Abadi, Zainal, Andre Kurniawan, Andril Arafat, Nur Ichsan Abdillah, and Daffa Raihan Senthot. 2021. “Analysis of Riser Variations in Recycled Aluminum Sand Casting on Hardness Values”. INVOTEK: Jurnal Inovasi Vokasional Dan Teknologi 21 (3):213-20. https://doi.org/10.24036/invotek.v21i3.940.