Geometric Complexity Research Articles

Defect detection in the presence of geometrical artefacts

Defect detection in non-destructive testing relies on the ability to detect signals arising from defects and distinguish them from those arising from noise. Ultrasonic arrays are capable of producing multiple views of a component through combinations of mode conversions and reflections of waves from boundaries, which potentially contain additional information about defects. Noise in these views can come from random sources such as electrical noise and thermal fluctuation, and coherent sources including stochastic microstructural noise, and boundary reflections giving rise to geometrical artefacts. The number of geometrical artefacts increases with both the geometrical complexity of the part under test, and with the number of reflections used to construct a view. This paper tackles the challenge of defect detection in the presence of geometrical artefacts by characterising the intensity distribution at each point in every view produced within a pristine sample, and using a hypothesis test as a means of defect detection. This information is combined with state-of-the-art data fusion routines, improving detection performance. Experimental work shows that this method improves performance compared to other methods of defect detection over the same scan area, which assume that the defect does not occupy the same location as an artefact in at least one view. Provided the pristine sample is characterised sufficiently well, hypothesis testing provides a robust method of defect detection in the presence of geometrical artefacts.

Equivalent Near-Field Corner Frequency Analysis of 3D Dynamic Rupture Simulations Reveals Dynamic Source Effects

Abstract Dynamic rupture simulations generate synthetic waveforms that account for nonlinear source and path complexity. Here, we analyze millions of spatially dense waveforms from 3D dynamic rupture simulations in a novel way to illuminate the spectral fingerprints of earthquake physics. We define a Brune-type equivalent near-field corner frequency (fc) to analyze the spatial variability of ground-motion spectra and unravel their link to source complexity. We first investigate a simple 3D strike-slip setup, including an asperity and a barrier, and illustrate basic relations between source properties and fc variations. Next, we analyze >13,000,000 synthetic near-field strong-motion waveforms generated in three high-resolution dynamic rupture simulations of real earthquakes, the 2019 Mw 7.1 Ridgecrest mainshock, the Mw 6.4 Searles Valley foreshock, and the 1992 Mw 7.3 Landers earthquake. All scenarios consider 3D fault geometries, topography, off-fault plasticity, viscoelastic attenuation, and 3D velocity structure and resolve frequencies up to 1–2 Hz. Our analysis reveals pronounced and localized patterns of elevated fc, specifically in the vertical components. We validate such fc variability with observed near-fault spectra. Using isochrone analysis, we identify the complex dynamic mechanisms that explain rays of elevated fc and cause unexpectedly impulsive, localized, vertical ground motions. Although the high vertical frequencies are also associated with path effects, rupture directivity, and coalescence of multiple rupture fronts, we show that they are dominantly caused by rake-rotated surface-breaking rupture fronts that decelerate due to fault heterogeneities or geometric complexity. Our findings highlight the potential of spatially dense ground-motion observations to further our understanding of earthquake physics directly from near-field data. Observed near-field fc variability may inform on directivity, surface rupture, and slip segmentation. Physics-based models can identify “what to look for,” for example, in the potentially vast amount of near-field large array or distributed acoustic sensing data.

Additive Manufacturing of Poly(phenylene Sulfide) Aerogels via Simultaneous Material Extrusion and Thermally Induced Phase Separation.

Additive manufacturing (AM) of aerogels increases the achievable geometric complexity, and affords fabrication of hierarchically porous structures. In this work, a custom heated material extrusion (MEX) device prints aerogels of poly(phenylene sulfide) (PPS), an engineering thermoplastic, via in situ thermally induced phase separation (TIPS). First, pre-prepared solid gel inks are dissolved at high temperatures in the heated extruder barrel to form a homogeneous polymer solution. Solutions are then extruded onto a room-temperature substrate, where printed roads maintain their bead shape and rapidly solidify via TIPS, thus enabling layer-wise MEX AM. Printed gels are converted to aerogels via postprocessing solvent exchange and freeze-drying. This work explores the effect of ink composition on printed aerogel morphology and thermomechanical properties. Scanning electron microscopy micrographs reveal complex hierarchical microstructures that are compositionally dependent. Printed aerogels demonstrate tailorable porosities (50.0-74.8%) and densities (0.345-0.684g cm-3), which align well with cast aerogel analogs. Differential scanning calorimetry thermograms indicate printed aerogels are highly crystalline (≈43%), suggesting that printing does not inhibit the solidification process occurring during TIPS (polymer crystallization). Uniaxial compression testing reveals that compositionally dependent microstructure governs aerogel mechanical behavior, with compressive moduli ranging from 33.0 to 106.5MPa.

A novel lung SBRT treatment planning: Inverse VMAT plan with leaf motion limitation to ensure the irradiation reproducibility of a moving target

This study exposed the implementation of a novel technique (VMATLSL) for the planning of moving targets in lung stereotactic body radiation therapy (SBRT). This new technique has been compared to static conformal radiotherapy (3D-CRT), volumetric-modulated arc therapy (VMAT), and dynamic conformal arc (DCA). The rationale of this study was to lower geometric complexity (54.9% lower than full VMAT) and hence ensure the reproducibility of the treatment delivery by reducing the risk for interplay errors induced by respiratory motion. Dosimetry metrics were studied with a cohort of 30 patients. Our results showed that leaf speed limitation provided conformal number (CN) close to the VMAT (median CN of VMATLSL is 0.78 vs 0.82 for full VMAT) and was a significant improvement on 3D-CRT and DCA with segment-weight optimized (respectively 0.55 and 0.57). This novel technique is an alternative to VMAT or DCA for lung SBRT treatments, combining independence from the patient's breathing pattern, from the size and amplitude of the lesion, free from interplay effect, and with dosimetry metrics close to the best that could be achieved with full VMAT.

Dynamics of episodic supershear in the 2023 M7.8 Kahramanmaraş/Pazarcik earthquake, revealed by near-field records and computational modeling

The 2023 M7.8 Kahramanmaraş/Pazarcik earthquake was larger and more destructive than what had been expected. Here we analyzed nearfield seismic records and developed a dynamic rupture model that reconciles different currently conflicting inversion results and reveals spatially non-uniform propagation speeds in this earthquake, with predominantly supershear speeds observed along the Narli fault and at the southwest (SW) end of the East Anatolian Fault (EAF). The model highlights the critical role of geometric complexity and heterogeneous frictional conditions in facilitating continued propagation and influencing rupture speed. We also constrained the conditions that allowed for the rupture to jump from the Narli fault to EAF and to generate the delayed backpropagating rupture towards the SW. Our findings have important implications for understanding earthquake hazards and guiding future response efforts and demonstrate the value of physics based dynamic modeling fused with near-field data in enhancing our understanding of earthquake mechanisms and improving risk assessment.

STUDY OF THE INFLUENCE OF TOOL GEOMETRY AND CUTTING MODES ON THE ACCURACY OF PROCESSING PARTS OBTAINED BY FDM PRINTING

FDM printing (rapid prototyping) is a production process during which you can quickly obtain parts with high geometric complexity, given dimensions and with low energy consumption. From the early stages, 3D printing was identified as a method of rapid prototyping of parts that have a high level of complexity and their manufacture by traditional methods (for example, mechanical processing on CNC machines) is impossible. Despite the advantages that additive manufacturing offers, it has not yet been incorporated into industrial mass production lines as an alternative to traditional technologies, due to the long manufacturing time of parts and the lack of repeatability. In some cases this may not be a serious problem, but in some industrial applications where high precision parts are required, there are limitations due to the surface roughness of the outer layer and the accuracy requirements. To eliminate these shortcomings, an additional processing process is required. The purpose of this study is to determine the most optimal parameters of the cutting tool and cutting modes (spindle rotation frequency, feed rate, depth of cut, diameter of the end mill, geometric parameters of the cutting edge) for mechanical processing of parts obtained by FDM printing from CoPET (PETg) plastic in order to obtain the specified parameters accuracy and surface roughness. The article describes the study of the work of four types of end mills, which differ in the material of the cutting part, geometry, number of cutting teeth, coating. A rectangular prism printed from CoPET plastic, without internal voids, 100% filling, was selected as a blank. Processing was carried out on a MIKRON WF-2 vertical milling machine. For end mills, the cutting process was investigated with two different strategies: milling of a closed groove over the entire working width of the mill; milling of an open groove with the side surface of the cutter. The suitability for effective processing of each type of tool is evaluated. Results were recorded and evaluated using an optical electron microscope.

Marginated aberrant red blood cells induce pathologic vascular stress fluctuations in a computational model of hematologic disorders.

Red blood cell (RBC) disorders such as sickle cell disease affect billions worldwide. While much attention focuses on altered properties of aberrant RBCs and corresponding hemodynamic changes, RBC disorders are also associated with vascular dysfunction, whose origin remains unclear and which provoke severe consequences including stroke. Little research has explored whether biophysical alterations of RBCs affect vascular function. We use a detailed computational model of blood that enables characterization of cell distributions and vascular stresses in blood disorders and compare simulation results with experimental observations. Aberrant RBCs, with their smaller size and higher stiffness, concentrate near vessel walls (marginate) because of contrasts in physical properties relative to normal cells. In a curved channel exemplifying the geometric complexity of the microcirculation, these cells distribute heterogeneously, indicating the importance of geometry. Marginated cells generate large transient stress fluctuations on vessel walls, indicating a mechanism for the observed vascular inflammation.

Efficient inverse-designed structural infill for complex engineering structures

Inverse design of high-resolution and fine-detailed 3D lightweight mechanical structures is notoriously expensive due to the need for vast computational resources and the use of very fine-scaled complex meshes. Furthermore, in designing for additive manufacturing, infill is often neglected as a component of the optimized structure. In this paper, both concerns are addressed using a so-called de-homogenization topology optimization procedure on complex engineering structures discretized by 3D unstructured hexahedrals.Using a rectangular-hole microstructure (reminiscent to the stiffness optimal orthogonal rank-3 multi-scale) as a base material for the multi-scale optimization, a coarse-scale optimized geometry can be obtained using homogenization-based topology optimization. Due to the microstructure periodicity, this coarse-scale geometry can be up-sampled to a fine single-scale physical geometry with optimized infill, with only a minor loss in structural performance and at a fraction of the cost of a fine-scale solution. The upsampling on 3D unstructured grids is achieved through stream surface tracing, aligning with the optimized local orientations. The periodicity of the physical geometry can be tuned, such that the material serves as a structural component and also as an efficient infill for additive manufacturing designs.The method is demonstrated through three examples of varying geometrical complexity. It achieves comparable structural performance to “brute force” state-of-the-art methods but stands out for its significant computational time reduction. By allowing multiple active layers, the mapped solution becomes more mechanically stable, leading to an increased critical buckling load factor without additional computational expense. The control of active layers also provides direct control over the internal structure, i.e., infill, ensuring that the infill is incorporated as a structural component and enhancing the manufacturability of the de-homogenization procedure. Furthermore, the proposed approach exhibits promising results, achieving volume fractions and weighted compliance values within 5% of the large-scale SIMP model, while demonstrating a computational efficiency improvement ranging from 10 times to over 250 times.

What Is in a Simplicial Complex? A Metaplex-Based Approach to Its Structure and Dynamics.

Geometric realization of simplicial complexes makes them a unique representation of complex systems. The existence of local continuous spaces at the simplices level with global discrete connectivity between simplices makes the analysis of dynamical systems on simplicial complexes a challenging problem. In this work, we provide some examples of complex systems in which this representation would be a more appropriate model of real-world phenomena. Here, we generalize the concept of metaplexes to embrace that of geometric simplicial complexes, which also includes the definition of dynamical systems on them. A metaplex is formed by regions of a continuous space of any dimension interconnected by sinks and sources that works controlled by discrete (graph) operators. The definition of simplicial metaplexes given here allows the description of the diffusion dynamics of this system in a way that solves the existing problems with previous models. We make a detailed analysis of the generalities and possible extensions of this model beyond simplicial complexes, e.g., from polytopal and cell complexes to manifold complexes, and apply it to a real-world simplicial complex representing the visual cortex of a macaque.

3D bioprinted multilayered cerebrovascular conduits to study cancer extravasation mechanism related with vascular geometry

Cerebral vessels are composed of highly complex structures that facilitate blood perfusion necessary for meeting the high energy demands of the brain. Their geometrical complexities alter the biophysical behavior of circulating tumor cells in the brain, thereby influencing brain metastasis. However, recapitulation of the native cerebrovascular microenvironment that shows continuities between vascular geometry and metastatic cancer development has not been accomplished. Here, we apply an in-bath 3D triaxial bioprinting technique and a brain-specific hybrid bioink containing an ionically crosslinkable hydrogel to generate a mature three-layered cerebrovascular conduit with varying curvatures to investigate the physical and molecular mechanisms of cancer extravasation in vitro. We show that more tumor cells adhere at larger vascular curvature regions, suggesting that prolongation of tumor residence time under low velocity and wall shear stress accelerates the molecular signatures of metastatic potential, including endothelial barrier disruption, epithelial–mesenchymal transition, inflammatory response, and tumorigenesis. These findings provide insights into the underlying mechanisms driving brain metastases and facilitate future advances in pharmaceutical and medical research.

Dual-grid mapping method for the advection-diffusion-reaction equation in a heterogeneous medium

Processes described by the advection-diffusion-reaction (ADR) equation often arise in heterogeneous media. Of particular interest is the case of layered or otherwise composite media exhibiting many layers or other intricate geometric complexity. Numerical models for processes in these types of media are generally accompanied by a significant computational cost due to the large number of grid nodes required to capture the detail of the heterogeneous domain. An approach addressing this issue involves obtaining approximate solutions on a coarse grid comprised of a small number of nodes and reconstructing a solution on a fine grid comprising a large number of nodes. In this paper, we discuss a projection-based framework for coarse-to-fine-grid approximation methods, which is used to derive a dual-grid mapping method. We initially utilise an interpolation-based mapping, and then consider a new discretisation-based adaptive mapping defined through the solution of coupled problems on subsets of the fine grid. With our new adaptive dual-grid mapping method, we are able to accurately approximate complex solutions on very coarse grids and reconstruct much finer scale approximations on fine grids. Code implementing the developed methods is provided and also applied to several test cases, where accuracy and significantly reduced computational cost are demonstrated in comparison to a numerical solution applied directly on the fine grid.

Correlation of Energy Density and Manufacturing Variables of AA6061 through Laser Powder Bed Fusion and Its Effect on the Densification Mechanism

Aluminum alloy processing via additive manufacturing (AM) technologies has increased in usage during the last decade. AM now enables manufacturing complex geometries not previously achieved through traditional manufacturing. Aluminum is usually processed using laser powder bed fusion (LPBF) technologies, which are used to manufacture metallic components of high geometrical complexity and dimensional accuracy and good mechanical, electrical, and chemical properties, which is why this technology is quite popular at industrial levels. To further develop quality control systems and new aluminum alloys using LPBF, there is a need to establish a predictive relationship between the parameters of the material. A study was carried out to investigate the relationship between energy density and process parameters such as laser power, scan speed, hatch spacing, scan pattern, and laser focus and its influence on the densification mechanism in additively manufactured components with aluminum alloys. AA6061 was selected due to its wide usage in different industries, given its low density and high mechanical performance. Relative density was analyzed using the Archimedes principle, and the quality and morphology of the AA6061 powder were analyzed through metallographic analysis. The process parameter selection was performed according to the best results obtained according to the laser power and energy density factors. The best manufactured samples had an energy density between 30 and 40 J/mm3, with relative densities above 99%.

Calculation of Transmission Line Worker Electric Field Induced Current Using Fourier-Enhanced Charge Simulation

Exposure to quasi-electrostatic field induced currents is a hazard of live-line transmission work. These steady-state induced currents are typically less than 1 mA, and their sensory effects range from imperceptible to painful depending on the person and conditions such as contact area and duration. Permanent injury from these currents is unlikely but they can distract workers, increasing the risk of injury from falls or other dangers. Identifying contact current severity and training workers can help reduce the risk of accidents. Measuring induced currents along a climbing route is time-consuming and simulation is challenging because of the geometric complexity of the worker, the transmission structure, conductor bundles, and electric fields in the climbing space. This research explores the suitability of a recently published adaptation of the charge simulation method for calculating worker-induced currents. The method uses Fourier principles to improve computational efficiency while explicitly modeling all bundle subconductors. The research also examines simplifications for modeling lattice structures and human geometry. Calculated currents compare well to measurements for a worker climbing a 400 kV lattice structure. This indicates the method is a practical option for calculating steady-state contact current severity. A simple calculation is suggested for estimating these currents.

3D Printed Bioinspired Hierarchical Surface Structure with Tunable Wettability

Abstract Nature has examples of impressive surfaces and interfaces with diverse wettability stemming from superhydrophilicity to superhydrophobicity. The multiscale surface structures found in biological systems generally have high geometric complexity, which makes it challenging to replicate their characteristics, especially using traditional fabrication techniques. It is even more challenging to fabricate such complex microstructures with tunable wettability. In this paper, we propose a method to tune the wettability of a micro-scale surface by changing the geometrical parameters of embedded micro-structures in the surface. By taking inspiration from an insect (springtails), we designed micropillar arrays with different roughness by adjusting geometric parameters such as reentrant angle, pitch distance, and the number of spikes and pillars. This study shows that, by changing geometrical parameters in microscale, the apparent contact angle, and hence the surface wettability can be calibrated. The microscale pillars were fabricated using a precise micro direct light processing (uDLP) three-dimensional (3D) printer. Different printing parameters were studied to optimize the geometric parameters to fabricate 3D hierarchical structures with high accuracy and resolution. By controlling the size of different features of the pillar, pillar number, and layout of the mushroom-shaped micropillars, the wettability of the surface is possible to be tuned from a highly nonwetting liquid/material combination to highly wetting material. Such wettability tuning capability expands the design space for many biomedical and thermofluidic applications.

A case study of hybrid manufacturing of a Ti-6Al-4V titanium alloy hip prosthesis

Hybrid manufacturing (HM) is a process that combines additive manufacturing (AM) and subtractive manufacturing (SM). It is becoming increasingly recognized as a solution capable of producing components of high geometric complexity, while at the same time ensuring the quality of the surface finish, rigour and geometric tolerance on functional surfaces. This work aims to study the surface finish quality of an orthopaedic hip resurfacing prosthesis obtained by HM. For this purpose, test samples of titanium alloy Ti-6Al-4V using two Power Bed Fusion (PBF) processes were manufactured, which were finished by turning and 5-axis milling. It was verified that, upon the machining tests, no differences in Ra and Rt were found between the various types of AM. Regarding the type of SM used, 5-axis milling provided lower roughness results with a consistent value of Ra = 0.6 µm. The use of segmented circle mills in 5-axis milling proved to be an asset in achieving a good surface finish. This work successfully validated the concept of HM to produce a medical device, namely, an orthopaedic hip prosthesis.As far as surface quality is concerned, it could be concluded that the optimal solution for this case study is 5-axis milling.

Reduced small-scale structural complexity on sponge-dominated areas of Indo-Pacific coral reefs

Corals provide a complex 3D framework that offers habitat to diverse coral reef fauna. However, future reefs are likely to experience reduced coral abundance. Sponges have been proposed as one potential winner on future coral reefs, but little is known of how they contribute to reef 3D structure. Given the ecological importance of structural complexity, it is critical to understand how changes in the abundance of structure-building organisms will affect the three-dimensional properties of coral reefs. To investigate the potentially important functional role of coral reef sponges as providers of structural complexity, we compared the structural complexity of coral- and sponge-dominated areas of an Indonesian coral reef, using 3D photogrammetry at a 4 m2 spatial scale. Structural complexity of 31 4 m2 quadrats was expressed as rugosity indicating reef contour complexity (R), vector dispersion indicating heterogeneity of angles between reef surfaces (1/k), and fractal dimension indicating geometrical complexity at five different spatial scales between 1 and 120 cm (D1–5). Quadrats were identified as high- or low-complexity using hierarchical clustering based on the complexity metrics. At high structural complexity, coral- and sponge-dominated quadrats were similar in terms of R and 1/k. However, smallest-scale refuge spaces (1–5 cm) were more abundant in coral-dominated quadrats, whereas larger scale refuge spaces (30–60 cm) were more abundant in sponge-dominated quadrats. Branching and massive corals contributed the most to structural complexity in coral-dominated quadrats, and barrel sponges in sponge-dominated quadrats. We show that smaller-scale refugia (1–5 cm) are reduced on sponge-dominated reefs at the spatial scale considered here (4 m2), with potential negative implications for smaller reef fauna.

Recent trends in the additive manufacturing of polyurethanes

AbstractPolyurethanes are remarkably versatile materials that offer exceptional control over structure–property relationships, making them the subject of extensive research and exploration across diverse applications. These materials have garnered significant attention due to their inherent chemical, mechanical, thermomechanical, biological and physical properties, further fueling interest in their potential uses. However, conventional processing methods, involving molds, high temperatures or solvents, impose limitations on geometric complexity, hindering their potential applications. Additive manufacturing, or 3D printing, has emerged as a transformative solution, enabling the fabrication of intricate geometries, unparalleled design flexibility, dematerialization and enhanced material properties. This mini‐review explores recent advancements in additive manufacturing techniques applied to polyurethanes, focusing on three prominent 3D printing modalities: vat photopolymerization, direct ink write and fused filament fabrication. Examining the successful integration of polyurethanes with these cutting‐edge 3D printing methods illuminates the remarkable progress achieved in tailoring part design, expanding the range of applications and unlocking novel material−object functionalities. This mini‐review aims to provide valuable insight into the latest trends and development in 3D printing polyurethanes, paving the way for their future utilization in diverse industries. © 2023 Society of Chemical Industry.

ADRANOS: A numerical tool developed to analyse coolant operating conditions of the EU-DEMO divertor

In the context of the activities of the EUROfusion action, the University of Palermo has carried out a research campaign to evaluate the thermal-hydraulic performance of the EU-DEMO divertor Single-Circuit Cooling (SCC) option. Given the exceptional geometric complexity of this divertor design, the search for coolant operating conditions that comply with the applicable design constraints cannot be performed by relying on detailed 3D computational fluid-dynamic calculations. For this purpose, the Advanced Divertor paRametric Analysis for coolaNt Operating Scenarios (ADRANOS) code has been developed. It is a novel numerical tool capable of quickly assessing the thermofluid-dynamic behaviour of the divertor cooling circuit with reduced computational cost, predicting the divertor performance map at different coolant inlet conditions and mass flow rates, and allowing for the effortless study of different circuit topologies.This study introduces the ADRANOS modelling approach, describes its validation process, and demonstrates its application to various configurations of the SCC divertor option. The results obtained showed that it is possible to find suitable coolant operating conditions characterized by low temperature and high pressure, posing a challenge for the adoption of Eurofer as a structural material.

Development and assessment of a methodology for abstraction of topology optimization results to enable the substitution of optimized beams

Improving mechanical topology optimization (TO) results by substituting biomimetic beams is one possibility to achieve designs of mechanical components that are highly sustainable and show good mechanical performance. Because of their geometric complexity, such designs were found to be well-suited for production by laser additive manufacturing. One obstacle of incorporating biomimetics beams in TO designs is the lack of detailed design methodologies. Röver et al. [“Methodology for integrating biomimetic beams in abstracted topology optimization results,” in Proceedings of the ASME 2022 International Mechanical Engineering Congress and Exposition. Volume 4: Biomedical and Biotechnology; Design, Systems, and Complexity Columbus, OH, 30 October–3 November (ASME, New York, 2022)] proposed a corresponding design concept. Building on their concept, we present in this work a detailed methodology for abstraction of TO results to a design consisting of ball nodes and cylindrical beams. Using such an auxiliary design, the internal forces and moments of the beams can be evaluated to allow for the substitution of suitable biomimetic beams to generate biomimetic component designs in a next step. We present a skeletonization algorithm based on the potential field approach. Using the skeletonization and an additional analysis of the dimensions of the beams in the TO result, the algorithm develops an auxiliary design of the original TO result. The final algorithm was applied to three common TO results to obtain one auxiliary component design each. The developed algorithm was found to generate abstractions that were well-suited for use in the methodology proposed in Röver et al. [“Methodology for integrating biomimetic beams in abstracted topology optimization results,” in Proceedings of the ASME 2022 International Mechanical Engineering Congress and Exposition. Volume 4: Biomedical and Biotechnology; Design, Systems, and Complexity Columbus, OH, 30 October–3 November (ASME, New York, 2022)], because internal forces and moments in the abstracted beams could be evaluated with less effort. Therefore, our work contributes to a detailed design methodology for biomimetic mechanical components in the field of design for additive manufacturing.

Using particle-loaded inks to selectively change the material properties in binder-jetted WC–Co parts

Functionally graded hardmetals offer a superior combination of fracture toughness and wear resistance and alleviate the compromise that conventional hardmetals must face between these two material properties. In tooling applications, they exhibit superior cutting performance compared to the conventionally employed hardmetals. Traditionally, graded tools are enabled by a surface treatment with nitrogen or carbon. This enables a tungsten carbide–cobalt (WC–Co) tool with a surface layer containing less cobalt (Co) than the core of the part. With this Co gradation, the wear properties can be improved due to the harder surface. If different loads act at different points in a tool and the geometric complexity of a tool increases, the requirements for a targeted positioning of the Co gradients become higher. A simple surface treatment does not allow a flexible distribution of the desired gradients. Binder jetting provides a solution to produce location-independent graded structures. In this work, the process was evaluated for the generation of Co gradients in WC–Co structures. Inks loaded with graphite particle contents of 2.5, 5, 7.5, and 10 m% were used to create differences in the carbon content in the green part. This induced a Co migration during the liquid phase sintering process. The sintering parameters were varied in time and temperature and studied regarding their effect on the microstructure and the porosity, the formation of the Co gradient, and the hardness. At low sintering times and temperatures, all carbon differences led to a Co gradient in the sintering part with a deviation of up to 10 m%. With an increase in sintering time and temperature, the Co distribution began to even out, and a deviation was observed only in the parts created with the inks containing 7.5 and 10 m% of particles. Hardness values of up to 1300 HV10 were obtained, which is comparable to conventionally produced WC–Co parts. The excess of carbon resulted in porosity in the parts leading to a reduced density. However, with inks containing 10 m% particles, densities of 94.26% were achieved at the longest sintering times and the highest temperature.