Pratikto Pratikto

Supplier selection is a complex problem in the current Industry 4.0 era. The large number of suppliers with different performance qualities makes it difficult for the company's internal parties to choose the appropriate supplier. The suitability of quality suppliers needed to supply raw materials needed by the industry is an important matter to be resolved. In the hand tractor assembly industry, this small and medium industry is also very dependent on the availability of supply materials, and of course it also depends on the selection of the supplier itself. In this study, the object of research is the 151 hand tractor assembly manufacturing industry using 10 main criteria for selecting suppliers. Each criterion has a weight that is calculated using the Fuzzy AHP method so as to obtain alternative supplier results that are displayed in order. A supplier is a company or individual that provides the raw materials needed by the company and its competitors to produce certain goods. In this study, a decision support system for supplier selection at the company has been developed using the AHP fuzzy method. The results of this study are expected to help companies in selecting suppliers that match the predetermined criteria. In building a decision support system that provides supplier recommendations, the authors apply the AHP fuzzy method in the process. With the Supplier Selection Decision Support System Using the AHP Fuzzy Method, it can help companies in selecting suppliers. Based on the research that has been done, suggestions can be made for a Decision Support System for Supplier Selection Using the Fuzzy AHP Method so that in the future it can facilitate the use of a more dynamic system

Currently, the availability of polypropylene, elastomer and sugar palm fiber (Arenga pinnata) is very abundant, which has a good impact on the potential for the development of new composite materials that have good properties and characteristics. Composites are generally a new material composed of two or more different materials with the aim of producing a new material that has better properties than the constituent material. In this study, polypropylene (PP) plastic and elastomer were used as a composite matrix reinforced with sugar palm fiber (Arenga pinnata). The purpose of this study was to determine the value of tensile strength, impact strength, and bending strength of composites with a weight fraction of 20 % (80:20), 30 % (70:30), and 40 % (60:40). Based on the results of the research on hybrid composites of polypropylene and fiber-reinforced elastomers, composites with a weight fraction of 20 % (80:20) got the lowest tensile strength value of 1.153 MPa, while composites with a weight fraction of 40 % (60:40) obtained the highest tensile strength value of 2.613 MPa. Composites with a weight fraction of 20 % (80:20) got the lowest tensile strain value of 0.0049 and the highest tensile strain value of 0.0067 was found in composites with a weight fraction of 40 % (60:40). For the impact strength, the 40 % (40:60) weight fraction composite got the lowest value of 45248.234 kJ/mm2, while the 20 % (80:20) weight fraction composite got the highest impact strength of 17649.97 kJ/mm2. For bending strength results, the composite with a weight fraction of 20 % (80:20) obtained the lowest bending strength of 1.7778 MPa, while the composite with a weight fraction of 30 % (70:30) obtained the highest bending strength of 4.8867 MPa. The highest bending strain was found in the composite with a weight fraction of 20 % (80:20), which was 0.0207.

Color and light are the main factors in the car manufacturing industry, with not much research, conducted on this topic, related to employee physical comfort. The factor affecting employee work comfort is the color factor and lighting time in their workplace environment. Color is the light, reflected by an object, then interpreted by the eye based on the light that hits the object. The value of the color wavelength in the spectrum of 380 nm to780 nm impacts worker performance. Good lighting will affect whether or not the room’s light conditions affect the illumination’s value. A good working room condition will affect the physical comfort of employees. Employee physical comfort has developed in many previous studies. However, research on the configuration of colors and lighting in the manufacturing industry’s work environment is still underdeveloped. This research aims to measure and determine the impact of color and lighting at specific color wavelengths on the illumination value and the employee’s physical comfort. It starts with studying the color, light, human comfort, then examines the effect on the manufacturing industry employees’ performance in the wiring installation assembly industry. Color and light settings are proven essential to get better human comfort. Green color with a wavelength of 490 nm to 570 can increase the highest illuminate average lux value of 12.43 %. Yellow can increase the heart rate by 4.85 %, while green can reduce Diastole by 2.95 % and Systole by 1.29 %. Pupillary size changes L by 23.17 % and R by 21.43 %. The effect of green color and lighting time can increase the value of illumination and decrease heart rate, blood pressure, and pupil size so that it impacts the physical comfort of employees.

This paper wants to know the effect of bending radius on the distribution of hardness, grain distribution and microstructure on the surface area of tensile stress and compressive stress after bending, quenching and tempering. Material testing helps determine and analyze material quality. The research was conducted on the bending of Hot Rolled Plate Steel material with a radius of 50 mm, 55 mm, 60 mm, 65 mm and 70 mm with a measurement distance of 1 mm, 2 mm and 3 mm, the highest value was obtained at a radius of 55 mm with a measurement distance of 1 mm. After getting the quench-temper treatment with a holding time of 30 minutes, the value of 498 HV was obtained at a radius of 70 mm with a measurement distance of 2 mm. Hardness test was performed using the austenite temperature of 900 °С, microstructure test results obtained finer grains in the compression area r=2.173 µm and in the tensile area r=2.34 µm. This observation aims to determine the microstructure of the material undergoing a heat treatment process at a temperature of 900 °С with a holding time of 30 minutes using water cooling media. The results of the observation of the microstructure of the test specimens before the quench-temper process showed that the structure of ferrite was more abundant than perlite, but after the quench-tempering process the results showed that there was more perlite than ferrite due to the presence of austenite. The treatment on the transformation of the Ar3 line causes the hardness to change the shape of the martensite microstructure into steel while the thickness of the carburizing layer increases with the increase in the carbonization temperature on the surface of the quenched specimen, resulting in the formation of martensite and residual austenite causing the coating to become hard.

Sustainable manufacturing is a critical phenomenon in the process of creating sustainable value. This is a way to increase innovation and resource quality. On the other hand, the partnership strategy is an important factor in efforts to improve company performance. The involvement of the partnership strategy is one of the factors that strengthen the achievement of sustainable values. Furthermore, this affects the sustainability of a manufacturing company's competitiveness, including Small and Medium Enterprises (SMEs). In this study, we focus on creating sustainable value and the role of partnership strategies in improving the business performance of SMEs engaged in the metal manufacturing industry. The Partial Least Squares (PLS) approach to Structural Equation Modeling (SEM) is used to evaluate relationships and effects based on survey data from small and medium industries. The results show that the creation of sustainable value, including products, processes, production, equipment, organization, and human values, has a significant impact (β=0.522; ρ<0.001) on increasing the competitiveness of small and medium enterprises. The effect of sustainable value creation on sustainable competitiveness is fully moderated by the partnership strategy (β=0.179; ρ=0.03), especially in the technology & equipment, and human resources. Apart from being a moderating variable, the partnership strategy has also been shown to significantly act as a partial mediating variable (β=0.135; ρ<0.05) for sustainable value creation in enhancing competitiveness. The partnership strategy's simultaneous involvement proves that the partnership strategy plays an important role in value creation to increase the competitiveness of sustainable manufacturing SMEs

Retailer-Oriented Closed-Loop Supply Chain (ROCLSC) is an integration of forward and reverse supply chains with retailer taking charge of the remanufacturing, distribution, and collecting activities. This type of mechanism is quite effective, since the majority of product returns management is performed by the retailer. However, in practical industries, the implementation of ROCLSC is still limited. In this study, we investigate a ROCLSC system that involves an Original Equipment Manufacturer (OEM) and a retailer. OEM plays a role as a producer of new products, while the retailer is in charge of remanufacturing, collecting, as well as selling and distributing both newly manufactured and remanufactured products. We develop a mathematical model to maximize the profit of each party. Although several studies have developed models for cores acquisition, here we apply a different cores switching mechanism. We introduced the fixed rate and flat rate mechanisms used in the business-to-business (B2B) system, where product functions are very important to consumers. In addition, this research focuses on ROCLSC where most of the existing cores acquisition models are Manufacturer-Oriented Closed-Loop Supply Chain (MOCLSC). The result of this study shows that the retailer will get higher profits when the product returns are acquired through the fixed rate mechanism, rather than the flat rate mechanism. Therefore, determining the optimal amount of cores collected through the fixed rate mechanism will increase the retailer’s profit, as well as joint profit of both parties. From the results, we also point out an interesting note that the retailer should increase efforts to sell new products along with the increasing proportion of consumer Willingness to Pay (WTP) for remanufactured products. Hence, both OEM and retailer profits can be increased consecutively

Welding method for high crack sensitivity of Q&T steel