BibTeX does not have the right entry for preprints. This is a hack for producing the correct reference:
@booklet{EasyChair:4652,
author = {Phatchamon Klinlek and Nara Samattapapong and Vorasiri De Cadenet},
title = {Modeling, Increasing Efficiency and Production Capacity in Melamine Dish Production Line},
howpublished = {EasyChair Preprint 4652},
year = {EasyChair, 2020}}