3D Printing and Additive Technologies

Additive manufacturing in chemistry and chemical engineering

Additive manufacturing (AM, 3D printing) is now widely used in almost all natural sciences: chemistry, physics, biology and medicine. This expansion of 3D printing is due to the universality of this manufacturing method, the ability to produce fully functional products of complex shapes from different materials using compact equipment that does not require high operating and maintenance costs.

Currently, the Laboratory of Metal-Complex and Nanoscale Catalysts of the IOCh RAS has fully implemented and is actively using the fused deposition modeling (FDM) and the selective laser melting of metal powder technology (SLM).

The laboratory uses the following additive manufacturing equipment: Onsint AM150 SLM printer for melting metal powders, F2 Lite, Picaso 3D Designer X and Picaso 3D Designer X Pro equipment for FDM.

Additive manufacturing equipment (3D printers) used in the laboratory to integrate new manufacturing technologies of the chemical reactors into the practice of fine organic synthesis: (a) Onsint AM150, using SLM technology; (b) F2 Lite, implementing FDM technology, including for high-temperature plastics; (c) Picaso Designer X desktop FDM printer for 3D printing with general purpose plastics.

FDM technology can be used to produce products from a wide range of thermoplastic polymers (PETG, PP, PLA, ABS, PA, PSU, PEI, PEEK, etc.). FDM manufacturing consists of layer by layer melting of thermoplastic material through the nozzle of a printhead, in which the material is melted and mechanically injected through the nozzle. The movement of the print head over the build platform results in the formation of each layer of the part. The peculiarity of using high melting point thermoplastics in additive manufacturing is the need to maintain a high temperature of the environment around the manufactured part in the printer chamber. To solve this task, the F2 Lite printer is equipped with a heated chamber capable of maintaining temperatures of up to 100 °C in the entire volume. The F2 printer's liquid-cooled printheads allow the use of materials with melting points of up to 550 °C. The Picaso Designer X and Picaso Designer X Pro FDM printers can be used to additively manufacture products that do not require high heat resistance from general purpose thermoplastics such as acrylonitrile-butadiene-styrene, polypropylene, polyethylene terephthalate-glycol, polylactide, etc. It should be noted that the F2 Lite and Picaso Designer X Pro printers have the ability to additively manufacture products in two different materials simultaneously, opening up a wide range of possibilities for the manufacturing of reactors and their components with complex geometries.

SLM technology enables the additive manufacturing of products from a wide range of constructional metal alloys: stainless steel, titanium alloys, nickel alloys and others. In particular, the laboratory of Academician V. P. Ananikov has mastered the additive manufacturing of chemical reactors from 316L stainless steel. The initial state of the metal is a fine dispersed powder with high fluidity due to the spherical shape of the powder particles. The metal powder is applied layer by layer to the printer's working platform and fused by a high-power laser beam (300W) according to the digital model of the part. The printed part is characterized by a high degree of material fusion, whose strength and thermal conductivity are not inferior to metal parts made by traditional methods (casting or subtractive methods).

Scientific research and implementation of practical projects using additive manufacturing have been carried out in the laboratory of V. P. Ananikov for more than 10 years. The results of the work have been published in the world's leading scientific journals and are actively cited. Examples of some of the research projects are described below.

Based on a systematic analysis of the possibilities of using additive manufacturing in chemistry and adjacent fields made in the review «Widely accessible 3D printing technologies in chemistry, biochemistry and pharmaceutics: applications, materials and prospects», it can be concluded that the most extensive field is the use of AT for the manufacturing of chemical reactors [DOI: 10.1070/RCR4980]. Another important field is the manufacturing of analytical cells and components for various analytical devices. A unique field of AT application is the creation of new catalytic forms, such as catalytic cartridges made of material containing catalytically active particles.

Schematic representation of the application of additive manufacturing technologies in various fields of chemistry.

The literature review has shown that the application of AT in chemistry contributes to the efficient optimization and speeding up of chemical synthesis, improving the accessibility and versatility of chemical research. The main achievement of this work is the formation of general ideas about the applicability of a wide range of additive manufacturing in chemical research among chemical researchers, and in this review such a systematic analysis is performed for the first time in the Russian-language scientific literature. The review emphasizes the importance of 3D printing in the development of new materials and chemical technologies. The work also provides an understanding of promising directions for future research, including the development of new materials for 3D printing of chemical equipment and the further integration of additive manufacturing into chemical practice and education.

For the successful manufacturing and further use of chemical reactors in the laboratory of Academician V. P. Ananikov, systematic and detailed studies were carried out on the stability of various polymeric materials in the various organic solvents, both in standard conditions and under heating.

In particular, it has been shown that the pronounced layered structure of FDM parts leads to peculiarities of interaction of FDM parts with solvent media. The study of such features is very important for the design of chemical reactors, since most reactions are carried out in the liquid phase. Article «Revealing interactions of layered polymeric materials at solid-liquid interface for building solvent compatibility charts for 3D printing applications» [DOI: 10.1038/s41598-019-56350-w] is dedicated to the study of interaction of layered polymeric products with liquid media. Based on the research results, compatibility tables of various materials for 3D printing specifically in the form of layered structures with organic solvents have been prepared. The authors solved the problem of determining the stability of FDM printed parts in various solvents, which is important for their use in chemical engineering, biology, and analytical chemistry. The research methodology included stability tests of special-shaped plastic samples in various solvents, as well as mechanistic study of fracture processes. Scanning electron microscopy methods were used to study the microstructure of surfaces before and after exposure to the solvent environment.

The development and application of a universal approach to evaluate the stability of FDM parts in different solvents and the classification of fracture types for parts made of different plastics is the main achievement of this work. The results of the work allow to make a more reasonable choice of material for the production of chemical equipment by FDM method in chemical engineering and other fields. Important data on the compatibility of various polymeric materials with solvents, necessary for their practical application in various fields of science and engineering are a significant contribution to the science of materials and chemical technology.

Different types of FDM part degradation observed in organic solvent environment.

Recently, new thermoplastic materials based on natural raw materials for FDM technology have been actively developed. Such materials are not inferior in their physical and mechanical characteristics to materials based on the fossil raw materials, but are characterized by much greater environmental friendliness and high safety of additive manufacturing. In particular, the IOCh RAS carried out a study of the applicability of polyethylene furanoate (PEF) for 3D printing by FDM method: «Three-Dimensional Printing with Biomass-Derived PEF for Carbon-Neutral Manufacturing» [DOI: 10.1002/anie.201708528]. This polymer can be synthesized from biomass and provide a carbon-neutral production cycle. The study shows the advantages of the new material compared to traditional 3D printing materials such as ABS and PLA, especially in the context of chemical stability.

The study applies an approach involving the synthesis of PEF from cellulose and its further use in the 3D printing process. A special feature of PEF is its high chemical stability and thermal stability, which makes it suitable for use in various environments, including contact with aggressive chemicals.

The main achievement of this work is the development of carbon-neutral production of polymeric materials using biomass, which contributes to the development of sustainable 3D printing technologies. This research provides a significant contribution to improving the environmental safety and sustainability of additive manufacturing, expanding the potential use of biodegradable polymers in a variety of applications.

Small chemical vessels made of polyethylene furanoate by FDM.

Addition of filler to the thermoplastic polymers improves their characteristics for use in additive manufacturing by FDM method: it reduces shrinkage of obtained parts, increases dimensional accuracy during printing, to some extent strengthens the finished part. As shown in a study published in the article «Sustainable application of calcium carbide residue as a filler for 3D printing materials» [DOI: 10.1038/s41598-023-31075-z], calcium carbide residue (CCR) can be used as such a filler. This approach can partially solve the problem of utilization of CCR, which is a by-product of acetylene production from calcium carbide.

It was found that CCR could be an effective filler for several types of commercially available plastics such as PLA, PETG, PA, ABS and SBS, with CCR content varying from 1% to 28%. The resulting composites were used to produce filaments that are fully compatible with commercial 3D printers.

The main scientific achievement of this research project is that the use of CCR as a filler improves the mechanical properties of composite materials, in particular the tensile strength and Young's modulus. For example, for a polyamide-based composite with the addition of 20% CCR, an increase of 9% in strength and 60% in Young's modulus was observed.

The results of this work open up new opportunities for CCR recycling, contributing to environmental protection and improving the performance of polymer construction materials. This research also stimulates further developments in additive manufacturing and composite materials production.

Some additive manufacturing technologies are characterized by the presence of a large number of defects in the final products, therefore, to improve products, it is necessary to have an understanding of the mechanisms of occurrence of such defects and strategies to reduce their number. These issues are the focus of the analytical review «Analysis, classification and remediation of defects in material extrusion 3D printing» [DOI: 10.59761/RCR5103], which classifies defects occurring in the FDM method and discusses ways to eliminate them during chemical reactor manufacturing challenges. The main problem solved in the review is to improve the quality of 3D-printed parts, especially important in chemical practice.

The authors of the article propose a detailed classification of 3D printing defects, including such parameters as size, spatial topology, nature of occurrence and location of defects. This approach allows for a better understanding of defect formation mechanisms and the development of methods to prevent defects from occurring.

The systematization of knowledge about defects occurring during 3D printing and the development of solutions for their elimination is an important scientific achievement of this work, which significantly improves the quality and reliability of chemical reactors manufactured using FDM technology. The impact of this work on the science and development of additive manufacturing is significant, as it provides a comprehensive approach to improving the quality of additively manufactured products, which open up new opportunities for their application in the chemical industry and other fields.

Classification of defects in FDM parts based on their topology.

It should be noted that the FDM is characterized by especially pronounced layered structure of the produced parts, which contain a large number of defects in the material volume. Such defects can deteriorate the functional characteristics of the parts, in particular, reduce the mechanical strength and lead to no impermeability. In the article «Improvement of quality of 3D printed objects by elimination of microscopic structural defects in fused deposition modeling» [DOI: 10.1371/journal.pone.0198370] provides the results of a systematic study of the influence of various parameters of FDM printing on the quality of the obtained products. The study solved the problem of improving the quality and reliability of FDM products by minimizing porosity, which leads to an increase in impermeability.

Among the FDM manufacturing process parameters, the most important are extrusion multiplier, temperature and printing speed. Wall thickness and geometry of the object also influence the tightness of the parts.

The main scientific achievement of the work is the development of methods for optimizing 3D printing parameters, which significantly improves the quality and stability of FDM parts for their use in industry and research. The impact of this research on science and technology is to provide methodological guidelines for improving the quality of 3D printing, which is important for a variety of applications of additively manufactured products.

Effect of the extrusion multiplier (k) on the impermeability of FDM parts: an increase in the value of k leads to an increase in the impermeability of the test parts.

In recent times, many areas of science and engineering have been greatly accelerated by the use of machine learning algorithms in everyday practice. The integration of machine learning methods with non-contact thermal imaging analysis of the strength of 3D-printed parts was carried out in the article «Integration of thermal imaging and neural networks for mechanical strength analysis and fracture prediction in 3D-printed plastic parts» [DOI: 10.1038/s41598-022-12503-y]. The methods developed in this research allow the mechanical strength of additive manufactured parts to be analyzed and their fracture to be predicted. Predicting the fracture time of parts is the main task solved within the work, which is of great importance for improving the reliability of products made by 3D printing, the inclusion of additive manufacturing at mechanical and chemical engineering.

The work uses thermographic analysis and machine learning methods. Researchers use thermographic cameras to analyze thermal effects in materials during mechanical testing. The data from the cameras is processed using neural networks to predict the fracture time of materials.

The main scientific achievement of the research is the development of a method for predicting with high accuracy the moment of fracture of plastic parts produced by 3D printing, based on the analysis of thermographic data using neural network algorithms. The results obtained represent a significant contribution to the field of additive manufacturing, increasing the safety and reliability of final products.

New tools for monitoring and controlling the quality of additive manufacturing parts will be a significant impact of the results of this work on materials science and the fields of science and engineering that use additive manufacturing in their practice. Perspectives for further research include the development of improved machine learning algorithms for even more accurate fracture prediction, and the application of this methodology to a wide range of materials and manufacturing processes.

(a) Portable thermal imaging analysis system consisting of a thermal imaging camera and a single-board computer; (b) FDM test sample during mechanical testing; (c) thermogram of the test sample at the beginning of the strength test; (d) thermogram of the test sample at the time of fracture.

Systematic work on improving the quality of parts manufactured by additive methods performed in the laboratory of V. P. Ananikov allowed to create laboratory chemical reactors suitable for working with gaseous reagents under pressure.

In particular, the study «3D Printing to Increase the Flexibility of the Chemical Synthesis of Biologically Active Molecules: Design of On-Demand Gas Generation Reactors» [DOI: 10.3390/ijms22189919] has developed immersion reactors to generate gases directly at the site of the reaction. The main chemical problem solved in this work is to simplify the process of obtaining gaseous reagents for organic synthesis, to minimize the use of pressurized equipment and to improve the safety of experiments with gaseous reagents, including explosive gases.

The authors used 3D printing to create reactors capable of generating various gases (e.g., acetylene, hydrogen, carbon dioxide) in a reaction environment directly from precursors. The use of this technology avoids the storage and use of gases under high pressure.

The main scientific achievement of the work is the development of compact and efficient reactors for gas generation, which can be adapted to different conditions of the chemical process and significantly simplify the procedure of synthesis of complex organic compounds. This opens up new perspectives for carrying out various chemical reactions using gaseous reagents under safer and more controlled conditions.

The scientific impact of this work includes improving the availability and safety of the use of gaseous reagents in organic synthesis and stimulating further research into the integration of additive technologies and chemical engineering.

Compact reactor for generating gases inside a vessel for carrying out a chemical reaction: (a) drawing of the reactor inside the reaction vessel, arrows indicate the gas flows generated inside the reactor and exiting into the reaction mass; (b, c) reactors for generating gases produced from polylactide and polypropylene, respectively; (d) fully assembled and finished reactor inside the reaction vessel.

It should be noted that fine organic synthesis under increased pressure in the reactor and using pressurized gaseous reagents is associated with increased danger. First of all, the danger of increased pressure is associated with the risk of reactor explosion with the formation of fragments and uncontrolled spread of flammable reaction mass. Researchers from the Laboratory of Metal-Complex and Nanoscale Catalysts of the IOCh RAS, in collaboration with scientists from the SPbU, have shown that reactors made using the FDM method are safer for chemical synthesis under pressure because the layered structure of the reactor prevents the formation of dangerous fragments in an emergency situation due to cracks in the reactor wall along the layers [DOI: 10.1039/D4RE00249K]. In addition, the researchers have developed engineering approaches for the manufacturing of bursting discs by FDM. Such discs can be integrated directly into the cap of a chemical reactor, or they can be produced as a separate safety module to be installed in any place of the chemical reactor. Due to the technical features of FDM printing, the thickness of the bursting discs can be smoothly adjusted to optimize the thickness for a defined pressure inside the reactor. Reactors with such bursting discs have been tested under both model and real organic synthesis conditions and have produced valuable products.

Chemical reactors of different designs equipped with side safety modules: (a-h) CAD models of single and double chamber reactors; (c-i) ready-to-use reactors made of PETG; (j) safety modules made of different materials by FDM method.

An actual field of additive technologies is the use of FDM printing to produce metal parts. An effective approach to solve this task was proposed by V. P. Ananikov lab researchers in the article «Development of 3D+G printing for the design of customizable flow reactors» [DOI: 10.1016/j.cej.2021.132670]. This research developed a method for the two-step manufacturing of metallized flow chemical reactors (3D+G printing), combining FDM printing and subsequent metallization of plastic reactors. The main task solved in this project is to develop a universal and affordable method to produce chemical reactors that can be adapted to different chemical processes.

The methodology involves the use of 3D printing followed by metallization (chemical and electroplating) to improve the chemical and mechanical resistance of plastic parts. Materials such as ABS plastic, copper and nickel have been used in the study.

The main scientific achievement of this research project is the creation of highly efficient, chemically stable flow reactors that can be used in various chemical processes, including photochemical and heterogeneous reactions. As a result of the study, a proven method for creating new, widely available chemical reactors of any configuration has been proposed, which is of great importance for the development of chemical engineering and continuous flow chemistry technologies for both laboratory and industrial applications.

Flow microreactors made by FDM printing followed by metallization (3D+G printing).

However, some engineering plastics without surface modification are capable of acting as efficient materials for compact chemical reactors, as shown in the article «Systematic study of FFF materials for digitalizing chemical reactors with 3D printing: superior performance of carbon-filled polyamide» [DOI: 10.1039/d2re00395c]. A range of thermoplastics, including carbon fiber filled polyamide-6 (PA6-CF), were used to manufacture the reactors in this study. As a result of this study, a new methodology for complex testing of FDM parts has been developed, which allows the influence of several external factors to be assessed simultaneously: heating, mechanical stress and exposure to organic solvent environment. PA6-CF was found to be an optimal material for the design of chemical reactors in laboratory conditions, with high chemical stability and heat resistance. In research project, flow reactors made of PA6-CF were manufactured using the FDM method and showed high efficiency in the process of alkyne hydrogenation, proving the possibility of carrying out this type of catalytic processes in flow-type systems, using a significantly reduced amount of expensive palladium catalyst in comparison with the implementation of the process in batch-type reactors. The research carried out makes it possible to improve the functionality of laboratory equipment and expands the prospects for the application of additive manufacturing in chemical engineering.

Flow microreactors for the hydrogenation reaction: (a) model of a flow reactor; (b) ready-to-use PA6-CF flow reactor; (c) model of a modular flow system for the hydrogenation process consisting of two flow modules.

V. P. Ananikov's scientific school intensively develops the field of photochemistry, which makes it possible to carry out difficult organic synthesis under relatively mild conditions. The manufacturing of photoreactors can also be greatly accelerated using additive manufacturing. In particular, the study «Exploring metallic and plastic 3D printed photochemical reactors for customizing chemical synthesis» [DOI: 10.1038/s41598-022-07583-9] has developed new photochemical reactors made of metal and plastic by additive manufacturing methods. Using the characteristics of digital design and 3D printing, this research project solves the task of designing photochemical reactors with a wide range of modification possibilities for optimizing reaction conditions and scaling up chemical synthesis.

Two 3D printing technologies were used for additive manufacturing: direct metal laser sintering (DMLS) for metal reactors and fused deposition modeling (FDM) for plastic ones. The reactors allow to carry out the photochemical reactions with high-precision temperature control and the ability to adjust the wavelength of the light sources.

As a result of the study, the high efficiency of the designed reactors for reproducible photochemical experiments with high product yields has been demonstrated, which is the main scientific achievement of this research. This opens up new possibilities for optimizing chemical synthesis, including more efficient scale-up of chemical compound production. The results make a significant contribution to the development of photochemistry and additive manufacturing, providing researchers with new tools and opportunities for further innovation in the field.

Photochemical reactors and additional components produced by additive manufacturing: (a) metallic photoreactor produced by DMLS; (b-d) reactors with components manufactured by FDM from heat resistant materials.

In the article «Analysis of 3D printing possibilities for the development of practical applications in synthetic organic chemistry» [DOI: 10.1007/s11172-016-1492-y] the authors show the advantages of using different types of construction plastics (PP, PLA, ABS, PETG) in the manufacturing of laboratory equipment using the FDM method. The main scientific achievement of this research is the successful application of 3D printing to produce labware used in chemical reactions such as cross-coupling and hydrothiolation. The study substantiates the importance of 3D printing in the development of chemical laboratories, opening up new opportunities for custom design and rapid manufacturing of equipment, as well as optimizing chemical processes. This study was the first systematic investigation of the application of additive manufacturing in chemistry carried out at the IOCh RAS.

Examples of various FDM labware demonstrating the potential of 3D printing to manufacture vessels of any shape (2016).

References

1. Kucherov F. A., Gordeev E. G., Kashin A. S., Ananikov V. P., «Three-Dimensional Printing with Biomass-Derived PEF for Carbon-Neutral Manufacturing», Angew. Chem. Int. Ed., 2017, 56, 15931-15935. https://doi.org/10.1002/anie.201708528

2. Kucherov F. A., Romashov L. V., Ananikov V. P., «Development of 3D+G printing for the design of customizable flow reactors», Chem. Eng. J., 2022, 430, 132670. https://dx.doi.org/10.1016/j.cej.2021.132670

3. Gordeev E. G., Ananikov V. P., «Widely accessible 3D printing technologies in chemistry, biochemistry and pharmaceutics: applications, materials and prospects», Russ. Chem. Rev., 2020, 89, 12, 1507–1561. https://doi.org/10.1070/RCR4980

4. Erokhin K. S., Naumov S. A., Ananikov V. P., «Analysis, classification and remediation of defects in material extrusion 3D printing», Russ. Chem. Rev., 2023, 92, 11, RCR5103. https://doi.org/10.59761/RCR5103

5. Erokhin K. S., Gordeev E. G., Samoylenko D. E., Rodygin K. S., Ananikov V. P., «3D Printing to Increase the Flexibility of the Chemical Synthesis of Biologically Active Molecules: Design of On-Demand Gas Generation Reactors», Int. J. Mol. Sci., 2021, 22(18), 9919. https://doi.org/10.3390/ijms22189919

6. Samoylenko D. E., Rodygin K. S., Ananikov V. P., «Sustainable application of calcium carbide residue as a filler for 3D printing materials», Sci. Rep., 2023, 13, 4465. https://doi.org/10.1038/s41598-023-31075-z

7. Erokhin K. S., Gordeev E. G., Ananikov V. P., «Revealing interactions of layered polymeric materials at solid-liquid interface for building solvent compatibility charts for 3D printing applications», Sci. Rep., 2019, 9, 20177. https://doi.org/10.1038/s41598-019-56350-w

8. Gordeev E. G., Erokhin K. S., Kobelev A. D., Burykina J. V., Novikov P. V., Ananikov V. P., «Exploring metallic and plastic 3D printed photochemical reactors for customizing chemical synthesis», Sci. Rep., 2022, 12, 3780. https://doi.org/10.1038/s41598-022-07583-9

9. Boiko D. A., Korabelnikova V. A., Gordeev E. G., Ananikov V. P., «Integration of thermal imaging and neural networks for mechanical strength analysis and fracture prediction in 3D-printed plastic parts», Sci. Rep., 2022, 12, 8944. https://doi.org/10.1038/s41598-022-12503-y

10. Korabelnikova V. A., Gordeev E. G., Ananikov V. P., «Systematic study of FFF materials for digitalizing chemical reactors with 3D printing: superior performance of carbon-filled polyamide», React. Chem. Eng., 2023, 8, 1613-1628. https://doi.org/10.1039/D2RE00395C

11. Korabelnikova V. A., Gyrdymova Y. V., Gordeev E. G., Potorochenko A. N., Rodygin K. S., Ananikov V.P., «3D printing for safe organic synthesis in mixed liquid/gas-phase chemistry», React. Chem. Eng., 2024. https://doi.org/10.1039/D4RE00249K

12. Gordeev E. G., Galushko A. S., Ananikov V. P., «Improvement of quality of 3D printed objects by elimination of microscopic structural defects in fused deposition modeling», PLoS ONE, 2018, 13, 6, e0198370. https://doi.org/10.1371/journal.pone.0198370

13. Gordeev E. G., Degtyareva E. S., Ananikov V. P., " Analysis of 3D printing possibilities for the development of practical applications in synthetic organic chemistry", Russ. Chem. Bull., 2016, 6, 1637-1643. https://doi.org/10.1007/s11172-016-1492-y