The presented paper experimentally demonstrates the potential expansion of stereolithographic prototype utilization. Two methods for manufacturing plastic prototypes are proposed, enabling the subsequent substitution of the polymer material with either metal or ceramics. The first method involves additional actions by the prototype designer during the modeling stage. The second method necessitates alterations in the technological processes of model preparation and prototype manufacturing using a stereolithography apparatus. Material substitution occurs in two stages. Initially, cavities in the prototype are filled with powder material or a mixture of powder and water. Although titanium powder was chosen as the test material, the proposed technology permits the utilization of a broad spectrum of powder materials, encompassing both metallic and ceramic options. The subsequent stage involves heat treatment, where the polymer is eliminated, and the metal powder is sintered while retaining the original shape and dimensions of the prototype. Heat treatment of the acquired prototypes was conducted in both argon and atmospheric air environments. The utilization of different gas media might induce chemical transformations in the material filling the prototype. The experiments lead to the conclusion that the proposed approaches show promise and merit further development. Additionally, we contemplate amalgamating the two methods in the future to attain an optimized final outcome. The data we have gathered could significantly contribute to broadening the scope of stereolithography applications, given that this technology presently represents one of the most precise, widespread, and accessible additive manufacturing methods.

Abstract—The work is aimed at improvement of the mechanical properties of polymers produced using laser stereolithography technology by modifying the composition of a photocuring resin (PCR) with a highly dispersed filler. A composition based on vinyl ester resin was developed as the starting material, and aluminum hydroxide was chosen as the filler. The addition of the filler to the original PCR leads to a noticeable increase in the viscosity of the composition at 25°C. Specimens obtained both by laser stereolithography technology and by initiating polymerization by incoherent UV radiation were studied simultaneously for comparison. A thermomechanical analysis of the specimens was carried out and their studies were carried out using the differential scanning calorimetry method to determine the thermomechanical characteristics and the degree of conversion of double bonds for these specimens. It has been confirmed that post-curing of specimens is a necessary step in achieving their high mechanical properties. It has been shown that the use of aluminum hydroxide as a PCR filler improves the physicomechanical and thermomechanical properties of cured specimens.

The work is aimed to increase mechanical properties of polymers produced by laser stereolithography technology by modifying the composition of photocurable resin (PCR) by highly dispersed filler. A resin based on vinyl ester was developed as an initial one, and aluminum hydroxide was chosen as a filler for it. Adding the filler to the initial PCR leads to a marked increase in the viscosity of the composition at 25 °C. For comparison samples obtained both by laser stereolithography technology and at initiation of polymerization by incoherent UV radiation were simultaneously studied. Thermomechanical analysis of the samples was carried out and the samples were studied by differential scanning calorimetry to determine the thermomechanical characteristics and the degree of conversion of double bonds for these samples. It has been confirmed that the post-treatment of the samples is a necessary step in achieving their high mechanical properties. It is shown that the use of aluminum hydroxide as a FPC filler leads to an increase in the physical-mechanical and thermomechanical properties of cured samples.

Findings from Bronze Age burials of Shengavit settlement have become a source of multiple studies referred to anthropological, and especially odontological, research based on 3d imaging and image processing techniques. The currently presented case is an example of palaeopathological analysis of bone tissue resorption caused by complications of dental pathologies. Thus by analogy with diagnostic procedures in clinical dentistry, conventional x-ray based cone-beam tomographic scanning have been applied and have shown its effectiveness as a study method. Through CBCT imaging we managed to reveal a hidden pathological process in the body of the studied semi-mandible fragment, though initially another pathological area located on the same finding was planned to be studied. Application of micro-computed tomography has improved analytical, or diagnostic, part of the current palaepathological study. It has brought to finding unusual morphological features hypothetically causing bone resorption as a complication of dental pathological conditions. However our intention to obtain 3d reconstructions as evidence supporting the most likely version required several attempts to correct image processing in line with the increase of imaging resolution.

Abstract. Studies of teeth represent a significant part of palaeoanthropological research. Over the past two decades these studies have significantly developed with implementation of high resolution imaging based on x-ray scanning techniques. Highly informative reconstructions based on image processing have provided an opportunity to study morphological layers and structures of teeth which are usually hidden under the outer layer of dental enamel. Thus micro-computed tomography of the studied teeth has been performed in order to obtain reconstructions of enamel and dentin surfaces. The material is represented by well-preserved teeth of an adolescent from Upper Palaeolithic archaeological site of Sunghir world-renowned archaeological site in Vladimir Oblast in the Russian Federation. The characteristic feature of the studied teeth is in their unusual, presumably archaic, morphology, which has been previously studied and described through measurements by application of automated digital odontometry method; however the mentioned study referred to the enamel surface. And in the current study these algorithms are applied to measure the surface of dentin. As this is the first successful attempt of measuring dentin surface morphology, the process has to be improved for complete automation. Nevertheless even currently applied approaches allow to compare enamel and dentin morphology through measurements.

The article reports on the effect the building orientation of the part, produced by laser stereolithography technology, has on achieving its best functional characteristics. Based on the example of IPLIT-3 and IPLIT-4 resins, the study shows that in contrast to the literature data on other commercial photocurable resins (PCRs), there is no definite advantage of the vertical orientation of the test samples compared to their horizontal orientation for obtaining the best values of the manufactured part functional characteristics.

3D imaging techniques, which started to be exact in regard to the current study with photogrammetry, have brought to development of measurement method – automated digital odontometry (aDo) – with wider opportunities in terms of understanding morphological characteristics of human (or, non-human) teeth and dentition. Revealing them through odontometric parameters, not as visual descriptions, as it has been accepted for decades and is widespread till today, digital measurement methods provide for various previously unattainable detailed objective studies including descriptions or comparisons. These types of studies, carried out for dental and anthropological applications, are of high demand in palaeoanthropology, especially in cases of rare combination of finding uniqueness and preservation degree with considerations of unusual morphology. Thus odontological samples from the Upper Palaeolithic Sunghir’ (individual C2) are of particular interest in the current study which is aimed to detect distinctive parameters related to morphological features and to compare the degree of feature expression on antimere teeth and teeth with lower degree of that feature expression.

A wide variety of methods are used in archaeological research today, including 3D imaging techniques (photogrammetry) which are involved at different stages starting from explorations preceding excavation to multiple studies. The archaeologically obtained material includes anthropological findings, among which odontological (related to human teeth) are of interest as they are composed of resistible tissues (hence are preserved well) and can serve for biological as well as historical interpretations. However, among the methods employed in odontological studies some are destructive and bring to unwelcome irreversible changes or even complete loss of the analysed samples. However, the existing and rapidly-developing techniques, especially, referring to 3D imaging and prototyping, suggest different approaches which can facilitate avoiding undesirable consequences of invasive methods of research. Thus they can provide for either preservation of findings through development and application of non-invasive study techniques, or, at least, preserve data referring the findings which have to be destroyed in order to receive valuable, in terms of research, information. It is shown on the example of the studied mandibular fragment from the Early Bronze archaeological site of Shengavit how multidisciplinary cooperation and the described workflow contribute to preservation of information regarding the finding and possible restoration of its original features. An effective communication between different professionals was provided due to implementing non-contact measurements techniques, obtaining and processing 3D images and 3D printing.

Разработана экспериментальная установка для лазерно-акустической томографии биологических тканей. Проведены экспериментальные исследования фантомных образцов. Разработана программа для преобразования графических данных лазерно-акустической томографии в стандартный медицинских формат. Ключевые слова: лазерная ультразвуковая томография, формат DICOM, биологическая ткань, цифровая модель, графические данные.

An experimental setup for laser ultrasonic tomography of biological tissues has been developed. Experimental studies of phantom samples were conducted. A program for converting graphic data of laser ultrasonic tomography into a standard medical format has been developed.

The photocuring of a series of methacrylic oligomers and oligomer–monomer mixtures with silicon powder additives with a particle size of up to 30 µm is studied. It is shown that up to a certain particle size, silicon can form stable suspensions with oligomer resins. A higher manufacturing accuracy compared to that of the original oligomer or oligomer–monomer base is achieved when using similar mixtures in 3D printing setups (laser stereolithographs). The possibility of obtaining plastic parts with a high content of chemically unbound silicon is also considered.

В статье приведена информация о модернизации установок лазерной стереолитографии, проведенной в ИПЛИТ РАН, филиале ФНИЦ «Кристаллография и фотоника» РАН в 2017–2018 годы. Рассмотрена конструкция установки лазерной стереолитографии на примере установки ЛС‑250. Приведены основные технические характеристики установок серии ЛС. Рассматриваются особенности и результаты модернизации установок.

The model of crosslinking polymerization in photopolymer for laser stereolithography has been proposed. The feature of this polymerization is that the initiation takes place by an irradiation with single pulse that should be enough to solidify the chosen parts of photopolymer. It is shown that despite of such initiation the polymerization passes the gel point due to the fast forming and crosslinking of polyradicals resulting in gel macromolecules. The influence of different factors (termination, trapping, crosslinking, cyclization) on position of the gel point is investigated. Branched level of macromolecules formed during polymerization is found to be mainly dependent on the rate of cyclization.

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