DEVELOPMENT DOTTED BOARD MODEL NESTING PROBLEM ON PLACEMENT PROCESS SURFACE TREATMENT AT PT DIRGANTARA INDONESIA

• Main Author: Nur Ikayanti, Chasanah
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/70154
• Institution: Institut Teknologi Bandung

The placement of objects on a media is one of the problems of cutting and packing. Placement problems are generally related to regular shapes, nesting problems are different from 2D cutting & packing problems in general because of the irregular shapes of the pieces. Irregular shapes require handling no usual geometries. The result of the nesting problem is a feasible layout for irregular part shapes. Random placement of objects results in a waste area, the larger the waste area, the more placement media are needed. So, it will affect the processing time. The placement problem purpose to maximize the number of parts to be transported on the board so that the required number of boards is minimum, so the processing time can be faster. Placement of parts into the media board is a difficult problem because there are several considerations such as the orientation of part placement, area limitations, and maximum board weight. The approach used is using the dotted-board model approach developed by Toledo (2013) and Al-Theeb (2021) as a reference model and reference for model development. However, the dotted-board model in previous research does not explain the implementation of dotted in terms of area or shape. In this study, the dotted-board model proposes a mathematical model used to represent the placement of parts on a board by checking the suitability of the shape of the part with the number of dotted horizontally and vertically. If the number of parts and dotted is large, then the number of decision variables (binary) will be even greater and cannot be solved optimally. So, this study proposes heuristic by developing a mathematical model and adding weight constraints. The heuristic model used with the decision variable is the number of parts placed on the board with the maximum area and weight limits. Taking the shape of the part is taken randomly in a batch of production processes. All parts in the queue must be placed on the board within the specified dimensions and no overlapping between parts occurs. In forming a feasible layout solution in this model, it does not consider the orientation rotation in the placement procedure or the limiting function. The development of this model also takes into account when a part has an area that exceeds or is greater than one side of a board which makes placement infeasible because the part exceeds or overlaps the board and part weight considerations. Testing the application of the model using 4 types of parts with a board area of 600unit area and a maximum weight of 300unit weight, obtained a maximum number of parts placed on the board as many as 36 parts with an area gap of 0.041% and a weight gap of 0.006%. By using hypothetical data to perform the surface treatment process for 500 parts, it takes 2.602 minutes.