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Additive manufacturing, or more commonly 3D printing, has been recently established as one of the most advanced technologies for fabricating multi-material parts. In this work, the possibility of manufacturing multi-metal parts by material extrusion process was studied for the first time. Three types of samples, named mixed, coupled and graded, resulting from deposition of two ferrous alloys: high carbon iron and stainless steel 316 L filaments, were successfully printed. After de-binding with different heating rates, they were isothermally sintered in the range of 1310−1400 °C for various holding times in argon atmosphere. Finally, some properties of the final parts, such as relative density, shrinkage, microstructural evolution, and hardness were analyzed. In conclusion, the relative density was measured up to 92 %, and the shrinkage recorded for the samples ranged between 10 % and 40 %. Based on the performed analyses, a relatively homogeneous microstructure was observed in the mixed sample, which indicates that the affordable metal extrusion technique could replace the conventional methods for metallic alloying.
Mehrdad Mousapour; Mika Salmi; Lassi Klemettinen; Jouni Partanen. Feasibility study of producing multi-metal parts by Fused Filament Fabrication (FFF) technique. Journal of Manufacturing Processes 2021, 67, 438 -446.
AMA StyleMehrdad Mousapour, Mika Salmi, Lassi Klemettinen, Jouni Partanen. Feasibility study of producing multi-metal parts by Fused Filament Fabrication (FFF) technique. Journal of Manufacturing Processes. 2021; 67 ():438-446.
Chicago/Turabian StyleMehrdad Mousapour; Mika Salmi; Lassi Klemettinen; Jouni Partanen. 2021. "Feasibility study of producing multi-metal parts by Fused Filament Fabrication (FFF) technique." Journal of Manufacturing Processes 67, no. : 438-446.
Laser powder bed fusion additive manufacturing is used for demanding applications in industries such as aerospace. However, machine-specific, optimized process conditions and parameters are required to assure consistent part quality. In addition, differences in supplied powder can cause variation in the mechanical properties of the final parts. In this paper, the variability in mechanical properties of 316L stainless steel produced with two different laser powder bed fusion machines from two different powder batches was studied by producing an identical set of tensile and impact toughness test specimens. The samples were subjected to stress-relieving, solution annealing and hot isostatic pressing to assess the effectiveness of standardized heat-treatments in reducing variation in the mechanical properties of the built parts. Porosity, microstructure, tensile properties, and impact toughness of the specimens were measured to study the effect of changing the material, machine, and heat treatment. The maximum differences observed between the studied machine-powder combinations were approximately 7% for tensile properties and approximately 20% for impact toughness. HIP reduced the variability in all other studied properties except elongation. All the specimens fulfil the minimum requirements set in ASTM F3184-16 for AM 316L.
Joni Reijonen; Roy Björkstrand; Tuomas Riipinen; Zaiqing Que; Sini Metsä-Kortelainen; Mika Salmi. Cross-testing laser powder bed fusion production machines and powders: Variability in mechanical properties of heat-treated 316L stainless steel. Materials & Design 2021, 204, 109684 .
AMA StyleJoni Reijonen, Roy Björkstrand, Tuomas Riipinen, Zaiqing Que, Sini Metsä-Kortelainen, Mika Salmi. Cross-testing laser powder bed fusion production machines and powders: Variability in mechanical properties of heat-treated 316L stainless steel. Materials & Design. 2021; 204 ():109684.
Chicago/Turabian StyleJoni Reijonen; Roy Björkstrand; Tuomas Riipinen; Zaiqing Que; Sini Metsä-Kortelainen; Mika Salmi. 2021. "Cross-testing laser powder bed fusion production machines and powders: Variability in mechanical properties of heat-treated 316L stainless steel." Materials & Design 204, no. : 109684.
Centralized supply chains (SCs) are prone to disruption, which makes them a risky choice for medical equipment production. Additive manufacturing (AM) allows for production localization and improvements in SC resilience. However, the comparative competitiveness of a localized SC from the time and cost perspective is still unclear. In this study, we investigate the competitiveness of localized medical part AM SCs against centralized ones by analyzing the responsiveness and cost of each SC. We utilize a real-world case study in which an AM service provider supplies medical parts to university medical centers in the Netherlands to construct six scenarios. We also develop a thorough empirical cost formulation for both central and local AM of patient-specific medical parts. The results of scenario analysis show that when utilizing the currently available AM technology, localized SC configurations significantly reduce the delivery time from about 54 to 27 h, but at a 4.3-fold higher cost. Hence, we illustrate that the cost difference between the localized and centralized scenarios can be reduced when state-of-the-art AM machines are utilized, demand volumes increase, and the distances between the SC network nodes expand. Moreover, our scenario analysis confirms that the cost of the measures taken to prevent dust dispersion associated with powder-bed fusion AM has a major impact on the total cost of localized AM SCs for medical parts. The results of this study contribute to the understanding of the relevant factors in deciding whether central or localized SC configurations can be used in the AM production of medical parts. Furthermore, this study provides managerial insights for decision-makers at governments and hospitals as well as AM service providers and AM equipment manufacturers.
Victor Verboeket; Siavash H. Khajavi; Harold Krikke; Mika Salmi; Jan Holmstrom. Additive Manufacturing for Localized Medical Parts Production: A Case Study. IEEE Access 2021, 9, 25818 -25834.
AMA StyleVictor Verboeket, Siavash H. Khajavi, Harold Krikke, Mika Salmi, Jan Holmstrom. Additive Manufacturing for Localized Medical Parts Production: A Case Study. IEEE Access. 2021; 9 (99):25818-25834.
Chicago/Turabian StyleVictor Verboeket; Siavash H. Khajavi; Harold Krikke; Mika Salmi; Jan Holmstrom. 2021. "Additive Manufacturing for Localized Medical Parts Production: A Case Study." IEEE Access 9, no. 99: 25818-25834.
Better visualization of tumor structure and orientation are needed in the postoperative setting. We aimed to assess the feasibility of a system in which oral and oropharyngeal tumors are resected, photographed, 3D modeled, and printed using additive manufacturing techniques. Three patients diagnosed with oral/oropharyngeal cancer were included. All patients underwent preoperative magnetic resonance imaging followed by resection. In the operating room (OR), the resected tissue block was photographed using a smartphone. Digital photos were imported into Agisoft Photoscan to produce a digital 3D model of the resected tissue. Physical models were then printed using binder jetting techniques. The aforementioned process was applied in pilot cases including carcinomas of the tongue and larynx. The number of photographs taken for each case ranged from 63 to 195. The printing time for the physical models ranged from 2 to 9 h, costs ranging from 25 to 141 EUR (28 to 161 USD). Digital photography may be used to additively manufacture models of resected oral/oropharyngeal tumors in an easy, accessible and efficient fashion. The model may be used in interdisciplinary discussion regarding postoperative care to improve understanding and collaboration, but further investigation in prospective studies is required.
Alexandria Irace; Anne Koivuholma; Eero Huotilainen; Jaana Hagström; Katri Aro; Mika Salmi; Antti Markkola; Heli Sistonen; Timo Atula; Antti Mäkitie. Additive Manufacturing of Resected Oral and Oropharyngeal Tissue: A Pilot Study. International Journal of Environmental Research and Public Health 2021, 18, 911 .
AMA StyleAlexandria Irace, Anne Koivuholma, Eero Huotilainen, Jaana Hagström, Katri Aro, Mika Salmi, Antti Markkola, Heli Sistonen, Timo Atula, Antti Mäkitie. Additive Manufacturing of Resected Oral and Oropharyngeal Tissue: A Pilot Study. International Journal of Environmental Research and Public Health. 2021; 18 (3):911.
Chicago/Turabian StyleAlexandria Irace; Anne Koivuholma; Eero Huotilainen; Jaana Hagström; Katri Aro; Mika Salmi; Antti Markkola; Heli Sistonen; Timo Atula; Antti Mäkitie. 2021. "Additive Manufacturing of Resected Oral and Oropharyngeal Tissue: A Pilot Study." International Journal of Environmental Research and Public Health 18, no. 3: 911.
Purpose Although additive manufacturing (AM) has been demonstrated to have significant potential in improving spare part delivery operations and has been adopted to a degree in the aviation and automotive industries, its use in spare part production is still limited in other fields due to a variety of implementation barriers. The purpose of this article is to assess the significance of previously reported barriers in the context of the machine-building industry. Design/methodology/approach Adoption barriers are identified from the literature and formulated as hypotheses, which are verified with a set of focus group interviews consisting of original equipment manufacturers (OEMs), AM service providers and quality inspection and insurance institutions. The results of the interviews are reported qualitatively, and the transcripts of the interviews are subjected to quantitative content analysis. Findings The article identifies distrust in quality, insufficient material and design knowledge among stakeholders and poor availability of design documentation on spare parts as the key barriers of adopting AM in the production of spare parts. The three key barriers are interconnected and training engineers to be proficient in design and material issues as well as producing high-quality design documentation will yield the highest increase in AM implementation in spare parts. Originality/value The article offers a unique approach as it investigates the subjective views of a cross-organizational group of industrial actors involved in the machine-building industry. The article contributes to the theory of digital spare parts by verifying and rejecting presented barriers of AM implementation and how they are interconnected.
Sergei Chekurov; Mika Salmi; Victor Verboeket; Tuomas Puttonen; Tuomas Riipinen; Antti Vaajoki. Assessing industrial barriers of additively manufactured digital spare part implementation in the machine-building industry: a cross-organizational focus group interview study. Journal of Manufacturing Technology Management 2021, 32, 909 -931.
AMA StyleSergei Chekurov, Mika Salmi, Victor Verboeket, Tuomas Puttonen, Tuomas Riipinen, Antti Vaajoki. Assessing industrial barriers of additively manufactured digital spare part implementation in the machine-building industry: a cross-organizational focus group interview study. Journal of Manufacturing Technology Management. 2021; 32 (4):909-931.
Chicago/Turabian StyleSergei Chekurov; Mika Salmi; Victor Verboeket; Tuomas Puttonen; Tuomas Riipinen; Antti Vaajoki. 2021. "Assessing industrial barriers of additively manufactured digital spare part implementation in the machine-building industry: a cross-organizational focus group interview study." Journal of Manufacturing Technology Management 32, no. 4: 909-931.
Medical imaging often presents objects in three-dimensional (3D) form to provide better visual understanding. In contrast, histopathology is typically presented as two-dimensional (2D). Our objective was to present the tumor dimensions in 3D by creating a 3D digital model of it and so demonstrate the location of the tumor and the histological slices within the surgical soft tissue resection specimen. We developed a novel method for modeling a tongue squamous cell carcinoma using commonly available instruments. We established our 3D-modeling method by recognizing and solving challenges that concern the selection of the direction of histological slices. Additional steps to standard handling included scanning the specimen prior to grossing and modeling the carcinoma, which required only a table scanner and modeling software. We present challenges and their solutions in modeling the resection specimen and its histological slices. We introduce a finished 3D model of a soft tissue resection specimen and the actual tumor as well as its histopathological grossing sites in 3D digital and printed form. Our novel method provides steps to create a digital model of soft tissue resection specimen and the tumor within. To our knowledge, this is the first attempt to present histopathological margins of a tongue tumor in 3D form, whereas previously, only 2D has been available. The creation of the 3D model does not call for predetermined grossing directions for the pathologist. In addition, it provides a crucial initiative to enhance oncological management. The method allows a better visual understanding of tumor margins, topography, and orientation. It thus provides a tool for an improved postoperative assessment and aids, for example, in the discussion of the need for additional surgery and adjuvant therapy.
Anne Koivuholma; Katri Aro; Antti Mäkitie; Mika Salmi; Tuomas Mirtti; Jaana Hagström; Timo Atula. Three-Dimensional Presentation of Tumor Histopathology: A Model Using Tongue Squamous Cell Carcinoma. Diagnostics 2021, 11, 109 .
AMA StyleAnne Koivuholma, Katri Aro, Antti Mäkitie, Mika Salmi, Tuomas Mirtti, Jaana Hagström, Timo Atula. Three-Dimensional Presentation of Tumor Histopathology: A Model Using Tongue Squamous Cell Carcinoma. Diagnostics. 2021; 11 (1):109.
Chicago/Turabian StyleAnne Koivuholma; Katri Aro; Antti Mäkitie; Mika Salmi; Tuomas Mirtti; Jaana Hagström; Timo Atula. 2021. "Three-Dimensional Presentation of Tumor Histopathology: A Model Using Tongue Squamous Cell Carcinoma." Diagnostics 11, no. 1: 109.
Additive manufacturing (AM, 3D printing) is used in many fields and different industries. In the medical and dental field, every patient is unique and, therefore, AM has significant potential in personalized and customized solutions. This review explores what additive manufacturing processes and materials are utilized in medical and dental applications, especially focusing on processes that are less commonly used. The processes are categorized in ISO/ASTM process classes: powder bed fusion, material extrusion, VAT photopolymerization, material jetting, binder jetting, sheet lamination and directed energy deposition combined with classification of medical applications of AM. Based on the findings, it seems that directed energy deposition is utilized rarely only in implants and sheet lamination rarely for medical models or phantoms. Powder bed fusion, material extrusion and VAT photopolymerization are utilized in all categories. Material jetting is not used for implants and biomanufacturing, and binder jetting is not utilized for tools, instruments and parts for medical devices. The most common materials are thermoplastics, photopolymers and metals such as titanium alloys. If standard terminology of AM would be followed, this would allow a more systematic review of the utilization of different AM processes. Current development in binder jetting would allow more possibilities in the future.
Mika Salmi. Additive Manufacturing Processes in Medical Applications. Materials 2021, 14, 191 .
AMA StyleMika Salmi. Additive Manufacturing Processes in Medical Applications. Materials. 2021; 14 (1):191.
Chicago/Turabian StyleMika Salmi. 2021. "Additive Manufacturing Processes in Medical Applications." Materials 14, no. 1: 191.
Design for additive manufacturing is adopted to help solve problems inherent to attaching active personal sampler systems to workers for monitoring their breathing zone. A novel and parametric 3D printable clip system was designed with an open source Computer-aided design (CAD) system and was additively manufactured. The concept was first tested with a simple clip design, and when it was found to be functional, the ability of the innovative and open source design to be extended to other applications was demonstrated by designing another tooling system. The clip system was tested for mechanical stress test to establish a minimum lifetime of 5000 openings, a cleaning test, and a supply chain test. The designs were also tested three times in field conditions. The design cost and functionalities of the clip system were compared to commercial systems. This study presents an innovative custom-designed clip system that can aid in attaching different tools for personal exposure measurement to a worker’s harness without hindering the operation of the worker. The customizable clip system opens new possibilities for occupational health professionals since the basic design can be altered to hold different kinds of samplers and tools. The solution is shared using an open source methodology.
Kirsi Kukko; Jan Sher Akmal; Anneli Kangas; Mika Salmi; Roy Björkstrand; Anna-Kaisa Viitanen; Jouni Partanen; Joshua M. Pearce. Additively Manufactured Parametric Universal Clip-System: An Open Source Approach for Aiding Personal Exposure Measurement in the Breathing Zone. Applied Sciences 2020, 10, 6671 .
AMA StyleKirsi Kukko, Jan Sher Akmal, Anneli Kangas, Mika Salmi, Roy Björkstrand, Anna-Kaisa Viitanen, Jouni Partanen, Joshua M. Pearce. Additively Manufactured Parametric Universal Clip-System: An Open Source Approach for Aiding Personal Exposure Measurement in the Breathing Zone. Applied Sciences. 2020; 10 (19):6671.
Chicago/Turabian StyleKirsi Kukko; Jan Sher Akmal; Anneli Kangas; Mika Salmi; Roy Björkstrand; Anna-Kaisa Viitanen; Jouni Partanen; Joshua M. Pearce. 2020. "Additively Manufactured Parametric Universal Clip-System: An Open Source Approach for Aiding Personal Exposure Measurement in the Breathing Zone." Applied Sciences 10, no. 19: 6671.
The purpose of this article is to present a design for additive manufacturing assignment focused on creativity rather than functionality and to analyze its results (N = 70) acquired during five years. The assignment teaches the unique advantages of additive manufacturing to engineering students and encourages learning from failure to achieve designs that are possible to manufacture. The students of the course assignment were in their fourth year of studies and pursued master’s degrees in mechanical engineering. The article presents the design for additive manufacturing course assignment in enough detail for it to be applied by educators in the sphere of additive manufacturing. The result assessment is performed with a numerical method and a jury method. The statistical significance of the correlation of the numerical approach with the jury approach is evaluated. The study conducts a multi-point creativity assessment on a large sample of parts created by students acquired over five years with the support of 10 jury members. This assessment process gives insight on how creativity in design for additive manufacturing can be quantified and can be readily applied by educators. The data of the jury evaluation are verified with an interrater reliability evaluation. Our results indicate that conducting the course assignment for multiple years increases the quality of the student work. The improvement of the results is theorized to be partly due to students gaining inspiration from an increasing number of high-quality parts from previous years of the assignment. The numerical method of result assessment can be used for evaluation when resources are scarce; however, the jury method should be used if possible.
Sergei Chekurov; Meng Wang; Mika Salmi; Jouni Partanen. Development, Implementation, and Assessment of a Creative Additive Manufacturing Design Assignment: Interpreting Improvements in Student Performance. Education Sciences 2020, 10, 156 .
AMA StyleSergei Chekurov, Meng Wang, Mika Salmi, Jouni Partanen. Development, Implementation, and Assessment of a Creative Additive Manufacturing Design Assignment: Interpreting Improvements in Student Performance. Education Sciences. 2020; 10 (6):156.
Chicago/Turabian StyleSergei Chekurov; Meng Wang; Mika Salmi; Jouni Partanen. 2020. "Development, Implementation, and Assessment of a Creative Additive Manufacturing Design Assignment: Interpreting Improvements in Student Performance." Education Sciences 10, no. 6: 156.
The COVID-19 pandemic has caused a surge of demand for medical supplies and spare parts, which has put pressure on the manufacturing sector. As a result, 3D printing communities and companies are currently operating to ease the breakdown in the medical supply chain. If no parts are available, 3D printing can potentially be used to produce time-critical parts on demand such as nasal swabs, face shields, respirators, and spares for ventilators. A structured search using online sources and feedback from key experts in the 3D printing area was applied to highlight critical issues and to suggest potential solutions. The prescribed outcomes were estimated in terms of cost and productivity at a small and large scale. This study analyzes the number and costs of parts that can be manufactured with a single machine within 24 h. It extrapolates this potential with the number of identical 3D printers in the world to estimate the global potential that can help practitioners, frontline workers, and those most vulnerable during the pandemic. It also proposes alternative 3D printing processes and materials that can be applicable. This new unregulated supply chain has also opened new questions concerning medical certification and Intellectual property rights (IPR). There is also a pressing need to develop new standards for 3D printing of medical parts for the current pandemic, and to ensure better national resilience.
Mika Salmi; Jan Sher Akmal; Eujin Pei; Jan Wolff; Alireza Jaribion; Siavash H. Khajavi. 3D Printing in COVID-19: Productivity Estimation of the Most Promising Open Source Solutions in Emergency Situations. Applied Sciences 2020, 10, 4004 .
AMA StyleMika Salmi, Jan Sher Akmal, Eujin Pei, Jan Wolff, Alireza Jaribion, Siavash H. Khajavi. 3D Printing in COVID-19: Productivity Estimation of the Most Promising Open Source Solutions in Emergency Situations. Applied Sciences. 2020; 10 (11):4004.
Chicago/Turabian StyleMika Salmi; Jan Sher Akmal; Eujin Pei; Jan Wolff; Alireza Jaribion; Siavash H. Khajavi. 2020. "3D Printing in COVID-19: Productivity Estimation of the Most Promising Open Source Solutions in Emergency Situations." Applied Sciences 10, no. 11: 4004.
The scope of this research is to characterize and optimize the vibration-assisted ball burnishing of additively manufactured 18% Nickel Maraging steel for tooling applications. We evaluate the suitability of vibration-assisted ball burnishing as an alternative method to post-process additively manufactured tool steel. To do so, we assessed a single pass post-processing technique to enhance surface roughness, surface micro-hardness, and residual stress state. Results show that ultrasonic burnishing after age hardening functionalizes additively manufactured surfaces for tooling applications creating a beneficial compressive residual stress state on the surface. The surface micro-hardness (HV1) varied between 503 and 630 HV1, and the average surface roughness (Ra) varied between 1.31 and 0.14 µm, depending on process parameters with a maximum productivity rate of 41.66 cm2/min making it an alternative approach to functionalize additively manufactured tool components.
Inigo Flores Ituarte; Mika Salmi; Suvi Papula; Juha Huuki; Bjorn Hemming; Eric Coatanea; Seppo Nurmi; Iikka Virkkunen. Surface Modification of Additively Manufactured 18% Nickel Maraging Steel by Ultrasonic Vibration-Assisted Ball Burnishing. Journal of Manufacturing Science and Engineering 2020, 142, 1 -38.
AMA StyleInigo Flores Ituarte, Mika Salmi, Suvi Papula, Juha Huuki, Bjorn Hemming, Eric Coatanea, Seppo Nurmi, Iikka Virkkunen. Surface Modification of Additively Manufactured 18% Nickel Maraging Steel by Ultrasonic Vibration-Assisted Ball Burnishing. Journal of Manufacturing Science and Engineering. 2020; 142 (7):1-38.
Chicago/Turabian StyleInigo Flores Ituarte; Mika Salmi; Suvi Papula; Juha Huuki; Bjorn Hemming; Eric Coatanea; Seppo Nurmi; Iikka Virkkunen. 2020. "Surface Modification of Additively Manufactured 18% Nickel Maraging Steel by Ultrasonic Vibration-Assisted Ball Burnishing." Journal of Manufacturing Science and Engineering 142, no. 7: 1-38.
In craniomaxillofacial surgical procedures, an emerging practice adopts the preoperative virtual planning that uses medical imaging (computed tomography), 3D thresholding (segmentation), 3D modeling (digital design), and additive manufacturing (3D printing) for the procurement of an end-use implant. The objective of this case study was to evaluate the cumulative spatial inaccuracies arising from each step of the process chain when various computed tomography protocols and thresholding values were independently changed. A custom-made quality assurance instrument (Phantom) was used to evaluate the medical imaging error. A sus domesticus (domestic pig) head was analyzed to determine the 3D thresholding error. The 3D modeling error was estimated from the computer-aided design software. Finally, the end-use implant was used to evaluate the additive manufacturing error. The results were verified using accurate measurement instruments and techniques. A worst-case cumulative error of 1.7 mm (3.0%) was estimated for one boundary condition and 2.3 mm (4.1%) for two boundary conditions considering the maximum length (56.9 mm) of the end-use implant. Uncertainty from the clinical imaging to the end-use implant was 0.8 mm (1.4%). This study helps practitioners establish and corroborate surgical practices that are within the bounds of an appropriate accuracy for clinical treatment and restoration.
Jan Sher Akmal; Mika Salmi; Björn Hemming; Linus Teir; Anni Suomalainen; Mika Kortesniemi; Jouni Partanen; Antti Lassila. Cumulative Inaccuracies in Implementation of Additive Manufacturing Through Medical Imaging, 3D Thresholding, and 3D Modeling: A Case Study for an End-Use Implant. Applied Sciences 2020, 10, 2968 .
AMA StyleJan Sher Akmal, Mika Salmi, Björn Hemming, Linus Teir, Anni Suomalainen, Mika Kortesniemi, Jouni Partanen, Antti Lassila. Cumulative Inaccuracies in Implementation of Additive Manufacturing Through Medical Imaging, 3D Thresholding, and 3D Modeling: A Case Study for an End-Use Implant. Applied Sciences. 2020; 10 (8):2968.
Chicago/Turabian StyleJan Sher Akmal; Mika Salmi; Björn Hemming; Linus Teir; Anni Suomalainen; Mika Kortesniemi; Jouni Partanen; Antti Lassila. 2020. "Cumulative Inaccuracies in Implementation of Additive Manufacturing Through Medical Imaging, 3D Thresholding, and 3D Modeling: A Case Study for an End-Use Implant." Applied Sciences 10, no. 8: 2968.
Undoubtedly, the main advantage of the additive manufacture technology is to allow building miniature structural parts with a large degree of complexity such as to replicate structural details of real-scale marine structures. This work presents a new technique for reproducing the structural response of large-scale thin-walled metallic structures when subjected to crushing loadings by using scaled-down additive manufactured models. This technique couples scaling laws for strain rate sensitive materials and a thickness distortion technique based on the structural collapse mode. In order to validate this coupled technique, the structural response of a large-scale crushing test of a web girder structure was experimentally replicated by using a 1/40 scale reduction model. The results and conclusions summarize the prospects and limitations of additive manufacturing of miniature complex marine structures for structural purposes and crashworthiness verification.
Miguel A.G. Calle; Mika Salmi; Leonardo M. Mazzariol; Marcilio Alves; Pentti Kujala. Additive manufacturing of miniature marine structures for crashworthiness verification: Scaling technique and experimental tests. Marine Structures 2020, 72, 102764 .
AMA StyleMiguel A.G. Calle, Mika Salmi, Leonardo M. Mazzariol, Marcilio Alves, Pentti Kujala. Additive manufacturing of miniature marine structures for crashworthiness verification: Scaling technique and experimental tests. Marine Structures. 2020; 72 ():102764.
Chicago/Turabian StyleMiguel A.G. Calle; Mika Salmi; Leonardo M. Mazzariol; Marcilio Alves; Pentti Kujala. 2020. "Additive manufacturing of miniature marine structures for crashworthiness verification: Scaling technique and experimental tests." Marine Structures 72, no. : 102764.
Increasingly, metal parts made by additive manufacturing are produced using powder bed fusion (PBF). In this paper we report upon the combined effects of PBF parameters, including power and scan speed, in layer-by-layer manufacturing of gas atomized non-modulated (NM) Ni-Mn-Ga alloy. The effects of process parameters upon PBF is studied by applying nine different parameter sets in the as-printed state and after homogenization and ordering. The chemical composition of the samples is analyzed using EDX attached to an SEM, and the crystal structures are determined by X-ray diffraction. The phase transformation temperatures are measured using a low-field ac susceptibility measurement system and the magnetic properties are measured with a vibrating sample magnetometer (VSM). Before the heat-treatment, all as-printed samples showed paramagnetic behavior with low magnetization and no phase transformations could be observed in the susceptibility measurements. After annealing, the samples recovered the ferromagnetic behavior with comparable magnetization to annealed gas atomized powder. The as-printed samples were composed of a mixture of different crystal structures. However, after annealing the original NM structure with a = b = 5.47 Å and c = 6.66 Å with a c/a -ratio of 1.22 was recovered and crystallographic twins could be observed in an SEM.
Frans Nilsén; Iñigo Flores Ituarte; Mika Salmi; Jouni Partanen; Simo-Pekka Hannula. Effect of process parameters on non-modulated Ni-Mn-Ga alloy manufactured using powder bed fusion. Additive Manufacturing 2019, 28, 464 -474.
AMA StyleFrans Nilsén, Iñigo Flores Ituarte, Mika Salmi, Jouni Partanen, Simo-Pekka Hannula. Effect of process parameters on non-modulated Ni-Mn-Ga alloy manufactured using powder bed fusion. Additive Manufacturing. 2019; 28 ():464-474.
Chicago/Turabian StyleFrans Nilsén; Iñigo Flores Ituarte; Mika Salmi; Jouni Partanen; Simo-Pekka Hannula. 2019. "Effect of process parameters on non-modulated Ni-Mn-Ga alloy manufactured using powder bed fusion." Additive Manufacturing 28, no. : 464-474.
Glottal inverse filtering (GIF) refers to technology to estimate the source of voiced speech, the glottal flow, from speech signals. When a new GIF algorithm is proposed, its accuracy needs to be evaluated. However, the evaluation of GIF is problematic because the ground truth, the real glottal volume velocity signal generated by the vocal folds, cannot be recorded non-invasively from natural speech. This absence of the ground truth has been circumvented in most previous GIF studies by using simple linear source-filter synthesis techniques with known artificial glottal flow models and all-pole vocal tract filters. Moreover, in a few previous studies, physical modeling of speech production has been utilized in synthesis of the test data for GIF evaluation. The evaluation strategy in previous GIF studies is, however, scattered between individual investigations and there is currently a lack of a coherent, common platform to be used in GIF evaluation. In order to address this shortcoming, the current study introduces a new environment, called OPENGLOT, for GIF evaluation. The key ideas of OPENGLOT are twofold: the environment is versatile (i.e., it provides different types of test signals for GIF evaluation) and open (i.e., the system can be used by anyone who wants to evaluate her or his new GIF method and compare it objectively to previously developed benchmark techniques). OPENGLOT consists of four main parts, Repositories I-IV, that contain data and sound synthesis software. Repository I contains a large set of synthetic glottal flow waveforms, and speech signals generated by using the Liljencrants-Fant (LF) waveform as an artificial excitation, and a digital all-pole filter to model the vocal tract. Repository II contains glottal flow and speech pressure signals generated using physical modeling of human speech production. Repository III contains pairs of glottal excitation and speech pressure signal generated by exciting 3D printed plastic vocal tract replica with LF excitations via a loudspeaker. Finally, Repository IV contains multichannel recordings (speech pressure signal, electroglottogram, high-speed video of the vocal folds) from natural production of speech. After presenting these four core parts of OPENGLOT, the article demonstrates the platform by presenting a typical use case.
Paavo Alku; Tiina Murtola; Jarmo Malinen; Juha Kuortti; Brad Story; Manu Airaksinen; Mika Salmi; Erkki Vilkman; Ahmed Geneid. OPENGLOT – An open environment for the evaluation of glottal inverse filtering. Speech Communication 2019, 107, 38 -47.
AMA StylePaavo Alku, Tiina Murtola, Jarmo Malinen, Juha Kuortti, Brad Story, Manu Airaksinen, Mika Salmi, Erkki Vilkman, Ahmed Geneid. OPENGLOT – An open environment for the evaluation of glottal inverse filtering. Speech Communication. 2019; 107 ():38-47.
Chicago/Turabian StylePaavo Alku; Tiina Murtola; Jarmo Malinen; Juha Kuortti; Brad Story; Manu Airaksinen; Mika Salmi; Erkki Vilkman; Ahmed Geneid. 2019. "OPENGLOT – An open environment for the evaluation of glottal inverse filtering." Speech Communication 107, no. : 38-47.
Additive manufacturing of digital spare parts offers promising new possibilities for companies to drastically shorten lead times and to omit storage costs. However, the concept of digital spare parts has not yet gained much footing in the manufacturing industry. This study aims to identify grounds for its selective rejection. Conducted from a corporate perspective, outlining a holistic supply chain network structure to visualize different digital spare part distribution scenarios, this survey study evaluates technical and economic additive manufacturing capabilities. Results are analyzed and discussed further by applying the Mann-Whitney test to examine the influence of the company size and the presence of 3D-printed end-use components within supply networks on gathered data. Machines’ limited build chamber volumes and the necessity of post-processing are considered as the main technical challenges of current additive manufacturing processes. Furthermore, it can be concluded that company sizes have a significant effect on perceived technological limitations. Overall, the results lead to the conclusion that the readiness level of the digital spare parts concept demands for further development.
Niklas Kretzschmar; Sergei Chekurov; Mika Salmi; Jukka Tuomi. Evaluating the Readiness Level of Additively Manufactured Digital Spare Parts: An Industrial Perspective. Applied Sciences 2018, 8, 1837 .
AMA StyleNiklas Kretzschmar, Sergei Chekurov, Mika Salmi, Jukka Tuomi. Evaluating the Readiness Level of Additively Manufactured Digital Spare Parts: An Industrial Perspective. Applied Sciences. 2018; 8 (10):1837.
Chicago/Turabian StyleNiklas Kretzschmar; Sergei Chekurov; Mika Salmi; Jukka Tuomi. 2018. "Evaluating the Readiness Level of Additively Manufactured Digital Spare Parts: An Industrial Perspective." Applied Sciences 8, no. 10: 1837.
The purpose of this paper is to verify the conceptual benefits of the implementation of additive manufacturing (AM) in spare part supply chains from the point of view of industry. Focus group interviews consisting of five sessions and 46 experts in manufacturing were conducted for this study. The focus group interviews served to identify the issues in the adoption of digital spare parts (DSP) and to expand on the available literature. The benefits found in the reviewed literature were partially verified by the participants but certain limitations, such as the excessive need of post processing, supplier quality parity, and ICT inadequacies, were presented that were absent or not highlighted in literature. The information gathered from the participants made it possible to create a realistic model of a digital spare part distribution network. According to the focus group interviews, digital spare parts could be deployed immediately for a specific type of product in the long tails of company spare part catalogues. However, improvements in AM, company ICT infrastructure, and 3D model file formats need to be achieved for a larger deployment of DSP.
Sergei Chekurov; Sini Metsä-Kortelainen; Mika Salmi; Irene Roda; Ari Jussila. The perceived value of additively manufactured digital spare parts in industry: An empirical investigation. International Journal of Production Economics 2018, 205, 87 -97.
AMA StyleSergei Chekurov, Sini Metsä-Kortelainen, Mika Salmi, Irene Roda, Ari Jussila. The perceived value of additively manufactured digital spare parts in industry: An empirical investigation. International Journal of Production Economics. 2018; 205 ():87-97.
Chicago/Turabian StyleSergei Chekurov; Sini Metsä-Kortelainen; Mika Salmi; Irene Roda; Ari Jussila. 2018. "The perceived value of additively manufactured digital spare parts in industry: An empirical investigation." International Journal of Production Economics 205, no. : 87-97.
Space technology has been an early adopter of additive manufacturing (AM) as a way of quickly producing relatively complex systems and components that would otherwise require expensive and custom design and production. Space as an environment and long-term survivability pose challenges to materials used in AM and these challenges need to be addressed. Atomic layer deposition (ALD) is an effective coating method enabling conformal and precise coating of the complete AM print. This work analyses how an ALD coating of aluminium oxide on acrylonitrile butadiene styrene (ABS) and polyamide PA 2200 plastic AM prints benefits and protects them. This was studied in the context of in-space propulsion fluidics, where propellant flow properties also matter. AM was performed with material extrusion and selective laser sintering methods that are commonly used. Tests were performed with a simple bang-bang controller test setup and a mass spectrometer, and the existence of the coating was confirmed with scanning electron microscope imaging.
Antti Kestila; Kalle Nordling; Ville Miikkulainen; Mikko Kaipio; Tuomas Tikka; Mika Salmi; Aleksi Auer; Markku Leskelä; Mikko Ritala. Towards space-grade 3D-printed, ALD-coated small satellite propulsion components for fluidics. Additive Manufacturing 2018, 22, 31 -37.
AMA StyleAntti Kestila, Kalle Nordling, Ville Miikkulainen, Mikko Kaipio, Tuomas Tikka, Mika Salmi, Aleksi Auer, Markku Leskelä, Mikko Ritala. Towards space-grade 3D-printed, ALD-coated small satellite propulsion components for fluidics. Additive Manufacturing. 2018; 22 ():31-37.
Chicago/Turabian StyleAntti Kestila; Kalle Nordling; Ville Miikkulainen; Mikko Kaipio; Tuomas Tikka; Mika Salmi; Aleksi Auer; Markku Leskelä; Mikko Ritala. 2018. "Towards space-grade 3D-printed, ALD-coated small satellite propulsion components for fluidics." Additive Manufacturing 22, no. : 31-37.
The purpose of this study is to demonstrate the ability of additive manufacturing, also known as 3D printing, to produce effective drug delivery devices and implants that are both identifiable, as well as traceable. Drug delivery devices can potentially be used for drug release in the direct vicinity of target tissues or the selected medication route in a patient-specific manner as required. The identification and traceability of additively manufactured implants can be administered through radiofrequency identification systems. The focus of this study is to explore how embedded medication and sensors can be added in different additive manufacturing processes. The concept is extended to biomaterials with the help of the literature. As a result of this study, a patient-specific drug delivery device can be custom-designed and additively manufactured in the form of an implant that can identify, trace, and dispense a drug to the vicinity of a selected target tissue as a patient-specific function of time for bodily treatment and restoration.
Jan Sher Akmal; Mika Salmi; Antti Mäkitie; Roy Björkstrand; Jouni Partanen. Implementation of Industrial Additive Manufacturing: Intelligent Implants and Drug Delivery Systems. Journal of Functional Biomaterials 2018, 9, 41 .
AMA StyleJan Sher Akmal, Mika Salmi, Antti Mäkitie, Roy Björkstrand, Jouni Partanen. Implementation of Industrial Additive Manufacturing: Intelligent Implants and Drug Delivery Systems. Journal of Functional Biomaterials. 2018; 9 (3):41.
Chicago/Turabian StyleJan Sher Akmal; Mika Salmi; Antti Mäkitie; Roy Björkstrand; Jouni Partanen. 2018. "Implementation of Industrial Additive Manufacturing: Intelligent Implants and Drug Delivery Systems." Journal of Functional Biomaterials 9, no. 3: 41.
The purpose of this paper is to investigate the post-processing of Co-Cr and 316L stainless steel components made by additive manufacturing (AM) using ultrasonic burnishing. AM is able to produce functional parts for medical and industrial applications; however, the parts require support removal and post-processing to achieve the technical requirements. To this end, ultrasonic burnishing is a formative method used to improve surface quality and increase surface hardness. The aim of this work is to characterize the effect of process variable (e.g. machine and workpiece relative displacements and spring compression) in the surface quality of AM burnished materials. Two separate design of experiments were performed to find optimal values for the process parameters. The analysis of the experimental result was performed using “Minitab 16” statistical software. To this end, an analysis of variance (ANOVA) was performed to study the effect and interactions of process parameter on the final surface quality. The results showed that surface roughness (Ra) was decreased to 0.18 µm for as-built Co-Cr and 0.55 µm for as-built 316L stainless steel. In addition, the relative increase in average hardness from as-built Co-Cr was 47.4% (i.e. 551.07 Hv) and 70.7% from as-built 316L stainless steel (i.e. 338.17 Hv). The optimal process parameters for post-processing Co-Cr material are around 0.05 mm/r for the feed and 1.5 mm for the spring compression, whereas post-processing of 316L requires 1000 mm/min for the feed speed, 0.025 mm for the side shift and 1 mm for spring compression, when taking also productivity into consideration. The results of this experiment show that the subtractive methods and labour-intensive post-processing of AM metal parts can be replaced by burnishing methods, thus reducing the cost barriers of additive technology and drive its adoption in industry.
Mika Salmi; Juha Huuki; Inigo Flores Ituarte. The ultrasonic burnishing of cobalt-chrome and stainless steel surface made by additive manufacturing. Progress in Additive Manufacturing 2017, 2, 31 -41.
AMA StyleMika Salmi, Juha Huuki, Inigo Flores Ituarte. The ultrasonic burnishing of cobalt-chrome and stainless steel surface made by additive manufacturing. Progress in Additive Manufacturing. 2017; 2 (1-2):31-41.
Chicago/Turabian StyleMika Salmi; Juha Huuki; Inigo Flores Ituarte. 2017. "The ultrasonic burnishing of cobalt-chrome and stainless steel surface made by additive manufacturing." Progress in Additive Manufacturing 2, no. 1-2: 31-41.