On the Analysis of a Compromised Additive Manufacturing System Using Spatio-Temporal Decomposition

Author(s):  
Sakthi Kumar Arul Prakash ◽  
Tobias Mahan ◽  
Glen Williams ◽  
Christopher McComb ◽  
Jessica Menold ◽  
...  

Abstract 3D printing systems have expanded the access to low cost, rapid methods for attaining physical prototypes or products. However, a cyber attack, system error, or operator error on a 3D printing system may result in catastrophic situations, ranging from complete product failure, to small types of defects which weaken the structural integrity of the product, making it unreliable for its intended use. Such defects can be introduced early-on via solid models or through G-codes for printer movements at a later stage. Previous works have studied the use of image classifiers to predict defects in real-time as a print is in progress and also by studying the printed entity once the print is complete. However, a major restriction in the functionality of these methods is the availability of a dataset capturing diverse attacks on printed entities or the printing process. This paper introduces a visual inspection technique that analyzes the amplitude and phase variations of the print head platform arising through induced system manipulations. The method uses an image sequence of a 3D printing process captured via an off the shelf camera to perform an offline multi-scale, multi-orientation decomposition to amplify imperceptible system movements attributable to a change in system parameters. The authors hypothesize that a change in the amplitude envelope and instantaneous phase response as a result of a change in the end effector translational instructions, to be correlated with an AM system compromise. A case study is presented that tests the hypothesis and provides statistical validity in support of the method. The method has the potential to enhance the robustness of cyber-physical systems such as 3D printers that rely on secure, high quality hardware and software to perform optimally.

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Sakthi Kumar Arul Prakash ◽  
Tobias Mahan ◽  
Glen Williams ◽  
Christopher McComb ◽  
Jessica Menold ◽  
...  

Abstract Three-dimensional printing systems have expanded the access to low cost, rapid methods for attaining physical prototypes or products. However, a cyber attack, system error, or operator error on a 3D-printing system may result in catastrophic situations, ranging from complete product failure, to small types of defects which weaken the structural integrity of the product. Such defects can be introduced early-on via solid models or through G-codes for printer movements at a later stage. Previous works have studied the use of image classifiers to predict defects in real-time and offline. However, a major restriction in the functionality of these methods is the availability of a dataset capturing diverse attacks on printed entities or the printing process. This paper introduces an image processing technique that analyzes the amplitude and phase variations of the print head platform arising through induced system manipulations. The method uses an image sequence of the printing process to perform an offline spatio-temporal video decomposition to amplify changes attributable to a change in system parameters. The authors hypothesize that a change in the amplitude envelope and instantaneous phase response as a result of a change in the end-effector translational instructions to be correlated with an AM system compromise. Two case studies are presented, one verifies the hypothesis with statistical evidence in support of the method while the other studies the effectiveness of a conventional tensile test to identify system compromise. The method has the potential to enhance the robustness of cyber-physical systems such as 3D printers.


Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3247
Author(s):  
Shirin Khaki ◽  
Emer Duffy ◽  
Alan F. Smeaton ◽  
Aoife Morrin

Consumer-level 3D printers are becoming increasingly prevalent in home settings. However, research shows that printing with these desktop 3D printers can impact indoor air quality (IAQ). This study examined particulate matter (PM) emissions generated by 3D printers in an indoor domestic setting. Print filament type, brand, and color were investigated and shown to all have significant impacts on the PM emission profiles over time. For example, emission rates were observed to vary by up to 150-fold, depending on the brand of a specific filament being used. Various printer settings (e.g., fan speed, infill density, extruder temperature) were also investigated. This study identifies that high levels of PM are triggered by the filament heating process and that accessible, user-controlled print settings can be used to modulate the PM emission from the 3D printing process. Considering these findings, a low-cost home IAQ sensor was evaluated as a potential means to enable a home user to monitor PM emissions from their 3D printing activities. This sensing approach was demonstrated to detect the timepoint where the onset of PM emission from a 3D print occurs. Therefore, these low-cost sensors could serve to inform the user when PM levels in the home become elevated significantly on account of this activity and furthermore, can indicate the time at which PM levels return to baseline after the printing process and/or after adding ventilation. By deploying such sensors at home, domestic users of 3D printers can assess the impact of filament type, color, and brand that they utilize on PM emissions, as well as be informed of how their selected print settings can impact their PM exposure levels.


2019 ◽  
Vol 56 (4) ◽  
pp. 801-811
Author(s):  
Mircea Dorin Vasilescu

This work are made for determine the possibility of generating the specific parts of a threaded assembly. If aspects of CAD generating specific elements was analysed over time in several works, the technological aspects of making components by printing processes 3D through optical polymerization process is less studied. Generating the threaded appeared as a necessity for the reconditioning technology or made components of the processing machines. To determine the technological aspects of 3D printing are arranged to achieve specific factors of the technological process, but also from the specific elements of a trapezoidal thread or spiral for translate granular material in supply process are determined experimentally. In the first part analyses the constructive generation process of a spiral element. In the second part are identified the specific aspects that can generation influence on the process of realization by 3D DLP printing of the two studied elements. The third part is affected to printing and determining the dimensions of the analysed components. We will determine the specific value that can influence the process of making them in rapport with printing process. The last part is affected by the conclusions. It can be noticed that both the orientation and the precision of generating solid models have a great influence on the made parts.


Author(s):  
Laxmi Poudel ◽  
Chandler Blair ◽  
Jace McPherson ◽  
Zhenghui Sha ◽  
Wenchao Zhou

Abstract While three-dimensional (3D) printing has been making significant strides over the past decades, it still trails behind mainstream manufacturing due to its lack of scalability in both print size and print speed. Cooperative 3D printing (C3DP) is an emerging technology that holds the promise to mitigate both of these issues by having a swarm of printhead-carrying mobile robots working together to finish a single print job cooperatively. In our previous work, we have developed a chunk-based printing strategy to enable the cooperative 3D printing with two fused deposition modeling (FDM) mobile 3D printers, which allows each of them to print one chunk at a time without interfering with the other and the printed part. In this paper, we present a novel method in discretizing the continuous 3D printing process, where the desired part is discretized into chunks, resulting in multi-stage 3D printing process. In addition, the key contribution of this study is the first working scaling strategy for cooperative 3D printing based on simple heuristics, called scalable parallel arrays of robots for 3DP (SPAR3), which enables many mobile 3D printers to work together to reduce the total printing time for large prints. In order to evaluate the performance of the printing strategy, a framework is developed based on directed dependency tree (DDT), which provides a mathematical and graphical description of dependency relationships and sequence of printing tasks. The graph-based framework can be used to estimate the total print time for a given print strategy. Along with the time evaluation metric, the developed framework provides us with a mathematical representation of geometric constraints that are temporospatially dynamic and need to be satisfied in order to achieve collision-free printing for any C3DP strategy. The DDT-based evaluation framework is then used to evaluate the proposed SPAR3 strategy. The results validate the SPAR3 as a collision-free strategy that can significantly shorten the printing time (about 11 times faster with 16 robots for the demonstrated examples) in comparison with the traditional 3D printing with single printhead.


2016 ◽  
Vol 2 (1) ◽  
pp. 44-47 ◽  
Author(s):  
Carolina Cardona ◽  
Abigail H Curdes ◽  
Aaron J Isaacs

Fused filament fabrication (FFF) is one of the most popular additive manufacturing (3D printing) technologies due to the growing availability of low-cost desktop 3D printers and the relatively low cost of the thermoplastic filament used in the 3D printing process. Commercial filament suppliers, 3D printer manufacturers, and end-users regard filament diameter tolerance as an important indicator of the 3D printing quality. Irregular filament diameter affects the flow rate during the filament extrusion, which causes poor surface quality, extruder jams, irregular gaps in-between individual extrusions, and/or excessive overlap, which eventually results in failed 3D prints. Despite the important role of the diameter consistency in the FFF process, few studies have addressed the required tolerance level to achieve highest 3D printing quality. The objective of this work is to develop the testing methods to measure the filament tolerance and control the filament fabrication process. A pellet-based extruder is utilized to fabricate acrylonitrile butadiene styrene (ABS) filament using a nozzle of 1.75 mm in diameter. Temperature and extrusion rate are controlled parameters. An optical comparator and an array of digital calipers are used to measure the filament diameter. The results demonstrate that it is possible to achieve high diameter consistency and low tolerances (0.01mm) at low extrusion temperature (180 °C) and low extrusion rate (10 in/min). 


Fourth Industrial Revolution gave birth to few different technologies, not known until now. One of them is 3D printing. If subtracting manufacturing is part of Industrial Revolution 3, Additive manufacturing is for sure part of Industrial Revolution 4.0. 3D printing has the potential to transform science and technology by creating bespoke, low-cost appliances that previously required dedicated facilities to make. 3D printers are used to initiate chemical reactions by printing the reagents directly into a 3D reactionware matrix, and so put reactionware design, construction and operation under digital control. Some models of 3D Printers can print uniquely shaped sugar confections in flavors such as chocolate, vanilla, mint, cherry, sour apple and watermelon. They can also print custom cake toppers–presumably in the likeness of the guest of honor.


2012 ◽  
Vol 6 (5) ◽  
pp. 618-626 ◽  
Author(s):  
Olaf Diegel ◽  
◽  
Andrew Withell ◽  
Deon de Beer ◽  
Johan Potgieter ◽  
...  

This research was initiated to develop low cost powders that could be used on 3D printers. The paper describes experiments that were undertaken with different compositions of clay-based powders, and different print saturation settings. An unexpected sideeffect of printing ceramic parts was the ability to control the part porosity by varying the powder recipe and print parameters. The cost of clay-based powder was, depending on the specific ingredients used, around US$2.00/Kg.


2020 ◽  
Vol 2020 (5) ◽  
pp. 120-1-120-5
Author(s):  
Ingeborg Tastl ◽  
Alexandra Ju

Designers need to specify the colors for their 3D objects in form of sRGB values, but, given the limitations of the color 3D printing process, they have no idea how those colors chosen on a screen will look once printed in 3D. In addition, HP Inc. wants to showcase the color capabilities of our 3D color printing systems in an effective way. This paper describes an aesthetically pleasing tool to effectively showcase the color capabilities of our color 3D printing systems. It is also a reference color system that enables designers 1) to select colors that are achievable with our printing systems, 2) to interactively composite color palettes for their 3D design and 3) to get the desired printed color in a time and cost-efficient way that minimizes iterations. The system itself consists of a series of subobjects where each sub-object shows how a color looks like when manufactured in different surface orientations. It can be disassembled and used for compositing color palettes for 3D objects, and it is also designed to be manufactured and cleaned fully assembled, showcasing the power of 3D printing.


2017 ◽  
Vol 870 ◽  
pp. 164-169 ◽  
Author(s):  
Cheng Tiao Hsieh

Within this couple of years, a group of skilled people called “Maker” are interested in building everything by themselves. They attempt to develop a small manufacturing environment where allows people to execute a low cost fabrication task. In order to achieve this goal, they utilized flexible and smart manufacturing machines like 3D printers, laser cutter and small CNC. Especially 3D printer, its excellent performances had grasped many government administrators’ attention and developing 3D printing industry has become an important policy of many countries. Some of 3D printing patents have been expired within recent years. This event makes opens sources of 3D printers grow very fast. The Kossel Mini, Rostock and Prusa i3 are the typical examples. All of development kits of the above printers can be freely obtained from the Internet. This event makes a low cost fabrication become possible. However, the quality of their printed parts is dependent on a series of calibrations. The calibrations include defining the dimensions of hard frame of the printer, configuring firmware and setting building parameters of software. In order to let users to go through entire calibrating process, this paper proposed a standard procedure to calibrate Kossel Mini as well as make it print a good quality part.


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