# Witness Report

2201 WordsAug 18, 20089 Pages
EBUS 504 Operations Modeling and Simulation Assignment 1: Witness Simulation Model Vivian WM Lam Student ID: 200251181 Part 1 – The Assembly Machine The Model: The Model Report: Machines: Parts: Buffers: The Optimum Operation Parameters: Inter arrival time: 16 (shortest machine cycle time & set-up time) Expected Maximum output for the system: (5000 -11) / 16 =311.8125 =311 (as expected) Reason: In order to achieve the OOP, first we need to find what is the shortest time needed for both parts to be ready to be assembled by MA A = 15 (machine runs time) + 1 (set-up time) =16 B = 12 (machine runs time) + 1 (set-up time) =13 Part B is already ready for the assembly machine after 13 minutes of running; but the assembly machine still needs both parts to make part D. Part A is finally ready after 16 minutes (critical time). The critical time can then be used to set as the inter arrival time. Enhancing System Performance In order to optimize the model’s performance, buffers have been used at the end of M1 and M2. The reason being the mode’s “one task at a time” nature; since the MA machine can only pull one part from either M1 or M2, not using buffer will mean (in the long term) that parts will get built up in machines and eventually reduce production efficiency. Since part A requires the longest time to be produced; In case MA is busy collecting parts B, part A will have to wait in the machine until it gets pick up by MA. Using buffers immediately corrects the problem and optimize the entire progress. For the optimum size of buffers: 1 Evidence: (The max value for the buffer is always 1) For 5000m: For 10000m: Part 2 – Flexible Manufacturing Cell Part A: The Model: Model Report: Parts: Buffer: Machines: Optimum Inter-arrival Time: M1 =