Precision Manufacturing Research Articles

Exploring the Impact of 3D Printing Parameters on the THz Optical Characteristics of COC Material.

In terahertz (THz) optical systems, polymer-based manufacturing processes are employed to ensure product quality and the material performance necessary for proper system maintenance. Therefore, the precise manufacturing of system components, such as optical elements, is crucial for the optimal functioning of the systems. In this study, the authors investigated the impact of various 3D printing parameters using fused deposition modeling (FDM) on the optical properties of manufactured structures within the THz radiation range. The measurements were conducted on 3D printed samples using highly transparent and biocompatible cyclic olefin copolymer (COC), which may find applications in THz passive optics for "in vivo" measurements. The results of this study indicate that certain printing parameters significantly affect the optical behavior of the fabricated structures. The improperly configured printing parameters result in the worsening of THz optical properties. This is proved through a significant change in the refractive index value and undesirable increase in the absorption coefficient value. Furthermore, such misconfigurations may lead to the occurrence of defects within the printed structures. Finally, the recommended printing parameters, which improve the optical performance of the manufactured structures are presented.

Microfluidic Precision Manufacture of High Performance Liquid Chromatographic Microspheres

A key bottleneck in developing chromatographic material is the chemically entangled control of morphology, pore structure, and material chemistry, which holds back precision material manufacture in order to pursue advanced separation performance. In this work, a precision manufacture strategy based on droplet microfluidics was developed, for production of highly efficient chromatographic microspheres with independent control over particle morphology, pore structure and material chemistry. The droplet‐synthesized microspheres display extremely narrow particle size distribution (CV<3%), enabling a 100% production yield due to complete elimination of sieving steps. More importantly, the size of the droplet‐synthesized microspheres is freely adjustable without the need for re‐optimizing chemical recipes or reaction conditions. The resulting materials exhibit excellent separation efficiencies, achieving a reduced plate height of hmin​=1.67. This precision manufacture strategy also allows for flexible pore design and continuous pore size adjustment across three orders of magnitudes, providing a novel vehicle for resolution fine‐tuning targeting protein separation. Besides traditional silica, organic‐inorganic hybrid silica, zirconia, and titania microspheres can also be precisely synthesized on the same platform, supporting various separation applications and operating conditions. Powered by precision manufacture, super‐throughput production, and versatile chemistry, the high‐performance droplet‐synthesized separation material will pave the way towards green and precision chromatographic industry.

Microfluidic Precision Manufacture of High Performance Liquid Chromatographic Microspheres.

A key bottleneck in developing chromatographic material is the chemically entangled control of morphology, pore structure, and material chemistry, which holds back precision material manufacture in order to pursue advanced separation performance. In this work, a precision manufacture strategy based on droplet microfluidics was developed,for production of highly efficient chromatographic microspheres with independent controloverparticle morphology, pore structureand material chemistry.The droplet-synthesized microspheres display extremely narrow particle size distribution (CV<3%), enabling a 100% production yield due to complete elimination of sieving steps. More importantly, the size of the droplet-synthesized microspheres is freely adjustable without the need for re-optimizing chemical recipes or reaction conditions. The resulting materials exhibit excellent separation efficiencies, achieving a reduced plate height of hmin​=1.67. This precision manufacture strategy also allows for flexible pore design and continuous pore size adjustment across three orders of magnitudes, providing a novel vehicle for resolution fine-tuning targeting protein separation. Besides traditional silica, organic-inorganic hybrid silica, zirconia, and titania microspheres can also be precisely synthesized on the same platform, supporting various separation applications and operating conditions. Powered by precision manufacture, super-throughput production, and versatile chemistry, the high-performance droplet-synthesized separation material will pave the way towards green and precision chromatographic industry.

Effect of sub-micron deformations at opposing strain rates on the micromagnetic behaviour of non-oriented electrical steel

We are entering an era of re-electrification, seeking high-power density electrical machines with minimal resource use. Significant performance gains in electrical machines have been achieved through precise manufacturing processes, including the shaping/cutting of soft magnetic materials. However, most studies have evaluated magnetic performance at a macro level, focusing on components, while the fundamental mechanisms, e.g., how the micromagnetic behaviour is affected by mechanical interference, remain unclear. In this study, we examine the impact of sub-micron deformations at opposing strain rates (10−2 to 101 s−1) on the micromagnetic behaviour of soft magnetic non-oriented electrical steel. Using a diamond probe to indent within a single grain of polycrystalline material at different velocities, we induce quasi-static and dynamic mechanical loading. Our analysis, employing magnetic force microscopy, transmission Kikuchi diffraction, and scanning transmission electron microscopy with a pixelated detector, reveals that magnetic texture disturbances rely on the time-dependent dislocation dynamics of the Fe-BCC material. Additionally, we compress micro-pillars to further investigate these effects under bulk-isolated deformation. These findings highlight the importance of considering even ultra-small loads, such as nano-indentations and micro-pillar compressions, in the manufacturing of next-generation electric machines, as they can affect magnetic texture and performance.

Acoustography by Beam Engineering and Acoustic Control Node: BEACON.

Acoustic manipulation has emerged as a valuable tool for precision controls and dynamic programming of cells and particles. However, conventional acoustic manipulation approaches lack the finesse necessary to form intricate, configurable, continuous, and 3D patterning of particles. Here, this study reports acoustography by Beam Engineering and Acoustic Control Node (BEACON), which delivers intricate, configurable patterns by guiding particles along custom paths with independent phase modulation. Leveraging analytical methods of orbital angular momentum beam via iterative Wirtinger hologram algorithm, this study accomplish acoustography by facilitating orbital angular momentum traps, enabling continuous 2D and 3D acoustic manipulation of microparticles in any desired geometry, with phase modulation independent of intensity. Utilizing on-chip acoustography, the BEACON platform markedly increases the space-bandwidth product to 31000 while attaining an enhanced resolution with a pixel size of ≈25µm, surpassing the typical resolution of over 200µm in previous holographic particle manipulation methods. The capabilities of BEACON are demonstrated in creating intricate triple helical tracing structures using microdroplets (20µm in diameter) and those carrying DNA to validate the effectiveness of the acoustography and phase control methods. This study offers new particle manipulation opportunities, paving the way for next-generation biomedical systems and the future of contact-free precision manufacturing.

Study on wear state of ultrasonic-assisted grinding of glass-ceramics with diamond tools based on DBO-BiLSTM

With the development of precision manufacturing technology, diamond tools play a vital role in industrial machining because of their high hardness and excellent wear resistance. However, tool wear can seriously affect machining accuracy and efficiency. In order to ensure the efficient and high-quality machining, it is of paramount importance to monitor the state of the tools used with the utmost accuracy. First, the fixed area of the diamond tool after machining was observed. The ratio of the number of abrasive particles falling off and the presence of scratches in the matrix were used as the evaluation indexes of the wear state of the diamond tool. The vibration signal was used as a monitoring signal to identify the wear state of the diamond tools. To obtain a feature set sensitive to the tool wear state, the vibration signal was analyzed in the time domain, frequency domain, and wavelet packet. The dimensionality of the sensitive feature set is reduced through the application of principal component analysis (PCA). The tool wear state was identified using the dung beetle optimizer bidirectional long short-term memory (DBO-BiLSTM) model and the bidirectional long short-term memory (BiLSTM) model. The results demonstrate that the DBO-BiLSTM has a higher accuracy in wear state identification, showing an improvement of 10.05% over the BiLSTM. Moreover, optimizing feature dimension reduction can enhance the model’s identification accuracy.

Precision Manufacturing in China of Replication Mandrels for Ni-Based Monolithic Wolter-I X-ray Mirror Mandrels

The X-ray satellite “Einstein Probe” of the Chinese Academy of Sciences (CAS) was successfully launched on 9 January 2024 at 15:03 Beijing Time from the Xichang Satellite Launch Center in China with a “Long March-2C” rocket. The Einstein Probe is equipped with two scientific X-ray telescopes. One is the Wide-field X-ray Telescope (WXT), which uses lobster-eye optics. The other is the Follow-up X-ray Telescope (FXT), a Wolter-I type telescope. These telescopes are designed to study the universe for high-energy X-rays associated with transient high-energy phenomena. The FXT consists of two modules based on 54 thin X-ray Wolter-I grazing incidence Ni-replicated mirrors produced by the Italian Media Lario company, as contributions from the European Space Agency and the Max Planck Institute for Extraterrestrial Physics (MPE), which also provided the focal-plane detectors. Meanwhile, the Institute of High Energy Physics (IHEP), together with the Harbin Institute of Technology and Xi’an Institute of Optics and Precision Mechanics, has also completed the development and production of the structural and thermal model (STM), qualification model (QM) and flight model (FM) of FXT mirrors for the Einstein Probe (EP) satellites for demonstration purposes. This paper introduces the precision manufacturing adopted in China of Wolter-I X-ray mirror mandrels similar to those used for the EP-FXT payload. Moreover, the adopted electroformed nickel replication process, based on a chemical nickel–phosphorus alloy, is reported. The final results show that the surface of the produced mandrels after demolding and the internal surface of the mirrors have been super polished to the roughness level better than 0.3 nm RMS and the surface accuracy is better than 0.2 μm, and the mirror angular resolution for single mirror shells may be as good as 17.3 arcsec HPD (Half Power Diameter), 198 arcsec W90 (90% Energy Width) @1.49 keV (Al-K line). These results demonstrate the reliability and advancement of the process. As the first efficient X-ray-focusing optics manufacturing chain established in China, we successfully developed the first focusing mirror prototype that could be used for future X-ray satellite payloads.

Pelatihan dan Pendampingan Operasional Mesin Bubut Bagi Karyawan di Kawasan Industri Logam Morowali

In the increasingly advanced and dynamic world of the manufacturing industry, the need for a skilled and qualified workforce is becoming increasingly important. One of the key skills required in the industry is the ability to operate a lathe effectively and efficiently. Lathes are used to shape and smooth workpieces by rotating the workpiece against a stationary tool. These machines enable precise and high-quality manufacturing processes, so employees need to master the correct and efficient operation of lathes. However, there is still a problem with employees who are not skilled enough to operate lathes in companies in the Morowali metal industry area. This condition can certainly hamper the productivity and efficiency of the company, and have an impact on the quality of the products produced. So, it is necessary to conduct training and mentoring to improve their knowledge and skills. Training is carried out using several methods, namely surveys through interviews to determine the appropriate type of training. Providing material to improve knowledge using the lecture method. Direct observation to train participants' skills in operating the lathe. Evaluation of training to measure the level of achievement. The evaluation results obtained an average pre-test score of 54.3 and a post-test of 84.6. There was an increase of 30.7 points after the participants participated in the training activities. Thus, the training activities showed success in improving employees' knowledge of lathe operation. In addition, each employee also showed skills in completing the job sheet that had been given. So, the training carried out provides various benefits for employees in developing careers and for companies in increasing their productivity.

Mass-Producible Transparent Flexible Passive-Cooling Film.

Passive cooling is regarded as the desired method for interior temperature regulation due to its advantage of energy consumption reduction. An ideal passive-cooling window is expected to exhibit a high emissivity in the mid-infrared (MIR, 8-13 μm) spectral range for cooling and a low transmittance in the near-infrared (NIR, 780-2100 nm) spectral range for reducing heat flow, while presenting a high transmittance in the visible (VIS, 400-780 nm) spectral range for daylighting. However, material structures that meet these requirements often come with high demands for precision in manufacturing and elevated processing costs, which have limited their potential for large-scale mass production. Here, we propose a mass-producible transparent flexible passive-cooling film that is relatively easy to process and low-cost and meets all of the requirements mentioned above. The film is made of poly(methyl methacrylate) mixed with Cs0.33WO3 nanoparticles, and it shows a high absorptance (80%) in NIR for blocking solar radiation penetration and a high emissivity (93%) in MIR for radiative cooling as well as a reasonable transmittance (40%) in VIS for visibility. Under solar intensity of ∼900 W/m2, a maximum temperature reduction of 8.4 and 7.8 °C has been achieved for a window coated by the film compared to the uncoated window in the condition of the absorbing chamber and car, respectively. Such a mass-producible transparent flexible passive-cooling film holds promising applications in large windows, such as those used in automobiles and buildings, where there is a high demand for both daylighting and cooling.

Effect of geometric defects on the mechanical properties of additive manufactured Ti6Al4V lattice structures

Lattice structures realized by additive manufacturing (AM) have the great potential for a broad range of engineering applications. However, the lattice structures are involved in geometric defects. This paper focuses the effect of geometric defects on the mechanical properties of Ti6Al4V lattice structures manufactured by laser powder bed fusion (L-PBF), three cell topologies, i.e., body centered cubic with vertical struts (BCCZ), face centered cubic with vertical struts (FCCZ), and face and body centered cubic with vertical struts (FBCCZ) were studied. X-ray computed tomography was used to extract the shape and the distribution of process-induced geometric defects of these three kinds of samples. Probability density distributions of geometric defects in each layer were also established to analyze the effect of the printing sequence on geometric defects. Then these distributions of geometric defects were inputted into Abaqus to build the modified statistical models to study the effect of geometric defects on mechanical properties. It is shown that the deviation of the cross-section radius exhibits normal distribution and the deviation of the center axis offset exhibits logarithmic distribution. And the middle layer of the sample has a better manufacturing precision. The modified statistical model can predict the mechanical properties within an error of 5 %. The strut thickness deviation had a more significant effect on the mechanical properties than the strut waviness.

Quantitative phase imaging verification in large field-of-view lensless holographic microscopy via two-photon 3D printing

Large field-of-view (FOV) microscopic imaging (over 100 mm2) with high lateral resolution (1–2 μm) plays a pivotal role in biomedicine and biophotonics, especially within the label-free regime. Lensless digital holographic microscopy (LDHM) is promising in this context but ensuring accurate quantitative phase imaging (QPI) in large FOV LDHM is challenging. While phantoms, 3D printed by two-photon polymerization (TPP), have facilitated testing small FOV lens-based QPI systems, an equivalent evaluation for lensless techniques remains elusive, compounded by issues such as twin-image and beam distortions, particularly towards the detector’s edges. Here, we propose an application of TPP over large area to examine phase consistency in LDHM. Our research involves fabricating widefield phase test targets with galvo and piezo scanning, scrutinizing them under single-shot twin-image corrupted conditions and multi-frame iterative twin-image minimization scenarios. By measuring the structures near the detector’s edges, we verified LDHM phase imaging errors across the entire FOV, with less than 12% phase value difference between areas. Our findings indicate that TPP, followed by LDHM and Linnik interferometry cross-verification, requires new design considerations for precise large-area photonic manufacturing. This research paves the way for quantitative benchmarking of large FOV lensless phase imaging, enhancing understanding and further development of LDHM technique.

Characterization and Dataset Compilation of Torque–Angle Curve Behavior for M2/M3 Screws

This research explores the torque–angle behavior of M2/M3 screws in automotive applications, focusing on ensuring component reliability and manufacturing precision within the recommended assembly specification limits. M2/M3 screws, often used in tight spaces, are susceptible to issues like stripped threads and inconsistent torque, which can compromise safety and performance. The study’s primary objective is to develop a comprehensive dataset of torque–angle measurements for these screws, facilitating the analysis of key parameters such as torque-to-seat, torque-to-fail, and process windows. By applying Gaussian curve fitting and Gaussian process regression, the research models and simulates torque behavior to understand torque dynamics in small fasteners and remarks on the potential of statistical methods in torque analysis, offering insights for improving manufacturing practices. As a result, it can be concluded that the proposed stochastics methodologies offer the benefit of fail-to-seat ratio improvement, allow inference, reduce the sample size needed in incoming test studies, and minimize the number of destructive test samples needed.

Synchronized magnet-induced displacement detection in non-magnetic plates via smart materials near-field sensing

Accurate monitoring of small displacements in non-magnetic thin-walled plates is essential for assessing their manufacturing precision and vibrational characteristics. Optical techniques are limited by environmental disturbances and spatial constraints, while contact methods are compromised by mechanical forces and wear. A synchronized magnet-induced displacement detection method (SMDDM) using heteropolar permanent magnets (HPMs) and smart materials for non-magnetic plates is proposed. Supported by a magnetic-mechanical–electrical coupling model and a joint algorithm with dynamic linear extension and analytic hierarchy process (DLE-AHP), the prototype’s parameters are refined through experimental design, neural networks, and multi-objective optimization. Comprehensive tests show that SMDDM achieves an accuracy of 2 μm and a resolution of 1 μm, with smaller measurement errors observed in low-frequency, small-displacement tests. This validates the method’s effectiveness in multi-scale displacement measurement and vibration testing, highlighting its potential for in-situ monitoring in thin-plate applications.

Characteristics of Shaped Charge Jets by the Shape of the Inhibitor Inserted into the Liner

The performance of a shaped charge bomb depends on the explosive performance, liner precision machining and manufacturing quality. The key performance is how uniformly the liner transforms into a jet. In order to reduce the performance of the shaped charge bomb from a protection point of view, this study investigated the characteristics of the jet formation and progression by inserting inhibitors of different shapes into the liner using flash X-ray experimental analysis techniques. The larger the volume filled inside the liner, the lower the rate of high-speed jet generation, which was well confirmed by experiments. Due to the effect of the inhibitor, it takes a considerable amount of time delay to form a jet after explosion compared to a normal shot, and quantity and mass of jet particles that can contribute to penetration are decreased, and the penetration power is also greatly reduced due to the scattering of segmented jets.

Dimensional change and springback of spherical shell in cryogenic forming

Cryogenic forming has been developed to manufacture thin-walled curved aluminum alloy components, whose final dimensions are affected by cryogenic shrinkage and springback. Therefore, dimensional changes of spherical shell in cryogenic forming were studied theoretically and experimentally. The cryogenic forming process was discussed to elucidate the factors affecting the dimensional change. The stress distribution was analyzed to qualitatively reveal the springback behavior. Cryogenic dimensional measurement devices were built to quantitatively evaluate the dimensional changes in the forming processes of punch cooling, springback, and specimen restoration to room temperature. The temperature dependencies of the elastic modulus and expansion coefficient were modeled to quantitatively calculate the effect of thermal expansion and contraction on the dimensions of specimen and punch. The theoretical analysis results indicate that depth reduction and opening expansion are produced by cryogenic springback, determined by the radial stress, hoop stress, and bending moment in different deformation regions. The cryogenic springback in the biaxial tensile stress zone was reduced by 37.8 % owing to the increasing radial deformation and decreasing bending deformation. In contrast, cryogenic springback in the tensile-compressive stress zone increased by 30.8 %. The punch cooling shrinkage and specimen warming expansion in depth direction can reduce for the dimensional deviation caused by springback but cause the opposite effect in hoop direction. Expansion and shrinkage were effectively predicted using the proposed model, with an error of less than 16 %. The deformation region of the biaxial tensile stress can be enlarged by the significantly improved hardening ability at cryogenic temperature, which benefits enhancing deformation uniformity and further reduces springback. Therefore, cryogenic forming offers considerable potential for the precision manufacturing of aluminum alloy deep-cavity thin-walled components.

Towards AI driven surface roughness evaluation in manufacturing: a prospective study

AbstractIn the era of Industry 4.0 and the digital transformation of the manufacturing sector, this article explores the significant potential of machine learning (ML) and deep learning (DL) techniques in evaluating surface roughness—a critical metric of product quality. The integration of edge computing with current computational resources and intelligent sensors has revolutionized the application of AI-driven algorithms in smart manufacturing. It provides real-time data analysis and decision-making capabilities that were unattainable only a decade ago. The research effort intends to improve data-driven decision-making for product quality evaluation by leveraging data integration from manufacturing operations and surface quality measurements. Although a substantial amount of research has been conducted in the related fields, it is still difficult to comprehend and compile all the data on surface roughness research predictive assessment in the form of a process pipeline. This thorough systematic analysis examines scholarly articles published between 2014 and 2024 focusing on surface roughness assessment in precision manufacturing settings. The article is thoroughly classified based on the manufacturing processes, datasets, and ML models used, giving light on the present status, prominent approaches, and existing issues in this sector. A table summarizing the relevant works in this domain providing an easy access to the current trends have been provided. The article not only compiles essential findings and identifies research gaps and similarities in existing methodologies, but it also discusses future research directions and open issues in AI-aided surface roughness evaluation. The critical analysis of the literature reveals a scientific gaps which includes consistent development of benchmarked datasets and making the AI models more explainable using the state-of-the-art explainable AI (XAI) algorithms. The ultimate objective of the article is not only to provide a guide for the practitioners in either of the three domains of AI, manufacturing or surface metrology but also to pave the path for more robust, efficient, and accurate surface quality evaluation processes in production.

Contactless Printing of Food Micro-Particles Controlled by Ultrasound

Traditional food 3D printing technology, which primarily relies on mechanical control, often faces challenges such as low resolution, stringent material requirements, limited flexibility, and cumbersome equipment. To overcome these limitations, we developed an innovative food 3D printing method utilizing ultrasonic phased arrays and subsequently designed a contactless printing device employing this advanced technology. The device effectively manipulates the phase and amplitude of the ultrasonic phased array to focus the sound field on a specific location. We have successfully demonstrated preliminary control over the suspension of small food particles, including popcorn, chocolate, honey, and marshmallows, using this apparatus. Following this, popcorn particles were selected for detailed practical printing and further analysis.Additionally, we established a software platform, Ultr_printing, based on Ultraino, for intelligent simulation and control of the printing process. Leveraging FPGA and Arduino controllers, this setup facilitates rapid signal transmission from personal computers to sensors, ensuring quick and adaptable movement of suspended particles. Experimental results confirm that the device consistently controls the food particles, irrespective of their motion state. Notably, it achieves a printing precision of 0.16 mm when handling popcorn particles measuring 1.5 mm in diameter. The process, entirely contactless and free from contamination, preserves the original flavor of the food particles. This technology is particularly effective for high-precision printing of micro-scale shapes and offers considerable benefits in assembly and precision manufacturing.

Model for atomization droplet size and energy distribution ratio at the distal end of an electrostatic nozzle

Electrostatic atomization minimum quantity lubrication (EMQL) employs the synergistic effect of multiple physical fields to atomize minute quantities of lubricant. This innovative methodology is distinguished by its capacity to ameliorate the atomization attributes of the lubricant substantially, which subsequently augments the migratory and infiltration proficiency of the droplets within the complex and demanding milieu of the cutting zone. Compared with the traditional minimum quantity lubrication (MQL), the EMQL process is further complicated by the multiphysical field influences. The presence of multiple physical fields not only increases the complexity of the forces acting on the liquid film but also induces changes in the physical properties of the lubricant itself, thus making the analysis of atomization characteristics and energy distribution particularly challenging. To address this objective reality, the current study has conducted a meticulous measurement of the volume average diameter, size distribution span, and the percentage concentration of inhalable particles of the charged droplets at various intercept positions of the EMQL nozzle. A predictive model for the volume-averaged droplet size at the far end of the EMQL nozzle was established with the observed statistical value F of 825.2125, which indicates a high regression accuracy of the model. Furthermore, based on the changes in the potential energy of surface tension, the loss of kinetic energy of gas, and the electric field work at different nozzle orifice positions in the EMQL system, an energy distribution ratio model for EMQL was developed. The energy distribution ratio coefficients under operating conditions of 0.1 MPa air pressure and 0 to 40 kV voltage on the 20 mm cross-section ranged from 3.094‰ to 3.458‰, while all other operating conditions and cross-sections had energy distribution ratios below 2.06‰. This research is expected to act as a catalyst for the progression of EMQL by stimulating innovation in the sphere of precision manufacturing, providing theoretical foundations, and offering practical guidance for the further development of EMQL technology.

Nanotechnology-enabled rapid investment casting of high-performance wrought aluminum alloys

High-performance wrought aluminium alloys are widely used in automobiles and aerospace industries owing to their high-volume precipitates after heat treatment. Investment casting as one of the precision manufacturing methods provides great potential to achieve excellent surface finishes and complex geometry for aluminium alloy components. However, these high-performance aluminium alloys are almost impossible to be investment cast due to their hot cracking susceptibility and severe shrinkage during solidification. In this study, we introduce nanotechnology to improve the processability of high-performance wrought aluminium alloys in investment casting by adding a small volume fraction of nanoparticles into the aluminium alloys. This work showed the unprecedented success of nanotechnology-enabled investment casting of high-strength wrought aluminium alloys (AA6061, AA2024, and AA7075) for excellent mechanical properties.

Simultaneous Color- and Dose-Controlled Thiol-Ene Resins for Multimodulus 3D Printing with Programmable Interfacial Gradients.

Drawing inspiration from nature's own intricate designs, synthetic multimaterial structures have the potential to offer properties and functionality that exceed those of the individual components. However, several contemporary hurdles, from a lack of efficient chemistries to processing constraints, preclude the rapid and precise manufacturing of such materials. Herein, the development of a photocurable resin comprising color-selective initiators is reported, triggering disparate polymerization mechanisms between acrylate and thiol functionality. Exposure of the resin to UV light (365nm) leads to the formation of a rigid, highly crosslinked network via a radical chain-growth mechanism, while violet light (405nm) forms a soft, lightly crosslinked network via an anionic step-growth mechanism. The efficient photocurable resin is employed in multicolor digital light processing 3D printing to provide structures with moduli spanning over two orders of magnitude. Furthermore, local intensity (i.e., grayscale) control enables the formation of programmable stiffness gradients with ≈150× change in modulus occurring across sharp (≈200µm) and shallow (≈9mm) interfaces, mimetic of the human knee entheses and squid beaks, respectively. This study provides composition-processing-property relationships to inform advanced manufacturing of next-generation multimaterial objects having a myriad of applications from healthcare to education.