Lost-wax Research Articles

Metal of the "Cimmerian elite" of the North Caucasus ( on the materials of tomb 3 of the Terese burial ground)

The article publishes the results of a study of bronze items from tomb 3 of the Terese burial ground (Central North Caucasus, Karachay-Cherkessia), one of the richest burials of the Koban culture of the Central North Caucasus during the Cimmerian campaigns in Transcaucasia and Western Asia.A typological analysis of the bridle accessories of a number of imported metal items from this complex shows that the burial belongs to a war-horseman of the late 8th centuryBC, who participated in military campaigns in Transcaucasia. ED XRF analysis reveals the main alloy groups used for production of the bridle and harness attachments from the Terese tomb 3 (26 samples) and Fars burial ground (2 samples). Tin bronzes and lead-tin bronzes with low, middle, and high tin concentration and a relatively low lead content clearly dominated the Terese selection. Lost wax casting into investment clay moulds was the main manufacturing technique. The Pb-isotope data of 23 samples obtained by MC-ICP-MS reveals the different sources of copper and lead as well as the recycling of scrap metal. Polymetallic ores of the Sadonsky ore field, located in North Ossetia was considered as one of the possible ore sources. Within the framework of the studied samples, arsenic bronze was recorded only as part of the inlay of two pins, originating from the Central Georgia which were probably made to order by a highly qualified Transcaucasian jeweller.

A Novel Manufacturing Method for Microwave Components by Lost Wax Casting

A novel manufacturing strategy for the detailed fabrication of complex and mechanically robust microwave components is presented. Additive printing of the full wax positive model with a multijet printer allows free shaping on the one hand, while metal casting provides mechanical stability for a variety of applications on the other. In addition to that a slotted waveguide model is used to improve the post-processing and performance. This combination is used with a rectangular waveguide for the E-band to demonstrate the performance of this manufacturing method at higher frequencies than previous publications. Measurements on the samples show comparable attenuation coefficients to the milled split-block counterpart, i.e., less than 5 dB/m, a good root mean square (RMS) surface roughness of the inner surfaces with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</sub> = 5.85 μm and astonishingly fine tolerances of 8.8±40.3 μm overall. Comparisons are also made between other published additive manufacturing processes.

Обь-Иртышское междуречье в эпоху раннего неолита – бронзы, Средневековья: культурогенез, хозяйство, мировоззрение (по материалам археологических комплексов)

This paper describes the research findings from the archaeological sites of the Neolithic – Early and Developed Bronze Age, the Middle Ages, located on the territory of Barabinskaya wood and steppe area in the Middle Omsk region, within the framework of the Russian Foundation for Basic Research (RFBR) projects. The excavations of diverse sites (burials, settlements, ritual sites) of various periods helped to obtain insights into residential and economic buildings, burials and ritual objects. As a result, new data on the economy and ideology shared by the representatives of some archaeological cultures, i.e. Odinovskaya, Krotovskaya, Andronovskaya (Fedorovskaya), Kyshtovskaya, were obtained. Based on the materials from the early Neolithic sites, a new archaeological culture Barabinskaya has been identified. The archaeological evidence of contacts between two Early Bronze Age populations, Odinovskaya and Krotovskaya cultures, during the 3rd millennium BC has been documented. The economy of the early Neolithic Middle Omsk population has been characterized as mainly based on fishing: taking into account the evidence of fishing development in Baraba microdistrict, the use of river and lake bio resources for this purpose as early as since the 8th–7th millennia BC is quite obvious. For the early Neolithic era, a specific method of preserving fish – “fish pits”, as well as fish smoking, – was documented. The bronze casting production acquires the first features of crafts. The analysis of the osteological materials from Odinovskaya culture sites in Central Baraba helps to reconstruct that economy as transitional from appropriating to producing type.&#x0D; The materials of the Middle Ages sanctuaries of the southern Khanty Kyshtovskaya culture are presented. The connection of cult complexes of this culture with small barns from the sacred places of the Siberian peoples and grave structures has been established. Based on the project results, two monographs were published.

Nickel-aluminium bronze (NiBRAl) casting alloy tribological/corrosion resistance properties improvement via deposition of a Cu-doped diamond-like carbon (DLC) thin film; optimization of sputtering magnetron process conditions

Diamond-like carbon is used as a solid-lubricant and a wear-resistance coating in various industries owing to excellent mechanical/tribological properties. In the present study, by doping copper metal to the DLC-based coating applied on the nickel-bronze-aluminum alloy (NiBRAl), the argon to methane blowing rate and the substrate temperature were optimized. The electrochemical analyses revealed that the corrosion resistance of the coated sample with pure DLC-coating increased almost three times more than the value obtained for the uncoated sample. Furthermore, it was demonstrated that the coefficient of friction value is reduced from 0.83 for the bare alloy to about 0.59 after applying the DLC-based coating. The Cu-DLC alloy with a 90:10 copper: carbon ratio (at 300 °C) showed the best anti-corrosion properties.

New Ecological Cast Bronzes for Fittings Manufactured from Recycled Waste

New Ecological Cast Bronzes for Fittings Manufactured from Recycled Waste

Parametric Characterization of Machined Textured Surfaces

Surface topography in general is not easy to characterize due to a great number of different features that appear on it. It is still more challenging for machined textured surfaces that are of high functional significance for tribological purposes. For practical reasons, there is a need to describe such surfaces using only a small number of parameters. Which of them represent surface details the best is still an open issue. To find out which parameters can be the most suitable in that case, three groups of machined textured surfaces were prepared. They were plateau-honed cylinder surfaces made of gray cast iron, steel, and bronze surfaces with isolated dimples and steel surfaces after abrasive blasting followed by lapping. All of them were measured by means of a white light interferometer. Different parameters and relationships were evaluated and based on them correlation and regression analyses were used. The basic description contained statistically independent parameters that can be used in production control, while the wider description in scientific research. In general, parameters of random surfaces were more intercorrelated than those of surfaces with isolated dimples. As was found for the basic description of random two-process surfaces, five parameters were enough while description of textured surfaces with isolated oil pockets needed six. In wider, scientific description, regardless the surface type seven parameters contained the necessary information about the surface. It was also proved that a pair of parameters, the emptiness coefficient Sp/Sz and Sq/Sa, can describe the shape of the ordinate distribution of machined textured surfaces better than, for example, skewness Ssk and kurtosis Sku, commonly used for that purpose.

Metallic Dental Implants Wear Mechanisms, Materials, and Manufacturing Processes: A Literature Review.

From the treatment of damaged teeth to replacing missing teeth, dental biomaterials cover the scientific interest of many fields. Dental biomaterials are one of the implants whose effective life depends vastly on their material and manufacturing techniques. The purpose of this review is to summarize the important aspects for metallic dental implants from biomedical, mechanical and materials science perspectives. The review article will focus on five major aspects as mentioned below. Tooth anatomy: Maximizing the implant performance depends on proper understanding of human tooth anatomy and the failure behavior of the implants. Major parts from tooth anatomy including saliva characteristics are explored in this section. Wear mechanisms: The prominent wear mechanisms having a high impact on dental wear are abrasive, adhesive, fatigue and corrosion wear. To imitate the physiological working condition of dental implants, reports on the broad range of mastication force and various composition of artificial saliva have been included in this section, which can affect the tribo-corrosion behavior of dental implants. Dental implants classifications: The review paper includes a dedicated discussion on major dental implants types and their details for better understanding their applicability and characteristics. Implant materials: As of today, the most established dental implant materials are SS316L, cobalt chrome alloy and titanium. Detailed discussion on their material properties, microstructures, phase transformations and chemical compositions have been discussed here. Manufacturing techniques: In terms of different production methods, the lost wax casting method as traditional manufacturing is considered. Selective Laser Melting (SLM) and Directed Energy Deposition (DED) as additive manufacturing techniques (AM) have been discussed. For AM, the relationships between process-property-performance details have been explored briefly. The effectiveness of different manufacturing techniques was compared based on porosity distribution, mechanical and biomechanical properties. Despite having substantial research available on dental implants, there is a lack of systematic reviews to present a holistic viewpoint combining state-of-the-art from biomedical, mechanical, materials science and manufacturing perspectives. This review article attempts to combine a wide variety of analyzing approaches from those interdisciplinary fields to deliver deeper insights to researchers both in academia and industry to develop next-generation dental implants.

Бубенчики из гробницы 19/2020 на плато Эски-Кермен: состав материала и реконструкция процесса изготовления

The given article studies two small bells found in the tomb 19/2020 in the narthex of the single-nave church in block II at Eski-Kermen plateau. These bells have slightly flattened body with a slit and a small ball inside; they are decorated with corrugated transverse stripes. One of the bells is completely preserved, the other is fragmented. The aim of the work was to determine the composition of the metal and the manufacturing technology of the bells. The X-ray fluorescence analysis of the elemental composition of the metal of the bells showed that the items themselves and the ball inside one bell were made of tin-lead bronze. All currently known reconstructions of the manufacturing technology of such products are described, with the most possible one as the making of wax model of bells comprising of two halves and, later, lost wax casting; clay form was also lost.

Lewke's Cannon: A Visual and Political Dialogue Captured in Gold and Silver

The Lewke cannon was one of the selected items in the Pilot Project Provenance Research on Objects of the Colonial Era launched in 2019. This cannon has gained attention globally because of its unique and unmatched decorations. While its history of being looted from the palace of Kandy has been recorded by various historians, very little attention has been given to the actual decoration on the cannon. This article shows that the decoration and inscription on the outer surface of the cannon were applied as a gift from the prominent Sri Lankan figure Lewke to King Sri Vijaya Rajasinha of Kandy in 1745-46 and as such represents an internal political moment in the Kandyan kingdom. The research into the cannon brings to the fore the Sri Lankan craftsmanship of this eighteenth-century South Asian region. While ancient Lankan motifs have been applied, the craftsmen were able to emphasize the motifs already present in the bronze cast from the seventeenth-century Netherlands, amongst which Lankan emblems, as well as adapt their motifs to better suit the decoration already present. In all, this contribution shows how an analysis of the decoration and the inscription provides us with new insight into the mid-eighteenth-century Sri Lankan social-political and cultural context, while at the same time revealing a global history of cultural diplomacy.

A Review of the History of Research in Lost-Wax Casting in Bronze Age China Over the Past Century

This study analyzes in detail the last century of scholarly study, in China and internationally, into China's Bronze Age lost-wax casting techniques. It finds that research beginning in the early twentieth century has differentiated five lost-wax casting research periods, linked to different research methods and new archaeological discoveries of bronzes and casting relics. The methods that can be identified with a particular research period are: complete lost-wax (before 1931); semi lost-wax (1931–1959); complete piece-mold (1960–1977); both casting technologies (1978–2018); hollowed lost-wax (after 2019). Research shows that piece-mold casting was the dominant casting technology in the territories of the Shang and Zhou dynasty (before 221 BC) kings, but craftspeople used lost-wax casting skillfully at the latest in the Qin dynasty (before 210 BC). Lost-wax artifacts influenced by other cultures are occasionally seen in the border areas of the Shang and Zhou kingdoms. Research on organic constituents in the clay cores of hollowed lost-wax artifacts may provide a definite answer to this question.

Tribosynthesis of friction films and their influence on the functional properties of copper-based antifriction composites for printing machines

Abstract This article is devoted to research of the tribosynthesis mechanism of antifriction films and their influence on the functional properties of antifriction composites based on copper alloyed with nickel and molybdenum with the CaF2 solid lubricant additions for operation at rotation speeds of 3,000–7,000 rph and increased loads of 3.0–5.0 MPa in air. Studies have shown that antifriction films are complex, dynamically changing formations on the surfaces of the composite and counterface, developing according to the bifurcation mechanism. The antifriction layer is decisive in the formation of the friction pair's tribological high-level properties, which provide the self-lubrication mode of the friction unit. The formation and permanent presence of the anti-seize film is associated with a balanced wear rate of the film and its constant formation again on these worn areas at rotation speeds of up to 7,000 rph and loads of up to 5.0 MPa. Due to the steady self-lubrication mechanism, the copper-based composite has significant advantages over cast bronze CuSn5ZnPb, which can only work with liquid lubrication in the friction units of printing machines. The performed studies make it possible to choose rational modes for operation of new high-speed antifriction Cu-composites based on the friction films analysis, predicting their high functional properties.

Ball Brooches in the Age of Citizen Science

Ball brooches make a difficult research theme in Denmark. This is mainly because very few of the hitherto published specimens were found in a context or under circumstances that help to shed light on their chronology. The most recently published study is a very brief paper by Jesper Laursen on the chronology and typology of ball brooches (Laursen 1984). Laursen’s paper was published at a time when hobby metal detecting was only at its early stages in Denmark. Therefore, this hobby had not yet had its impact on the material. Metal detecting favors objects with much metal and since cultivated soil contains a lot of iron waste most hobby detectorists tend to screen for iron. Consequently, objects of bronze, silver and gold will have a tendency to dominate the finds brought in by these people, and especially massive objects. Thus, ball brooches, especially the cast bronze specimens, would have a good chance to be detected and collected. As the internet developed, some private sites were established were the finders themselves published their finds. Recently the app named DIME launched by University of Aarhus (in September 2018) and until today (29.09.2021) 121.186 finds have been registered by private users in the database. The newly available information, correlated with the previous ones, offers the possibility of a preliminary study of the ball brooches, which we propose in this article.

Effect of radiant emittance of an LED curing light on the cuspal deflection of a simulated tooth cavity in bulk-fill composite restoration: A novel simulation method.

In this study, a novel method for simulating human teeth was developed, with which the effect of radiant emittance of an LED curing light on the cuspal deflection was investigated. A mesio-occluso-distal (MOD) cavity was replicated using a heat-pressed ceramic and lost wax technique, and the cuspal compliance and cuspal deflection of the replicated ceramic teeth and extracted human teeth were evaluated. The replicated ceramic teeth were restored using a nano bulk-fill composite and photopolymerized using three different protocols. Data were analyzed with t-test and one-way ANOVA (α=0.05). The cuspal compliance and cuspal deflection of the replicated ceramic teeth and extracted human teeth were similar. Cuspal deflections did not differ significantly among the tested photopolymerization protocols. Thus, the replicated ceramic teeth were an effective simulation of human teeth. During bulk-fill composite restoration of the MOD cavity, cuspal deflection was not affected by changing the radiant emittance of the LED light.

Nickel-aluminium bronze cast into 3D sand printed moulds: Kappa II phase and segregation of phosphorus

During a study to relate tensile properties to cast microstructures in commercial Ni-Al bronze castings being produced using 3D sand printed moulds it was observed that some of the Fe3Al κII phase contained unusual microstructural features in etched metallographic specimens taken from as-cast test bar material. These features were found to be associated with the segregation of P impurity in some of the κII forms. This segregation formed P rich zones, some of which contained Fe2P, within several κII particles. P is thought to have promoted the spheroidal shape of κII since the rosette forms only contained minor levels of P. Small areas rich in Ti, V, and Mo and containing some C, and thought to be carbides, were also found within the spheroidal shaped κII particles. These observations suggest that further study of the influence of P and other impurity elements is needed since compositional variations and microstructural effects could affect corrosion performance.

The Shang dynasty remains at the Guoyuanzui site in Lutai Mountain, Huangpi District, Wuhan

Abstract The Hubei Provincial Institute of Cultural Relics and Archaeology et al. excavated at the Guoyuanzui site in Lutai Mountain, Huangpi District, Wuhan, Hubei from 2019 to 2020, and discovered a series of Shang dynasty remains, including residential and bronze casting areas. Features related to bronze casting include architectural structures, ash ditches, ash pits, red burnt soil pits, furnaces, round-shaped burnt ground surfaces, clay mold pits, and backfill pits. Unearthed artifacts range from bronzes, casting-related artifacts, pottery artifacts, and stone objects. Most of the Shang dynasty casting remains found at Guoyuanzui are of the same period as those of the Huayuanzhuang phase in Huanbei Shang City through Yinxu Phase I. The Guoyuanzui site is another Shang dynasty core settlement in the middle of the Yangtze River after Panlongcheng. The excavation at Guoyuanzui is significant for the discussion of the Shang dynasty’s strategic management of South China, and thus is of immense value in revealing the civilizational developmental trajectory in the middle reach of the Yangtze River.

Casting-on: Technical study of a unique hollow-cast copper vessel dated to the sixth dynasty using X-ray computerized tomography

The article studied casting-on technique that was used to manufacture a hollow-cast vessel with a narrow neck. Casting-on technique, lost-wax addition, is casting a new part to attach with a pre-existing object whether cast or hammered. The case study is a small hollow-cast vessel dated back to the Sixth Dynasty [2465–2323 BCE]. It was excavated in Pepe-nefer mastaba at the Southern Upper Egypt, Edfu region. Non-invasive multi-detector computerized tomography (MDCT) and micro-analytical techniques (SEM-EDS, PXRD) were used to investigate the studied vessel. The metallographic microscope was used to examine the microstructure of both the pre-cast body and the casting-on part. SEM-EDS analysis was used to identify their elemental compositions. PXRD was used to analyze the brownish-red patina on the entire vessel’s outer surface. Also, PXRD was used to identify the chemical composition of the core material that inside the vessel. Axial, sagittal 2D CT slices and 3D CT reconstruction images revealed both the pre-cast body and the casting-on part were made by direct lost-wax casting technique. SEM-EDS analyses identified the chemical compositions of the pre-cast body and the casting-on part as copper-lead and copper-arsenic alloys respectively with a trace of iron in both. PXRD identified the cuprite with trace of copper as the chemical composition of the brownish-red patina that cover the entire vessel’s outer surface. The study proved that the casting-on technique was already practiced during the Sixth Dynasty as a metallurgical repair method for an imperfect pre-cast vessel. CT results helped to draw an ideational schematic representation for the casting process of both the two vessel’s parts. The study concluded that the studied vessel may be one of the early trails to manufacture the hollow-cast copper vessels during the Old kingdom.

METHODS OF MANUFACTURING GEARS

This article discusses the manufacture of gears with two methods (copy method and run-in method). The largest number of gear wheels are made of carbon and alloy steels, and less often of cast iron, bronze and plastic. In the manufacture of gears, two fundamentally different methods are used. copy method and run method. Gears, especially high-precision gears, must have dimensional stability, therefore, in their manufacture, high requirements are placed on material homogeneity and balance of internal stresses.

Clinical Applications of Polyetheretherketone in Removable Dental Prostheses: Accuracy, Characteristics, and Performance.

The high-performance thermoplastic polyetheretherketone (PEEK) has excellent mechanical properties, biocompatibility, chemical stability, and radiolucency. The present article comprehensively reviews various applications of PEEK in removable dental prostheses, including in removable partial dentures (RPDs) (frameworks and clasps), double-crown RPDs, and obturators. The clinical performance of PEEK in removable dental prostheses is shown to be satisfactory and promising based on the short-term clinical evidence and technical complications are scarce. Moreover, the accuracy of RPDs is a vital factor for their long-term success rate. PEEK in removable dental prostheses is fabricated using the conventional lost-wax technique and CAD/CAM milling, which produces a good fit. Furthermore, fused deposition modeling is considered to be one of the most practical additive techniques. PEEK in removable prostheses produced by this technique exhibits good results in terms of the framework fit. However, in light of the paucity of evidence regarding other additive techniques, these manufacturers cannot yet be endorsed. Surface roughness, bacterial retention, color stability, and wear resistance should also be considered when attempting to increase the survival rates of PEEK removable prostheses. In addition, pastes represent an effective method for PEEK polishing to obtain a reduced surface roughness, which facilitates lower bacterial retention. As compared to other composite materials, PEEK is less likely to become discolored or deteriorate due to wear abrasion.

Technological Insights into the Evolution of Bronze Bell Metal Casting on the Korean Peninsula

Bronze cast bells have been designed and developed for hundreds of years, with the worldwide spread of several faiths and religions such as Buddhism, Catholicism, and Protestantism. The exceptional ringtones of bronze bell metals have scientific healing and cultural importance. In this review article, we highlight the evolution of bronze bell metal over the decades, its composition, and the complex fabrication technologies used to date. Furthermore, we overview ancient and modern casting alloy technology, especially bronze bell castings in Asia. The bell shape, materials, and alloy casting technology have undergone dramatic change over the years. For comparison, we include different bronze cast bells and their characteristics produced from the Middle Ages to the present times. Based on the data obtained from the bell casting technology surrounding the Korean Peninsula, the major trends in the evolution of bronze bell castings and long-standing traditions of mold materials and alloys are described. In the present review, the effects of different elements on bell materials are qualitatively overviewed, with an assessment of the material and casting properties, service life, and bell sound. We also highlight the challenges of conventional bronze casting and possible solutions for future investment castings and rapid prototyping of bronze bells.

Preliminary clinical effect evaluation of digital head and neck radiotherapy oral positioning stents

Objective: To develop a designing software of digital oral positioning stent for radiotherapy of head and neck, and to compare its clinical effect with traditional oral positioning stents made by lost wax process. Methods: Thirty patients with nasopharyngeal cancer who received oral examination before radiotherapy in the prosthodontics department from July to December, 2021, were selected and divided into three groups according to the patients' wishes, 10 per group: one group without radiotherapy oral positioning stents, one group with traditional oral positioning stents (traditional stents group), and the third group with digital oral positioning stents (digital stents group). Patients' ages range from 20 years old to 71 years old. There were 15 males and 15 females involved in this study. The manufacturing time and comfort of the two positioning stents were evaluated, and the radiation doses of the radiotherapy target areas and surrounding healthy tissues were statistically analyzed at the end of radiotherapy. Results: The manufacturing time of digital stents group [(209±7) min] was much less than that of traditional stents group [(490±10) min] (t=69.85, P<0.001). The comfort of patients' wearing of digital stents [first wearing: 5 (3, 6) score; at the end of radiotherapy: 4 (3, 5) score] was better than that of traditional ones [first wearing: 7 (3, 7) score; at the end of radiotherapy: 7 (3, 7) score] (U=22.00, P=0.033; U=20.50, P=0.023). There was no significant differences in the target radiation doses among the three groups, and the radiation doses of tongue [traditional stents group: (36.74±5.45) Gy; digital stents group: (35.96±4.98) Gy] and mandible [traditional stents group: (35.46±4.19) Gy; digital stents group: (35.34±3.98) Gy] were significantly lower in the patients wearing oral positioning stents than in the patients without oral positioning stents [tongue: (41.49±4.46) Gy; madible: (39.32±3.52) Gy] (P<0.05). Conclusions: Oral positioning stents for nasopharyngeal carcinoma radiotherapy could greatly reduce the exposure doses of tongue and madible of patients. Digital oral positioning stents designed and manufactured by independently developed software had higher production efficiency than the traditional method, and patients' evaluation of comfort was better.