Guide to Choosing the Right Milling Cutter for Industrial Use

In the realm of precision manufacturing, milling operations play a pivotal role. Milling cutters, serving as the "teeth" of milling processes, come in diverse types with varying performance characteristics that directly impact machining efficiency, accuracy, and surface quality. This guide provides engineers and manufacturers with a thorough reference for selecting appropriate milling tools based on specific processing requirements.

Milling tools can be categorized according to different classification standards:

• Solid End Mills: Feature integrated cutter body and teeth design with compact structure and excellent rigidity, suitable for high-precision machining. However, the entire tool must be replaced when worn, resulting in higher costs.
• Welded Milling Cutters: Utilize teeth fixed to the cutter body through welding, offering lower costs but reduced tooth strength and durability compared to solid end mills.
• Indexable Milling Cutters: Employ replaceable inserts mechanically clamped to the cutter body. The replaceable inserts reduce tooling costs and improve production efficiency, making them the most widely used milling tools today.

• End Mills: Used for face milling, contour milling, slot milling, and represent the most commonly used tools in milling operations.
• Face Mills: Designed for large-area face milling with high processing efficiency.
• T-Slot Cutters: Specialized for machining T-slots, frequently used in machine tool worktables and similar components.
• Keyseat Cutters: Specifically for keyway machining, commonly applied in shaft parts.
• Gear Cutters: Engineered for gear manufacturing with high precision and efficiency.

• Single-Flute End Mills: Generate lower cutting forces, suitable for thin-walled parts or high-precision machining.
• Multi-Flute End Mills: Offer higher cutting efficiency, ideal for heavy roughing operations.

As the most commonly used milling tools, end mills can be further classified by their head shapes:

• Square End Mills: Feature 90-degree right-angle heads for general-purpose machining including face milling, contour milling, and slot milling.
• Ball Nose End Mills: With spherical heads for complex contour machining like surface milling and mold processing. The spherical design prevents hard contact between cutting edges and workpieces, improving surface quality.
• Corner Radius End Mills: Incorporate rounded corners to enhance tool durability and reduce chipping risks, particularly suitable for high-strength materials.
• Tapered End Mills: Feature conical bodies for specialized applications like deep cavity machining and bevel processing.
• Undercutting End Mills (Lollipop Cutters): Characterized by circular heads and slender shanks for machining undercut structures.
• Chamfering End Mills: Designed specifically for part chamfering to improve aesthetics and safety.
• Roughing End Mills: Equipped with multiple serrated cutting edges for rapid material removal in roughing operations.

Primarily used for face milling, these tools feature large-diameter cutter bodies with multiple cutting edges for high-efficiency machining. Unlike the vertical cutting approach of end mills, face mills employ horizontal cutting. They're typically employed for machining large-part planes such as machine tool beds and mold bases.

These specialized tools feature T-shaped heads capable of machining complete T-slot profiles in single operations. Commonly used in machine tool worktables and fixtures for securing workpieces or jigs.

These thin-blade milling tools are primarily for metal cutting. Varieties include:

• Straight Tooth Blades: For softer materials like aluminum and copper.
• Wavy Tooth Blades: For harder materials including steel and iron.
• Trapezoidal Tooth Blades: For thin-walled tubing, minimizing burr formation.

Widely applied in automotive, precision engineering, and construction industries.

These single- or multi-edge rotary tools are primarily for face milling, featuring simple structures and low costs suitable for small-batch production or simple machining. Typically mounted on milling machine spindles for workpiece cutting through rotation.

Specialized tools with specific profiles for machining complex-contour parts. Custom-shaped according to part geometries (e.g., gear cutters, spline cutters), they enable single-operation machining of intricate profiles, enhancing efficiency and precision.

• Convex Radius Cutters: For external convex radii.
• Concave Radius Cutters: For internal concave radii.
• Chamfer Form Cutters: For chamfer machining.

These utilize replaceable inserts (typically carbide or ceramic) mounted on steel bodies. The replaceable inserts reduce tooling costs and boost productivity, making them ideal for heavy roughing or high-hardness material machining.

• Carbon Tool Steel: Low-cost and easy to machine, but with poor wear/heat resistance, suitable for low-speed soft material cutting.
• High-Speed Steel (HSS): Offers good hardness, wear/heat resistance for high-speed cutting, but with poor toughness and chipping susceptibility.
• Carbide: Exceptional hardness, wear/heat resistance for high-speed hard material cutting, though costly and brittle.
• Ceramic: Extreme hardness/heat resistance for high-speed cutting of difficult materials like superalloys and hardened steel, but extremely brittle.
• Cermet: Combines ceramic/metal advantages with good hardness, wear/heat resistance and moderate toughness, ideal for finishing/semi-finishing.
• Stellite: Non-ferrous alloy with excellent wear/heat resistance for high-temperature, high-speed cutting.

Appropriate cutter selection requires comprehensive evaluation of:

• Workpiece Material: Different materials demand specific tool materials and geometries.
• Machining Requirements: Varying needs dictate different tool types and precision levels.
• Machine Capability: Power, speed, and rigidity influence tool selection.
• Tool Dimensions: Must match workpiece size and machining range.
• Cost Efficiency: Select cost-effective options while meeting processing requirements.

Milling depth and width directly determine cutter size. Generally, larger machining dimensions require larger tools, with typical diameters ranging from Φ16-Φ630mm.

For large-area parts, smaller-diameter cutters are recommended, ideally with about 70% cutting edge engagement. Machine spindle diameter also influences selection - face mill diameter (D) should be approximately 1.5 times the spindle diameter (d): D = 1.5d.

Hole milling particularly requires careful diameter selection, as improper sizing may damage workpieces or tools.

Cutting power and workpiece size are critical factors. For face mills, ensure required power falls within machine capacity. For small end mills, verify machine maximum RPM meets minimum cutting speed requirements (typically 60m/min).

Tooth count significantly impacts performance. For example, a 100mm diameter cutter might have 8 teeth (fine-pitch) or 6 teeth (coarse-pitch). Coarse-pitch tools with larger chip pockets reduce friction among workpiece, tool body, and chips, making them better for roughing.

Note: At identical feed rates, fine-pitch tools impose less load per tooth than coarse-pitch versions.

Finishing typically uses ground inserts for dimensional accuracy, edge positioning precision, and superior surface finish. Roughing benefits from pressed inserts for cost reduction. Small-depth/feed operations with non-sharp positive rake carbide inserts may shorten tool life.

The primary distinction lies in cutting direction - end mills can cut with both end and side edges, while face mills primarily perform horizontal cutting.

These versatile tools machine specific shapes and holes, suitable for milling, copying, profiling, boring, slotting, and drilling. With cutting teeth on both ends and sides, they effectively cut various materials in multiple directions.

Several differences exist: drills create holes and thus require point angles for positioning, while mills for face milling lack such angles. Additionally, drills feature tapered bottoms for workpiece penetration, whereas mills have flat bottoms.