Tool adhesion occurs when the cutting tool on a CNC lathe sticks to the workpiece material. This phenomenon can lead to material buildup on the tool surface, affecting machining quality and efficiency. To solve this issue, it is essential to understand the material characteristics and the causes of adhesion to provide appropriate solutions.

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1. Aluminum and Its Alloys

Aluminum and its alloys are based on aluminum with added metal elements to improve physical and mechanical properties.

• Pure aluminum: High ductility and low hardness.

• Aluminum-magnesium alloy: Magnesium has a similar melting point to aluminum but higher ductility.

• Aluminum-zinc alloy: Zinc melts at about 419°C, lower than aluminum.

• Aluminum-silicon alloy: Silicon exists as hard and brittle particles, prone to fracture during cutting.

The melting point of aluminum and its alloys is relatively low (~660°C). During machining, contact temperatures may reach 400°C. Although below melting point, this is sufficient to cause tool adhesion. Aluminum alloys have high ductility (10%-30%) and plasticity, which can increase chip formation and the risk of tool sticking.

Effective Solutions:

• Tool material: Use carbide tools.

• Tool coating: Choose tools with diamond or TiN (Titanium Nitride) coatings.

• Cutting parameters: Cutting speed 100–300 m/min, feed rate 0.2–0.5 mm/rev.

• Coolant selection: Use high-efficiency coolant designed for aluminum alloys.

• Cutting oil: Select sulfur-, chlorine-, or phosphorus-containing cutting oils.

• Tool geometry: Edge radius 0.01–0.02 mm, minor edge honing radius 0.02–0.03 mm.

• Technical tips: Check tool sharpness every 30–60 minutes; prefer high-speed cutting.

• Coolant injection: Use high-pressure coolant to ensure complete coverage of the cutting zone.

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2. Copper and Its Alloys

Copper and its alloys are based on copper with added metals to enhance physical and mechanical properties.

• Pure copper: Extremely ductile, relatively soft.

• Brass (copper-zinc alloy): Zinc melts at ~419°C, softens easily, and can adhere to the tool.

• Bronze (copper-tin alloy): High wear resistance but prone to adhesion at high cutting temperatures.

• Aluminum bronze: High hardness, high-temperature cutting may cause tool adhesion.

Effective Solutions:

• Tool material: Use tungsten carbide (WC-Co) with grain size 0.4–0.6 µm.

• Tool coating: TiAlN (Titanium Aluminum Nitride) or SiN coatings to improve heat resistance and reduce adhesion.

• Cutting parameters: Cutting speed 50–200 m/min, feed 0.1–0.3 mm/rev.

• Coolant selection: High-performance coolants for copper alloys, e.g., Castrol Syntilo 9954 or Blaser Blasocut BC25.

• Cutting oil: Sulfur- and chlorine-containing oils, e.g., Castrol Alusol R or Quaker RIMOLINE 70.

• Tool geometry: Edge radius 0.02–0.03 mm, minor edge honing radius 0.03–0.04 mm.

• Technical tips: Check sharpness every 20–40 minutes; use efficient cutting methods.

• Coolant injection: High-pressure coolant to fully cover the cutting zone.

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3. Stainless Steel

Stainless steel is an alloy with chromium (≥10.5%), offering excellent corrosion resistance and mechanical properties.

• Austenitic stainless steel: High toughness and ductility, strong work hardening tendency.

• Martensitic stainless steel: Low thermal conductivity, heat accumulates during cutting, leading to tool adhesion.

• Duplex stainless steel: Combines austenitic and ferritic properties, high strength, good corrosion resistance.

Effective Solutions:

• Tool material: High-hardness, wear-resistant carbide.

• Tool coating: TiAlN or TiSiN coatings for heat resistance and reduced adhesion.

• Cutting parameters: Speed 50–150 m/min, feed 0.05–0.2 mm/rev; moderate speed reduces heat and work hardening.

• Coolant: High-performance coolant for stainless steel.

• Cutting oil: Sulfur- and chlorine-containing oils.

• Tool geometry: Edge radius 0.01–0.02 mm, ensure sharp edges to reduce cutting resistance.

• Technical tips: Check sharpness every 20–40 minutes; use high-speed cutting if possible.

• Coolant injection: High-pressure coolant to fully cover the cutting zone.

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4. Low Carbon Steel

Low carbon steel (<0.25% C) has good toughness and ductility.

• Example: AISI 1018, soft low-alloy steel.

Effective Solutions:

• Tool material: HSS or carbide for wear resistance.

• Tool coating: TiN or AlTiN to enhance wear resistance and reduce adhesion.

• Cutting parameters: Speed 80–150 m/min, feed 0.1–0.3 mm/rev.

• Coolant: High-performance steel coolant.

• Cutting oil: Sulfur- and chlorine-containing oils.

• Tool geometry: Edge radius 0.01–0.02 mm, keep cutting edge sharp.

• Technical tips: Check sharpness every 20–40 minutes; prefer high-speed cutting.

• Coolant injection: High-pressure coolant ensures full coverage.

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5. Low Carbon Steel and Carbon Steel

Carbon content varies, affecting strength and ductility.

• Low carbon steel (AISI 1018): <0.25% C, highly ductile.

• Medium carbon steel (AISI 1045): 0.25–0.6% C, prone to build-up edge.

• High carbon steel (AISI 1095): >0.6% C, high hardness, may stick at high temperature.

Effective Solutions:

• Tool material: Fine-grain tungsten carbide (0.2–0.4 µm).

• Tool coating: TiN, AlTiN, or TiSiN for heat resistance and reduced adhesion.

• Cutting parameters: Speed 80–180 m/min, feed 0.1–0.25 mm/rev.

• Coolant: High-performance coolant suitable for low/medium/high carbon steels.

• Cutting oil: Oils with high-pressure additives.

• Tool geometry: Edge radius 0.01–0.03 mm, sharp edge, smooth to minimize adhesion.

• Technical tips: Check sharpness every 20–40 minutes; use proper cutting fluid for high-carbon steel.

• Coolant injection: High-pressure coolant for full coverage.

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6. Titanium and Its Alloys

Titanium alloys combine high strength, low density, and excellent corrosion resistance.

• Pure titanium: Low thermal conductivity, high strength, prone to tool adhesion.

• Titanium-aluminum alloy: High strength, corrosion-resistant, may react chemically during cutting.

• Titanium-molybdenum alloy: Excellent mechanical properties, poor thermal conductivity, prone to adhesion.

Effective Solutions:

• Tool material: Ultra-fine carbide (<0.5 µm).

• Tool coating: AlTiN or TiSiN for heat resistance and reduced adhesion.

• Cutting parameters: Speed 30–90 m/min, feed 0.1–0.3 mm/rev; low speed to reduce heat.

• Coolant: High-performance coolant for titanium alloys.

• Cutting oil: Oils with high-pressure additives.

• Tool geometry: Edge radius 0.02–0.04 mm, sharp, smooth cutting edge.

• Technical tips: Check sharpness every 20–30 minutes; use high-speed cutting when possible.

• Coolant injection: High-pressure coolant ensures full coverage of cutting zone.