CNC Machining Processes

 

CNC Machining Processes: Grooving, Drilling, Boring, and Threading

Here's an overview of CNC processes and tool selection for grooving, drilling, boring, and threading, along with information on axis overtravel.

Grooving

Process: Grooving creates a narrow recess in the workpiece. This can be external (on the outside diameter) or internal (on the inside diameter) and on the face.

Tool Selection:

• Grooving Inserts: These come in various widths, corner radii, and geometries, optimized for specific materials and grooving types.
• Tool Holders: Rigid holders are essential to prevent vibration and ensure accuracy.
• Insert Material: Carbide is common, with coatings to improve wear resistance and tool life.

Considerations:

• Groove Width and Depth: These determine the insert size and the number of passes.
• Material: The workpiece material affects cutting speed, feed rate, and insert grade selection.
• Chip Control: Proper chip formation and evacuation are crucial to prevent tool breakage and poor surface finish.
• Coolant: Applying coolant helps to dissipate heat and improve tool life.

Drilling

Process: Drilling creates holes in the workpiece.

Tool Selection:

• Drills:
  • Twist Drills: General-purpose drilling.
  • Indexable Insert Drills: For larger diameter holes, offering high feed rates and good chip control.
  • Spade Drills: Efficient for deep holes.
  • Center Drills: To create a starting hole for accurate positioning.
• Coolant-Fed Drills: These provide coolant directly to the cutting edge, improving performance and tool life, especially in deep-hole drilling.

Considerations:

• Hole Diameter and Depth: These factors influence drill size, type, and cutting parameters.
• Material: The workpiece material determines drill geometry, coating, and cutting speed.
• Hole Tolerance and Finish: These dictate the need for subsequent operations like reaming or boring.
• Chip Evacuation: Especially important in deep-hole drilling, requiring peck drilling or coolant-fed tools.