Selection of suitable tools
- Use high hardness, high wear resistance tools such as carbide or ceramic tools.
- Optimize tool geometries to reduce cut hardening and chip-accumulation tumors.
Table of Contents:
CNC machining of stainless steel: Definitions, Types, Challenges and Processes
- January 16, 2025
- Tony
1. What is CNC machining of stainless steel?
CNC machining of stainless steel is a manufacturing method that uses CNC machinery and equipment to precisely cut and shape stainless steel materials. Due to its high hardness and machining difficulty, stainless steel plays an important role in CNC machining and is widely used in the manufacture of products that require high strength and corrosion resistance.
2. Common types of CNC machining of stainless steel
1. Austenitic stainless steel
- Characteristics: The most common type of stainless steel with excellent corrosion resistance and good molding properties.
- Common types: 304, 316, 316L (316L is a low-carbon version with stronger corrosion resistance).
- Applications: Widely used in food processing equipment, chemical containers and medical devices.
- Processing difficulties: high toughness and low thermal conductivity easily lead to tool wear, cutting requires higher cooling efficiency.
2. Ferritic stainless steel
- Characteristics: Medium strength, excellent resistance to stress corrosion, strong magnetic properties.
- Common types: 430, 409 (430 good corrosion resistance, 409 commonly used in high temperature environments).
- Applications: for automotive exhaust systems, household appliances and industrial machinery parts.
- Processing difficulties: high hardness, easy to cause cutting edge chipping, processing needs to optimize the tool angle.
3. Martensitic stainless steel
- Features: high strength and high hardness, excellent wear resistance, but relatively low corrosion resistance.
- Common types: 410, 420, 440C (440C has the highest hardness and is suitable for cutting tools).
- Applications: Used for high-strength demand components such as knives, bearings and turbine parts.
- Machining difficulties: high hardness, machining requireshigh-performancee tools and precise cooling control.
4. Duplex Stainless Steel
- Characteristics: Combines the properties of austenitic and ferritic stainless steels with excellent strength and pitting resistance.
- Common types: 2205, 2507 (2507 is super duplex stainless steel, stronger corrosion resistance).
- Applications: Widely used in oil and gas pipelines, shipbuilding and chemical equipment.
- Processing difficulties: cutting hardening significantly, tool wear increases, need to adjust the cutting parameters to extend tool life.
5. Precipitation hardening stainless steel
- Characteristics: strengthened by heat treatment, with very high strength and hardness, while maintaining a certain degree of corrosion resistance.
- Common types: 17-4PH, 15-5PH (17-4PH mechanical properties are stable, suitable for high-precision occasions).
- Applications: Widely used in aerospace, military and precision instrument components.
- Difficulty in processing: difficult to process after hardening, requires the use of high hardness tools and precision machine tools.
Each stainless steel model faces different challenges in CNC machining due to its specific properties. Choosing the right CNC cutting tools, coolant and cutting parameters according to the type and model of stainless steel is the key to ensuring machining efficiency and finished product quality.
3. Challenges of CNC machining of stainless steel
- High Strength and Toughness:
Stainless steel’s strength and toughness increase tool wear and lower machining efficiency. - Cutting Hardening:
Machining causes surface hardening, making further cutting more difficult and demanding sharper tools. - Low Thermal Conductivity:
Heat concentrates in the cutting zone, overheating tools, reducing lifespan, and affecting accuracy. - Strong Material Adhesion:
Stainless steel tends to form chip buildup, degrading surface quality and dimensional accuracy. - High Tool Requirements:
Specialized tools like carbide or ceramic are needed; poor selection leads to inefficiency or damage. - Cooling and Lubrication:
Effective cooling is critical to prevent overheating, surface burns, and machining errors. - Complex Parameter Adjustment:
Precise control of feed rate, cutting depth, and speed is vital to avoid vibrations and precision loss. - Material Diversity:
Different stainless steel grades (e.g., 304, 316L, 17-4PH) require tailored strategies, adding complexity.
4. Tips and strategies for CNC machining of stainless steel
Optimization of cutting parameters
- Low cutting speeds for longer tool life.
- Moderate feed rate to avoid cut hardening or tool damage.
- Shallow cutting depth to reduce heat concentration.
Enhance cooling and lubrication
- Select high-efficiency coolant to avoid overheating and surface burns.
- Use high pressure or jet cooling to remove chips.
Avoiding cutting hardening
- Maintain continuous cutting and avoid cutting the same area repeatedly.
- Use sharp tools to minimize surface hardening.
Manage swarf
- Adjust parameters to control chip flow and avoid chip entanglement.
- Use chipbreakers or chip crushers when necessary.
Optimize machining strategy
- Roughing and finishing are done in steps to improve efficiency and accuracy.
- Select different tool combinations according to machining requirements.
Adjustment for material
Different models (e.g. 304, 316L, 17-4PH) need to adjust cooling methods, tools and parameters accordingly.
Use high rigidity machine tool
Improve the rigidity of the machine tool to reduce vibration and ensure machining accuracy.
5. Popular CNC Machining Methods for Stainless Steel
Turning
Turning is widely used to machine external rounds, internal holes, and end faces of stainless steel parts. It removes excess material with a cutting tool to shape the part. Proper control of cutting speed, feed, and depth is necessary to prevent overheating and cutting hardening.
Milling
Milling processes flat surfaces, grooves, and beveled edges by removing material with rotary tools. Choosing the right tool material and geometry enhances efficiency and reduces wear. Common milling cutter materials for stainless steel include carbide and coated tools.
Drilling
Drilling is essential for creating precise holes in stainless steel parts. CNC drilling machines ensure accurate control of hole position, depth, and diameter. Using appropriate speeds and feed rates is important to prevent overheating and tool damage.
Grinding
Grinding is a high-precision method for refining stainless steel surfaces and removing thin layers of material. Selecting the right grinding wheel with high hardness and wear resistance ensures effective results.
Electrical Discharge Machining (EDM)
EDM removes stainless steel material through electrical discharges between an electrode and the workpiece. It’s ideal for machining complex shapes or hard-to-cut stainless steel, offering high precision and excellent surface finish.
Laser Cutting
Laser cutting quickly processes stainless steel, particularly for complex shapes. A high-energy laser beam melts and removes material. This method offers high precision and speed, making it ideal for cutting thin sheet materials.
Waterjet Cutting
Waterjet cutting uses high-pressure water to cut stainless steel without heat, preventing material deformation or hardening. It is suitable for cutting complex shapes and thick materials.
Laser Marking
Laser marking etches text, patterns, or numbers onto stainless steel surfaces by vaporizing or oxidizing the material. It ensures precise, permanent marks that won’t wear off.
6. Surface treatment for CNC machining of stainless steel
Polishing treatment
After CNC machining stainless steel, surface imperfections can be removed by polishing to make it smooth and bright, enhancing the appearance and corrosion resistance. Commonly used in decorative parts and high-end equipment shells.
Brushed treatment
Brushed treatment creates a fine texture on the surface of stainless steel, which not only increases aesthetics, but also improves corrosion and abrasion resistance, and is widely used in the home appliance and automotive industries.
Electroplating treatment
After CNC machining stainless steel, it can be covered with a metal film by electroplating to improve corrosion resistance and appearance, commonly used in electronic products and automotive parts.
Sandblasting
Sandblasting removes surface dirt through high-speed jetting of sand particles, increases surface roughness, and improves coating adhesion and corrosion resistance. It is suitable for industrial equipment and construction materials.
Phosphatizing
Phosphating treatment generates a phosphate film on the surface of stainless steel through a chemical reaction to enhance corrosion resistance, applicable to machine parts and automobile parts.
Nitriding treatment
Nitriding treatment improves the hardness and wear resistance of stainless steel and is suitable for parts that require high strength after CNC machining, such as cutting tools and bearings.
Coating treatment
Coating treatment improves the corrosion resistance and aesthetics of stainless steel by covering it with a protective coating. Commonly used in the construction, aerospace and automotive industries.
Pickling treatment
After CNC machining of stainless steel, pickling removes oxides and dirt, restores metallic luster, and enhances corrosion resistance, especially for cleaning after welding or machining.
7. Industry applications
Automotive industry
CNC machining of stainless steel is widely used in the automotive industry, especially in the production of high-strength components, such as engine parts, exhaust systems, and structural body parts.
Due to its excellent corrosion resistance and high strength, stainless steel is commonly used in the manufacture of automotive parts to ensure the reliability and durability of vehicles in harsh environments.
Aerospace industry
In the aerospace sector, CNC machined stainless steel is used to manufacture critical components such as aircraft structural parts, engine parts and fuel systems.
The strength, corrosion resistance and good high temperature performance of stainless steel materials make them one of the preferred materials for aerospace applications.
Medical industry
CNC machined stainless steel has a wide range of applications in the medical industry, especially in the production of medical devices and implants. For example, surgical instruments, artificial joints, and dental implants are CNC machined from stainless steel.
The biocompatibility, antimicrobial properties and corrosion resistance of stainless steel materials make them ideal for use in the manufacture of medical devices.
Electronics industry
In the electronics industry, stainless steel is commonly used in CNC machining for the manufacture of electronic product housings, connectors and other precision parts.
Its good mechanical properties and corrosion resistance, make stainless steel can effectively protect the internal electronic components to extend the service life of the product.
Chemical and energy industries
Stainless steel is widely used in the chemical and energy industries to produce equipment such as reactors, piping, valves and pumps.
CNC machining can ensure that these zero stainless steel parts of high precision and high temperature resistance, corrosion resistance, to meet the chemical and energy industry in the harsh working environment of the high requirements.
Marine industry
CNC machining stainless steel is widely used in shipbuilding, especially in seawater contact parts, such as hull structural components, pipelines and marine equipment.
Corrosion-resistant stainless steel is able to meet the challenges of the marine environment and ensure the safety and durability of ships.
8. How to improve the efficiency of CNC machining of stainless steel?
- Optimize cutting parameters:
Adjust cutting speed, feed, and depth to improve efficiency and prevent overheating or cutting hardening. - Choose the right tool material:
Use wear-resistant, high-temperature tools like carbide or coated tools to extend tool life and reduce replacements. - Use efficient coolant:
Proper coolant lowers cutting temperature, reduces tool wear, and maintains machining accuracy, improving efficiency. - Optimize tool paths and sequences:
Plan tool paths and sequences to reduce unnecessary movements and idle time, speeding up machining. - Regular tool change and maintenance:
Regularly inspect and replace worn tools, and maintain equipment to ensure stable, efficient machining. - Reasonable cutting strategy:
Use larger cuts for roughing and focus on precision for finishing to improve overall efficiency.
9. Why choose a professional CNC machining service?
Why Choose Professional CNC Machining Services?
Professional CNC machining services ensure high accuracy and quality, meeting tight tolerances. With advanced equipment and technology, specialized companies can handle various materials and complex designs, boosting efficiency, reducing waste, and lowering costs. Custom services and technical support also guarantee timely delivery and optimal results.
How to Choose a Professional CNC Machining Service Provider?
When choosing a CNC machining provider, evaluate their technical capabilities and equipment to ensure they can handle complex tasks. Check their industry experience and customer feedback for consistent quality and on-time delivery.
Trusted providers like Allied Metal, with extensive experience and advanced technology, offer high-quality, customized services at competitive prices, along with after-sales support.
10. Summary
Stainless steel CNC machining is an integral part of modern industry. By mastering the processing skills, choosing the right materials and equipment, it can effectively respond to the processing challenges and broaden the application areas. In the future, with the popularization of intelligent manufacturing technology, stainless steel CNC machining will usher in more innovation and development opportunities.
