This document summarizes simulation of CNC machining processes in PTC CREO. It discusses the various steps involved in milling simulation in CREO including reference models, workpieces, operations, and fixtures. It also covers types of milling simulations like profile, face, volume, and pocket milling. The document then presents a case study on simulating the machining of an arm board and chassis for an LP12 turntable. Several issues encountered are discussed like left over material in corners and thin ribs. The simulations were used to generate G-code for CNC machining testing in foam.