Advanced Manufacturing Technology Research Articles

Microstructural characteristics and properties of wire arc additive manufactured 304L austenitic stainless steel cylindrical components by different arc welding processes

Wire arc additive manufacturing (WAAM) is an advanced additive manufacturing (AM) technology that offers low cost and high deposition rates, making it suitable for building large metal parts for structural engineering applications. However, various welding procedures result in differing heat inputs and repetitive heating treatments throughout the deposition process, which can affect the microstructural and mechanical characteristics of the parts. In the current study, cylindrical parts made of 304L austenitic stainless steel (ASS) were manufactured using the WAAM technique, employing both gas metal arc welding (GMAW) and cold metal transfer (CMT) processes. This study explores the correlation between WAAM techniques and their effects on the bead geometry, microstructure and mechanical properties. The microstructure of the cylinders consisted of vertically growing austenite dendrites with residual ferrite (δ) within the austenite (γ) matrix. Compared to the bottom region (region ①), the top region (region ②) contained more residual ferrite. Although the microstructural characteristics from region ① to region ② are similar, they exhibit different ferrite morphologies. The rapid cooling rate in the CMT-AM process resulted in finer structures and a greater presence of ferrite phases in both regions compared to the GMAW-AM method. Cylinders produced by the CMT process displayed nearly uniform properties across both regions and demonstrated superior tensile properties, hardness, and impact toughness relative to those made using the GMAW technique. The WAAM 304L ASS cylinders also showed enhanced performance compared to stainless steel manufactured using traditional industrial forging standards, indicating that WAAM-processed 304L ASS cylinders are suitable for industrial applications.

Supporting decision-making of collaborative robot (cobot) adoption: The development of a framework

Collaborative robots (cobots) are emerging in manufacturing as a response to the current mass customization production paradigm and the fifth industrial revolution. Before adopting this technology in production processes and benefiting from its advantages, manufacturers need to analyze the investment. Therefore, this study aims to develop a decision-making framework for cobot adoption, incorporating a comprehensive set of quantitative and qualitative criteria, to be used by decision-makers in manufacturing companies. To achieve that objective, a qualitative study was conducted by collecting data through interviews with key actors in the cobot (or advanced manufacturing technologies) adoption decision process in manufacturing companies. The main findings of this study include, firstly, an extensive list of decision criteria, as well as some indicators to be used by decision-makers, some of which are new to the literature. Secondly, a decision-making framework for cobot adoption is proposed, as well as a set of guidelines to use it. The framework is based on a weighted scoring method and can be customizable by the manufacturing company depending on its specific context, needs, and resources. The main contribution of this study consists in assisting decision-makers of manufacturing companies in performing more complete and sustained decision analyses regarding cobots adoption.

Additive manufacturing of ultrahigh-resolution Poly(ε-caprolactone) scaffolds using melt electrowriting

Melt electrowriting (MEW) is an advanced additive manufacturing technology that produces high-resolution scaffolds for medical applications. Although there are many valuable parameter groups for MEW, the corresponding principles need to be clarified to improve the success of printing high-fidelity scaffolds. To this end, we investigate the print limit of MEW with respect to the minimum interfiber distance and the maximum print period based on a medical-grade poly(ε-caprolactone) material. The results indicate that relatively large turning loops and low turning speeds improve the print accuracy of the scaffolds; however, excessively large turning loops and low turning speeds result in fiber accumulation on the edge of the scaffolds, resulting in print failure. The turning loops with 500 μm in diameter and turning speeds of 0.625 × CTS (critical translation speed) can achieve well-defined MEW scaffolds with an interfiber distance down to 25 μm. For printing such high-resolution scaffolds, the constant printing process can last one week. Fiber placement gets random when the fiber diameter is larger than 2.5 μm, caused by the melt polymer degradation and shear thinning in the printing process. Additionally, we verify that the method of charge neutralization is not beneficial for improving the fiber overlay. This is a fundamental study clarifying the principles of printing high-resolution MEW scaffolds, being capable of extending the application of the MEW products.

Fourth industrial (r)evolution? Investigating the use of technology bundles and performance implications

PurposeThe purpose of this paper is to investigate how different manufacturing technologies are bundled together and how these bundles influence operations performance and, indirectly, business performance. With the emergence of Industry 4.0 (I4.0) technologies, manufacturing companies can use a wide variety of advanced manufacturing technologies (AMT) to build an efficient and effective production system. Nevertheless, the literature offers little guidance on how these technologies, including novel I4.0 technologies, should be combined in practice and how these combinations might have a different impact on performance.Design/methodology/approachUsing a survey study of 165 manufacturing plants from 11 different countries, we use factor analysis to empirically derive three distinct manufacturing technology bundles and structural equation modeling to quantify their relationship with operations and business performance.FindingsOur findings support an evolutionary rather than a revolutionary perspective. I4.0 technologies build on traditional manufacturing technologies and do not constitute a separate direction that would point towards a fundamental digital transformation of companies within our sample. Performance effects are rather weak: out of the three technology bundles identified, only “automation and robotization” have a positive influence on cost efficiency, while “base technologies” and “data-enabled technologies” do not offer a competitive advantage, neither in terms of cost nor in terms of differentiation. Furthermore, while the business performance impact is positive, it is quite weak, suggesting that financial returns on technology investments might require longer time periods.Originality/valueRelying on a complementarity approach, our research offers a novel perspective on technology implementation in the I4.0 era by investigating novel and traditional manufacturing technologies together.

An acoustic imaging recognition based cutting tools wear state prediction method

Online monitoring of cutting tools wear is an important component of advanced manufacturing technology, which can greatly improve the processing efficiency and reduce the production cost. In this paper, a cutting tools wear state prediction method based on acoustic imaging recognition is developed. By applying the advantages of the functional generalized inverse beamforming method in the sound field reconstruction, the acoustic signal is used as the carrier to reconstruct the three-dimensional space radiated sound field. And then, slice the reconstructed sound field image and input it into the convolutional neural network model as a sample, to process and classify the image and mines the feature information related to state from the sound field image. By incorporating amplitude and phase information of the sound field, the presented method utilizes spatial domain mapping to accurately identify the noise source and address challenges such as low recognition rate and difficult diagnosis under weak fault conditions. Furthermore, the paper also demonstrates the recognition of sound field states through a fault experiment in sound box simulation, based on these theories. And the recognition of sound field states is achieved through a simulation fault experiment conducted on the sound box, thereby validating the feasibility of the state monitoring method based on pattern recognition of sound and image. Finally, the experimental object is selected as the four-edge carbide milling cutter, and the cutting tools wear state is monitored by integrating sound field reconstruction techniques with convolution feature extraction methods to validate the robustness of the proposed approach.

Induced alterations driven compromised structural properties in additively manufactured products

PurposeAdditive manufacturing also known as 3D printing is an evolving advanced manufacturing technology critical for the new era of complex machinery and operating systems. Manufacturing systems are increasingly faced with risk of attacks not only by traditional malicious actors such as hackers and cyber-criminals but also by some competitors and organizations engaged in corporate espionage. This paper aims to elaborate a plausible risk practice of designing and demonstrate a case study for the compromised-based malicious for polymer 3D printing system.Design/methodology/approachThis study assumes conditions when a machine was compromised and evaluates the effect of post compromised attack by studying its effects on tensile dog bone specimens as the printed object. The designed algorithm removed predetermined specific number of layers from the tensile samples. The samples were visually identical in terms of external physical dimensions even after removal of the layers. Samples were examined nondestructively for density. Additionally, destructive uniaxial tensile tests were carried out on the modified samples and compared to the unmodified sample as a control for various mechanical properties. It is worth noting that the current approach was adapted for illustrating the impact of cyber altercations on properties of additively produced parts in a quantitative manner. It concurrently pointed towards the vulnerabilities of advanced manufacturing systems and a need for designing robust mitigation/defense mechanism against the cyber altercations.FindingsDensity, Young’s modulus and maximum strength steadily decreased with an increase in the number of missing layers, whereas a no clear trend was observed in the case of % elongation. Post tensile test observations of the sample cross-sections confirmed the successful removal of the layers from the samples by the designed method. As a result, the current work presented a cyber-attack model and its quantitative implications on the mechanical properties of 3D printed objects.Originality/valueTo the best of the authors’ knowledge, this is the original work from the team. It is currently not under consideration for publication in any other avenue. The paper provides quantitative approach of realizing impact of cyber intrusions on deteriorated performance of additively manufactured products. It also enlists important intrusion mechanisms relevant to additive manufacturing.

SCATTERING OF ELECTROMAGNETIC WAVES ON FLAT GRID TWO-PERIODIC STRUCTURES

Context. One of the scientific hypotheses for the creation of nonreciprocal optical metasurfaces is based on the use of a wave channel in which rays of the direct and reverse diffraction scenarios are realized on two-periodic flat structures with nonlinear elements. Such processes in the nanometer wavelength range of electronic devices require precise calculations of the interaction of waves and microstructures of devices. It is also important to describe the behavior of antenna devices in mobile communications. Expanding the wavelength range of stable communication is achieved by using prefractal structures in antenna devices in combination with periodic structuring. Similar modeling problems arise when electromagnetic waves penetrate materials with a crystalline structure (radio transparency).
 Objective. To test this hypothesis, it is necessary to carry out mathematical modeling of the process of scattering of electromagnetic waves by metasurfaces under conditions of excitation of several diffraction orders. It is known that among two-periodic flat lattices of different structures there are five types that fill the plane. These are the Bravais grilles. The problem of scattering of an incident monochromatic TE polarized wave on a metal screen with recesses in two-periodic structures filled with silicon was considered.
 Method. The paper builds mathematical models for the study of spatial-amplitude spectra of metasurfaces on Brave lattices and gives some results of their numerical study. The condition for determining the diffraction orders propagating over the grating is proposed. Scattered field amplitudes are from the solution of the boundary value problem for the Helmholtz equation in the COMSOL Multiphysics 5.4 package. Similar problem formulations are possible when studying the penetration of an electromagnetic field into a crystalline substance.
 Results. Obtained relations for diffraction orders of electromagnetic waves scattered by a diffraction grating. The existence of wavelengths incident on a two-periodic lattice for which there is no reflected wave is shown for different shapes (rectangular, square, hexagonal) of periodic elements in the center of which a depression filled with silicon was made. Distributions of reflection coefficients for different geometric sizes of colored elements and recesses are given. The characteristics of the electric field at resonant modes in the form of modulus isolines show the nature of the interaction of the field over the periodic lattice and the scatterersdepressions. At the resonant wavelengths of the incident waves, standing waves appear in the scatterers.
 Conclusions. A mathematical model of the set of diffraction orders propagating from a square and hexagonal lattice into halfspace is proposed z >= 0. It has been shown that flat periodic lattice with square or hexagonal periodicity elements and resonant scatterers in the form of cylindrical recesses filled with silicon can produce a non-mirrored scattered field in metal. The response of the lattices to changes in the wavelength of the incident field by the structure of diffraction orders of the scattered field and high sensitivity to the rotation of the incident plane were revealed. The two-periodic lattices have prospects for creating anti-reflective surfaces of various devices. Two-periodic lattices have prospects for creating anti-reflective surfaces for various devices, laser or sensor electronic devices, antennas in mobile communication elements, and radio transparency elements. They have more advanced manufacturing technologies in relation to spatial crystal structures.

Global buckling and resistances of austenitic stainless steel semi-oval hollow section beam-columns

As advanced manufacturing technologies become increasingly mature in civil engineering, novel tubular sections, characterised by appealing architectural appearance and prominent structural efficiency, can be fabricated, with an example being semi-oval hollow section. The present paper reports an experimental and numerical investigation into the global buckling behaviour and resistances of austenitic stainless steel semi-oval hollow section beam-columns under combined compression and bending. An experimental programme was firstly performed on ten austenitic stainless steel semi-oval hollow section beam-column specimens and included initial geometric imperfection measurements and eccentric compression tests. The obtained test failure loads, load–mid-height lateral deflection curves and failure modes were fully reported. Following the experimental programme, a numerical modelling programme was conducted, including validation studies to validate developed finite element models against the test results and parametric studies to generate additional numerical data. Given that the existing European code and American specification do not cover the design of stainless steel semi-oval hollow section components, the applicability of the codified design interaction curves for austenitic stainless steel circular hollow section beam-columns to their semi-oval hollow section counterparts was evaluated based on the obtained test and numerical data. The European code was found to result in relatively accurate and consistent resistance predictions for austenitic stainless steel semi-oval hollow section beam-columns with Class 1 and 2 cross-sections, but the resistance predictions for those with Class 3 cross-sections were conservative and scattered. The American specification was shown to offer overall accurate and consistent resistance predictions, but some resistance predictions were marginally unsafe.

Efficiency and factors influencing China’s outward direct investment in ASEAN and the European Union: a comparative analysis

ABSTRACT This research examines China’s outward direct investment efficiency in ASEAN and the European Union (EU) using a stochastic frontier investment gravity model. We find that China’s investment efficiency in EU15 remained stable from 2003 to 2020, while efficiency in ASEAN and EU13 declined. China benefits from EU15’s advanced manufacturing and management technologies due to its high economic development. However, with an investment efficiency of 0.259, there is untapped potential. In ASEAN, factors like higher economic freedom positively impact China’s investment efficiency, and infrastructure opportunities negatively impact China’s investment efficiency. Economic distance positively affects China’s investment in EU countries, especially in EU15. But higher economic freedom intensifies global competition, limiting China’s direct investment, particularly in EU13. The EU’s infrastructure and updated investment agreements facilitate China’s investment, while the ‘Belt and Road’ initiative has limited impact.

Design and Control of a Flexure-Based Dual Stage Piezoelectric Micropositioner

AbstractIn the field of advanced manufacturing technology, there is a growing need for high-precision micro/nano positioners. The traditional single stage actuated positioners have encountered performance limitation in achieving longer travel range and higher precision. This motivates us to develop a novel dual stage piezoelectric-actuated micropositioner presented in this paper. The micropositioner incorporates displacement amplification mechanisms to overcome the limited range of piezoelectric actuators. Design considerations such as flexure characteristics and material selection are discussed, and structural analysis is performed using finite element analysis (FEA). For precise positioning, the dual stage control strategy is investigated and compared with the conventional proportional-integral-derivative (PID) single stage control method. In the proposed positioner, a combination of parallelogram and bridge mechanisms is utilized. The bridge mechanism works to amplify the piezoelectric actuator displacement output. The parallelogram mechanism, integrated within the system, helps mitigate resonance modes and contributes to the achievement of linearized motion. The characteristics of the micropositioner were evaluated using analytical modelling and FEA. Multiple analysis was used to optimise the positioner’s design parameters. Furthermore, experimental studies were carried out to validate the characteristics of the micropositioner performance in terms of achievable output travel range and sustained positioning accuracy.

Preparation and properties of a bismaleimide resin modified with a propargyl compound for electron beam irradiation curing

N, N, N′, N′ -Tetrapropargyl- p, p′-diaminodiphenylmethane (TPDDM) is synthesized and used to blended with 4,4′-bismaleimide diphenylmethane (BDM) as propargyl compound in a molten state to obtain a TPDDM modified bismaleimide (BTP) resin. The BTP resins are cured under electron-beam (EB) irradiation as well as heat. The cure degree and reactions of BTP resins are studied. The thermal stability and mechanical properties of the cured BTP resins are further investigated. The results show that the BTP resins can be cured under EB irradiation and have over 82% degree of cure, which increases with the increase of EB irradiation dose. The cure reactions of EB-cured BTP resin are similar to that of heat-cured BTP resin. The temperature at 5% weight loss ( Td5) and mechanical properties of the cured BTP resins are close analogies between EB and heat cure processes although the cure degrees of EB-cured BTP resins are lower. The glass transition temperature ( Tg) and flexural modulus of the EB-cured BTP resin are higher than that of the heat-cured BTP resin. The Tg of the EB-cured BTP resin can reach over 385°C. The TPDDM-modified BDM is a candidate bismaleimide resin for the EB irradiation curing process in advanced manufacturing technology.

Bibliometric Analysis of Personalized 3D-Printed Concrete-Based Modules for Construction: Leveraging the Ordinatio Method

The research landscape of personalized 3D-printed concrete-based modules for construction and their impact on thermal performance through generative design methods is explored through a bibliometric analysis. Comprehensive analysis techniques, including bibliographic data and visualization with VoSviewer, are employed to unveil collaborative networks, influential articles, research trends, and emerging themes within this domain. Global contributions are showcased, with citations predominantly from the UK and USA, while Denmark and Australia demonstrate a significant impact relative to publication numbers. Prominent authors like Buswell, Mechtcherine, and Zhang are highlighted through co-authorship analysis, revealing evolving collaborative patterns over time. Seminal works and influential authors are identified through co-citation analysis, providing insights into intellectual networks. Source citation analysis emphasizes the importance of sustainability and advanced manufacturing methods through key journals in the field. Keyword co-occurrence analysis identifies the core themes, including 3D concrete printing, additive manufacturing, and sustainability. Emerging trends indicate a growing focus on sustainability and adopting advanced manufacturing technologies. These insights have implications for future research, guiding impactful contributions in this evolving field.

Advances of GelMA-Based Hydrogel in Nerve Repair and Regeneration

Nerve repair and regeneration are still challenging issues in the world, mainly due to the complex anatomic structure and limited regeneration ability of natural nerves. Tissue engineering provides a structure and function similar to nerve tissue through scaffold materials, seed cells, and active factors, which is a promising method to treat nerve injury. Gelatin methacrylate (GelMA) hydrogel is a kind of gelatin modified by methacrylamide, which possesses adjustable mechanical properties, convenient processability, and excellent biocompatibility, has been widely used in nerve tissue engineering. In this paper, the research progress of GelMA-based hydrogel in nerve repair and regeneration in recent five years is reviewed, with emphasis on the advanced manufacturing technologies of three-dimensional (3D) GelMA scaffold and the application systems that can effectively promote nerve repair and regeneration. We also evaluated the challenges and prospects of GelMA-based hydrogels in the field of nerve repair and regeneration, which is of guiding significance to the research of nerve tissue engineering.

Sensor Technologies for Hydraulic Valve and System Performance Monitoring: Challenges and Perspectives

AbstractHydraulic fluid power systems are essential for a range of engineering applications such as transportation, heavy industry, and robotics. The scale of the industry is such that hydraulic pumps are estimated to account for 15% of all the energy consumption in the European Union and yet the average efficiency of fluid power systems is only 22%. The digitalization of hydraulic systems offers significant advantages in terms of energy efficiency, performance, reduced maintenance, and automation. However, this requires advances in the integration of smart sensing technologies to provide real‐time feedback on the operation and health of hydraulic components. This review details developing trends in hydraulic fluid power research and provides an overview of progress related to the digitalization of these systems and their integration within an Industry 4.0 framework. The fundamentals of relevant sensor technologies and innovative approaches for integrating sensors into hydraulics systems are discussed. Methods to deliver power to the sensors and associated electronics through harvested pressure ripples are also reviewed. An outlook with respect to future directions in this field is given, including an assessment of the potential for exploiting advanced manufacturing technologies, in particular additive manufacturing, to facilitate successful sensor integration into hydraulic fluid power systems.

An Optimization Study Focused on Lattice Structured Custom Arm Casts for Fractured Bones Inspiring Additive Manufacturing

In case of fractures, cracks or damage to bone tissues, it is important to use casts, fixatives and protective equipment. Especially in cases where long-term use of casts is required, soft tissue wounds may occur in the human body due to their moisture and airtight structure. For this reason, the use of casts with custom designs, breathable materials, and high mechanical properties has become widespread in recent years. This study focuses on the design of custom arm casts using advanced additive manufacturing technologies and lightweight materials. By utilizing Voronoi lattice structures and hexagonal surface meshes, optimized designs adaptable to additive manufacturing were obtained from a standard arm cast. All cast geometries were investigated under 196N and 380N forces. Then, the impact of a 100g and 1000g concrete piece with a speed of 12.5m/s on the arm cast was investigated. As a result of the analyzes, stress, impact plate velocities, deformation, strain and deformation energy were evaluated. The results showed that the designed arm casts have up to 60% better impact strength compared to conventional arm casts. Based on the findings of this study, the use of custom arm casts with optimized lattice structures designed for additive manufacturing will demonstrate high performance.

Design, Engineering Analysis, and Fabrication of a Prototype Electromechanical Finger Fixator Control System

This paper investigates a new external fixator system for treating finger contractures. This innovative system is electric and user-friendly, providing precise readings of the angles of diseased finger joints. Accurate measurements of the angles of the diseased finger joints can assist therapists and patients during rehabilitation procedures. The fixator consists of ten parts assembled using polyether-ether-ketone (PEEK) for the plastic components and stainless steel for the metal components. The design model was engineered, drawn, and analyzed using SolidWorks Computer-Aided Design software. The verification process utilizes finite element analysis to demonstrate that the maximum stress was lower than the yield strength of the chosen materials. As a result, the new device design is robust and stable enough to withstand the anticipated loading conditions of human fingers. Subsequently, a prototype was fabricated using advanced additive manufacturing technology, specifically fused deposition modeling (FDM). The proposed fixator is simple to control, reliable, easy to use, and reproducible. It enables device users to exercise their finger joints throughout the day without requiring the assistance of specialists.

Ratcheting Effect of 304 Stainless Steel Manufactured by Laser Metal Deposition Under Uniaxial Cyclic Stress

Laser metal deposition (LMD) is an advanced manufacturing technology which has become increasingly popular in recent years. The cyclic tests of 304 austenitic stainless steel (SS304) manufactured by LMD are conducted under symmetrical and asymmetrical cyclic stress. In the results, it is shown that SS304 manufactured by LMD exhibits cyclic softening/hardening and ratcheting effect under symmetrical cyclic stress. The ratcheting strain and ratcheting strain rate of the smooth specimen both increase as the cyclic stress amplitude under the asymmetric cyclic stress. The ratcheting strain and ratcheting strain rate of the smooth specimen change non‐monotonously as the mean stress increases. As the stress amplitude increases, the area of fatigue fracture becomes smaller until no fatigue crack initiation zone can be observed. In this case, only the characteristic of plastic fracture is significant. Park et al.'s model has the worst predicted accuracy. Modified Goodman equation and Smith–Watson–Topper model have the similar predicted accuracy.

Preface

The 2023 4th International Conference on Advanced Materials and Intelligent Manufacturing (ICAMIM 2023) was held in Guangzhou, China during December 1st to 3rd, 2023. The series of ICAMIM conference was created with the aim to be an interdisciplinary incubator for the worldwide exchange of information and innovative ideas about the latest research results in the fields of advanced materials and intelligent manufacturing.At ICAMIM 2023, we wished to bring together a broad community of researchers from different branches of the rapidly developing complex science to discuss the fundamental theoretical challenges as well as experimental and applied aspects of many practical problems. The agenda was conducted mainly based on three parts, covering keynote speeches, oral & poster presentations, and academic tour.There were six keynote speeches and many regular oral talks in the morning and afternoon sessions. The topics of keynote speeches cover: a) Scientific Carbon Reduction, Green Development, Manufacturing Industry to Achieve the Goal of “Double Carbon” Efforts; b) ChatGPT with Intelligent Manufacturing System; c) Challenges Facing the Industrialization of Sodium-Ion Batteries; d) Microstructure Control and Application Properties of Ultra-High Strength and Toughness Steels; e) Double Growing Carbon Background Material Base Environmental Functional Materials Development Prospects; f) Current Status and Development of the New Materials Industry in Guangdong. These speeches allowed all the participants to interact with the speakers and people around and get some new insights from each other. An academic discussion part was also held, the topic of which was related to the recent and anticipated future progress in advanced materials and intelligent manufacturing, discussing a variety of questions and opinions important for the understanding of the technology and management methods of the industry itself.The papers submitted to this Conference were carefully reviewed by expert referees, covering topics on: Composites, New feature Materials, Integrated Manufacturing Systems, Advanced Manufacturing Technology, Intelligent Mechatronics, etc. We are very grateful to the reviewers for their efficient and thoughtful actions. Various excellent papers were included here based on the referee reports.We are thankful to the members of Technical Program Committee for their time and efforts in preparing the program of ICAMIM 2023. We also appreciate the behind-the-scenes work of the members of Organizing Committee in preparing the conference site, arrangements for excursions and accommodation, handling the financial support for participants, and so on. Finally, we acknowledge the publishing support from Journal of physics: Conference SeriesThe Committee of ICAMIM 2023List of Committee Member is available in this pdf.

Photopolymerized 3D Printing Materials for Optical Elements

AbstractThe optical element is a key part of manufacturing optoelectronic systems, which can realize functions such as imaging, spectroscopy, image transmission, filtering, and more. The design and manufacture of optical elements is a key issue that restricts its development, and the traditional optical component preparation method is less capable of preparing optical elements with complex structures and multiple materials. As a mature advanced manufacturing technology, photopolymerization 3D printing technology has the advantages of high printing precision and small layer thickness, which plays an important role in the preparation of optical elements. This review paper briefly provides a concise overview of the benefits and applications of photopolymerization 3D printing technology in optical element preparation The development overview and research progress of materials used for the preparation of optical elements by photopolymerization 3D printing are discussed. Finally, it summarizes the current limitations, challenges, future development prospects, and potential applications in the realm of optical element manufacturing.

Precision cutting mechanics and mechanical performance testing on the spindle of machine tool

The manufacturing industry is the foundation of national development. With science and technology developing, precision turning technology has gradually become one of the cutting-edge technologies of advanced manufacturing technology. In the paper, the turning mechanics model is established based on the principle of metal cutting, and the corresponding cutting force is calculated. Considering the cutting force, material weight, flange weight, and other loads, the analysis model of the CK61125 machine tool spindle is constructed based on the finite element method, and the corresponding maximum strain and modal solution are calculated. The results are that when the 30, 000 N load is applied, the largest strain of the spindle is 0.0013 mm/mm, and the largest stress is 265 MPa. When the 100, 000 N load is applied, the strain of the spindle largest is 0.0015 mm/mm, and the stress is 290 MPa. The four orders of vibration modes of the spindle are obtained, which are 215.3 Hz, 256.2 Hz, 436.33 Hz, and 974.5 Hz. By comparison with the experiment, the spindle vibration frequencies are 87.8 Hz and 625 Hz, while the spindle rotating testing speeds are 100 rpm, 500 rpm, and 800 rpm.