CNC Process Planning and Sequencing

 

CNC Process Planning and Sequencing

CNC process planning and sequencing involves determining the most efficient and effective order of operations to transform a raw workpiece into a finished part using a CNC machine. This includes:

• Operation Selection: Identifying the necessary machining operations (e.g., facing, turning, drilling, milling, tapping, grinding).
• Machine Selection: Choosing the appropriate CNC machine based on part geometry, size, tolerance requirements, and available machine capabilities.
• Setup Planning: Defining how the workpiece will be fixtured and oriented for each operation, including the selection of workholding devices (e.g., vises, chucks, fixtures).
• Sequencing: Arranging the selected operations in a logical order to ensure efficient material removal, maintain part accuracy, and minimize tool changes and setups. Common sequencing principles include:
• Roughing before Finishing: Removing the bulk of the material in roughing passes before achieving the final dimensions and surface finish with finishing passes.
• Datum Priority: Machining critical datum surfaces early in the process to establish accurate references for subsequent operations.
• Face before Hole: Machining flat surfaces before drilling or tapping holes that rely on these surfaces for location.
• Inside before Outside: