CNC machining depends on the right tools, tool materials, and workholding methods. Good tooling helps create precision parts, keeps machines stable, and improves surface finish. Both CNC milling and CNC turning use different tools based on the shape and type of part being made.
5.1 Cutting Tools for Milling
CNC milling uses rotating tools that move along several axes to shape the workpiece. The most common milling tools are:
End Mills
End mills are multi-point cutters used for pockets, slots, and sharp edges. They are excellent for detailed or complex features in metals and plastics.
Face Mills
Face mills are used to create flat surfaces. They remove material quickly, making them ideal for large, smooth faces on a part.
Ball-Nose Cutters
These tools have a rounded end. They are used for curved shapes, 3D surfaces, and smooth contours—common in aerospace, automotive, and product design work.
5.2 Cutting Tools for Turning
CNC turning uses tools that stay still while the workpiece spins. These tools shape round or conical parts.
Inserts
Inserts are small replaceable cutting tips. They come in different shapes for roughing, finishing, or threading.
Boring Bars
Boring bars enlarge holes inside a rotating workpiece. They help make accurate internal diameters.
Threading Tools
Threading tools cut internal or external threads on shafts, rods, and other round parts.
5.3 Tool Materials
The material of the cutting tool affects speed, strength, and durability.
Carbide
Carbide tools are very hard and heat-resistant. They are great for high-speed cutting and tough metals.
HSS (High-Speed Steel)
HSS is more flexible and less brittle than carbide. It works well for general machining and softer materials.
Coated Tools
Coatings, such as TiN or TiAlN, help tools last longer by reducing heat and friction. They improve performance in both milling and turning operations.
5.4 Workholding Methods
Workholding keeps the part secure during machining. The method depends on whether the part is being milled or turned.
Milling Workholding: Vises, Clamps, Fixtures
- Vises hold small to medium parts tightly.
- Clamps secure flat or large pieces.
- Fixtures are custom setups used for complex shapes or high-repeat jobs.
Turning Workholding: Chucks, Collets
- Chucks grip the outside of round parts.
- Collets hold small or delicate pieces with high accuracy.
Good workholding improves precision, safety, and surface finish.
5.5 Toolpath Types and Programming Strategies
Toolpaths guide the cutting tool through the material. They are created in CAD/CAM software and turned into G-code for the CNC machine.
Common toolpaths include:
- Facing (cleaning the surface)
- Profiling (cutting the outer shape)
- Pocketing (removing material inside a shape)
- Drilling (making holes)
- Turning passes (roughing and finishing on round parts)
Good programming strategies focus on:
- reducing cycle time
- protecting the tool
- improving accuracy
- achieving a better surface finish
Manufacturers use these strategies to produce high-quality CNC machined parts for automotive, aerospace, medical, electronics, and industrial applications.