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All Journal Jurnal Lebesgue : Jurnal Ilmiah Pendidikan Matematika, Matematika dan Statistika
Riki Ridwan Margana
Universitas Widyatama
Decision Sciences, Operations Research & Management Education Mathematics

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ANALISIS RANCANGAN PERBAIKAN DESIGN MOLD DENGAN MENGGUNAKAN METODE TAGUCHI DI PT X Yani Iriani; Sri Lestari; Riki Ridwan Margana; Irfan Rifai
Jurnal Lebesgue : Jurnal Ilmiah Pendidikan Matematika, Matematika dan Statistika Vol. 4 No. 3 (2023): Jurnal Lebesgue : Jurnal Ilmiah Pendidikan Matematika, Matematika dan Statistik
Publisher : LPPM Universitas Bina Bangsa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46306/lb.v4i3.512

Abstract

PT X Indonesia is one of the Korean Foreign Manufacturing Companies (PMA) that produce injection molding. December 2022 PT X Indonesia received customer complaints from PT. Y  because of defects in products such as: gas burn, white spot, weld line, bending, short shoot, bubbles, flashing, silver, wrong color, and contamination. Flashing is a type of defect that the largest number of ratios reaches 10% while the defect restriction of the customer is 2% so the company and the authors choose the theme of improvement in 2018 is the improvement of molding design to reduce flashing defects in plastic products. The method used in the proposed improvement of molding design is the taguchi method by making 4 point suggestion that is the level 1 slot dimension: Hight 70mm taper 15 °, level 2: Hight 70mm taper 10 °, level 3: High 70mm taper 5 °; insert level 1 dimension: 70mm taper insert 1 °, level 2: 70mm taper deepness insert 2 °, level 3: 70mm taper deepth insert 3 °; clamping tolerance force level 1: + 5%, level 2: + 8%, level 3: + 10% and parting line line length 1: 10mm, level 2: 20mm, level 3: 30mm. The proposed best molding design improvements are in Slast dimensions: Hight 70 mm taper 15 °, Insert: 70mm taper deepness 2 °, clamping force tolerance + 10%, Parting Line Length: 30mm. The smallest flashing flaw was found to be 0.1% in confirmatory experimental conditions, much smaller than the specified target defects of 2%. Cost reduction cost obtained by PT ART Mold Indonesia with the proposed repair on Molding design that is Rp 115.600.000,00 per 1 molding. The cost savings incurred by customers of PT ART Mold Indonesia is worth Rp 784.080.000,00 per year
ANALISIS PENGAMBILAN KEPUTUSAN UNTUK PENGADAAN MESIN FOTOCOPY DI PT BCD MENGGUNAKAN PENDEKATAN MODEL MATEMATIKA NET PRESENT VALUE Riki Ridwan Margana; Alifah Nur Astari
Jurnal Lebesgue : Jurnal Ilmiah Pendidikan Matematika, Matematika dan Statistika Vol. 4 No. 3 (2023): Jurnal Lebesgue : Jurnal Ilmiah Pendidikan Matematika, Matematika dan Statistik
Publisher : LPPM Universitas Bina Bangsa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46306/lb.v4i3.524

Abstract

PT BCD is one of the large distributor companies in Bandung, West Java, which distributes medicines, pharmaceutical equipment and various other consumer goods. PT BCD carries out various activities to support the success of its distribution, one of which is administrative activities in the form of printing sales invoices, tax invoices, printing reports, and archiving reports. Every day, more than 1000 copies need to be printed by a photocopier as reporting and archiving material. By 2024, PT BCD management plans to procure 2 photocopy machines because the old ones often experience problems and cause delays in administrative activities. For this procurement, PT BCD management received offers from several vendors in the form of rental or purchase decisions. Due to this problem, the PT BCD procurement team carried out a decision-making analysis for the procurement of photocopy machines at PT BCD using a mathematical economic model approach using the NPV method. From this analysis, a decision was obtained in the form of selecting Vendor B with a purchasing decision for the photocopy machine procurement activity at PT BCD. This decision was taken because Vendor B with a purchase decision was able to provide the most profitable offer, namely IDR 22,152,300,- when compared to the rental decision which set a price of IDR 48,509,800
PERANCANGAN SISTEM PENDUKUNG KEPUTUSAN SEVERITY INKLUSI BAHAN BAKU BAJA DENGAN MENGGUNAKAN LOGIKA FUZZY MAMDANI Riki Ridwan Margana; Yani Iriani; Imtiyaz Imtiyaz
Jurnal Lebesgue : Jurnal Ilmiah Pendidikan Matematika, Matematika dan Statistika Vol. 5 No. 1 (2024): Jurnal Lebesgue : Jurnal Ilmiah Pendidikan Matematika, Matematika dan Statistik
Publisher : LPPM Universitas Bina Bangsa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46306/lb.v5i1.564

Abstract

Steel is one of the raw materials used by PT. XYZ in the manufacture of its defense products; therefore, quality control (QC) and checking process become the most essential part in the process. To ensure that the steel raw materials used reach the standards, metallurgical properties are examined using several criteria must be carried out well, as microstructure, grain size, decarburization and impurities (inclusions). Inclusions or impurities are unwanted non-metal compounds and are the main factor for the initial appearance of ductile fracture and brittle facture during the production process. The severity of the inclusions in steel raw materials affects the next process so that errors in readings to determine the severity of minor or major inclusions must be minimized. This is because when the inclusion severity level that read is included in the major level then the steel raw material cannot be used and turns to be scrap and causes losses to the company. To minimize the matters, operator accuracy is required in analyzing by a comparison table, because this method analyzes the inclusion compounds one by one and it takes ± 1 minute to determine the severity. The purpose of this research is to build a quality decision-making system based on fuzzy mamdani logic that is used to determine the severity of inclusions and to compare the results of system processing with operators to see the accuracy of the system and time efficiency that has been built. In this study using the Mamdani fuzzy logic method with the variables used are Alumina inclusion length, Silicate inclusion length, Alumina inclusion width and Silicate inclusion width. The system is built using matlab software. The system test results from the 6 samples used to obtain comparisons according to the operator and the system are stated to be minor, making the accuracy obtained quite good and in terms of time, the determination process with the system takes less time, namely ± 2 seconds
Co-Authors Alifah Nur Astari Imtiyaz Imtiyaz Irfan Rifai Sri Lestari Yani Iriani Yani Iriani