How to choose turning inserts scientifically?
The selection of turning inserts directly affects machining efficiency, tool life and workpiece quality. The following analyzes the key decision logic from five dimensions: material properties, geometric parameters, coating technology, machining scenarios and economy.
Blade material: "hardness" matching the processing material
Classification of cemented carbide grades
YG type (cobalt-based): suitable for cast iron and non-ferrous metals, such as YG6X (rough machining), YG3X (finishing machining)
YT type (titanium-based): used for steel cutting, such as YT15 (general purpose), YT30 (finishing machining)
YW type (universal alloy): the first choice for stainless steel and heat-resistant alloys, such as YW1 (general purpose), YW2 (wear-resistant)
Ceramic blades: suitable for high-hardness materials (HRC45 and above), but brittle and require low feed
CBN blades: the ultimate choice for high-speed machining of hardened steel (HRC55+) and cast iron
Geometric parameters: the "invisible code" that determines cutting performance
1.Tip radius (rε)
Rough machining: 0.8-1.2mm (increase strength)
Fine machining: 0.4-0.8mm (reduce surface roughness)
Intermittent cutting requires a smaller radius to reduce impact
2.Rake angle (γ0)
Positive rake angle (8°-15°): low cutting force, suitable for aluminum alloys and stainless steel
Negative rake angle (-5°-0°): high rigidity, used for steel and cast iron
3.Back angle (α0)
Rough machining: 6°-8° (reduce back tool wear)
Fine machining: 10°-12° (reduce friction)
4.Edge treatment
Honning edge (0.02-0.05mm): general processing
Chamfered edge (0.05-0.2mm×-15°): intermittent cutting and anti-chipping
Coating technology: "magic armor" that increases lifespan
1.General coating
TiAlN (gold): resistant to high temperature oxidation (1100°C), suitable for steel parts
TiCN (gray): high hardness, suitable for cast iron
AlCrN (blue-gray): anti-adhesion in stainless steel processing
2.Special coating
Diamond coating: ultra-fine processing of aluminum alloy and graphite
Composite coating (such as TiAlN+MoS2): anti-friction in stainless steel deep hole processing
Processing scenario adaptation: optimal solution under different working conditions
Practical skills: Quick diagnosis of blade failure
Flank wear (VB>0.3mm): coating failure or excessive feed
Broken edge: insufficient edge strength, need to increase chamfer or reduce cutting depth
Built-up edge: low cutting temperature, increase linear speed or use sulfur-containing coating
When selecting turning inserts, it is necessary to establish a four-dimensional coordinate system of "material - geometry - coating - working conditions" and dynamically optimize it in combination with the actual processing conditions of the enterprise. It is recommended to verify the parameters through the cutting database provided by the manufacturer, and pay attention to the specifications of the ISO 1832 standard for insert models, so as to achieve a leap from empirical judgment to scientific decision-making.
