technologies Article On the Part Quality, Process Parameters and In-Die Pressures in Indirect Squeeze Casting Anders E. W. Jarfors 1,2, * , Jie Zhou 2 , Andong Du 2,3 , Jinchuan Zheng 2 and Gegang Yu 2   Citation: Jarfors, A.E.W.; Zhou, J.; Du, A.; Zheng, J.; Yu, G. On the Part Quality, Process Parameters and In-Die Pressures in Indirect Squeeze Casting. Technologies 2021, 9, 95. https://doi.org/10.3390/ technologies9040095 Academic Editor: Salvatore Brischetto Received: 29 October 2021 Accepted: 24 November 2021 Published: 2 December 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Materials and Manufacturing, School of Engineering, Jönköping University, P.O. Box 1026, 551 11 Jönköping, Sweden 2 Institute of Semi-Solid Metal Technology, China Academy of Machinery Sciences and Technology (Jiangle), No. 22 Huancheng East Road, Jiangle County, Sanming City 353300, China; zhou_j09@163.com (J.Z.); b20170186@xs.ustb.edu.cn (A.D.); 13901302341@139.com (J.Z.); yugg@cam.com.cn (G.Y.) 3 Department of Materials Processing and Control Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Xueyuan Road No. 30, Haidian District, Beijing 100083, China * Correspondence: anders.jarfors@ju.se Abstract: Squeeze casting is a process that can produce the highest quality castings. In the current study, the effect of the process settings and the in-die conditions on rejection rates is studied through a full-scale experimental study. Factors affecting the as-cast part quality were investigated in the current study from two different viewpoints. The first part of the study was to investigate the influence of the process settings on the part rejection rate, and the second was to understand the conditions in the die and the effects on the part rejection rate to understand better the reasons and sensitivity of the squeeze casting process. Keywords: squeeze casting; process parameters; filling; acceleration; pressure; sensing; rejection rate; aluminium; component casting 1. Background Squeeze casting is a process that can produce the highest quality castings but has a somewhat longer cycle time than other processes such as high pressure die casting (HPDC). The main types are direct squeeze casting and indirect squeeze casting, where the main difference is that for direct squeeze casting, pressure is acting directly on the part, and for indirect squeeze casting, pressure is acting through a runner, but with very little pressure loss compared to HPDC [1,2]. In a recent work by Fiorese et al. [3], the root mean square acceleration significantly impacted the part quality in HPDC. This entity was defined as α RMS = 1 T T  0   dv dt  2 dt (1) where v is speed (m/s), t is time (s) and T is the duration or investigated period(s). The α RMS value had a direct correlation to the properties, suggesting that the accelera- tion between the first and the second phase in HPDC determines the quality and not just the actual speed itself. In Fiorese et al. [3] the input was from the piston motion itself, but in reality, the motion of the melt front would be most critical, and a possibility to assess this indirectly would be through die cavity measurements. There is very little work made on squeeze casting regarding filling and product quality which is the focus of this work. The pressures in the runners and die cavity have a profound impact on casting quality. Recent development in sensor technology increases the possibility of using die sensing technology to understand the filling and solidification dynamics better. In HPDC, the initial peak in heat flux is in the order of 5–10 MW/m 2 [4]. and for Squeeze Casting in the order Technologies 2021, 9, 95. https://doi.org/10.3390/technologies9040095 https://www.mdpi.com/journal/technologies