Heidi Piili

• D.Sc.(Tech.) - Laser Materials Processing | D.Sc.(Tech.) - Chemical Engineering| Adjunct Professor - In-situ detection of PBF-LB | M.Sc.(Tech.) - Chemical Engineering | Professional Teacher (AmO)
• Senior Research Scientist at University of Turku

In this study, nickel-based superalloy, Alloy 718 (IN718), processed by powder bed fusion, was welded to wrought AISI 316L using laser welding. The effect of building direction, pre-weld heat treatment, and laser linear energy density on the weld strength of the dissimilar joints was examined. It was shown that employing a lower energy density impr...

Light weight and high-performance metals are usually desired for transport applications for economic and environmental benefits, especially in automotive and aerospace. Conventional manufacturing (CM) methods used in manufacturing motor vehicle and aircraft components often lead to compromises, for example by adding non-function excess materials fo...

Additive manufacturing (AM) is an advanced method of manufacturing complex parts layer by layer based on digital model. Pandemic showed that AM was the go-to technology for the production of emergency medical equipment. Recent growth in post-pandemic world around software of AM shows that AM can be a revolutionary change for several industries. Las...

3D printing is a solid part of the health care environment, and in the future, it could assume a more innovative role in the work carried out by practical nurses. However, the educational context may not support the preparedness to face and adapt new and creative technologies on the part of practical nursing students. This study aimed to describe p...

The advancements of digitization and the fourth industrial revolution has introduced several modern technologies, among which additive manufacturing (AM), known also as industrial 3D printing, has significant role. Additive manufacturing has the potential to revolutionize products, production, and businesses in various fields of engineering, such a...

The development of modern manufacturing technologies such as additive manufacturing and other laser-based manufacturing technologies have increased their usage, especially in engineering education. Education must correspond to different applications of these technologies to ensure the quality of their usage in the manufacturing industry. Laser-base...

Powder bed fusion using a laser beam (PBF-LB/M) is considered one of the most versatile additive manufacturing methods as the parts printed have high resolution thanks to the low layer thickness used. The powder packing density ( PD ) of the powder layer has a significant impact on the density, surface roughness and other mechanical properties of t...

Laser powder bed fusion for metals is a method of producing end use components for industrial use. Powder bed fusion machines are relatively small and are usually used to create only the critical part of the larger assembly. Therefore, L-PBF manufactured parts must be attached to each other for example by welding. The industrial world needs to be a...

Additive manufacturing of metals is a way of producing high-quality end-use parts. Technical alloys, for example Inconel 718, can be used to obtain a lot of benefits for example wear, corrosion, and heat resistance. Laser welding of Inconel 718 is a standard process, but there is rather limited amount of information of welding of additively manufac...

This research explores real-time database systems’ evolution, focusing on unique features and the addressed challenges. It examines the role of multi-material additive manufacturing quality domain databases in innovation and maintaining standards. It also looks at the challenges of implementing quality manufacturing systems from a technology, organ...

Additive manufacturing (AM) is a process in which parts are built up layer by layer, introducing novel approaches to how parts can be manufactured with less material waste, shorter lead times and lower costs than traditional manufacturing. One of the key advantages of AM over conventional manufacturing is its design flexibility, which enables for m...

Additive manufacturing (AM), commonly known as 3D printing, has vast amount of technological opportunities, but it also necessitates specialized expertise among its specialists, adopters, users etc. As AM continues to demonstrate its potential and has high growth rates in fields of its use, applications, systems etc., the importance of AM education...

The implementation of laser powder bed fusion (PBF-LB) on ceramics is far more demanding than their metallic and polymeric counterparts for bone tissue engineering (BTE). The review will shed light on bioinert ceramics-based biomaterials manufacturing through PBF-LB incorporating alumina and yttria-stabilized zirconia as oxide-based ceramics and ni...

Digitalization is changing the industry. As this change accelerates its speed, it also requires a transformation process where knowledge transfer between industry and research institutes play a significant role. There is a need to be more fluent, flexible, and efficient in order to get the latest research results into industrial implementation as q...

Laser powder bed fusion for metals is a method of producing end use components for industrial use. Powder bed fusion machines are relatively small, and are usually used to create only the critical part of the larger assembly. Therefore, L-PBF manufactured parts must be attached to each other for example by welding. The industrial world needs to be...

Axially compressed circular cylindrical shells with large diameter-to-thickness ratios are highly sensitive to initial geometric imperfections thus leading to a significant reduction in load-bearing capacity. The extreme sensitivity to imperfections has been previously addressed and mitigated through the introduction of stiffeners but still remains...

Powder bed fusion (PBF) additive manufacturing has the potential for significant impact in a range of engineering applications due to its ability to produce complex and free-form components in a precise manner. The size of components, however, is limited by the internal build volume of the employed PBF machines. Using laser welding, small individua...

Additive manufacturing (AM) of metals is a complex process considering its fundamental physical and mechanical aspects. Understanding the processes is challenging as they are affected by many factors, so they are experimentally expensive and time consuming to study. Simulation has been identified as an important tool to overcome this challenge. The...

Lean practices in industry offered by lean management (LM) tools have revolutionized industrial production and operation. These tools allow for incorporation of pragmatic steps to reduce waste, improve flow of goods, and increase productivity in industrial settings. Novel manufacturing methods such as additive manufacturing (AM) promotes resource e...

Additive manufacturing (AM) is a promising technology for designing complex metallic pieces for different sectors with resource and time effectiveness. Titanium (Ti) is an essential critical material for AM development. AM can produce intricate and cost-effective components with Ti alloys for the transportation sector which would not be possible wi...

Nowadays, additive manufacturing, known as 3D printing, is vigorously employed at various enterprises due to the ability of industrial series production and customization in conjunction with geometry freedom. While, material design and fabrication of composite materials, meeting the desired architecture and properties, is another promising applicat...

The data available in this article include 3D mechanical designs used for the computer-aided fabrication of metal honeycombs produced by additive manufacturing and studied in [1]. In addition, the force-displacement data utilized to evaluate the mechanical performance of the metal used in this study are available via the digital image correlation t...

Initial geometric imperfections have been identified as the main cause for the large discrepancies between experimental and theoretical buckling loads of thin-walled circular cylindrical shells under axial compression. The extreme sensitivity to imperfections has been previously addressed and mitigated through the introduction of stiffeners; howeve...

Variety of ultra-high strength steels (UHSS) with different microstructural characteristics is becoming available with continuous development of the manufacturing process in the steel industries. In order to effectively design structures made of such steel grades, a detailed knowledge of the mechanical properties is vital. Fire safety design is one...

The present work provides an overview on an additive manufacturing (AM) design case of a novel battery cell lid structure (patent pending) for electrical vehicle applications. The benefits of AM have not yet been explored on metal case structures of prismatic battery cells. The method allows the manufacturing of complex hollow structures and integr...

Powder bed fusion (PBF) is an additive manufacturing method that enables complex metallic components to be manufactured with high precision. The microstructure, mechanical properties and cross‐sectional behaviour of PBF additively manufactured stainless steel circular hollow sections are investigated through experiments in this paper, with a view t...

Honeycomb structures have a wide range of applications, from medical implants to industrial components. In addition, honeycombs play a critical role when passive protection is required due to their low density and high energy absorption capabilities. With the transition of additive manufacturing from a rapid prototyping approach to a manufacturing...

The data available in this article presents the microstructural information achieved via scanning electron microscopy and electron backscatter diffraction to evaluate the microstructure of maraging stainless steel 13Cr10Ni1.7Mo2Al0.4Mn0.4Si, in its as-built and heat-treated conditions, fabricated by laser powder bed fusion. In addition, the statist...

Additive manufacturing (AM) has undergone different phases of technological changes from being a mere manufacturing method for consumer goods, prototyping, and tooling to industrial series production of functional end-use parts. The seven AM sub-categories allow the creation of unprecedented designs that are otherwise impossible using conventional...

This study investigates the effects of build orientations, heat treatment, and mechanical machining (as processing and post-processing factors) on the microstructure, quasi-static mechanical properties, strain hardening, notch toughness, and residual stress of additive manufactured 13Cr10Ni1.7Mo2Al0.4Mn0.4Si maraging stainless steel, known commerci...

Ultra-high strength steels (UHSS) have a determining role in construction and industry. Furthermore, welding as the primary joining process for steel has a similar role in promoting its applications. Therefore, welded UHSS have a vital role in related applications. However, due to their complex microstructures, these steels are more prone to harmfu...

Powder bed fusion (PBF) is a commonly employed metal additive manufacturing (AM) process in which components are built, layer-by-layer, using metallic powder. The component size is limited by the internal build volume of the employed PBF AM equipment; the fabrication of components larger than this volume therefore requires mechanical joining method...

Axially compressed circular cylindrical shells with large diameter-to-thickness ratios are known to be highly sensitive to initial geometric imperfections, which can drastically reduce their load-carrying capacity. Their design typically involves the application of severe knock-down factors on their theoretical buckling loads, which greatly impair...

The capability of additive manufacturing to produce parts with complicated geometrical features is one of the unique advantages of this technology over traditional production methods. However, the intricate interaction between concentrated stress fields imposed by various geometrical profiles, inherent defects, and external loads must be comprehens...

This report aims to overview the development actions from a knowledge-based know-how cluster of metal additive manufacturing (AM) in Finland's South Karelia region. This report also investigates the need for regional industries to become more aware and open towards using AM in their production lines. At first, a brief history of additive manufactur...

Additive manufacturing, (AM), includes seven subcategories that can directly manufacture components structures from a computer-designed model layer by layer. Laser-based powder bed fusion (L-PBF) is one of type of the subcategories of AM. L-PBF is a fast and cost-efficient production method that offers the advantages of being implementable with a d...

E-learning refers to learning that can be obtained online using an electronic device either as self-study or guided teaching. Blended learning that combines traditional face-to-face learning and e-learning methods is also often used. E-learning is not a new phenomenon, but the coronavirus pandemic has significantly increased the need for online tea...

Additive manufacturing (AM) is a technology where an object is manufactured layer by layer based on 3D CAD data enabling new kind of freedom for design. AM is widely used especially in the universities and universities of applied sciences supporting the education of technical subjects which has increased the popularity of the technology. This has a...

Additive manufacturing, also referred to as 3D printing, has the potential to revolutionise the construction industry , offering opportunities for enhanced design freedom and reduced material use. There is currently, however , very limited data concerning the performance of additively manufactured metallic structural elements. To address this, an e...

Stainless steel 316L is a frequently used metal in additive manufacturing owing to its favorable strength-ductility synergy and corrosion resistance, and laser powder bed fusion (L-PBF) is the most commonly applied additive manufacturing method for processing 316L. Manufacturing components from stainless steel 316L via L-PBF benefits the geometrica...

Additive manufacturing (AM) is at the verge of being recognised as one of the main manufacturing methods among the traditional ones. The largest obstacle in using AM in the companies is the lack of knowledge about the possibilities of the technology. One sub-problem caused by this is the lack of qualified machine operators in companies due to the i...

This study presents the development of a new pedagogical method, namely the model of technical pedagogy, for learning additive manufacturing (AM) due to the speed of the technological development. The speed of the technological development of AM is faster than of the educational one; curricula and teaching methods have to evolve all the time in ord...

As the working life and the working environment are constantly changing the experts are required to have more skills, and an ability to learn how to solve varying multidisciplinary problems with other experts. The organizations which openly share information and create by working together achieve better results and their employees feel better. This...

Learning environment is a physical environment which enables and supports interaction and learning of an individual. Practical learning happens usually in a physical learning environment allowing students to learn through using a certain technology when engineering education is in focus. 3D printing offers a low-cost and easy to access way to learn...

Laser based powder bed fusion (L-PBF) is used to manufacture parts layer by layer with the energy of laser beam. The use of L-PBF for building functional parts originates from the design freedom, flexibility, customizability, and energy efficiency of products applied in dynamic application fields such as aerospace and automotive. There are challeng...

This chapter provides a rough overall view of the current state of additive manufacturing, how the status quo was reached and what the future looks like, and how these issues are related to the Manufacturing 4.0 context. Chapter focuses on the most developed and studied form of additive manufacturing—laser based powder bed fusion of metal materials...

Laser powder bed fusion (L-PBF) is a suitable manufacturing method for end-use complicated metal parts. However, cyclic thermal load belongs to the nature of the process and it creates residual stresses in the parts due to their subsequent thermal expansions and contractions. These residual stresses make the parts exposed to deformations. Aim of th...

High-speed imaging is nowadays a widely used monitoring system in laser based powder bed fusion (L-PBF), because it enables observation of the occurring process phenomena. The quality-price ratio of the high-speed cameras has significantly increased over the last few years, and therefore it is a more suitable method for monitoring. This study conce...

A possible field benefitting from this geometrical freedom offered by L-PBF is electrochemistry, as electrodes can be designed with unprecedented freedom to increase the efficiency of electrochemical processes. In this study an optimized electrode to be manufactured with L-PBF designed. Literature was used to determine critical factors affecting th...

Additive manufacturing, as a sustainable production technology which provides designers with more freedom, is establishing its place in the modern industry. Among its various processes, powder bed fusion technique is one of the most popular ones due to its high-quality products which have near-net-shape density and relatively acceptable mechanical...

Tämän julkaisun ensimmäinen osa pyrkii pureutumaan lasten ja nuorten digitalisaatiokasvatukseen sekä määrittelemään tämän kannalta keskeisiä käsitteitä. Tämän julkaisun toinen osa rakentaa näiden määritelmien kautta digitalisaatiokasvatuksen monikerroksellista mallia, jossa keskiössä on digitaalinen tekeminen, digitaalinen osaaminen, digitaalinen t...

There has been increasing interest in Laser Powder Bed Fusion (L-PBF) of metallic materials as a promising manufacturing technology. Although most L-PBF systems utilize laser beams with continuous wave emission (L-PBF(CW)), the possibility of using pulsed lasers (L-PBF(P)) has become available in some industrial L-PBF machines over the past few yea...

Process monitoring has been used in laser processing since 1980`s. Nevertheless, there are only a few commercially available monitoring systems at the moment for additive manufacturing R&D purposes. One reason for this small-scale use of monitoring in additive manufacturing industry might be that additive manufacturing is a relatively modern manufa...

Galvanic exchange involving dissolution of iron and the simultaneous growth of platinum onto 316 L stainless steel was investigated for specimens manufactured by 3D-printing, and the behavior was compared to conventional stainless steel. Novel phenomena associated with the 3D-printed steel, but not conventional steel, reacting in three distinct pha...

Engineering education in modern days require continuous development in didactics, pedagogics and used practical methods. 3D printing provides excellent opportunity to connect different engineering areas into practice and produce learning by doing applications. The 3D-printing technology used in this study is FDM (Fused deposition modeling). FDM is...

Manufacturing of work pieces from stainless steel with laser additive manufacturing, known also as laser sintering or 3D printing may increase energy and material efficiency. The use of powder bed fusion offers advantages to make parts for dynamic applications of light weight and near-net-shape products. Due to these advantages among others, PBF ma...

Additive manufacturing (AM) is a modern way to produce parts for industrial use. Even though the technical knowledge and research of AM processes are strong in Finland, there are only few industrial applications. Aim of this study is to collect practical knowledge of companies who are interested in industrial use of AM, especially in South-Eastern...

Additive manufacturing (AM) of metallic materials has widened the horizon for customized part production by completely eliminating tools and fixtures of manufacturing. Its subsequent importance lies in economic aspects of the use of metal AM for mass customization (MC). This study analyses the manufacturing time and cost per part for MC of metallic...

Additive manufacturing (AM) of stainless steel is a technology that enables fabrication of structures too complicated for any traditional methods. This freedom of design can be exploited by designing parts that improve the performance of both, the part and the system as a whole. Traditionally, hydraulic blocks are designed to be manufactured with t...

Stainless-steel rods were manufactured by laser additive manufacturing (LAM or "3D-printing") from a stainless-steel (316L) powder precursor, and then investigated and compared to conventional stainless steel in electrochemical experiments. The LAM method used in this study was based on "powder bed fusion", in which particles with an average diamet...

Whole text available in Finish language http://www.doria.fi/handle/10024/120218 Additive manufacturing (shortened as AM), or more commonly 3D printing, consists of wide variety of different modern manufacturing technologies. AM is based on direct printing of a digital 3D model to a final product which is fabricated adding material layer by layer....

Nowadays, lasers are applied in many industrial processes: the most developed technologies include such processes as laser welding, hybrid welding, laser cutting of steel, etc. In addition to laser processing of metallic materials, there are also many industrial applications of laser processing of non-metallic materials, like laser welding of polym...

Laser additive manufacturing is an established and constantly developing technique. Structural assessment should be a key component to ensure directed evolution towards higher level of manufacturing. The macroscopic properties of metallic structures are determined by their internal microscopic features, which are difficult to assess using conventio...

Laser technology has been used in industrial processes for several decades. The most advanced development and implementation took place in laser welding and cutting of metals in automotive and ship building industries. However, there is high potential to apply laser processing to other materials in various industrial fields. One of these potential...

Laser technology provides advantages for paper material processing as it is non-contact method and provides freedom of geometry and reliable technology for non-stop production. Reason for low utilization of lasers in paper manufacturing is lack of published research. This is main reason to study utilization of on-site multi-monitoring system (MMS)...

Paper making and converting industry in Europe is suffering from transfer of basic manufacturing to fast-growing economies, such as China and Brazil. Pulp and paper production volume in Finland, Sweden and France was the same in 2011 as it was in 2000. Meanwhile China has tripled its volume and Brazil doubled. This is a situation where innovative s...

Laser additive manufacturing (LAM) is a fabrication technology, which enables production of complex parts from metallic materials with mechanical properties comparable to those of conventionally machined parts. These LAM parts are manufactured via melting metallic powder layer by layer with laser beam.

Laser additive manufacturing (LAM), known also as 3D printing, is a powder bed fusion (PBF) type of additive manufacturing (AM) technology used to fabricate metal parts out of metal powder. The development of the technology from building prototype parts to functional parts has increased remarkably in 2000s. LAM of metals is promising technology tha...

Laser additive manufacturing (LAM) is a fabrication technology that enables production of complex parts from metallic materials with mechanical properties comparable to conventionally manufactured parts. In the LAM process, parts are manufactured by melting metallic powder layer-by-layer with a laser beam. This manufacturing technology is nowadays...

Traditional industry sectors, like paper making industry, tend to stay within well-known technology rather than going forward towards promising, but still quite new technical solutions and applications. This study analyses the feasibility of the laser cutting in large-scale industrial paper making processes. Aim was to reveal development and proces...

Even though technology for laser cutting of paper materials has existed for over 30 years, it seems that results of applications of this technology and possibilities of laser cutting systems are not easily available. The aim of this study was to analyze the feasibility of the complex geometry laser cutting of paper materials and to analyze the inno...

This study is based on observed outcomes of motivation sources and collaboration elements from a living lab style co-operation project. In this project, researchers of engineering science and an individual artist co-operated closely. The goal was to create an artwork made from corrugated board by utilizing laser cutting technology. In the context o...

Can be found: http://www.doria.fi/handle/10024/116094. Additive manufacturing, or 3D printing, is globally one of most interesting area in developing of manufacturing technologies. This technology is suitable for fabrication off industrial products and it interests actors in fields of computer sciences, economics, medical sciences and design&arts....

Laser additive manufacturing (LAM) is a layer wise fabrication method in which a laser beam melts metallic powder to form solid objects. Although 3D printing has been invented 30 years ago, the industrial use is quite limited whereas the introduction of cheap consumer 3D printers, in recent years, has familiarized the 3D printing. Interest is focus...

Available/saatavissa: http://urn.fi/URN:ISBN:978-952-265-671-1 Suurelle yleisölle lisäävä valmistustekniikka eli ns. 3D-tulostustekniikka näyttäytyy lehtien otsikoissa ja artikkeleissa esiin pulpahtavana ”muotiaiheena”, mutta sekä muovien 3D-tulostustekniikka että metallienkin vastaava valmistustekniikka on ollut olemassa maailmalla ja Suomessa 80-...

This paper introduces laser additive manufacturing as a new method for the fabrication of micro fuel cells: The method opens up the capability of ultrafast prototyping, as the whole device can be produced at once, starting from a digital 3D model. In fact, many different devices can be produced at once, which is useful for the comparison of competi...

In this paper we present the first ever micro fuel cell fabricated by laser additive manufacturing (LAM) of stainless steel. LAM is a process where localized laser melting of precursor powder is carried out layer-by-layer, until the final 3D shape is finished. We used stainless steel 316L powder (31 µm particle size) as starting material. This limi...