A Study of Comparing CAD/CAM Simulated Machining Time with Practical CNC Machining Time and the Influence of the Parameter Setting in CNC

• Main Author: Wan, Jinming
• Format: Dissertation
• Language: English
• Published: Ann Arbor ProQuest Dissertations & Theses 2018
• Subjects: Engineering; Mechanical engineering
• ISBN: 9780438227354; 0438227352

CNC machining is characterized by high precision, efficiency, and reliability, which make it the popular choice in the manufacturing industry. It can satisfy the diverse, quickly-changing market needs. The integration of CAD/CAM with CNC makes the machining process simpler and more convenient. Specifically, the 3D visualization and simulation in CAD/CAM software significantly reduce the design time and help identify earlier any incorrect processing step in the practical CNC machining.
Nevertheless, there is still a strong demand to improve the integration of CAD, CAM and CNC to achieve even more efficient CNC machining. To realize this goal, the following problems need to be addressed. First, the current CNC machining program has many parameters, which generate a huge number of parametric combinations, making it difficult for an operator to do correct machine settings, especially for a beginner. Second, the software's simulated results cannot truly reflect the practical machining process, resulting in the vast number of trials in order to seek the machine setting and consequently causing the increasing cost for the real production process. Third, because the CAD/CAM software does not include many key factors that affect the CNC machining process, it cannot reveal the actual machining process.
This research compares the simulated machining time with the practical machining time in order to figure out whether the CAD/CAM software can reflect the practical machining process. Meanwhile, the design of experiments is used to discover what kind of influences the tool paths present in machining time and tool life and how cutting tools affect the machining processes. Through such a systematic approach, this research is able to identify the optimal parameters for the practical CNC machining.
In conclusion, the CAD/CAM software cannot accurately reflect the situation of a practical CNC machining process. To prevent tool wear, the tool path should avoid abrupt turns and thus prevent the generation of severe cutting forces. For the same machining geometry, different tool paths need to use different cutting tools to get desirable results. Specifically, the outside cutting method needs to use large-diameter cutting tools with more flutes while the inside cutting method should use small diameter cutting tools with fewer flutes to take chips away.