Lean Manufacturing and MRP to streamline the production of metal structures in the construction industry

Authors

Lopez-Uchuya, Keimy

Zamudio-Guido, Victor

Altamirano Flores, Ernesto

Abstract

The construction industry is one of the most demanded sectors in the Peruvian market and this is reflected in its contribution to the national GDP, which since 2017 has maintained a constant growth of no less than 4%, however, one of the problems The ones he constantly complains about are the late deliveries of projects. It was found that 67% of Peruvian construction companies deliver their works out of date. Internally, the lack of specialization of the companies that proliferate in a country with high rates of informality such as Peru is observed. This leads to internal problems that eventually end up delaying the delivery of projects. Through comparisons of the sector, it has been found that the common delay of the most successful companies in the sector does not exceed 11 days, a situation that is not reflected in the majority of construction companies, which are mostly small or medium-sized companies with almost null knowledge of useful tools that engineering has to offer. The case study evaluated in this research, Yañac SAC, is a construction company dedicated to various services, among which is the assembly of metal structures for construction such as beams and columns. This company presents delays in the deliveries of its projects, which generates costs that amount to s/127,405.39 and, to combat this, the Lean Manufacturing methodology and its tools are applied, among which is Value Stream Mapping, 5S and SMED. in combination with MRP1 to reduce the impact of the problem. Finally, as a result of the simulation, it was possible to obtain a model within the 5% error with respect to the real production and applying the improvements in the productive times from the investigation of scientific articles, an improvement of 22% was found with respect to the initial scenario. , managing to meet up to 459 production requests for beams and columns per month. From the economic validation, a NPV greater than 0, an internal rate of return (IRR) greater than the COK, and a benefit-cost ratio greater than 1 were determined, indicating that the project is profitable. Similarly, a low level of social and environmental impact was determined, so it is concluded that the project is viable in these two aspects.