scholarly journals Indirect Temperature Measurement in High Frequency Heating Systems

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2561
Author(s):  
Alexander Oskolkov ◽  
Igor Bezukladnikov ◽  
Dmitriy Trushnikov

One of the biggest challenges of fused deposition modeling (FDM)/fused filament fabrication (FFF) 3D-printing is maintaining consistent quality of layer-to-layer adhesion, and on the larger scale, homogeneity of material inside the whole printed object. An approach for mitigating and/or resolving those problems, based on the rapid and reliable control of the extruded material temperature during the printing process, was proposed. High frequency induction heating of the nozzle with a minimum mass (<1 g) was used. To ensure the required dynamic characteristics of heating and cooling processes in a high power (peak power > 300 W) heating system, an indirect (eddy current) temperature measurement method was proposed. It is based on dynamic analysis over various temperature-dependent parameters directly in the process of heating. To ensure better temperature measurement accuracy, a series-parallel resonant circuit containing an induction heating coil, an approach of desired signal detection, algorithms for digital signal processing and a regression model that determines the dependence of the desired signal on temperature and magnetic field strength were proposed. The testbed system designed to confirm the results of the conducted research showed the effectiveness of the proposed indirect measurement method. With an accuracy of ±3 °C, the measurement time is 20 ms in the operating temperature range from 50 to 350 °C. The designed temperature control system based on an indirect measurement method will provide high mechanical properties and consistent quality of printed objects.

Author(s):  
Arash Alex Mazhari ◽  
Randall Ticknor ◽  
Sean Swei ◽  
Stanley Krzesniak ◽  
Mircea Teodorescu

AbstractThe sensitivity of additive manufacturing (AM) to the variability of feedstock quality, machine calibration, and accuracy drives the need for frequent characterization of fabricated objects for a robust material process. The constant testing is fiscally and logistically intensive, often requiring coupons that are manufactured and tested in independent facilities. As a step toward integrating testing and characterization into the AM process while reducing cost, we propose the automated testing and characterization of AM (ATCAM). ATCAM is configured for fused deposition modeling (FDM) and introduces the concept of dynamic coupons to generate large quantities of basic AM samples. An in situ actuator is printed on the build surface to deploy coupons through impact, which is sensed by a load cell system utilizing machine learning (ML) to correlate AM data. We test ATCAM’s ability to distinguish the quality of three PLA feedstock at differing price points by generating and comparing 3000 dynamic coupons in 10 repetitions of 100 coupon cycles per material. ATCAM correlated the quality of each feedstock and visualized fatigue of in situ actuators over each testing cycle. Three ML algorithms were then compared, with Gradient Boost regression demonstrating a 71% correlation of dynamic coupons to their parent feedstock and provided confidence for the quality of AM data ATCAM generates.


Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1100
Author(s):  
Adam Steckiewicz ◽  
Kornelia Konopka ◽  
Agnieszka Choroszucho ◽  
Jacek Maciej Stankiewicz

In this article, novel 3D printed sensors for temperature measurement are presented. A planar structure of the resistive element is made, utilizing paths of a conductive filament embedded in an elastic base. Both electrically conductive and flexible filaments are used simultaneously during the 3D printing procedure, to form a ready–to–use measuring device. Due to the achieved flexibility, the detectors may be used on curved and irregular surfaces, with no concern for their possible damage. The geometry and properties of the proposed resistance detectors are discussed, along with a printing procedure. Numerical models of considered sensors are characterized, and the calculated current distributions as well as equivalent resistances of the different structures are compared. Then, a nonlinear influence of temperature on the resistance is experimentally determined for the exemplary planar sensors. Based on these results, using first–order and hybrid linear–exponential approximations, the analytical formulae are derived. Additionally, the device to measure an average temperature from several measuring surfaces is considered. Since geometry of the sensor can be designed utilizing presented approach and printed by applying fused deposition modeling, the functional device can be customized to individual needs.


2020 ◽  
Vol 62 (7) ◽  
pp. 727-732
Author(s):  
L. Zárybnická ◽  
D. Machová ◽  
K. Dvořák

Abstract This paper presents the effect of additives on the quality of a product created by 3D print. The product is created by the most widely used 3D printing method - Fused Deposition Modeling (FDM). Polylactic acid (PLA) filaments are tested without and with the addition of carbon fibers or copper. The specimens are characterized by different methods, such as mechanical testing, measuring roughness by digital microscope with a large depth of field and thermal analysis. In fact, FDM is a problematic process with numerous criterions that affect printing quality. Printing parameters such as print temperature, pad temperature, print speed for 3D printing, printing orientation etc. have an important impact on the performance and quality of FDM components. Due to the correct parameters, the product of the required quality with a longer service life is obtained. The results of testing show that the quantity and choice of the right ingredient has a major impact on the mechanical properties and overall quality of the investigated product.


2021 ◽  
Vol 338 ◽  
pp. 01005
Author(s):  
Damian Dzienniak ◽  
Jan Pawlik

Additive manufacturing has been gaining popularity and availability year by year, which has resulted in its dynamic development. The most common 3D printing method as of today, FDM (Fused Deposition Modeling), owing to its peculiarity, does not always guarantee producing objects with low surface roughness. The authors of the present article have taken on the analysis of the impact of FDM printing on the roughness of the filament thus processed. They also investigate the relationship between the roughness of the unprocessed filament (made of polycaprolactam, that is, polyamide 6 or PA6) with admixtures of other materials (carbon fiber, glass fiber) and the surface quality of the manufactured object. The main subject of the analysis is the side surfaces of 3D prints, as it is their quality that is usually directly dependent on many factors connected with the process of the laying of the consecutive layers. The authors check step by step whether there exists a pronounced relationship between the roughness of the original filament material and the roughness of the obtained surface.


2021 ◽  
Vol 27 (11) ◽  
pp. 1-12
Author(s):  
Giovanni Gómez-Gras ◽  
Marco A. Pérez ◽  
Jorge Fábregas-Moreno ◽  
Guillermo Reyes-Pozo

Purpose This paper aims to investigate the quality of printed surfaces and manufacturing tolerances by comparing the cylindrical cavities machined in parts obtained by fused deposition modeling (FDM) with the holes manufactured during the printing process itself. The comparison focuses on the results of roughness and tolerances, intending to obtain practical references when making assemblies. Design/methodology/approach The experimental approach focuses on the comparison of the results of roughness and tolerances of two manufacturing strategies: geometric volumes with a through-hole and the through-hole machined in volumes that were initially printed without the hole. Throughout the study, both alternates are explained to make appropriate recommendations. Findings The study shows the best combinations of technological parameters, both machining and three-dimensional printing, which have been decisive for obtaining successful results. These conclusive results allow enunciating recommendations for use in the industrial environment. Originality/value This paper fulfills an identified need to study the dimensional accuracy of the geometries obtained by additive manufacturing, as no experimental evidence has been found of studies that directly address the problem of the FDM-printed part with geometric and dimensional tolerances and desirable surface quality for assembly.


Author(s):  
Shajahan Bin Maidin ◽  
Zulkeflee Abdullah ◽  
Ting Kung Hieng

One of the disadvantages of fused deposition modeling (FDM) is waste produced during the printing processes. This investigation focuses on using 100% recycled Acrylonitrile Butadiene Styrene (ABS) for the FDM process. The recycling begins with re-granule the waste ABS material and produces it into a new filament. The new recycled filament was used to print the test specimen. Investigation on the mechanical properties and the surface quality of the test specimen and comparison with standard ABS specimen was done. The result shows that the recycled ABS can be produced into filament with 335°C of extrusion temperature and 1.5 mm/s travel speed of the extruder conveyor. The surface roughness of recycled specimen is 6.94% higher than the standard ABS specimen. For ultimate tensile strength, there is a small difference in X and Y orientation between the standard and the recycled ABS specimen which are 22.93% and 19.98%, respectively. However, in Z orientation, it is 52.33% lower. This investigation proves that ABS can be recycled without significantly affecting its mechanical properties.


Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 466 ◽  
Author(s):  
Yiqiao Wang ◽  
Wolf-Dieter Müller ◽  
Adam Rumjahn ◽  
Andreas Schwitalla

In this review, we discuss the parameters of fused deposition modeling (FDM) technology used in finished parts made from polyether ether ketone (PEEK) and also the possibility of printing small PEEK parts. The published articles reporting on 3D printed PEEK implants were obtained using PubMed and search engines such as Google Scholar including references cited therein. The results indicate that although many have been experiments conducted on PEEK 3D printing, the consensus on a suitable printing parameter combination has not been reached and optimized parameters for printing worth pursuing. The printing of reproducible tiny-sized PEEK parts with high accuracy has proved to be possible in our experiments. Understanding the relationships among material properties, design parameters, and the ultimate performance of finished objects will be the basis for further improvement of the quality of 3D printed medical devices based on PEEK and to expand the polymers applications.


Author(s):  
Renkai Huang ◽  
Ning Dai ◽  
Dawei Li ◽  
Xiaosheng Cheng ◽  
Hao Liu ◽  
...  

Surface finish, especially the surface finish of functional features, and build time are two important concerns in additive manufacturing. A suitable part deposition orientation can enhance the surface quality of functional features and reduce the build time. This article proposes a novel method to obtain an optimum part deposition orientation for industrial-grade 3D printing based on fused deposition modeling process by considering two objective functions at a time, namely adaptive feature roughness (the weighted sum of all feature roughnesses) and build time. First, mesh segmentation and level classification of features are carried out. Then, models for evaluation of adaptive feature roughness and build time are established. Finally, a non-dominated sorting genetic algorithm-II based on Compute Unified Device Architecture is used to obtain the Pareto-optimal set. The feasible of the algorithm is evaluated on several examples. Results demonstrate that the proposed parallel algorithm obtains a limiting solution that enhances the surface quality of functional features significantly and reduces average running time by 94.8% compared with the traditional genetic algorithm.


2019 ◽  
Vol 11 (12) ◽  
pp. 168781401989619 ◽  
Author(s):  
Zhiyong Li ◽  
Dawei Zhang ◽  
Liangchen Shao ◽  
Shanling Han

To improve the blockage and printing quality of the color mixing nozzle of fused deposition modeling color 3D printer, the feed parameters of fused deposition modeling color 3D printer were studied by vibration test. The acceleration sensor was fixed up the color mixing nozzle to analyze the vertical vibration of the nozzle. The vibration test of different feed speed, torque, and material were performed under the actual printing condition. Vertical vibration of the nozzle was characterized by an acceleration sensor. The comparative analysis of the actual testing results indicates that the optimum feed parameters are feed torque of triple torque extruder, feed speed of 20 mm/s, and feed material of ABS. Further analysis shows that higher feed torque can be used to improve the printing quality of the color mixing nozzle. The appropriate feed speed of the color 3D printer can not only reduce the accumulation of wire material at a lower speed but also reduce the blockage caused by too-high feed speed. It is proposed that the feed material with smaller flow behavior index and no phase transition in the melting process shows smaller vibration acceleration amplitude.


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