Increasing the manufacturing efficiency of WAAM by advanced cooling strategies

Reisgen, Uwe; Sharma, Rahul; Mann, Samuel Micha; Oster, Lukas

doi:10.1007/s40194-020-00930-2

Cited by 51 publications

(16 citation statements)

References 13 publications

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“…The yield and tensile strength showed to be not affected by active cooling. Reisgen et al [18] evaluated different cooling strategies using steel (G3Si1). Active cooling via water bath, high-pressure air, and aerosol were compared regarding the resulting cooling times, microstructure, and hardness.…”

Section: Thermal Influences During Waam Of Steel Structuresmentioning

confidence: 99%

Mechanical properties of wire and arc additively manufactured high-strength steel structures

2021

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Additive manufacturing with steel opens up new possibilities for the construction sector. Especially direct energy deposition processes like DED-arc, also known as wire arc additive manufacturing (WAAM), is capable of manufacturing large structures with a high degree of geometric freedom, which makes the process suitable for the manufacturing of force flow-optimized steel nodes and spaceframes. By the use of high strength steel, the manufacturing times can be reduced since less material needs to be deposited. To keep the advantages of the high strength steel, the effect of thermal cycling during WAAM needs to be understood, since it influences the phase transformation, the resulting microstructure, and hence the mechanical properties of the material. In this study, the influences of energy input, interpass temperature, and cooling rate were investigated by welding thin walled samples. From each sample, microsections were analyzed, and tensile test and Charpy-V specimens were extracted and tested. The specimens with an interpass temperature of 200 °C, low energy input and applied active cooling showed a tensile strength of ~ 860–900 MPa, a yield strength of 700–780 MPa, and an elongation at fracture between 17 and 22%. The results showed the formation of martensite for specimens with high interpass temperatures which led to low yield and high tensile strengths (Rp0.2 = 520–590 MPa, Rm = 780–940 MPa) for the specimens without active cooling. At low interpass temperatures, the increase of the energy input led to a decrease of the tensile and the yield strength while the elongation at fracture as well as the Charpy impact energy increased. The formation of upper bainite due to the higher energy input can be avoided by accelerated cooling while martensite caused by high interpass temperatures need to be counteracted by heat treatment.

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Section: Thermal Influences During Waam Of Steel Structuresmentioning

confidence: 99%

Mechanical properties of wire and arc additively manufactured high-strength steel structures

2021

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“…A combination of high-pressure air cooling and a watercooled base table is chosen to avoid any issues normally associated with electrical safety and maintenance requirements of a water cooling system, as investigated in [14]. Owing to longer cooling times (t 8/5 ), the proposed high-pressure air cooling allows for fewer changes in microstructure and hardness.…”

Section: The Cooling Systemmentioning

confidence: 99%

“…At the same time the build-up time was reduced by more than a half. Reisgen et al [14] compared water bath cooling, high-pressure air cooling and aerosol cooling of the structural steel deposit using the GMA process. They found that the water bath cooling has the highest cooling effect although it makes the manipulation of the workpiece more difficult and constrains the degrees of freedom of the manufacturing process.…”

Section: Introductionmentioning

confidence: 99%

WAAM system with interpass temperature control and forced cooling for near-net-shape printing of small metal components

Kozamernik

Bračun

Klobčar

2020

Int J Adv Manuf Technol

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In an attempt to find a solution similar to the FDM 3D printers which would allow cost-effective and reliable additive manufacturing of metal components, this paper proposes a three-axis WAAM system capable of reliably printing small, near-net-shape metal objects. The system consists of gas metal arc (GMA) process equipment, a three-axis CNC positioning system, the interpass temperature control and forced cooling of the base plate and the deposit. The main challenge addressed is the minimisation of shape distortions caused by excessive heat accumulation when printing small objects. The interpass temperature control uses an IR pyrometer to remotely measure the last deposited layer and a control system to keep the interpass temperature below the predefined value by stopping the deposition after each layer in order to allow the deposit to cool. This results in a stable and more repeatable shape of the deposit, even when the heat transfer conditions are changing during the build-up process. The combination of adaptive interlayer dwell time and forced cooling significantly improves system productivity. Open-source NC control and path generation software is used, which enables fast and easy creation of the control code. Different control methods are evaluated through the printing of simple walls, and the printing accuracy is evaluated by printing small shell objects. As the results show, the interpass temperature control allows small objects to be printed at near-net shape with a deviation of 2%, which means that successful printing of 3D shapes can be achieved without trial and error approach.

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“…In view of this, WAAM productivity can be increased by adopting an interlayer cooling strategy that limits idle time by forcing the cooling of the lastly deposited layer. [ 4 ] Toward this aim, different methodologies have been studied: water bath, high‐pressure air, aerosol, CO 2 gas jet, and a combined system with an air jet and a water‐cooled platform. [ 4–11 ] However, when thinking about the industrial applicability of cooling strategies, the one performed with a high‐pressure air jet is the most feasible, especially in case of large‐scale structures.…”

Section: Introductionmentioning

confidence: 99%

“…[ 4 ] Toward this aim, different methodologies have been studied: water bath, high‐pressure air, aerosol, CO 2 gas jet, and a combined system with an air jet and a water‐cooled platform. [ 4–11 ] However, when thinking about the industrial applicability of cooling strategies, the one performed with a high‐pressure air jet is the most feasible, especially in case of large‐scale structures. Currently, the issue of forced interlayer cooling has been mainly addressed process‐wise with the support of numerical simulations [ 5,6 ] or with the aim to reduce parts’ distortions, [ 7,8 ] whereas limited effort has been devoted to assess the effect of different cooling conditions on the final mechanical properties of printed parts.…”

Section: Introductionmentioning

confidence: 99%

Influence of Interlayer Forced Air Cooling on Microstructure and Mechanical Properties of Wire Arc Additively Manufactured 304L Austenitic Stainless Steel

Tonelli

Sola

Laghi

et al. 2021

steel research int.

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Wire‐and‐arc additive manufacturing (WAAM) is an innovative technology that involves deposition of subsequent layers of molten materials. Due to the high deposition rates, this technology is suitable for the production of large‐scale complex structures. Further enhancement in the productivity can be achieved by an interlayer cooling strategy that reduces idle time between depositions. However, the effect of the interlayer cooling on microstructure and mechanical properties has to be addressed. In this view, the present work compares microstructural features and mechanical properties of WAAM‐produced plates of austenitic AISI 304 L, focusing on the effect of both active interlayer air cooling and possible anisotropy induced by the additive process. Microstructural and mechanical characterization was conducted on samples extracted along the longitudinal, transverse, and diagonal directions to the deposition layers of WAAM plates, processed with and without interlayer active cooling. Results showed no remarkable influence of cooling conditions on the microstructure and mechanical properties of WAAM plates, which are indeed affected by the anisotropy induced by the additive process. The observed anisotropy in the elastic modulus, independent from different cooling conditions, was related to the crystallographic texture consequent to the highly oriented microstructure typically induced by the process.

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Increasing the manufacturing efficiency of WAAM by advanced cooling strategies

Cited by 51 publications

References 13 publications

Mechanical properties of wire and arc additively manufactured high-strength steel structures

Mechanical properties of wire and arc additively manufactured high-strength steel structures

WAAM system with interpass temperature control and forced cooling for near-net-shape printing of small metal components

Influence of Interlayer Forced Air Cooling on Microstructure and Mechanical Properties of Wire Arc Additively Manufactured 304L Austenitic Stainless Steel

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