Multi-jet Modelling Research Articles

Developing Rib Bone Surrogates for High Dynamic Impact Assessment with Additive Manufacturing and Post-mortem Human Subjects (PMHS)-Based Evaluation

The conception of ballistic personal protective equipment requires a comprehensive understanding of the human body’s response to dynamic loads. The objective of this study is to develop rib bone surrogates enhancing new anthropomorphic test devices for personal protective equipment evaluation at high dynamic impacts. These are fabricated with additive manufacturing and compared to post-mortem human subjects (PMHS) data from literature. The 5th rib of the finite element Global Human Body Model Consortium (GHBMC) male 50th percentile (M50) model was extracted and transferred to a CAD model. This CAD model was divided into 30 sections with specific cortical bone thicknesses in all directions (caudal, cranial, cutaneous and pleural) from an equivalent rib of an M50 PMHS. Three different additive manufacturing technologies (direct metal laser melting, fused filament fabrication and multi jet modeling) were used to reproduce the M50 PMHS 5th rib surrogate. A total of 57 specimens were dynamically (500 mm/s) loaded to failure in a bending scenario imitating a frontal thoracic impact. Force, displacement, stiffness, and energy at failure were determined. Also, the strain distribution using 3D digital image correlation was recorded and compared to PMHS data from literature. The rib surrogates show deviations from the PMHS characteristic values. Nevertheless, there are also common characteristics in key variables to certain age groups of the PMHS data, which will facilitate the further development and improvement of adequate surrogates for a more realistic representation of the human body’s response to high dynamic loads.

Application-inspired additive manufacturing of Raman optics

While additive manufacturing (AM) enables the production of versatile optical components, the limited knowledge of manufacturing processes makes the development of accurate simulation tools and evaluation criteria challenging. In this work, we present a novel approach to address the specific challenges in the AM of optics by designing and fabricating freeform probe lenses for Raman Spectroscopy (RS) using the Multi-Jet Modeling (MJM) printing process. We successfully integrate the lenses into an RS system and demonstrate their performance in detecting melamine with a maximum signal-to-noise ratio of 164+16−14. We outline the capabilities and limitations of the AM process and adapt simulations to reveal the potential impact of manufacturing tolerances and diffraction effects on layered optical components. Based on our results, we highlight the potential to develop novel design standards for the AM of optics, providing a platform for further exploration and investigation.

Students' perception of three-dimensionally printed teeth in endodontic training.

In endodontic education, there is a need for thorough training prior to students embarking on clinical treatment. The aim of this study was to use three-dimensional printing technology to create a new model and to compare its suitability for training purposes with resin blocks and extracted teeth. Multi-jet-modelling (MJM) produced the 3D model replicating a common difficulty in root-canal morphology. An evaluation study comprising 88students was run in the sixth semester (summer 2018 and winter 2018/2019). A new questionnaire assessed students' perception of training models and educational environment. Welch's t-test analysed significant differences. The most pronounced differences between models were noted when rating material hardness, radiopacity, root-canal configuration and suitability for practising. Students estimated their learning outcome as greater with 3D-printed teeth compared to resin blocks. Three-dimensionally printed teeth received significantly lower ratings with regard to enthusiasm, the learning of fine motor skills and spatial awareness, when compared to human teeth (p≤.001). However, 3D-printed teeth were appreciated for additional benefits, such as their cleanliness, availability and standardisation of training opportunities with complex root-canal configurations. Students preferred extracted human teeth to 3D-printed teeth with respect to their physical characteristics and training experience. However, educational advantages may compensate for the shortcomings. The new questionnaire proved both adequate and accurate to assess the models and educational environment in endodontic training. The new 3D-printed teeth enhanced the learning opportunities.

Accuracy of Geometry of Plastic Gear Produced with 3D Printing Technology

The article concerns the accuracy of the geometry of a single-stage gear made of plastic with 3D printing technology. The aim of the paper has been to assess the accuracy of gears made by 3D printing methods. The accuracy assessment has been made in relation to the accuracy of the same steel gears made by machining. Gear virtual solid models, necessary for using 3D printing technology, have been created based on steel gear using Reverse Engineering Technique. Plastic gears have been printed with two 3D Printing methods: Selective Laser Sintering (SLS) and Multi Jet Modeling (MJM) from plastics used in these methods. Gear geometry has been measured using a measuring machine. In order to determine the manufacturing accuracy, the accuracy classes of the geometrical parameters of gear have been used. It has been found out that the manufacturing accuracy for both 3D Printing technology methods is similar but worse than for machining. The obtained results of gears accuracy made by SLS and MJM methods correspond to the International Tolerance (IT) grade 12 or higher. Milling process produce the IT grades indicated. The originality of the work is the study of the accuracy of gears geometry made using two different 3D printing methods. The test results obtained are the basis for conducting research on the impact of individual parameters of 3D printing technology on gears accuracy.

Development of a 3D printed anthropomorphic lung phantom for image quality assessment in CT

PurposeTo design a 3D printed anthropomorphic lung vessel phantom for CT image quality assessment and to evaluate the phantom image and dose characteristics. MethodsAn in-house algorithm generated a vessel tree model, based on human lungs anatomy, which was 3D printed using a multi jet modeling printer (0.25 mm ≤ vessel diameters ≤ 8.25 mm) and inserted in an elliptical holder (thorax surrogate).The phantom was scanned (Toshiba Aquilion Genesis CT) and compared in terms of attenuation (Hounsfield units, HU) and dose characteristics with studies of five patients (normal BMI) and a commercial torso phantom, performed with the same thorax protocol. The pixel value distribution in the lung area was assessed with histograms. To investigate the adjustment of tube current modulation, tube load and CTDI were compared. ResultsThe histogram peaks for respectively vessels and surrounding tissue were at 105 HU and −985 HU (3D printed phantom), at −25 HU and −1000 HU (torso phantom) and at 25 HU and −875 HU (average patient). The contrast between vessels and surrounding was −1090 HU (3D printed), −975 HU (torso phantom), and −900 HU (average patient). The measured HU values (soft tissue and vertebra) were (32 ± 15) HU and (210 ± 71) HU (average patient); (4 ± 4) HU, (390 ± 39) HU (torso phantom) and (119 ± 5) HU, (951 ± 31) HU (3D printed phantom and holder). CTDIvol was (1.9 ± 4.7 mGy) for patients, 1.9 mGy for the torso phantom and 2.1 mGy for the 3D printed lung phantom. ConclusionsAn anthropomorphic 3D printed lung phantom was developed and its CT image and dose characteristics evaluated. The phantom has the potential to provide clinically relevant and reproducible measures of CT image quality.

Highly removable water support for Stereolithography

Current stereolithography (SL) technology can print there-dimensional (3D) objects with high precision and fast speed. However, for a complex computer-aided design (CAD) model, the fabricated structures have a significant amount of additional support structures that are required in order to ensure the model can be fabricated. However, these support structures may be difficult to remove. Even worse, the removal of the support structures may cause unexpected damage to delicate features and leave undesired surface marks. Although some special materials have been utilized in support structures such as water-soluble materials for the fused deposition modeling (FDM) process and wax for the multi-jet modeling (MJM) process, such support materials have not been available for the SL process. In this paper, a novel SL process using highly removable and widely available water as supports is presented. The process uses solid ice to surround the built parts in the layer-by-layer fabrication process. A cooling device is used to freeze the water into ice for each layer. The photocurable resin is spread on ice surface and then solidified by a projection image. Accordingly, a complex 3D object can be fabricated without using traditional support structures. After the fabrication process, the additional ice structure can easily be removed leaving no undesired marks on the bottom surfaces. Two test cases are presented to show the effectiveness of the presented highly removable water support method.

Dynamics of Capillary-Driven Flow in 3D Printed Open Microchannels.

Microchannels have applications in microfluidic devices, patterns for micromolding, and even flexible electronic devices. Three-dimensional (3D) printing presents a promising alternative manufacturing route for these microchannels due to the technology's relative speed and the design freedom it affords its users. However, the roughness of 3D printed surfaces can significantly influence flow dynamics inside of a microchannel. In this work, open microchannels are fabricated using four different 3D printing techniques: fused deposition modeling (FDM), stereolithography (SLA), selective laser sintering, and multi jet modeling. Microchannels printed with each technology are evaluated with respect to their surface roughness, morphology, and how conducive they are to spontaneous capillary filling. Based on this initial assessment, microchannels printed with FDM and SLA are chosen as models to study spontaneous, capillary-driven flow dynamics in 3D printed microchannels. Flow dynamics are investigated over short (∼10-3 s), intermediate (∼1 s), and long (∼102 s) time scales. Surface roughness causes a start-stop motion down the channel due to contact line pinning, while the cross-sectional shape imparted onto the channels during the printing process is shown to reduce the expected filling velocity. A significant delay in the onset of Lucas-Washburn dynamics (a long-time equilibrium state where meniscus position advances proportionally to the square root of time) is also observed. Flow dynamics are assessed as a function of printing technology, print orientation, channel dimensions, and liquid properties. This study provides the first in-depth investigation of the effect of 3D printing on microchannel flow dynamics as well as a set of rules on how to account for these effects in practice. The extension of these effects to closed microchannels and microchannels fabricated with other 3D printing technologies is also discussed.

Tolerance Analysis of 3d-MJM parts according to IT grade

In this study we investigate the dimensional accuracy of 3D printed objects and define the International Tolerance (IT) Grade for the linear sizes of parallel opposite surfaces and the diameter of a cylinder. Eight (8) exact parts were printed by an Objet Eden250 3D printer using the Multi Jet Modelling (MJM) process. The printed objects were measured and their dimensions analysed to define the IT grade of the specific process. MJM is an Additive Manufacturing (AM) or 3D Printing manufacturing process that can be used in place of CNC to save weeks of lead time, allows us to create parts with a superior strength to weight ratio and can significantly improve the efficiency of the completed system. MJM process is used for a great variety of applications on concept models to model performance parts as functional prototypes, jigs and fixtures, manufacturing tooling and sometimes even production parts. The result of this investigation is that the MJM 3D printing process can produce objects with IT11 grade or better, which classify it to the Fits area of IT grades.

Direct rapid prototyping evaluation on multijet and fused deposition modeling patterns for investment casting

The continuation from rapid prototyping into rapid tooling technologies allows speedy fabrication of sacrificial patterns for investment casting process. Direct expendable pattern fabrication with intricate features using rapid prototyping techniques significantly reduces the fabrication cost when associated with single- or low-volume production. During investment casting process, rapid prototyping patterns are subjected to high melting temperatures, high viscosities, and high thermal stress such as dewaxing and shell mold cracking. Furthermore, ceramic shell may cause crack during melting and burning out of the patterns and also incomplete collapsibility. Although rapid prototyping process can build parts with high stiffness rapidly, the part surface suffered a staircase effect and shrinkage during investment casting process solidification. This paper presents a direct approach of multijet modeling and fused deposition modeling on acrylate- and acrylonitrile–butadiene–styrene-based materials to be used as expendable patterns for the investment casting process. Thermal analyses were conducted on the rapid prototyping materials that exhibit mass loss and expansion. Quality assessment and benchmarking were performed between the rapid prototyping and the metal part on accuracy, surface roughness, and part built time. It was found that both the materials have dimensional deviation when employed in investment casting process and acrylate patterns have better surface roughness as compared to acrylonitrile–butadiene–styrene patterns. Additionally, multijet modeling recorded a significantly shorter lead time when more than a single part can be produced during the rapid prototyping process. It was observed that the shell mold after burnout experiences cracking. Results also showed that acrylate-based materials decomposed above 500℃, meanwhile acrylonitrile–butadiene–styrene was above 600℃. Acrylate material had a coefficient of thermal expansion and linear dimensional deviation as compared with acrylonitrile–butadiene–styrene. No ash was observed in the ceramic molds when the part burnout temperatures are above 500℃ acrylate material and 600℃ for acrylonitrile–butadiene–styrene.

Improving the fidelity of aerodynamic probes using additive manufacturing

Purpose – This paper aims to offer the aerodynamic testing community a new procedure for manufacturing high-quality aerodynamic probes suitable for 3D flow measurements with consistent geometry and calibration by taking advantage of the additive manufacturing technology. Design/methodology/approach – The design methodology combines the advantages and flexibilities of computer aided design (CAD)/computer aided manufacturing (CAM) along with the use of computational fluid dynamics to design and analyse suitable probe shapes prior to manufacturing via rapid prototyping. Findings – A viable procedure to design and possibly batch manufacture geometrically accurate pneumatic probes with consistent calibration is shown to be possible through this work. Multi-jet modelling prototyping methods with wax-based support materials are found to be a cost-effective method when clean and long sub-millimetre pressure channels are to be cut. Originality/value – Utilisation of the geometry consistency that is made possible by 3D printing technology for the design and development of pneumatic probes is described. It is suggested that the technique could lead to batch production of identical probes, thus avoiding precious time of a skilled labourer and elaborate individual calibration requirement.

Dimensional accuracy of dental casting patterns created by 3D printers.

Contrary to widespread incise CAD/CAM, little is known about the dental application of 3D printing, especially the possibility of using 3D printing with organic material. The resin patterns of a full crown model were created by four types of 3D printers, a thermofusion device (CX), a digital light processing stereo-lithograph device (B9), a laser stereo-lithograph device (DW) and a multi-jet modeling device (PJ). The dimensional accuracy of the outer and inner diameters and depths of the created model crowns, and the surface roughness of sidewall were investigated. The outer diameters were smaller than the designed value in most conditions. The inner diameters were smaller than the designed value in any enlargement ratio except B9. The depth of CX or B9 tended to become shallower, though that of PJ or DW tended to increase. The surface roughness along the tooth axis direction was greater than that perpendicular to the tooth axis.

Three-dimensional printed millifluidic devices for zebrafish embryo tests

Implementations of Lab-on-a-Chip technologies for in-situ analysis of small model organisms and embryos (both invertebrate and vertebrate) are attracting an increasing interest. A significant hurdle to widespread applications of microfluidic and millifluidic devices for in-situ analysis of small model organisms is the access to expensive clean room facilities and complex microfabrication technologies. Furthermore, these resources require significant investments and engineering know-how. For example, poly(dimethylsiloxane) soft lithography is still largely unattainable to the gross majority of biomedical laboratories willing to pursue development of chip-based platforms. They often turn instead to readily available but inferior classical solutions. We refer to this phenomenon as workshop-to-bench gap of bioengineering science. To tackle the above issues, we examined the capabilities of commercially available Multi-Jet Modelling (MJM) and Stereolithography (SLA) systems for low volume fabrication of optical-grade millifluidic devices designed for culture and biotests performed on millimetre-sized specimens such as zebrafish embryos. The selected 3D printing technologies spanned a range from affordable personal desktop systems to high-end professional printers. The main motivation of our work was to pave the way for off-the-shelf and user-friendly 3D printing methods in order to rapidly and inexpensively build optical-grade millifluidic devices for customized studies on small model organisms. Compared with other rapid prototyping technologies such as soft lithography and infrared laser micromachining in poly(methyl methacrylate), we demonstrate that selected SLA technologies can achieve user-friendly and rapid production of prototypes, superior feature reproduction quality, and comparable levels of optical transparency. A caution need to be, however, exercised as majority of tested SLA and MJM resins were found toxic and caused significant developmental abnormalities in zebrafish embryos. Taken together, our data demonstrate that SLA technologies can be used for rapid and accurate production of devices for biomedical research. However, polymer biotoxicity needs to be carefully evaluated.

Emerging Applications of Bedside 3D Printing in Plastic Surgery.

Modern imaging techniques are an essential component of preoperative planning in plastic and reconstructive surgery. However, conventional modalities, including three-dimensional (3D) reconstructions, are limited by their representation on 2D workstations. 3D printing, also known as rapid prototyping or additive manufacturing, was once the province of industry to fabricate models from a computer-aided design (CAD) in a layer-by-layer manner. The early adopters in clinical practice have embraced the medical imaging-guided 3D-printed biomodels for their ability to provide tactile feedback and a superior appreciation of visuospatial relationship between anatomical structures. With increasing accessibility, investigators are able to convert standard imaging data into a CAD file using various 3D reconstruction softwares and ultimately fabricate 3D models using 3D printing techniques, such as stereolithography, multijet modeling, selective laser sintering, binder jet technique, and fused deposition modeling. However, many clinicians have questioned whether the cost-to-benefit ratio justifies its ongoing use. The cost and size of 3D printers have rapidly decreased over the past decade in parallel with the expiration of key 3D printing patents. Significant improvements in clinical imaging and user-friendly 3D software have permitted computer-aided 3D modeling of anatomical structures and implants without outsourcing in many cases. These developments offer immense potential for the application of 3D printing at the bedside for a variety of clinical applications. In this review, existing uses of 3D printing in plastic surgery practice spanning the spectrum from templates for facial transplantation surgery through to the formation of bespoke craniofacial implants to optimize post-operative esthetics are described. Furthermore, we discuss the potential of 3D printing to become an essential office-based tool in plastic surgery to assist in preoperative planning, developing intraoperative guidance tools, teaching patients and surgical trainees, and producing patient-specific prosthetics in everyday surgical practice.

Comparison of prosthetic models produced by traditional and additive manufacturing methods.

PURPOSEThe purpose of this study was to verify the clinical-feasibility of additive manufacturing by comparing the accuracy of four different manufacturing methods for metal coping: the conventional lost wax technique (CLWT); subtractive methods with wax blank milling (WBM); and two additive methods, multi jet modeling (MJM), and micro-stereolithography (Micro-SLA).MATERIALS AND METHODSThirty study models were created using an acrylic model with the maxillary upper right canine, first premolar, and first molar teeth. Based on the scan files from a non-contact blue light scanner (Identica; Medit Co. Ltd., Seoul, Korea), thirty cores were produced using the WBM, MJM, and Micro-SLA methods, respectively, and another thirty frameworks were produced using the CLWT method. To measure the marginal and internal gap, the silicone replica method was adopted, and the silicone images obtained were evaluated using a digital microscope (KH-7700; Hirox, Tokyo, Japan) at 140X magnification. Analyses were performed using two-way analysis of variance (ANOVA) and Tukey post hoc test (α=.05).RESULTSThe mean marginal gaps and internal gaps showed significant differences according to tooth type (P<.001 and P<.001, respectively) and manufacturing method (P<.037 and P<.001, respectively). Micro-SLA did not show any significant difference from CLWT regarding mean marginal gap compared to the WBM and MJM methods.CONCLUSIONThe mean values of gaps resulting from the four different manufacturing methods were within a clinically allowable range, and, thus, the clinical use of additive manufacturing methods is acceptable as an alternative to the traditional lost wax-technique and subtractive manufacturing.

Application of 3D printing technology in aerodynamic study

3D printing, as an additive process, offers much more than traditional machining techniques in terms of achievable complexity of a model shape. That fact was a motivation to adapt discussed technology as a method for creating objects purposed for aerodynamic testing. The following paper provides an overview of various 3D printing techniques. Four models of a standard NACA0018 aerofoil were manufactured in different materials and methods: MultiJet Modelling (MJM), Selective Laser Sintering (SLS) and Fused Deposition Modeling (FDM). Various parameters of the models have been included in the analysis: surface roughness, strength, details quality, surface imperfections and irregularities as well as thermal properties.

FUNCTIONAL COMPONENTS PRODUCED BY MULTI-JET MODELLING COMBINED WITH ELECTROFORMING AND MACHINING

In fuel cell technology, certain components are used that are responsible for guiding liquid media. When these components are produced by conventional manufacturing, there are often sealing issues, and trouble- and maintenance-free deployment cannot be ensured. Against this background, a new process combination has been developed in a joint project between the University of Duisburg-Essen, the Center for Fuel Cell Technology (ZBT), and the company Galvano-T electroplating forming GmbH. The approach is to combine multi-jet modelling (MJM), electroforming and milling in order to produce a defined external geometry. The wax models are generated on copper base plates and copper-coated to a desirable thickness. Following this, the undefined electroplated surfaces are machined to achieve the desired measurement, and the wax is melted out. This paper presents, first, how this process is technically feasible, then describes how the MJM on a 3-D Systems ThermoJet was adapted to stabilise the process.In the AiF-sponsored ZIM project, existing limits and possibilities are shown and different approaches of electroplating are investigated. This paper explores whether or not activation of the wax structure by a conductive initial layer is required. Using the described process chain, different parts were built: a heat exchanger, a vaporiser, and a reformer (in which pellets were integrated in an intermediate step). In addition, multiple-layer parts with different functions were built by repeating the process combination several times.

The observance of biomechanical effects on the estimation of common ankle foot orthoses in cerebral palsy

Rapid prototyping (RP) is a technique which produce 3D model of a part from the CAD model using the additive manufacturing technology. Unlike the traditional method of manufacturing, in this technique small layers are added on top of one another to form the final part. This allows rapid prototyping to create very complex parts in relatively less time period. In recent years this technique has been applied to medical field.Common RP techniques used in the medical field are Selective Laser Sintering, Fused Deposition Modeling, Multi-Jet Modeling and Stereolithography. But for most of the above methods, the working principle remains the same. The input data for model generation is obtained from Magnetic Resonance Imaging (MRI) or Computer Tomography (CT) scan which is converted to a 3D model by image processing software. This 3D model is converted to STL format which is read by the RP machine by creating thin slices of the model.Clubfoot, a challenging foot deformity generally occurs at birth, is caused by the abnormal posturing of the foot which becomes twisted so that the sole cannot be placed flat on the ground. The treatment for clubfoot should begin immediately, preferably in the first week of birth since the tissues, tendons, ligaments and bones of the new born's foot will yield to gentle pressure over time. The treatment involves manipulations and serial casting for correction and orthosis for maintenance.This paper focuses on the applications of rapid prototyping in designing a corrective orthosis which will replace serial casting in the treatment of Clubfoot in children. Rapid prototyping has proven to facilitate, speed up and improve the quality of procedures and products.

Application of Rapid Prototyping in the Treatment of Clubfoot in Children

Rapid prototyping (RP) is a technique which produce 3D model of a part from the CAD model using the additive manufacturing technology. Unlike the traditional method of manufacturing, in this technique small layers are added on top of one another to form the final part. This allows rapid prototyping to create very complex parts in relatively less time period. In recent years this technique has been applied to medical field.Common RP techniques used in the medical field are Selective Laser Sintering, Fused Deposition Modeling, Multi-Jet Modeling and Stereolithography. But for most of the above methods, the working principle remains the same. The input data for model generation is obtained from Magnetic Resonance Imaging (MRI) or Computer Tomography (CT) scan which is converted to a 3D model by image processing software. This 3D model is converted to STL format which is read by the RP machine by creating thin slices of the model.Clubfoot, a challenging foot deformity generally occurs at birth, is caused by the abnormal posturing of the foot which becomes twisted so that the sole cannot be placed flat on the ground. The treatment for clubfoot should begin immediately, preferably in the first week of birth since the tissues, tendons, ligaments and bones of the new born's foot will yield to gentle pressure over time. The treatment involves manipulations and serial casting for correction and orthosis for maintenance.This paper focuses on the applications of rapid prototyping in designing a corrective orthosis which will replace serial casting in the treatment of Clubfoot in children. Rapid prototyping has proven to facilitate, speed up and improve the quality of procedures and products.

Collapsibility Studies of MJM Acrylate Patterns for Investment Casting

Direct rapid investment casting (IC) is among the favorable and economical casting process due to its flexibility in fabricating any geometrical part features within a shorter lead time. Polymer based materials used in rapid prototyping (RP) technologies are exhibiting significant cost reduction for low volume production and are potentially replacing conventional wax materials as sacrificial patterns in IC process. This paper reports on the collapsibility characteristics of acrylate patterns during the burnout process for IC molds. The acrylate based patterns were fabricated by a Multijet Modelling (MJM) process with hollow internal structure. The MJM patterns were then Slurry procedure were introduced for producing toughest ceramic mould to prevent cracking occurrence. Results showed that the acrylate patterns start to decomposed gradually from the ceramic mold at 350°C and at 600°C, a total clean burnout without any residues and ash content was attained. This study shows that acrylate patterns built from RP technologies are suitable for fabricating ceramic molds and are highly potential in substituting conventional wax for IC process.

Evaluation of Different Internal Structure and Build Orientation for Multijet Modeling Process

Rapid Prototyping (RP) technology has proven its capability to produce complex parts with shorter lead time. This advantage could benefit tremendously in application such as the Investment Casting (IC) process. The focus of the study is the production of sacrificial IC patterns produced using Multijet Modeling (MJM) RP technology. It includes the evaluation of dimensional accuracy and the surface roughness of part with a hollow and quasi hollow inner support patterns. Different internal structure's pattern were developed using CAD software, and the part were fabricated using MJM technique in two different build orientations. Analyses were done using Coordinate Measuring Machine (CMM) and the surface roughness tester. Results show that part built with 90º orientation is better than part built with 0º orientation both in terms of accuracies and roughness. Different internal structure similarly affects the final part quality, though the post processing steps also have their influence, thus making it no clear different among the parts. However, it demonstrated parts with square structure produced the best dimensional accuracy and the part with hatch structure produced the best surface roughness.