Guide to Choosing Sandvik Coromant Turning Inserts

Turning, as one of the core processes in metal cutting, sees its efficiency and precision largely determined by tool selection. Among various tool types, turning inserts play a pivotal role. Choosing the most suitable insert for specific machining requirements directly impacts production efficiency, machining quality, and tool life. Sandvik Coromant, as a global leader in cutting tools, offers a comprehensive range of turning inserts covering various materials, machining methods, and working conditions.

Imagine this scenario: you're facing an urgent turning task requiring high-precision part machining within tight deadlines. However, due to improper insert selection, you encounter frequent vibration, chipping, and even workpiece rejection, severely impacting production schedules and quality. Such situations not only cause frustration but also significant financial losses for manufacturers.

Selecting the appropriate turning insert requires careful consideration of multiple parameters including insert geometry, material grade, shape (nose angle), size, nose radius, and lead angle. These interdependent factors collectively determine cutting performance, durability, and machining suitability.

Insert geometry is crucial for chip control and machining performance. Based on different requirements, insert geometries fall into three basic categories:

• Finishing: Designed for small depths of cut and low feed rates, featuring sharp cutting edges and reduced cutting forces for superior surface finish.
• Medium: Versatile geometry suitable for medium to light roughing operations, offering good adaptability in depth of cut and feed rate.
• Roughing: Engineered for heavy depths of cut and high feed rates, featuring maximum edge strength and wear resistance for demanding conditions.

Material grade selection depends on workpiece material, machining method, and conditions. Common material classifications include:

• ISO P (Steel): For carbon steel, alloy steel, and tool steel machining.
• ISO M (Stainless Steel): For austenitic, ferritic, martensitic, and duplex stainless steels.
• ISO K (Cast Iron): For gray iron, ductile iron, and compacted graphite iron.
• ISO N (Non-ferrous): For aluminum, copper, and magnesium alloys.
• ISO S (Heat-resistant): For nickel-based, cobalt-based, and titanium alloys.
• ISO H (Hardened): For hardened steels and high-hardness cast irons.

The nose angle determines insert shape, with larger angles offering greater strength but requiring higher cutting forces and machine power:

• Large Nose Angle: Higher edge strength allows increased feed rates but generates more vibration. Ideal for heavy roughing of rigid workpieces.
• Small Nose Angle: Reduced cutting forces minimize vibration, suitable for thin-walled or slender workpieces but limited in depth of cut.

Size selection depends on depth of cut and toolholder space:

• Large Inserts: Offer better stability and edge strength for heavy machining.
• Small Inserts: Preferred for finishing or space-constrained applications.

This critical parameter affects surface finish, chip control, and insert strength:

• Small Radius: Better for light cuts with reduced vibration but lower strength.
• Large Radius: Enables heavier cuts with higher feed rates but increases radial forces.

Generally, nose radius should equal or be smaller than depth of cut to minimize vibration.

The angle between cutting edge and feed direction influences chip formation and force direction:

• Large Lead Angle: Directs forces toward chuck, reducing vibration but increasing cutting forces.
• Small Lead Angle: Reduces edge load, enabling higher feeds but increasing radial forces.

Wiper geometry improves surface finish at standard parameters or increases feed rates while maintaining finish quality:

• -WMX: Broadest chip range for maximum productivity.
• -WL: Improves chip control at reduced feeds/depths.
• -WF: Reduces cutting forces for vibration-prone operations.
• -WR: Enhanced edge strength for interrupted cuts.

• Positive Rake: Single-sided with low cutting forces, ideal for internal turning and slender workpieces.
• Negative Rake: Double/single-sided with high edge strength, preferred for external turning and heavy conditions.

Optimal turning insert selection requires balanced consideration of geometry, material grade, shape, size, nose radius, and lead angle. By analyzing workpiece requirements and consulting technical resources, manufacturers can significantly enhance machining performance while reducing production costs. Special geometries like Wiper and rake angle variations provide additional optimization opportunities for specific applications.