THE INFLUENCE OF ADDITIVE TECHNOLOGY ON THE QUALITY OF THE SURFACE LAYER AND THE STRENGTH STRUCTURE OF PROSTHETIC CROWNS

Tribologia ◽  
2018 ◽  
Vol 280 (4) ◽  
pp. 13-22
Author(s):  
Łukasz BOJKO ◽  
Wojciech RYNIEWICZ ◽  
Anna M. RYNIEWICZ ◽  
Marcin KOT ◽  
Paweł PAŁKA
Keyword(s):  
Surface Layer ◽  
Layer Structure ◽  
Casting Process ◽  
Additive Technology ◽  
Cocrmo Alloy ◽  
Casting Technology ◽  
Stomatognathic System ◽  
Cad Cam ◽  
Hard Structures

Prosthetic crowns reproduce the damaged hard structures of the patient’s own teeth and take over their natural functions, thus securing the correct reconstruction of the stomatognathic system. The aim is to evaluate the crowns for premolars and molars produced by casting, milling, and Selective Laser Melting technologies, in terms of the accuracy of reproducing the degree against the prosthetic pillar, the analysis of the surface layer structure of the step, and the micromechanical parameters of the alloy. The study material included CoCrMo alloy crowns. The conducted study allowed finding that the tightness of prosthetic crowns made using traditional casting technology as well as in SLM milling and technology is comparable and meets clinical requirements. Structural crown analyses confirmed the very good quality of the surface layer obtained with milling technology and SLM technology using the CAD/CAM method. SLM and digital milling allow the formation of precise and durable structures constituting the foundation of crowns in a time much shorter than the casting process.

Using Simulation to Improve the Quality of the Metallic Industrial Components Made by Rapid Casting

2015 ◽  
Vol 808 ◽  
pp. 187-192
Author(s):  
Alina Popan ◽  
Nicolae Bâlc ◽  
Alexandru Popan ◽  
Nicolae Panc ◽  
Cristina Stefana Borzan
Keyword(s):  
Surface Defects ◽  
Casting Process ◽  
Complex Geometries ◽  
Thin Sections ◽  
Vacuum Casting ◽  
Rapid Casting ◽  
Casting Technology ◽  
Small Series ◽  
Complex Shapes

Industrial parts with complex shapes are characterized by thin sections and complex geometries. Rapid vacuum casting is an ideal technology to manufacture complicated parts in small series production or prototypes. Contributions regarding simulation and analyzing of the parts made by rapid vacuum casting technology are presented in this study. Using dedicated software for simulating the casting process was analyzed and optimized the time of casting, the complete filling with material and also reducing the surface defects.

scholarly journals Design guidelines for plastic casting using 3D printing

2020 ◽  
Vol 15 ◽  
pp. 155892502091603 ◽  
Author(s):  
Paweł Zmarzły ◽  
Damian Gogolewski ◽  
Tomasz Kozior
Keyword(s):  
Surface Layer ◽  
3D Printing ◽  
Textile Industry ◽  
Dimensional Accuracy ◽  
Casting Process ◽  
Design Guidelines ◽  
Design Stage ◽  
Technological Inheritance ◽  
Finished Sample

The main aim of the presented tests was to assess the possibility of using 3D printing and casting material to produce casting molds and prototypes, especially in production of existing models. The analysis was based on the assessment of dimensional accuracy and quality of the surface layer of a finished prototype and the intermediate elements made during the production process. The mold was made using the PolyJet Matrix additive technology, and then a silicone mold was cast which was used to prepare a finished sample for testing in accordance with the design assumptions. Based on the results of metrological measurements, the phenomenon of technological inheritance in terms of error transfer in the foundry industry was evaluated. The measurements obtained suggest that in case of casting process, the hereditary features are transferred from individual casting processes, which is especially prominent in the case of surface texture quality. This confirms the occurrence of the phenomenon of the so-called technological inheritance and the need to analyze it. The results of the tests can be a guide for technologists who design molds, core boxes, and casting models, concerning the corrections (shrinkage) that need to be introduced at the design stage in order to obtain a product (casting) of satisfactory dimensional accuracy and quality of the surface layer. The result can also be useful for casting materials reinforced with glass fiber, carbon fiber, which are common materials in 3D printing and textile industry.

Research on Horizontal Electromagnetic Continuous Casting of Sn-P Bronze Strips

2007 ◽  
Vol 26-28 ◽  
pp. 377-380
Author(s):  
Chun Hua Hui ◽  
Ting Ju Li ◽  
Wen Zhong Jin
Keyword(s):  
Electromagnetic Field ◽  
Continuous Casting ◽  
Casting Process ◽  
Optical Microscope ◽  
Shrinkage Cavity ◽  
Casting Technology ◽  
Graphite Mold ◽  
Electromagnetic Continuous Casting ◽  
A Current

In order to improve the quality of tin-phosphor bronze strips, the horizontal electromagnetic continuous casting technology, i.e. imposing alternating electromagnetic field to the horizontal continuous casting process of tin-phosphor bronze strips was developed. The effect of electromagnetic field on the quality of tin-phosphor bronze strips was studied with electron probe microanalysis (EPMA) and optical microscope. The results showed that when the alternating electromagnetic field with 50 Hz frequency and 18 A current was imposed, the crystal grain of the tin-phosphor bronze strips was obviously refined and the segregation and shrinkage cavity were greatly reduced. The quality of tin-phosphor bronze strips was remarkably improved, so the annealing time was shortened from 7 hours to 5 hours, and the service life of graphite mold was extended from 168 hours to 334 hours.

Foresight of Material Surface Engineering as a Tool Building a Knowledge-Based Economy

2012 ◽  
Vol 706-709 ◽  
pp. 2511-2516 ◽  
Author(s):  
Anna Danuta Dobrzańska-Danikiewicz
Keyword(s):  
Quality Of Life ◽  
Surface Layer ◽  
Surface Structure ◽  
Functional Properties ◽  
Layer Structure ◽  
Structure And Properties ◽  
Knowledge Based ◽  
Knowledge Based Economy ◽  
Engineering Materials

Throughout history, a substantial or often leap technological progress, was determined by the availability of new engineering materials, which usually stimulated the improvement in the quality of life. The development of engineering materials constitutes one of the most significant elements in the field of science and technology, and innovative policy in Poland and Europe as regards the knowledge-based economy (KBE). The enhancement of the product functional properties, required by the new strategies of engineering materials development, as well as materials processing technologies is frequently connected with appropriate formation of the engineering materials surface layer structure and properties. Functional properties of many products depend not only on the possibility of transferring the mechanical load across the whole element section or its physicochemical properties, but, most often, they depend mainly on the surface layer structure and properties. The application of foresight methodology in the assessment of the state and prospects regarding the development of technology related to the formation of the materials surface structure and properties provides the possibility to manage knowledge in this field. It can be achieved through a formalization of the explicit and tacit knowledge gathering and use in order to increase production competitiveness, effectiveness, and innovation, improve the quality of life and achieve sustainable development. The objectives accomplished in such a way contribute to the increase in intellectual capital by enhancing the effectiveness of using the existing knowledge, creating new knowledge, as well as increasing the level of understanding and disseminating knowledge. The implemented foresight project will result in identifying the priority innovative technologies and strategic research trends in the scope of surface structure and properties formation of engineering materials and biomaterials whose development in the country will be of key importance within next 20 years.

scholarly journals Possibility for Replicating Mechanoscopic Surface Marks in the Hybrid Vacuum-Pressure Casting Process

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 874
Author(s):  
Mariusz Frankiewicz ◽  
Karol Kobiela ◽  
Tomasz Kurzynowski
Keyword(s):  
Geometrical Structure ◽  
Casting Process ◽  
Polymer Materials ◽  
Vacuum Pressure ◽  
Pressure Casting ◽  
Main Research ◽  
Casting Technology ◽  
The Individual ◽  
Cast Parts

Vacuum-pressure casting technology allows small batches of components to be manufactured from polymer materials, mainly from thermosetting plastics such as polyurethane and epoxy resins. Apart from being very simple, the process is also advantageous in that it offers a very accurately reproduced geometrical structure of the surfaces of master patterns used in mold manufacturing. This article presents the results of analyses performed for the process of replicating mechanoscopic marks with the use of three vacuum casting variants, including a hybrid vacuum-pressure casting process developed in particular for the replication purposes. The main research objective was to analyze and evaluate the influence of the parameters of the individual process variants on the quality of the obtained cast parts and on the replication accuracy without introducing additional artifacts on their surfaces. The article discusses the individual stages of the process and provides an analysis of their parameters. The replicas were evaluated for their porosity and reproduction quality with the use of CT methods and comparative photographs obtained from a light microscope.

scholarly journals Microstructure and Thermoelectric Properties of (Bi0.48Sb1.52)Te3 Thick Films Prepared with Tape Casting Method

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 140
Author(s):  
Lichen Liu ◽  
Ziping Cao ◽  
Min Chen ◽  
Jun Jiang
Keyword(s):  
Thermoelectric Properties ◽  
Low Cost ◽  
Thick Films ◽  
Tape Casting ◽  
Casting Process ◽  
Casting Method ◽  
Glass Substrates ◽  
Conductive Films ◽  
Casting Technology

This paper reports the fabrication and characterization of (Bi0.48Sb1.52)Te3 thick films using a tape casting process on glass substrates. A slurry of thermoelectric (Bi0.48Sb1.52)Te3 was developed and cured thick films were annealed in a vacuum chamber at 500–600 °C. The microstructure of these films was analyzed, and the Seebeck coefficient and electric conductivity were tested. It was found that the subsequent annealing process must be carefully designed to achieve good thermoelectric properties of these samples. Conductive films were obtained after annealing and led to acceptable thermoelectric performance. While the properties of these initial materials are not at the level of bulk materials, this work demonstrates that the low-cost tape casting technology is promising for fabricating thermoelectric modules for energy conversion.

scholarly journals Probing of the internal damage morphology in multilayered high-temperature superconducting wires

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
You-He Zhou ◽  
Cong Liu ◽  
Lei Shen ◽  
Xingyi Zhang
Keyword(s):  
Magnetic Flux ◽  
Layer Structure ◽  
Extreme Environment ◽  
Uniaxial Tensile ◽  
Internal Damage ◽  
Amorphous Phases ◽  
Superconducting Wires ◽  
Mechanical Quality ◽  
Loading System

AbstractThe second generation HTS wires have been used in many superconducting components of electrical engineering after they were fabricated. New challenge what we face to is how the damages occur in such wires with multi-layer structure under both mechanical and extreme environment, which also dominates their quality. In this work, a macroscale technique combined a real-time magneto-optical imaging with a cryogenic uniaxial-tensile loading system was established to investigate the damage behavior accompanied with magnetic flux evolution. Under a low speed of tensile strain, it was found that the local magnetic flux moves gradually to form intermittent multi-stack spindle penetrations, which corresponds to the cracks initiated from substrate and extend along both tape thickness and width directions, where the amorphous phases at the tip of cracks were also observed. The obtained results reveal the mechanism of damage formation and provide a potential orientation for improving mechanical quality of these wires.

scholarly journals Influence of Sequential CAD/CAM Milling on the Fitting Accuracy of Titanium Three-Unit Fixed Dental Prostheses

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1401
Author(s):  
Doo-Bin Song ◽  
Man-So Han ◽  
Si-Chul Kim ◽  
Junyong Ahn ◽  
Yong-Woon Im ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Computer Aided Design ◽  
Dental Prostheses ◽  
Computer Aided ◽  
Cad Cam ◽  
Fixed Dental Prostheses ◽  
Gap Data ◽  
Aided Design ◽  
Fitting Accuracy

This study investigated the fitting accuracy of titanium alloy fixed dental prostheses (FDP) after sequential CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) fabrication. A three-unit FDP model connecting mandibular second premolars and molars was prepared and scanned to fabricate titanium FDPs by CAD/CAM milling. A total of six FDPs were sequentially milled in one titanium alloy disk using a new set of burs every time (n = 4). The fitting accuracy of FDPs was mesiodistally evaluated by a silicone replica technique and the measurement was triplicated at four different locations: MO (marginal opening), MG (marginal gap), AG (axial gap), and OG (occlusal gap). Data were statistically analyzed using ANOVA and Tukey’s HSD test. The fitting accuracy of PMMA (polymethyl methacrylate) FDPs milled using the worn or new bur were evaluated by the same procedure (n = 6). The mean dimensions of titanium FDP for all measuring positions, except for AG, were significantly increased from the third milling. However, no difference was noted between the first FDP and the second FDP milled with the same set of burs. Severe edge chippings were observed in all milling burs. Detrimental effects of the worn burs on the fitting accuracy were demonstrated in the CAD/CAM-milled PMMA FDP. The results recommend proper changing frequency of cutting burs to achieve the quality of fit and predictable outcomes for dental CAD/CAM prostheses.

Development of Electromagnetic Swirling Flow in Immersion Nozzle in Continuous Casting Process of Steel

2011 ◽  
Vol 295-297 ◽  
pp. 1284-1288 ◽  
Author(s):  
De Wei Li ◽  
Zhi Jian Su ◽  
Li Wei Sun ◽  
Katsukiyo Marukawa ◽  
Ji Cheng He
Keyword(s):  
Continuous Casting ◽  
Swirling Flow ◽  
Casting Process ◽  
Continuous Casting Process ◽  
New Process ◽  
Electromagnetic Generator ◽  
Set Up ◽  
The Magnetic Field ◽  
Immersion Nozzle

Swirling flow in an immersion nozzle is effective on improving quality of casting block and casting speed in continuous casting process of steel. However, a refractory swirl blade installed in the nozzle is liable to cause clogging, which limit the application of the process. In this study a new process is proposed, that is a rotating electromagnetic field is set up around an immersion nozzle to induce a swirling flow in it by Lorentz force. New types of swirling flow electromagnetic generator are proposed and the effects of the structure of the generator, the coil current intensity and frequency on the magnetic field and on the flow field in the immersion nozzle are numerically analyzed.

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