting method which has the characters of simple technology and low production cost reaches the level of precision casting.

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