Laser Powder Bed Fusion of Inconel 718 Tools for Cold Deep Drawing Applications: Optimization of Printing and Post-Processing Parameters

Cho-Pei Jiang; Andi Ard Maidhah; Shun-Hsien Wang; Yuh-Ru Wang; Tim Pasang; Maziar Ramezani

doi:10.3390/ma16134707

Laser Powder Bed Fusion of Inconel 718 Tools for Cold Deep Drawing Applications: Optimization of Printing and Post-Processing Parameters

Materials (Basel). 2023 Jun 29;16(13):4707. doi: 10.3390/ma16134707.

Authors

Cho-Pei Jiang^{1

2}, Andi Ard Maidhah³, Shun-Hsien Wang⁴, Yuh-Ru Wang⁵, Tim Pasang⁶, Maziar Ramezani⁷

Affiliations

¹ Department of Mechanical Engineering, National Taipei University of Technology, Taipei 10608, Taiwan.
² High-Value Biomaterials Research and Commercialization Center, National Taipei University of Technology, Taipei 10608, Taiwan.
³ College of Mechanical and Electrical Engineering, National Taipei University of Technology, Taipei 10608, Taiwan.
⁴ Graduate Institute of Mechatronics, National Taipei University of Technology, Taipei 10608, Taiwan.
⁵ Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei 10608, Taiwan.
⁶ Department of Manufacturing and Mechanical Engineering Technology, Oregon Institute of Technology, 3201 Campus Drive, Klamath Falls, OR 97601, USA.
⁷ Department of Mechanical Engineering, Auckland University of Technology, 55 Wellesley Street East, Auckland 1010, New Zealand.

Abstract

Inconel 718 (IN 718) powder is used for a laser powder bed fusion (LPBF) printer, but the mechanical properties of the as-built object are not suited to cold deep drawing applications. This study uses the Taguchi method to design experimental groups to determine the effect of various factors on the mechanical properties of as-built objects produced using an LPBF printer. The optimal printing parameters are defined using the result for the factor response to produce an as-built object with the greatest ultimate tensile strength (UTS), and this is used to produce a specimen for post-processing, including heat treatment (HT) and surface finishing. The HT parameter value that gives the maximum UTS is the optimal HT parameter. The optimal printing and HT parameter values are used to manufacture a die and a punch to verify the suitability of the manufactured tool for deep drawing applications. The experimental results show that the greatest UTS is 1091.33 MPa. The optimal printing parameters include a laser power of 190 W, a scanning speed of 600 mm/s, a hatch space of 0.105 mm and a layer thickness of 40 μm, which give a UTS of 1122.88 MPa. The UTS for the post-processed specimen increases to 1511.9 MPa. The optimal parameter values for HT are heating to 720 °C and maintaining this temperature for 8 h, decreasing the temperature to 620 °C and maintaining this temperature for 8 h, and cooling to room temperature in the furnace. Surface finishing increases the hardness to HRC 55. Tools, including a punch and a die, are manufactured using these optimized parameter values. The deep drawing experiment demonstrates that the manufactured tools that are produced using these values form a round cup of Aluminum alloy 6061. The parameter values that are defined can be used to manufacture IN 718 tools with a UTS of more than 1500 MPa and a hardness of more than 50 HRC, so these tools are suited to cold deep drawing specifications.

Keywords: Inconel 718; deep drawing; optimization; post-processing; power bed fusion.

Abstract

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