A complete analysis of the top 10 CNC machining materials: material selection and process guide from aluminum to stainless steel
A complete analysis of the top 10 CNC machining materials: material selection and process guide from aluminum to stainless steel
In the field of CNC machining, the choice of materials directly affects machining efficiency, part quality and production costs. Different materials have unique physical and mechanical properties, such as hardness, thermal conductivity, ductility and wear resistance, which determine cutting parameters, tool selection and machining strategies.
This article will analyze in detail 10 common CNC machining materials, including aluminum, low carbon steel, titanium, brass, tool steel, high temperature alloy, copper, alloy steel, stainless steel and plastic, analyze their processing characteristics, applicable scenarios and optimization solutions, and help engineers and manufacturers make more scientific material selection decisions.
1.Detailed introduction to the top 10 CNC machining materials
(1) Aluminum
1) Characteristics and advantages
Lightweight: low density (2.7 g/cm³), suitable for aerospace and automotive lightweight parts.
High thermal conductivity: fast heat dissipation, suitable for electronic heat sinks and LED housings.
Easy to process: small cutting force, low tool wear, suitable for high-speed machining.
2) Difficulties in processing
Tool sticking problem: Aluminum chips easily stick to the tool, affecting the surface finish.
Thermal expansion: Temperature changes may cause dimensional errors.
3)Optimization plan
Tool selection:
Use sharp carbide tools, diamond coating is recommended (to reduce built-up edge).
2-edge or 3-edge milling cutter, large chip groove design.
Cutting parameters:
Speed (S): 2000-8000 RPM (depending on the rigidity of the machine tool).
Feed (F): 0.1-0.3 mm/tooth.
Cooling method: air cooling or water-soluble cutting fluid (avoid aluminum oxidation caused by oil-based coolant).
4)Typical applications
UAV frames, automobile engine blocks, 3C product housings.
(2) Low carbon steel (such as A36, 1018)
1) Characteristics and advantages
Low cost: widely used in structural parts and mechanical parts.
Good weldability and machinability: suitable for turning, milling and drilling.
2)Processing difficulties
Easy to produce burrs: need to be deburred later.
Medium and low hardness: long chips may be generated during cutting, affecting chip removal.
3)Optimization plan
Tool selection:
High-speed steel (HSS) or coated carbide tools (TiN/TiCN).
Cutting parameters:
Turning: VC=100-200 m/min, f=0.1-0.3 mm/rev.
Milling: S=500-1500 RPM, F=500-1000 mm/min.
Cooling method: emulsion or oil-based cutting fluid.
4)Typical applications
Shaft parts, gears, brackets.
(3) Titanium (such as Ti-6Al-4V)
1) Characteristics and advantages
High strength + lightweight: better specific strength than steel, used in aviation and medical implants.
Corrosion resistance: suitable for chemical and marine environments.
2)Processing difficulties
Low thermal conductivity: cutting heat is concentrated in the tool, resulting in rapid wear.
Work hardening: Hardened layer is easily produced during cutting, which increases tool wear.
3)Optimization plan
Tool selection:
Diamond coating or CBN (cubic boron nitride) tools.
Cutting parameters:
Low speed (VC=30-60 m/min), large cutting depth (reduce work hardening).
Cooling method: High-pressure coolant (>70 bar) or liquid nitrogen cooling.
4)Typical applications
Aircraft engine blades, artificial joints, racing car parts.
(4) Brass (such as C36000)
1) Characteristics and advantages
Easy to cut: Leaded brass (C36000) has short chips and is suitable for precision turning.
Corrosion resistance + good conductivity: used for electronic connectors and musical instruments.
2) Processing difficulties
Soft materials are easy to deform: deformation caused by over-tightening should be avoided.
3)Optimization plan
Tool selection:
High-speed steel or uncoated carbide tools (sharp cutting edge).
Cutting parameters:
High-speed cutting (VC=150-300 m/min), high feed (f=0.2-0.5 mm/rev).
Cooling method: dry cutting or minimal lubrication (MQL).
4)Typical applications
Faucet valve core, musical instrument reed, electrical terminal.
(5) Tool Steel (such as D2, H13)
1) Characteristics and advantages
High hardness + wear resistance: used for molds and stamping tools.
The hardness can reach HRC 60+ after heat treatment.
2)Processing difficulties
The tool wears quickly: high wear-resistant tools are required.
3)Optimization plan
Tool selection:
CBN or ceramic tools (finishing), carbide (roughing).
Cutting parameters:
Low speed (VC=50-100 m/min), small cutting depth (ap<1 mm).
Cooling method: oil-based cutting fluid (reduce thermal shock).
4)Typical applications
Injection molds, stamping molds, tool cutting tools.
(6) High-temperature alloys (such as Inconel 718)
1) Characteristics and advantages
High temperature resistance: can maintain strength in environments above 700°C, suitable for aircraft engines and gas turbines.
High strength + corrosion resistance: suitable for extreme environments (such as oil and nuclear power equipment).
2)Processing difficulties
Severe work hardening: the material hardens during cutting, causing tool edge breakage.
High cutting force: requires a high-rigidity machine tool, otherwise it is easy to vibrate.
Poor thermal conductivity: cutting heat is concentrated on the tool, shortening its life.
3)Optimization plan
Tool selection:
Ceramic tools (Al₂O₃/Si₃N₄) or CBN (cubic boron nitride).
Special groove design (enhanced chip breaking ability).
Cutting parameters:
Extremely low speed (VC=20-50 m/min), small cutting depth (ap<0.5 mm).
High feed (f>0.1 mm/rev) to reduce work hardening.
Cooling method:
High-pressure cooling (>100 bar) or low-temperature cold air.
4)Typical applications
Aircraft engine blades, rocket nozzles, nuclear power valves.
(7) Copper (such as C11000)
1) Characteristics and advantages
High electrical/thermal conductivity: used for electronic components and radiators.
Corrosion resistance: suitable for marine and chemical environments.
2)Processing difficulties
High viscosity: chips are easy to stick to the tool, affecting the surface quality.
Low hardness and easy to deform: clamping should be cautious.
3)Optimization plan
Tool selection:
Diamond-coated tools (mirror processing) or sharp cemented carbide.
Large rake angle (γ>15°) reduces cutting force.
Cutting parameters:
High-speed cutting (VC=200-400 m/min), medium feed.
Cooling method:
Dry cutting or minimal lubrication (MQL) to avoid oxidation.
4)Typical applications
Circuit board electrodes, heat exchangers, and artwork engraving.
(8) Alloy steel (such as 4140, 4340)
1) Characteristics and advantages
High strength + toughness: hardness can reach HRC 30-50 after quenching and tempering.
Good wear resistance: used for gears and shaft parts.
2)Processing difficulties
Difficult processing after heat treatment: cutting parameters need to be adjusted.
3)Optimization plan
Tool selection:
Coated carbide (TiAlN) or CBN (finishing).
Cutting parameters:
Before quenching and tempering: VC=150-250 m/min.
After quenching and tempering: VC=80-120 m/min, small cutting depth.
Cooling method:
Emulsion or oil-based cutting fluid.
4)Typical applications
Automobile crankshafts, hydraulic rods, mold inserts.
(9) Stainless steel (such as 303, 316)
1) Characteristics and advantages
Corrosion resistance: Contains chromium to form a passivation film, suitable for food and medical.
Aesthetics: Commonly used for appearance parts.
2)Processing difficulties
Processing hardening: Low-speed cutting can easily lead to surface hardening.
Difficult chip breaking: Long chips wrap around the tool.
3)Optimization plan
Tool selection:
High-cobalt high-speed steel (HSS-Co) or metal ceramics.
Sharp cutting edge + chip breaker design.
Cutting parameters:
Medium to high speed (VC=50-150 m/min), avoid low speed.
Cooling method:
High lubricity cutting oil.
4)Typical applications
Surgical instruments, chemical pipelines, high-end kitchenware.
(10) Plastics (such as PEEK, nylon)
1) Characteristics and advantages
Lightweight + insulation: used in electronics and medical treatment.
Chemical corrosion resistance: Some plastics (such as PTFE) are acid and alkali resistant.
2)Processing difficulties
Thermal deformation: low melting point, easy to melt due to overheating.
Elastic recovery: the size may rebound after processing.
3)Optimization plan
Tool selection:
Single-edge or double-edge sharp milling cutter (reduce cutting heat).
Zero rake angle or negative rake angle (enhanced chip evacuation).
Cutting parameters:
High speed (S>5000 RPM), low feed (F<500 mm/min).
Cooling method:
Compressed air cooling to prevent cutting fluid from corroding plastic.
4)Typical applications
Insulation gaskets, bearing bushings, 3D printing post-processing.
2. Summary and selection suggestions for CNC machining materials
Material comparison quick reference table:
3. Detailed description of material selection principles
In CNC machining, material selection needs to comprehensively consider the functional requirements, use environment, cost budget and processing feasibility of the parts. The following is a more detailed introduction to the material selection principles:
(1) Strength priority principle
For parts that need to withstand high loads or impacts, high-strength materials should be given priority:
1) Ultra-high strength requirements (such as aviation structural parts, armor plates):
Titanium alloy (Ti-6Al-4V) and nickel-based high-temperature alloy (Inconel 718) are preferred. Although these materials are difficult to process, they have excellent specific strength and fatigue resistance. For example, aircraft engine blades must use high-temperature alloys to withstand mechanical stress under extreme temperatures.
2) Medium strength requirements (such as molds and drive shafts):
Alloy steel (such as 4140, 4340) or tool steel (such as D2, H13) can be used. After quenching and tempering, these materials can reach a hardness of HRC 30-50 and have good wear resistance, making them suitable for manufacturing key components such as gears and crankshafts.
(2) Lightweight demand principle
In the automotive, aerospace and other fields, weight reduction is the core goal:
1) Metal lightweight:
Aluminum alloy (such as 6061, 7075) is the most common choice. Its density is only 1/3 of that of steel and it is easy to process. For scenarios with higher requirements (such as aerospace fasteners), titanium alloy can be used. Its strength is equivalent to that of steel but its weight is reduced by 40%.
2) Non-metallic solutions:
Engineering plastics (such as PEEK and carbon fiber reinforced plastics) can significantly reduce weight while ensuring strength, and are suitable for drone frames, medical devices, etc. For example, spinal implants made of PEEK are both lightweight and have X-ray penetration.
(3) Corrosion resistance/high temperature resistance principle
Material selection in harsh environments requires special attention to chemical stability and thermal stability:
1) Chemical/marine environment:
Austenitic stainless steel (such as 316L) contains molybdenum and is resistant to chloride corrosion, making it an ideal material for seawater pipelines. Duplex stainless steel (such as 2205) combines high strength and corrosion resistance.
2) High temperature environment (>800°C):
Nickel-based high-temperature alloys (such as Inconel 625) maintain high temperature strength through solid solution strengthening and are used in gas turbine combustion chambers. If cost is limited, heat-resistant stainless steel (such as 310S) can be selected.
(4) Functional property principle
Specific functional requirements directly affect material selection:
1) Conductive/thermal conductive components:
Oxygen-free copper (C10100) has a conductivity of up to 100% IACS and is the first choice for high-voltage cables. Aluminum alloys (such as 1050) have excellent heat dissipation performance and are widely used in LED substrates.
2)Electromagnetic shielding:
Brass (C36000) combines conductivity and easy processing and is suitable for 5G base station shielding covers.
(5) Economic principle
Reduce costs while meeting performance requirements:
1) Mass production:
Low carbon steel (A36) and free-cutting steel (12L14) have low raw material costs and low tool wear. For example, these materials are often used in standard fasteners.
2) Rapid prototyping:
ABS plastic processing costs are only 1/5 of metal, which is suitable for verification parts.
4. Summary
In actual production, the choice of materials often determines the success or failure of a product. This article systematically sorts out the characteristics and application scenarios of various materials in CNC machining, hoping to provide a practical reference for your production decisions. It is recommended that readers can:
Establish a material performance database for quick comparison and selection
Carry out small-batch trial processing and verification for key parts
Regularly communicate with suppliers and manufacturers to understand the latest material development trends
Combined with CNC machining technology, optimize the matching plan of materials and processes
Only by deeply understanding the characteristics of materials can the potential of CNC machining be fully realized. We look forward to your exploration of CNC machining materials solution that are more suitable for your own products in practice.
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