Image-Based Slicing and Tool Path Planning for Hybrid Stereolithography Additive Manufacturing

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Hang Ye ◽  
Chi Zhou ◽  
Wenyao Xu
Keyword(s):  
Laser Scanning ◽  
Tool Path ◽  
High Surface ◽  
Binary Image ◽  
Test Cases ◽  
High Surface Quality ◽  
Binary Images ◽  
2D Pattern ◽  
Slicing Method ◽  
Traditional Approaches

The hybrid stereolithography (SLA) process integrates a laser scanning-based system and a mask projection-based system. Multiple laser paths are used to scan the border of a 2D pattern, whereas a mask image is adopted to solidify the interior area. By integrating merits of two subsystems, the hybrid SLA process can achieve high surface quality without sacrificing productivity. For the hybrid system, closed polygonal contours are required to direct the laser scanning, and a binary image is also needed for the mask projection. We proposed a novel image-based slicing method. This approach can convert a 3D model into a series of binary images directly, and each image is corresponding to the cross section of the model at a specific height. Based on the resultant binary image, we use an image processing method to gradually shrink the pattern in the image. Boundaries of the shrunk image are traced and then restored as polygons to direct the laser spot movement. The final shrunk image serves as the input for the mask projection. Experimental results of test cases demonstrate that the proposed method is substantially more efficient than the traditional approaches. Its accuracy is also studied and discussed.

Image Based Slicing and Tool Path Planning for Hybrid Stereolithography Additive Manufacturing

2016 ◽  
Author(s):  
Hang Ye ◽  
Chi Zhou ◽  
Wenyao Xu
Keyword(s):  
Laser Scanning ◽  
Tool Path ◽  
High Surface ◽  
Binary Image ◽  
Experimental Result ◽  
High Surface Quality ◽  
Binary Images ◽  
Direct Laser ◽  
2D Pattern ◽  
Traditional Approaches

Hybrid stereolithograpgy (SLA) process synthesizes the laser scanning based SLA system and mask projection based SLA system. It adopts laser as the energy source for scanning the border of a 2D pattern, whereas a mask image is used to solidify the interior area. By integrating the merits of the two subsystems, the hybrid SLA process can achieve relatively high surface quality without sacrificing the productivity. For the hybrid system, closed polygon contours are required to direct laser scanning, and a binary image is also needed for mask projection. We proposed a novel image based slicing method. This method can convert the 3D model into a series of binary images directly, and each image is corresponding to the cross-session of the model at a specific height. Based on the resultant binary image, we use image processing method to gradually shrink the image. The contours of shrunk image are traced and then restored as polygons to direct the laser spot movement. The final shrunk image will serve as the input for mask projection. The experimental result of several test cases demonstrate that proposed method is substantially more time-efficient than traditional approaches.

A Direct Tool Path Planning Algorithm for Line Scanning Based Stereolithography

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Chi Zhou
Keyword(s):  
Path Planning ◽  
Laser Scanning ◽  
Tool Path ◽  
Current System ◽  
High Surface ◽  
Tool Path Planning ◽  
Three Dimensional Model ◽  
High Surface Quality ◽  
Planning Algorithm ◽  
Path Planning Algorithm

This paper presents a novel tool path planning approach for polygonal mirror scanning based stereolithography (STL) process. Compared with traditional laser scanning and mask projection based STL process, the polygonal mirror scanning based process can build part with high surface quality and precision without losing the fabrication efficiency. As an emerging additive manufacturing (AM) process, no efficient tool path planning algorithm is available in current system. This paper presents a direct tool path planning algorithm without converting the three-dimensional model into two-dimensional contours. Different test cases are used to verify its efficiency and effectiveness. Compared with the commercial software, the proposed algorithm is several times faster. Physical parts are also built using the tool path generated by the proposed algorithm.

A Direct Tool Path Planning Algorithm for Line Scanning Based Stereolithography

2014 ◽  
Author(s):  
Chi Zhou
Keyword(s):  
Path Planning ◽  
Laser Scanning ◽  
Tool Path ◽  
Current System ◽  
High Surface ◽  
Tool Path Planning ◽  
High Surface Quality ◽  
Efficiency And Effectiveness ◽  
Planning Algorithm ◽  
Path Planning Algorithm

This paper presents a novel tool path planning approach for polygonal mirror scanning based Stereolithography (SL) process. Compared with traditional laser scanning and mask projection based SL process, the polygonal mirror scanning based process can build part with high surface quality and precision without losing the fabrication efficiency. As an emerging additive manufacturing process, no efficient tool path planning algorithm is available in current system. This paper presented a direct tool path planning algorithm without converting the 3-Dimentional model into 2-Dimentional contours. Different test cases are used to verify its efficiency and effectiveness. Compared with the commercial software, the proposed algorithm is several times faster. Physical parts are also built using the tool path generated by the proposed algorithm.

Effect of Implicitly Derived Infill Patterns on Mechanical Properties

2017 ◽  
Author(s):  
Davis W. Adams ◽  
Cameron J. Turner
Keyword(s):  
Mechanical Properties ◽  
Fused Deposition Modeling ◽  
Tool Path ◽  
Stress And Strain ◽  
Test Cases ◽  
Fused Deposition ◽  
Thin Walls ◽  
Strain Data ◽  
Deposition Modeling ◽  
Slicing Method

One of the most important steps in the preprocessing stage of fused deposition modeling is the generation of a set of instructions that control every movement of the tool head, known as GCode, which is created by a slicer software. The tool path is dependent on various user defined inputs including infill pattern, infill density, layer height, and feed rate. All current slicers generate the path explicitly and do not consider certain geometries that will create critical voids such as thin walls and small corners. This work replicates a new implicit slicing method in which functionally derived infill patterns are overlaid onto each layer of a part reducing the possibility of voids and flaws. Further research investigating the effects of varying implicit infill patterns have on mechanical properties is also included. Stress and strain data is gathered for three different test cases, and the resulting mechanical properties for each case are compared.

scholarly journals Development of an Analyzing and Tuning Methodology for the CNC Parameters Based on Machining Performance

2020 ◽  
Vol 10 (8) ◽  
pp. 2702 ◽  
Author(s):  
Ben-Fong Yu ◽  
Jenq-Shyong Chen
Keyword(s):  
High Speed ◽  
Tool Path ◽  
High Surface ◽  
Tracking Error ◽  
Numerical Control ◽  
Machining Performance ◽  
High Surface Quality ◽  
Dynamic Errors ◽  
Proper Values ◽  
Cnc Controller

This paper proposes the development of a tuning methodology which can set the proper values of the Computer Numerical Control (CNC) parameters to achieve the required machining performance. For the conventional operators of machine tools, the CNC parameters were hard to be adjusted to optimal settings, which was a complicated and time-consuming task. To save time in finding optimal CNC parameters, the objective of this research was to develop a practical methodology to tune the CNC parameters effectively for easy implementation in the commercial CNC controller. Firstly, the effect of the CNC parameters in the CNC controller on the tool-path planning was analyzed via experiments. The machining performance was defined in the high-speed (HS) mode, the high-accuracy (HP) mode, and the high-surface-quality (HQ) mode, according to the dynamic errors of several specified paths. Due to the CNC parameters that have a particularly critical effect on the dynamic errors, the relationship between the CNC parameters and the dynamic errors was validated by the measured data. Finally, the tuning procedure defined the anticipated dynamic errors for the three machining modes with the actual machine. The CNC parameters will correspond with anticipated dynamics errors based on several specified paths. The experimental results showed that the HS mode was the fastest to complete the path, and the completion time of the HP and HQ modes were increased by 37% and 6%, respectively. The HP mode had the smallest dynamic errors than other modes, and the dynamic errors of the HS and HQ modes are increased by 66% and 16%. In the HQ mode, the motion oscillation was reduce significantly, and the tracking error of the HS and HP modes were increased by 85% and 28%. The advantage of the methodology is that it simplifies set-up steps of the CNC parameters, making it suitable for practical machine applications.

scholarly journals Experimental investigation of the machining characteristics in diamond wire sawing of unidirectional CFRP

2021 ◽  
Author(s):  
Lukas Seeholzer ◽  
Stefan Süssmaier ◽  
Fabian Kneubühler ◽  
Konrad Wegener
Keyword(s):  
Surface Quality ◽  
Influencing Factors ◽  
Material Properties ◽  
High Surface ◽  
Workpiece Surface ◽  
High Surface Quality ◽  
High Productivity ◽  
Surface Temperatures ◽  
Process Forces ◽  
The Wire

AbstractEspecially for slicing hard and brittle materials, wire sawing with electroplated diamond wires is widely used since it combines a high surface quality with a minimum kerf loss. Furthermore, it allows a high productivity by machining multiple workpieces simultaneously. During the machining operation, the wire/workpiece interaction and thus the material removal conditions with the resulting workpiece quality are determined by the material properties and the process and tool parameters. However, applied to machining of carbon fibre reinforced polymers (CFRP), the process complexity potentially increases due to the anisotropic material properties, the elastic spring back potential of the material, and the distinct mechanical wear due to the highly abrasive carbon fibres. Therefore, this experimental study analyses different combinations of influencing factors with respect to process forces, workpiece surface temperatures at the wire entrance, and the surface quality in wire sawing unidirectional CFRP material. As main influencing factors, the cutting and feed speeds, the density of diamond grains on the wire, the workpiece thickness, and the fibre orientation of the CFRP material are analysed and discussed. For the tested parameter settings, it is found that while the influence of the grain density is negligible, workpiece thickness, cutting and feed speeds affect the process substantially. In addition, higher process forces and workpiece surface temperatures do not necessarily deteriorate the surface quality.

scholarly journals From Macro to Mesoporous ZnO Inverse Opals: Synthesis, Characterization and Tracer Diffusion Properties

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 196
Author(s):  
Shravan Kousik ◽  
Diane Sipp ◽  
Karina Abitaev ◽  
Yawen Li ◽  
Thomas Sottmann ◽  
...  
Keyword(s):  
Open Porosity ◽  
Laser Scanning ◽  
High Surface ◽  
Stop Band ◽  
Correlation Spectroscopy ◽  
Laser Scanning Microscopy ◽  
Added Value ◽  
Confocal Laser ◽  
Inverse Opals ◽  
Mesoporous Zno

Oxide inverse opals (IOs) with their high surface area and open porosity are promising candidates for catalyst support applications. Supports with confined mesoporous domains are of added value to heterogeneous catalysis. However, the fabrication of IOs with mesoporous or sub-macroporous voids (<100 nm) continues to be a challenge, and the diffusion of tracers in quasi-mesoporous IOs is yet to be adequately studied. In order to address these two problems, we synthesized ZnO IOs films with tunable pore sizes using chemical bath deposition and template-based approach. By decreasing the size of polystyrene (PS) template particles towards the mesoporous range, ZnO IOs with 50 nm-sized pores and open porosity were synthesized. The effect of the template-removal method on the pore geometry (spherical vs. gyroidal) was studied. The infiltration depth in the template was determined, and the factors influencing infiltration were assessed. The crystallinity and photonic stop-band of the IOs were studied using X-Ray diffraction and UV-Vis, respectively. The infiltration of tracer molecules (Alexa Fluor 488) in multilayered quasi-mesoporous ZnO IOs was confirmed via confocal laser scanning microscopy, while fluorescence correlation spectroscopy analysis revealed two distinct diffusion times in IOs assigned to diffusion through the pores (fast) and adsorption on the pore walls (slow).

scholarly journals Low-Roughness-Surface Additive Manufacturing of Metal-Wire Feeding with Small Power

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4265
Author(s):  
Bobo Li ◽  
Bowen Wang ◽  
Greg Zhu ◽  
Lijuan Zhang ◽  
Bingheng Lu
Keyword(s):  
Additive Manufacturing ◽  
High Surface ◽  
Deposition Process ◽  
High Energy ◽  
Width Ratio ◽  
Thin Wall ◽  
Small Power ◽  
High Surface Quality ◽  
Wall Structures ◽  
Wire Feed

Aiming at handling the contradiction between power constraint of on-orbit manufacturing and the high energy input requirement of metal additive manufacturing (AM), this paper presents an AM process based on small-power metal fine wire feed, which produces thin-wall structures of height-to-width ratio up to 40 with core-forming power only about 50 W. In this process, thermal resistance was introduced to optimize the gradient parameters which greatly reduces the step effect of the typical AM process, succeeded in the surface roughness (Ra) less than 5 μm, comparable with that obtained by selective laser melting (SLM). After a 10 min electrolyte-plasma process, the roughness of the fabricated specimen was further reduced to 0.4 μm, without defects such as pores and cracks observed. The ultimate tensile strength of the specimens measured about 500 MPa, the relative density was 99.37, and the Vickers hardness was homogeneous. The results show that the proposed laser-Joule wire feed-direct metal deposition process (LJWF-DMD) is a very attractive solution for metal AM of high surface quality parts, particularly suitable for rapid prototyping for on-orbit AM in space.

scholarly journals Investigation on the Surface Quality Obtained during Trochoidal Milling of 6082 Aluminum Alloy

Machines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 75
Author(s):  
Nikolaos E. Karkalos ◽  
Panagiotis Karmiris-Obratański ◽  
Szymon Kurpiel ◽  
Krzysztof Zagórski ◽  
Angelos P. Markopoulos
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Process Parameters ◽  
Manufacturing Industry ◽  
High Surface ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
High Surface Quality ◽  
Trochoidal Milling

Surface quality has always been an important goal in the manufacturing industry, as it is not only related to the achievement of appropriate geometrical tolerances but also plays an important role in the tribological behavior of the surface as well as its resistance to fatigue and corrosion. Usually, in order to achieve sufficiently high surface quality, process parameters, such as cutting speed and feed, are regulated or special types of cutting tools are used. In the present work, an alternative strategy for slot milling is adopted, namely, trochoidal milling, which employs a more complex trajectory for the cutting tool. Two series of experiments were initially conducted with traditional and trochoidal milling under various feed and cutting speed values in order to evaluate the capabilities of trochoidal milling. The findings showed a clear difference between the two milling strategies, and it was shown that the trochoidal milling strategy is able to provide superior surface quality when the appropriate process parameters are also chosen. Finally, the effect of the depth of cut, coolant and trochoidal stepover on surface roughness during trochoidal milling was also investigated, and it was found that lower depths of cut, the use of coolant and low values of trochoidal stepover can lead to a considerable decrease in surface roughness.

Sign in / Sign up

Export Citation Format

Share Document