Analisis Rasio dan Siklus Penambahan Pasir Silika Baru Pada Pasir Bekas Guna Minimalisir Cacat Cor Bubble Produk Cylinder Liner di PT. Bioli Lestari

Sidiq, Aldiansyah Razief (2026) Analisis Rasio dan Siklus Penambahan Pasir Silika Baru Pada Pasir Bekas Guna Minimalisir Cacat Cor Bubble Produk Cylinder Liner di PT. Bioli Lestari. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Industri pengecoran logam dituntut menghasilkan produk dengan kualitas tinggi, terutama pada komponen cylinder liner. Salah satu permasalahan yang sering terjadi pada proses sand casting adalah cacat cor bubble akibat gas yang terjebak di dalam logam cair. Kondisi tersebut dipengaruhi oleh rendahnya permeabilitas pasir cetak yang mengalami penurunan akibat penggunaan berulang. PT. Bioli Lestari masih menggunakan pasir bekas sebagai media cetak dan melakukan penambahan pasir silika baru tanpa rasio maupun siklus yang terukur, sehingga kualitas hasil pengecoran belum stabil dan tingkat produk reject masih tinggi. Penelitian ini bertujuan menentukan rasio penambahan pasir silika baru yang optimal pada pasir bekas serta menentukan siklus penggunaan pasir yang tepat sebelum dilakukan penambahan pasir silika baru. Penelitian menggunakan metode eksperimen dengan pengujian distribusi ukuran butir pasir, permeabilitas, simulasi pengecoran menggunakan Altair Inspire Cast, serta validasi terhadap jumlah cacat bubble pada produk cylinder liner. Variasi rasio pasir bekas dan pasir silika baru yang digunakan yaitu 100%:0%, 90%:10%, 80%:20%, 70%:30%, 60%:40%, dan 50%:50%. Pengujian siklus dilakukan hingga 14 siklus penggunaan pasir. Hasil penelitian menunjukkan bahwa rasio pasir bekas dan pasir silika baru 80%:20% merupakan rasio minimum yang masih memenuhi standar reject bubble yang dihasilkan di perusahaan, sedangkan rasio 70%:30% direkomendasikan sebagai rasio operasional karena memberikan nilai permeabilitas yang lebih tinggi, jumlah cacat bubble yang rendah, serta faktor keamanan yang lebih baik terhadap penurunan kualitas pasir. Penggunaan pasir secara berulang menyebabkan peningkatan butiran halus yang menurunkan permeabilitas dan meningkatkan jumlah produk reject. Berdasarkan hasil pengujian, pasir bekas masih layak digunakan hingga siklus ke-8, setelahnya, diperlukan penambahan pasir silika baru untuk menjaga permeabilitas dan meminimalkan cacat bubble.
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The metal casting industry is required to produce high quality products, particularly cylinder liners. One of the common problems in the sand casting process is casting defects caused by gas bubbles trapped in the molten metal. This condition is influenced by the low permeability of the molding sand, which deteriorates due to repeated use. PT. Bioli Lestari still uses spent sand as a molding medium and adds new silica sand without a measured ratio or cycle, resulting in unstable casting quality and a high product rejection rate. This study aims to determine the optimal ratio of new silica sand to be added to used sand and to determine the appropriate sand usage cycle before adding new silica sand. The study employs an experimental method involving testing the sand particle size distribution and permeability, casting simulations using Altair Inspire Cast, and validation of the number of bubble defects in cylinder liner products. The variations in the ratio of used sand to new silica sand used were 100%:0%, 90%:10%, 80%:20%, 70%:30%, 60%:40%, and 50%:50%. Cycle testing was conducted for up to 14 cycles of sand use. The results showed that a ratio of 80% used sand to 20% new silica sand was the is the minimum ratio that still meets the standard for bubbles rejects at the company, while a 70%:30% ratio was recommended as the operational ratio because it provided higher permeability, a low number of bubble defects, and a better safety margin against sand quality degradation. Repeated use of sand leads to an increase in fine particles, which reduces permeability and increases the number of rejected products. Based on the test results, used sand remains suitable for use up to the 8th cycle; after that, new silica sand must be added to maintain permeability and minimize bubble defects.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Pengecoran Pasir, Cacat bubble, Permeabilitas, Rasio Pasir Pengecoran, Siklus Penggunaan Pasir
Subjects:	T Technology > TS Manufactures > TS174 Maintainability (Engineering) . Reliability (Engineering) T Technology > TS Manufactures > TS233 Sand casting. Metal castings--Thermal properties. T Technology > TS Manufactures > TS320 Steel--Metallurgy.
Divisions:	Faculty of Vocational > Mechanical Industrial Engineering (D4)
Depositing User:	Aldiansyah Razief Sidiq
Date Deposited:	08 Jul 2026 09:09
Last Modified:	08 Jul 2026 09:09
URI:	http://repository.its.ac.id/id/eprint/134542

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