Printing Layer Thickness Research Articles

Evaluation of the mechanical properties and degree of conversion of 3D printed splint material

ObjectiveTo evaluate the effect of post-curing method, printing layer thickness, and water storage on the mechanical properties and degree of conversion of a light-curing methacrylate based resin material (IMPRIMO® LC Splint), used for the fabrication of 3D printed occlusal splints and surgical guides. Methods96 bar-shaped specimens were 3D printed (Asiga MAX), half of them with a layer thickness of 100 μm (Group A), and half with 50 μm (Group B). Each group was divided in three subgroups based on the post-curing method used: post-curing with light emitting diode (LED) and nitrogen gas; post-curing with only LED; and non-post-curing. Half of the specimens from each subgroup were water-stored for 30 days while the other half was dry-stored (n = 8). Flexural strength and flexural modulus were evaluated. Additional specimens were prepared and divided in the same way for surface hardness (n = 96), fracture toughness, and work of fracture (n = 96). Five specimens were selected from each subgroup for evaluating the degree of conversion (DC). Data were collected and statistically analyzed with 1-way, 2-way ANOVA, and Tukey post-hoc analysis (α = 0.05). ResultsThe 2-way ANOVA showed that the post-curing method and water storage significantly affected the investigated mechanical properties (P < 0.001). The 1-way ANOVA revealed a statistically significant difference among the tested groups on the investigated properties (P < 0.001). After water storage, the 100 μm subgroup post-cured with only LED showed higher flexural strength (51 ± 9) than the 50 μm and 100 μm subgroups that were post-cured with LED in addition to nitrogen gas atmosphere (38 ± 5, 30 ± 3) (p < 0.05). The 50 μm subgroup post-cured with only LED showed the highest significant flexural modulus values (1.7 ± 0.08) (p < 0.05). However, the 50 μm subgroup post-cured with LED plus nitrogen showed significantly higher surface hardness values (p < 0.05) among the investigated groups. The non-post-cured subgroups showed the lowest values, which were significantly different from the other subgroups (p < 0.05). ConclusionThe post-curing method, water storage, and printing layer thickness play a role in the mechanical properties of the investigated 3D Printed occlusal splints material. The combination of heat and light within the post-curing unit can enhance the mechanical properties and degree of conversion of 3D printed occlusal splints. Flexural strength and surface hardness can increase when decreasing printing layer thickness.

Effects of printing layer thickness on mechanical properties of 3D-printed custom trays

Statement of problemThe layer thickness serves as a straightforward and controllable parameter to alter the mechanical properties of 3D-printed custom trays. However, how the printing layer thickness affects the mechanical properties of the trays is not fully understood. PurposeThe purpose of this in vitro study was to investigate the effects and their underlying mechanisms and to optimize the mechanical properties through modulation of the printing layer thickness. Material and methodsPolylactic acid (PLA) specimens were 3D-printed with 5 layer thicknesses from 0.1 mm to 0.5 mm. The bond, flexural, and tensile strengths were measured by using a universal test machine. Postfracture interfaces were examined by means of scanning electron microscopy. Additionally, the printing dimensional accuracy was estimated by measuring the size deviations between the printed and virtual specimens, and the printing times were recorded. ResultsWith increasing PLA printing layer thickness, the tensile bond strength first increased and then decreased, peaking at a thickness of 0.4 mm. While the flexural and tensile strengths decreased, the printing dimensional accuracy remained constant from 0.1 mm to 0.4 mm and then decreased at 0.5 mm. The printing time sharply decreased as printing layer thickness increased. ConclusionsModerate layer thickness provided the best properties for 3D-printed custom trays.

A modified creep model of polylactic acid (PLA‐max) materials with different printing angles processed by fused filament fabrication

AbstractThe creep behavior caused by the viscous mechanical effect of biodegradable polylactic acid (PLA‐max) material is of great significance to its application. To better understand the creep properties of PLA‐max materials processed by fused filament fabrication, the effects of printing parameters including printing angle and layer thickness on them are studied theoretically and experimentally. The experimental results show that within the range of loading stress and loading time, the creep deformation of the PLA‐max material decreases with the increase of the printing angle or the decrease of the layer thickness. The experimental results are processed and analyzed, and a modified Burger model is proposed to quantitatively analyze the creep deformation of PLA‐max. In this modified Burger model, the four parameters are functions of printing angle and stress level. The modified model can accurately calculate the creep deformation of the specimen at other printing angles, which provides an important reference for the design of functional structures with specific mechanical properties.

Characterization of novel 3D printed plastic scintillation dosimeters

We propose a new methodology for the fabrication and evaluation of scintillating detector elements using a consumer grade fusion deposition modeling (FDM) 3D printer. In this study we performed a comprehensive investigation into both the effects of the 3D printing process on the scintillation light output of 3D printed plastic scintillation dosimeters (PSDs) and their associated dosimetric properties. Fabrication properties including print variability, layer thickness, anisotropy and extrusion temperature were assessed for 1 cm3 printed samples. We then examined the stability, dose linearity, dose rate proportionality, energy dependence and reproducibility of the 3D printed PSDs compared to benchmarks set by commercially available products. Experimental results indicate that the shape of the emission spectrum of the 3D printed PSDs do not show significant spectral differences when compared to the emission spectrum of the commercial sample. However, the magnitude of scintillation light output was found to be strongly dependent on the parameters of the fabrication process. Dosimetric testing indicates that the 3D printed PSDs share many desirable properties with current commercially available PSDs such as dose linearity, dose rate independence, energy independence in the MV range, repeatability, and stability. These results demonstrate that not only does 3D printing offer a new avenue for the production and manufacturing of PSDs but also allows for further investigation into the application of 3D printing in dosimetry. Such investigations could include options for 3D printed, patient-specific scintillating dosimeters that may be used as standalone dosimeters or incorporated into existing 3D printed patient devices (e.g. bolus or immobilization) used during the delivery of radiation therapy.

Fused Filament Fabricated Polypropylene Composite Reinforced by Aligned Glass Fibers

3D printing using fused composite filament fabrication technique (FFF) allows prototyping and manufacturing of durable, lightweight, and customizable parts on demand. Such composites demonstrate significantly improved printability, due to the reduction of shrinkage and warping, alongside the enhancement of strength and rigidity. In this work, we use polypropylene filament reinforced by short glass fibers to demonstrate the effect of fiber orientation on mechanical tensile properties of the 3D printed specimens. The influence of the printed layer thickness and raster angle on final fiber orientations was investigated using X-ray micro-computed tomography. The best ultimate tensile strength of 57.4 MPa and elasticity modulus of 5.5 GPa were obtained with a 90° raster angle, versus 30.4 MPa and 2.5 GPa for samples with a criss-cross 45°, 135° raster angle, with the thinnest printed layer thickness of 0.1 mm.

Additive Manufacturing of Tailored Macroporous Ceramic Structures for High‐Temperature Applications

Pathlines of fluid flow are strategically guided through additively manufactured ceramic structures with specified porosity and pore diameter variations. With additional tunable parameters such as printing layer thickness and ceramic particle size, tailored porous structures hold opportunities for application-specific designs in thermofluidic systems. Further details can be found in the article number 2000158 by Sadaf Sobhani and co-workers.

Augmentation of conductive pathways in carbon black/PLA 3D-printed electrodes achieved through varying printing parameters

3D-printing of conductive carbon materials in sensing applications and energy storage devices has significant potential, however high resistivity of 3D-printed filaments poses a challenge. Strategies to enhance sensors post printing are time consuming and can reduce structural integrity. In this work, we investigated the effects different printing layer thickness and orientation can have on the electron transfer kinetics and resistivity of conductive materials. The response of these electrodes was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and imaging. Electrodes printed with the lowest layer thickness of 0.1 mm in a vertical orientation had the greatest conductivity. With increasing print layer thickness and printing in a horizontal orientation, the electrode was more resistive. This work is the first to demonstrate the significant impact 3D-printing parameters can have on the electron transfer kinetics of carbon conductive electrodes. The implications of this study are important in defining the manufacturing process of electrodes for all applications.

Influence of Manufacturing Parameters and Post Processing on the Electrical Conductivity of Extrusion-Based 3D Printed Nanocomposite Parts.

The influence of manufacturing parameters of filament extrusion and extrusion-based Additive Manufacturing (AM), as well as different post processing techniques, on the electrical conductivity of 3D printed parts of graphene nanoplatelets (GNP)-reinforced acrylonitrile butadiene styrene (ABS) has been analyzed. The key role of the manufacturing parameters to obtain electrically conductive filaments and 3D printed parts has been demonstrated. Results have shown that an increase in extrusion speed, as well as lower land lengths, induces higher extrudate swelling, with the consequent reduction of the electrical conductivity. Additionally, filaments with lower diameter values, which result in a higher surface-to-cross-section ratio, have considerably lower electrical conductivities. These factors tune the values of the volume and surface electrical conductivity between 10−4–100 S/m and 10−8–10−3 S/sq, respectively. The volume and surface electrical conductivity considerably diminished after 3D printing. They increased when using higher printing layer thickness and width and were ranging between 10−7–10−4 S/m and 10−8–10−5 S/sq, respectively. This is attributed to the higher cross section area of the individual printed lines. The effect of different post processing (acetone vapor polishing, plasma and neosanding, which is a novel finishing process) on 3D printed parts in morphology and surface electrical conductivity was also analyzed.

Tensile failure strength and separation angle of FDM 3D printing PLA material: Experimental and theoretical analyses

It is discovered in this investigation that there exist two different failure modes and a special separation angle which is the demarcation point of the two different failure modes when FDM (Fused Deposition Modelling) 3D printing materials fail under a tensile load. In order to further understand the mechanical properties of FDM 3D printing materials and promote the use of FDM 3D printing materials, their tensile failure strengths at different printing angles and separation angles are measured and analysed theoretically. A new separate-modes of transversely isotropic theoretical failure model is established to predict the tensile failure strength and separation angle of FDM 3D printing PLA (polylactic acid) material based on the hypothesis of transverse isotropy and the classical separate-modes failure criterion. During this research, the tensile specimens designed according to the current test standard ISO (527-2-2012) for plastic-multi-purpose specimens are fabricated in 7 different printing angles (0∘, 15∘, 30∘, 45∘, 60∘, 75∘, 90∘) and three levels of printing layer thickness (0.1 mm, 0.2 mm, 0.3 mm). Experimental results show that the tensile failure strength increases with the increase of the printing angle or the decrease of the layer thickness. Meanwhile, inter-layer failure tends to occur when the printing angle is small and in-layer failure tends to occur when the printing angle is big. In comparison with the results predicted by the established theoretical model, all values of the Generalized-Relative-Root-Mean-Square Error are close to zero and the experimental separation angles are also between 45∘ and 60∘. So the predictive capacity of the theoretical model is affirmed by experimental results.

Surface morphology and drug loading characterization of 3D-printed methacrylate-based polymer facilitated by supercritical carbon dioxide

Polymers have been shown to have viable applications in the biomedical field, from controlled drug delivery systems to biological implants. The preparation and processing of polymers into bio-systems have nevertheless encountered some technical challenges in part customization and adverse effects to the human body functions and recovery. This study proposes the utilization of 3D printing technology and supercritical carbon dioxide (scCO2) processing to deliver a drug-impregnated polymeric material system which can be engineered and tuned to suit a particular implantation procedure and dramatically improve patient outcomes. In this work, an acrylate-based polymer is 3D-printed using stereolithography, then impregnated with flurbiprofen drug using scCO2. Drug loading above 24 % by mass is achievable under the tested conditions. The correlation of drug loading and material surface roughness with different process parameters, including 3D printing layer thickness, scCO2 processing temperature, pressure and treatment time, are investigated and empirically modeled using the linear regression methods.

Implementation of an elastoplastic constitutive model for 3D-printed materials fabricated by stereolithography

In this study, an elastoplastic constitutive model is developed to implement a quantitative description of the mechanical behavior of materials fabricated by stereolithography (SLA). Considering the characteristics of the SLA printing process and the influence of the printing angle and layer thickness, the transversely isotropic elastic model and the Hill anisotropic yield model are used to describe the mechanical behavior of SLA-printed materials. In the analysis of the elasticity and strength of SLA-printed materials, equations to predict the elastic modulus and ultimate tensile strength are derived. Uniaxial tensile tests are carried out to obtain the elastic modulus and ultimate tensile strength of the standard SLA-printed materials under different printing angles and layer thicknesses. The parameters of the constitutive model are employed in ABAQUS to simulate the mechanical behavior of a cellular structure and compare it with the experimental results. The results demonstrate that the elastoplastic constitutive model developed in this study can effectively describe the mechanical behavior of SLA-printed materials.

Intaglio Surface Dimension and Guide Tube Deviations of Implant Surgical Guides Influenced by Printing Layer Thickness and Angulation Setting.

To measure overall intaglio dimensional and tube deviations of implant guides printed at 50 and 100 µm layer thickness at 0°, 45°, and 90° angulation using a stereolithographic (SLA) printer. A surgical implant guide design from a subject missing a maxillary right central incisor, used as the original standard tessellation language (STL) were stereolithographically fabricated at each thickness and angulation, 50 and 100 µm layer thickness at 0°, 45°, and 90° angulation (n = 10 each group). The guide was then scanned using cone beam computed tomography. The digital imaging and communications in medicine (DICOM) scanned files were then converted to an STL format. The overall dimensional deviations of the intaglio surface and the positioning of the implant guide tube were then superimposed onto the original designed STL file using best-fitting alignment. A t-test and an F-test as well as ANOVA followed by a post hoc t-test were used to determine statistical significant differences (α = 0.05) for the intaglio surface and guide tube deviation, respectively. The overall intaglio surface discrepancies (µm) printed at 0°, 45°, and 90° were 55.07 ± 1.36, 52.39 ± 2.09, and 61.02 ± 15.96 for 50 µm layer; and 98.38 ± 10.55, 84.47 ± 10.61, and 90.26 ± 5 for 100 µm layer with statistically significant differences for both t-test and F-test, p < 0.001. The maximal guide tube linear deviations (µm) printed at 0°, 45°, and 90° were 10.78 ± 3.84, 8.16 ± 3.68, and 12.57 ± 5.39 for 50 µm layer (ANOVA, p = 0.096); and 10.95 ± 5.23, 16.79 ± 4.97, and 22.63 ± 2.81 for 100 µm layer (ANOVA, p < 0.001). The maximal guide tube angular deviations (°) printed at 0°, 45°, and 90° were 1.29 ± 0.30, 0.64 ± 0.13, and 0.56 ± 0.21 for 50 µm layer (ANOVA, p < 0.001); and 1.57 ± 0.29, 0.86 ± 0.14, and 1.02 ± 0.31 for 100 µm layer (ANOVA, p = 0.034). There was a statistical difference in the deviations between 50 and 100 µm layer printing in all printed angulations except at 0° (t-test, p = 0.05, p = 0.03, and p = 0.001 for 0°, 45°, and 90°) and linear deviations (t-test, p < 0.001, p = 0.009, and p = 0.001 for 0°, 45°, and 90°). Printing at 50 µm layer reduces dimensional intaglio deviations in general and reduces tube angular deviations with different angulations of printing. However, the deviations were only ∼60 to 100 µm for the intaglio dimension deviations; and ∼0.04 to 0.26 mm and ∼0.25° to ∼2° for tube deviations.

Blind Watermarking for 3-D Printed Objects by Locally Modifying Layer Thickness

We propose a new blind watermarking algorithm for 3D printed objects that has applications in metadata embedding, robotic grasping, counterfeit prevention, and crime investigation. Our method can be used on fused deposition modeling (FDM) 3D printers and works by modifying the printed layer thickness on small patches of the surface of an object. These patches can be applied to multiple regions of the object, thereby making it resistant to various attacks such as cropping, local deformation, local surface degradation, or printing errors. The novelties of our method are the use of the thickness of printed layers as a one-dimensional carrier signal to embed data, the minimization of distortion by only modifying the layers locally, and one-shot detection using a common paper scanner. To correct encoding or decoding errors, our method combines multiple patches and uses a 2D parity check to estimate the error probability of each bit to obtain a higher correction rate than a naive majority vote. The parity bits included in the patches have a double purpose because, in addition to error detection, they are also used to identify the orientation of the patches. In our experiments, we successfully embedded a watermark into flat surfaces of 3D objects with various filament colors using a standard FDM 3D printer, extracted it using a common 2D paper scanner and evaluated the sensitivity to surface degradation and signal amplitude.

Surface Performance Analysis of in House Developed Digital Light Processing based 3D Printer

Digital light processing (DLP) 3D printing is an additive manufacturing (AM) process that is utilized to produce parts by means of the photopolymerization process in which resin is cured by UV light. Vat photo-polymerization is a type of AM. it's a liquid bath of a polymeric resin which is cured layer by layer through precise control with the assistance of stepper motor UV light. Printing time, layer thickness, and lumens of the light play a crucial role within the printing. A series of specimens was designed, printed, and tested. Total printing time, layer thickness, and layer exposure time were examined. We utilized a 365 nm frequency of photopolymer vat. This paper studied printing parameters like surface roughness, printing speed and role of layer size, etc. It has found that if the printing speed 250 mm/min then the surface quality will be better otherwise surface roughness will increase if it will be greater than 250 mm/min.

Influence of change in layer thickness on mechanical properties of components 3D printed on Zortrax M 200 FDM printer with Z-ABS filament material & Accucraft i250+ FDM printer with low cost ABS filament material

Some important factors influencing cost of components 3D printed on FDM printer in ABS material are (1) brand and model of FDM printer (2) brand of ABS filament (3) % infill (4) layer thickness (5) print speed. One can easily reason out, that in FDM printing layer thickness is a significant factor affecting cost, by doubling layer thickness we can reduce print time by a factor of ½ approximately& hence reduce cost.But what is the effect of increasing layer thickness on mechanical properties. This experimental work focuses on understanding effect of change of layer thickness on mechanical properties of FDM printed components. Tensile test specimen type 1 of dimensions as specified in standard ASTM D 638 have been printed on Zortrax M200 LPD printer using Z-ABS filament material and Accucraft i250 + FDM printer using low cost ABS filament material. Test specimens are then tested on Instron 3382 electromechanical universal testing system at strain rate 5 mm/min. The results of this study are, for test specimens printed on edge i.e. with length overall and thickness parallel to build platform, change in layer thickness has no significant effect on tensile strength as direction of loading is parallel to layers.

Design and fabrication of transdermal drug delivery patch with milliprojections using material extrusion 3D printing

ABSTRACTThis paper investigates the effect of various 3D printing parameters on a transdermal drug delivery system with milliprojections printed using poly(lactic acid) (PLA). The parameters studied involve printing temperature, layer thickness, extrusion width, infill width, and nozzle orifice diameter. Their effects on the final print quality were evaluated based on the surface finish and dimensional accuracy of the milliprojections. The change in the molecular weights of the polymers after extrusion and printing suggests thermal degradation. Further thermal analysis also showed that 3D printing decreases polymer crystallinity. The parameters studied showed varying effects on print quality with respect to PLA types and the dimensions involved. In general, it is sensible to process at temperature close to the melting point of a semicrystalline polymer or at the lowest temperature for which the polymer flows for an amorphous polymer. Although the layer thickness and extrusion width affect each dimension differently, it was found to be a reasonable approach to choose a thinner layer for a more accurate tip, and a thinner infill width for more accurate part diameters. Lastly, it was found that the smaller nozzle orifice and increased spacing between milliprojections produced better surface finish but had no significant effect on part accuracy. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48777.

Anisotropy of poly(lactic acid)/carbon fiber composites prepared by fused deposition modeling

ABSTRACTIt is well known that 3D printed parts prepared by fused deposition modeling (FDM) exhibit large anisotropy of mechanical properties. In this article, poly(lactic acid; PLA)/carbon fiber (CF) composites with different built orientations (X, Y, Z) were prepared by FDM. The effects of printing temperature, speed, orientations, and layer thickness on the mechanical properties of the composites were systematically investigated. The mechanical properties of PLA/CF composites show more significant anisotropy. The orientation of the fibers along the printing direction is displayed by scanning electron microscopy. Printing parameters bring almost no effect on mechanical properties of the X‐construct oriented specimen, and bring obvious effect on those of the Y‐construct oriented specimen and Z‐construct oriented specimen. According to the analysis, carbon fiber can amplify this anisotropy from layer fashion, and the key factors from printing parameters are porosity and bond strength between fuses. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48786.

Biocompatible micro, soft bellow actuator rapidly manufactured using 3D-printed soluble mold

A micro, soft bellow actuator, which is fabricated using a biocompatible material (polydimethylsiloxane (PDMS)) and operates in a pneumatic manner that is harmless to the living body, has been experimentally validated using 3D-printed soluble molds and supports. Typical planar microfabrication techniques for flexible pneumatic actuators with complex geometries generally have inherent design limitations owing to the manner in which 2D thin films are stacked and require multiple lithographic and alignment steps. In this study, micro bellow actuators with 3D structures that cannot be fabricated using the existing softlithography techniques were designed by simulating the mechanical behavior of the actuator based on the nonlinear elastic properties of PDMS. The subsequently designed 3D-printed soluble-mold technique was used to fabricate the bellow actuators with a 10 µm resolution, while taking into consideration the printing quality, which depends on the printing direction and layer thickness of the 3D printer. On evaluating the operating performance, the micro bellow actuator showed a displacement of 1540 µm at the applied pneumatic pressure of 60 kPa and can apply a force of 0.14 N. Even after 10 000 repetitive operations, the change in the operating characteristic was less than 0.44%. It was also demonstrated that fast prototyping of actuators within 48 h is possible without any process revision, even with variable design changes or other soft polymer materials. The reported fabrication technique is a superior approach for fabricating 3D, sealed, soft pneumatic actuators for micro, soft robot applications.

Characterization of 3D-printed lenses and diffraction gratings made by DLP additive manufacturing

PurposeAn Autodesk Ember three-dimensional (3D) printer was used to print optical components from Clear PR48 photocurable resin. The cured PR48 was characterized by the per cent of light transmitted and the index of refraction, which was measured with a prism spectrometer. Lenses and diffraction gratings were also printed and characterized. The focal length of the printed lenses agreed with predictions based on the thin lens equation. The periodicity and effective slit width of the printed gratings were determined from both optical micrographs and fits to the Fraunhofer diffraction equation. This study aims to demonstrate the advantages offered by a layer-by-layer DLP printing process for the manufacture of optical components for use in the visible region of the electromagnetic spectrum.Design/methodology/approachA 3D printer was used to print both lenses and diffraction gratings from Standard Clear PR48 photocurable resin. The manufacturing process of the lenses and the diffraction gratings differ mainly in the printing angle with respect to the printer x-y-axes. The transmission diffraction gratings studied here were manufactured with nominal periodicities of 10, 25 and 50 µm. The aim of this study was to optically determine the effective values for the distance between slits, d, and the effective width of the slits, w, and to compare these values with the printed layer thickness.FindingsThe normalized diffraction patterns measured in this experiment for the printed gratings with layer thickness of 10, 25 and 50 µm are shown by the solid dots in Figures 8(a)-(c). Also shown as a red solid line are the fits to the experimental diffraction data. The effective values of d and w obtained from fitting the data are compared to the nominal layer thickness of the printed gratings. The effective distance between slits required to fit the diffraction patterns are well approximated by the printed layer thickness to within 14, 4 and 16 per cent for gratings with a nominal 10, 25 and 50 µm layer thickness, respectively.Research limitations/implicationsChromatic aberration is present in all polymer lenses, and the authors have not attempted to characterize it in this study. These materials could be used for achromatic lenses if paired with a crown-type material in an achromatic doublet configuration, because this would correct the chromatic aberration issues. It is worthwhile to compare the per cent transmission in cured PR48 resin (approximately 80 per cent) to the percent transmission found in common optical materials like BK7 (approximately 92 per cent) over the visible region. The authors attribute the lower transmission in PR48 to a combination of surface scattering and increased absorption. At the present time, the authors do not know what fraction of the lower transmission is related to the surface quality resulting from sample polishing.Practical implicationsThere are inherent limitations to the 3D manufacturing process that affect the performance of lenses. Approximations to a curved surface in the design software, the printing resolution of the Autodesk Ember printer and the anisotropy due to printing in layers are believed to be the main issues. The performance of the lenses is also affected by internal imperfections in the printed material, in particular the presence of bubbles and the inclusion of debris like dust or fibers suspended in air. In addition, the absorption of wavelengths in the blue/ultraviolet produces an undesirable yellowing in any printed part.Originality/valueOne of the most interesting results from this study was the manufacture of diffraction gratings using 3D printing. An analysis of the diffraction pattern produced by these printed gratings yielded estimates for the slit periodicity and effective slit width. These gratings are unique because the effective slit width fills the entire volume of the printed part. This aspect makes it possible to integrate two or more optical devices in a single printed part. For example, a lens combined with a diffraction grating now becomes possible.

Research on an automatic leveling method with a feedback mode for a parallel 3D printer

PurposeThe purpose of this study is to propose an automatic leveling method for a printing platform based on a three-point coordinate feedback. The proposed method is used in fused deposition modeling additive manufacturing systems. The coordinate error of the leveled plane is constrained to within  ± 0.2 mm, which is less than the printed layer thickness.Design/methodology/approachFirst, the model of the forward and inverse solutions of the parallel arm is obtained based on the principles of vector algebra. Second, the automatic leveling mechanism for collecting the z-coordinate is designed. The best position of the virtual origin plane is obtained by comparing the z-coordinates of the test points. Finally, after making multiple adjustments through a closed-loop z-coordinate feedback, the parallelism of the printing plane and the virtual origin plane is limited to an effective range.FindingsThe experimental results show that after three leveling attempts, the z-coordinate of the test points can be constrained to within  ± 0.2 mm, which shows that this method can effectively achieve automatic leveling in a delta three-dimensional (3D) printer.Originality/valueThis study presents a novel and distinctive delta 3D printer leveling system by designing a leveling mechanism and a leveling algorithm. The method uses a closed-loop feedback mode to make the leveling process simple, convenient and efficient without requiring major changes to the printer. The error after leveling is less than the printed layer thickness, which fully guarantees the accuracy of the leveling process.