CNC machines have revolutionized manufacturing by performing various machining operations with unmatched precision and consistency.
This capability is largely due to the variety of CNC machining tools, each tailored to specific tasks.
These tools reduce the need for manual intervention, minimizing errors caused by fatigue or inconsistencies from human operators.
Among the various tools, CNC cutting tools stand out as the most commonly used due to their versatility.
Však, CNC machine tools encompass much more, including turning, vrtání, and grinding tools, each with unique features that cater to diverse machining needs.
This article explores the different types of CNC machine tools, breaking down their functions and applications.
If you’re interested in understanding these essential tools, read on for a comprehensive guide.
1. CNC Milling Tools (CNC Cutting Tools)
CNC frézování tools are versatile and can perform a wide range of operations, včetně řezání, vrtání, and shaping.
They are used in milling machines, which rotate a multi-point cutting tool to remove material from the workpiece.
Here are some of the most common types of CNC milling tools:
End Mills
Definition and Basic Function: End mills are used for slotting, profiling, and contouring.
They are one of the most commonly used milling tools and can perform a variety of operations on the workpiece.
Features:
- Flute Count: End mills come with different numbers of flutes (cutting edges).
Fewer flutes (NAPŘ., 2-flute) are better for roughing operations, while more flutes (NAPŘ., 4-flute) are better for finishing operations. - Helix Angle: The helix angle affects the chip evacuation and cutting force. Higher helix angles (NAPŘ., 45°) provide better chip evacuation and smoother cuts.
- Materiál: End mills are commonly made from high-speed steel (HSS), carbide, or coated materials to enhance performance.
Slab Mills
Definition and Basic Function: Slab mills are used for heavy-duty milling operations, such as cutting large, flat surfaces.
They are designed to remove large amounts of material quickly and efficiently.
Features:
- Large Diameter: Slab mills have a larger diameter compared to other milling tools, allowing them to cover a wider area in a single pass.
- Multiple Teeth: They have multiple teeth for rapid material removal and smooth finishes.
- Strong Construction: Slab mills are built to withstand the high forces generated during heavy cutting operations.
Face Mills
Definition and Basic Function: Face mills are used for flat surface finishing. They are designed to provide a smooth, high-quality finish on the workpiece.
Features:
- Replaceable Inserts: Face mills often use replaceable inserts, which can be changed when worn out, reducing downtime and costs.
- Multiple Inserts: They have multiple inserts arranged around the circumference, allowing for a wide cutting width and smooth finishes.
- Adjustable Inserts: Some face mills have adjustable inserts, enabling fine-tuning of the cutting depth and angle.
Fly Cutters
Definition and Basic Function: Fly cutters are used for roughing operations and creating flat surfaces. They are simple and effective for quick, preliminary work.
Features:
- Single Blade: Fly cutters typically have a single blade mounted on a shaft, which rotates to cut the material.
- Adjustable Blade: The blade can be adjusted to control the cutting depth and angle.
- Low Cost: Fly cutters are generally less expensive than other milling tools, making them a cost-effective option for roughing operations.
Hollow Mills
Definition and Basic Function: Hollow mills are used for internal machining, such as reaming and boring. They are essential for creating precise internal features.
Features:
- Hollow Design: The hollow design allows for internal machining, such as enlarging existing holes or creating smooth internal surfaces.
- Multiple Cutting Edges: Hollow mills have multiple cutting edges arranged around the inside diameter, providing a smooth and precise finish.
- Adjustable Inserts: Some hollow mills have adjustable inserts, allowing for fine-tuning of the cutting diameter.
2. CNC Turning Tools
Otočení CNC tools are essential for shaping cylindrical parts. They remove material from the workpiece as it rotates, creating precise diameters and lengths.
These tools are widely used in industries such as aerospace, automobilový průmysl, and medical device manufacturing.
Here are some of the most common types of CNC turning tools:
Boring Tools
Definition and Basic Function: Boring tools are used to enlarge existing holes in the workpiece. They are essential for achieving high precision and can create very fine tolerances.
Features:
- Single-Point Boring Bars: These are the most common type of boring tool, consisting of a single cutting edge attached to a bar. They are versatile and can handle various hole sizes.
- Adjustable Boring Heads: These allow for fine adjustments to the diameter of the hole, making them ideal for precision work.
- Modular Boring Systems: These systems consist of interchangeable components, allowing for flexibility in setup and use.
Chamfering Tools
Definition and Basic Function: Chamfering tools are used to create chamfers (beveled edges) on the workpiece.
Chamfering improves the aesthetics and functionality of the part, reducing stress concentrations and improving fit and finish.
Features:
- Single-Point Chamfering Tools: These tools have a single cutting edge and are simple to use.
- Multi-Point Chamfering Tools: These tools have multiple cutting edges, allowing for faster material removal and smoother finishes.
- Adjustable Chamfering Tools: These allow for fine adjustments to the angle and depth of the chamfer.
Knurling Tool
Definition and Basic Function: Knurling tools are used to create a pattern on the surface of the workpiece, typically for gripping purposes.
Knurling is common in hand tools and consumer products.
Features:
- Straight Knurls: Create straight patterns on the surface of the workpiece.
- Diamond Knurls: Create diamond-shaped patterns, which are more aggressive and provide a better grip.
- Curved Knurls: Create curved patterns, which are less aggressive and more decorative.
Parting Tool
Definition and Basic Function: Parting tools are used to cut the workpiece to a specific length. They are essential for creating precise lengths and separating parts.
Features:
- Single-Point Parting Tools: These tools have a single cutting edge and are simple to use.
- Multi-Point Parting Tools: These tools have multiple cutting edges, allowing for faster material removal and smoother cuts.
- Adjustable Parting Tools: These allow for fine adjustments to the cutting depth and width.
3. Drilling Tools
CNC drilling tools are specifically designed to create holes in a workpiece.
They are often used in conjunction with a drill press or a milling machine, and they play a crucial role in many manufacturing processes.
Here are some of the most common types of CNC drilling tools:
Center Drills
Definition and Basic Function: Center drills are used to create a starting point for drilling operations.
They ensure that the drill bit starts in the correct position, preventing the bit from walking or wandering off the intended location.
Features:
- Pilot Point: The tip of a center drill is designed to create a small, precise pilot hole. This pilot hole guides the main drill bit, ensuring accurate alignment.
- Multiple Angles: Center drills often have multiple angles on the cutting edges to provide a clean and precise start to the hole.
- Short Length: They are typically short and rigid, which helps in maintaining accuracy and stability during the initial drilling phase.
Ejector Drills
Definition and Basic Function: Ejector drills are used for deep-hole drilling.
They use a two-tube system to remove chips and cool the workpiece, ensuring that the drill bit remains sharp and the hole is clean and precise.
Features:
- Two-Tube System: The inner tube contains the cutting edges, while the outer tube provides a channel for coolant and chip removal.
- High Efficiency: The two-tube system allows for continuous chip removal and cooling, making ejector drills highly efficient for deep-hole drilling.
- Long Length: Ejector drills are available in long lengths, making them suitable for drilling deep holes in various materials.
Twist Drills
Definition and Basic Function: Twist drills are the most common type of drill bit, used for general-purpose drilling.
They are versatile and can handle a wide range of materials, from metals to plastics.
Features:
- Helical Flutes: The helical flutes on the drill bit help to remove chips and cool the workpiece, ensuring a clean and precise hole.
- Point Angle: The point angle varies depending on the material being drilled.
Například, a 118-degree point angle is common for general-purpose drilling, while a 135-degree point angle is used for harder materials. - Materiál: Twist drills are commonly made from high-speed steel (HSS), kobalt, or carbide, each offering different levels of durability and performance.
4. Grinding Tools
Broušení tools are essential in CNC obrábění for achieving high precision and fine finishes.
They use an abrasive wheel to remove material from a workpiece, providing high accuracy and smooth surfaces.
Here are some of the most common types of grinding tools:
Surface Grinders
Definition and Basic Function: Surface grinders are used to grind flat surfaces. They provide a smooth, high-quality finish and are essential for achieving precise flatness and parallelism.
Features:
- Abrasive Wheel: The grinding wheel is made of abrasive particles bonded together. Common materials include aluminum oxide, silicon carbide, and diamond.
- Reciprocating Table: The workpiece is mounted on a reciprocating table that moves back and forth under the grinding wheel.
- Coolant System: A coolant system is used to prevent overheating and remove swarf (metal particles).
Cylindrical Grinders
Definition and Basic Function: Cylindrical grinders are used to grind cylindrical surfaces.
They are ideal for creating precise diameters and lengths and can handle both external and internal surfaces.
Features:
- Rotary Workhead: The workpiece is held in a rotary workhead that rotates the part under the grinding wheel.
- Multiple Wheels: Some cylindrical grinders have multiple wheels for different operations, such as roughing and finishing.
- Coolant System: A coolant system is used to prevent overheating and remove swarf.
Centerless Grinders
Definition and Basic Function: Centerless grinders are used to grind small, cylindrical parts without the need for centers.
They are efficient and precise, making them ideal for high-volume production.
Features:
- Regulating Wheel: The regulating wheel controls the rotation of the workpiece and feeds it into the grinding wheel.
- Grinding Wheel: The grinding wheel removes material from the workpiece.
- Blade: A blade supports the workpiece between the grinding wheel and the regulating wheel.
Internal Grinders
Definition and Basic Function: Internal grinders are used to grind internal surfaces.
They are essential for creating precise internal features and can handle a variety of hole sizes and depths.
Features:
- Grinding Wheel: The grinding wheel is mounted on a spindle that can be inserted into the workpiece.
- Adjustable Spindle: The spindle can be adjusted to accommodate different hole sizes and depths.
- Coolant System: A coolant system is used to prevent overheating and remove swarf.
5. Different Types of Materials Used in Making CNC Machine Tools
The materials used in the construction of CNC machine tools play a crucial role in their performance, trvanlivost, and efficiency.
Each material has unique properties that make it suitable for specific applications.
Here are some of the most common materials used in making CNC machine tools:
Uhlíková ocel
Definition and Basic Properties: Carbon steel is an alloy of iron and carbon, with carbon content typically ranging from 0.1% na 2.1%.
It is known for its strength, trvanlivost, and relatively low cost.
Features:
- Pevnost: Carbon steel offers good tensile strength and hardness, making it suitable for general-purpose tools.
- Houževnatost: It is resistant to impact and wear, making it durable in various machining operations.
- Nákladově efektivní: Carbon steel is generally less expensive than other tool materials, učinit z něj nákladově efektivní volbu pro mnoho aplikací.
Vysokorychlostní ocel (HSS)
Definition and Basic Properties: High-speed steel (HSS) is a type of tool steel known for its ability to retain hardness at high temperatures.
It contains alloying elements such as tungsten, molybden, Chromium, and vanadium, which enhance its performance.
Features:
- Odolnost proti teplu: HSS can maintain its hardness and cutting edge at high temperatures, making it suitable for high-speed cutting operations.
- Houževnatost: It is tough and resistant to chipping and breaking, making it durable in demanding applications.
- Všestrannost: HSS tools are versatile and can be used for a wide range of materials, včetně kovů, Plasty, and wood.
Cemented Carbides
Definition and Basic Properties: Cemented carbides, also known as tungsten carbides,
are composite materials consisting of fine grains of carbide particles (typically tungsten carbide) bonded together with a metallic binder (usually cobalt or nickel).
Features:
- Nosit odpor: Cemented carbides offer excellent wear resistance, making them ideal for high-wear applications.
- Tvrdost: They are extremely hard, capable of maintaining a sharp cutting edge even under high cutting speeds and temperatures.
- Trvanlivost: Cemented carbides are highly durable and can handle tough materials and demanding conditions.
Cutting Ceramics
Definition and Basic Properties: Cutting ceramics are advanced materials made from ceramic compounds such as alumina (aluminum oxide), silicon nitride, and cubic boron nitride (CBN).
They are known for their high hardness and heat resistance.
Features:
- High Hardness: Cutting ceramics is extremely hard, capable of maintaining a sharp cutting edge even at very high cutting speeds.
- Odolnost proti teplu: They can withstand high temperatures, making them suitable for high-speed cutting and dry machining.
- Chemical Inertness: Cutting ceramics are chemically inert, which reduces the risk of chemical reactions with the workpiece material.
6. Common Coatings Used in CNC Machining Tools
Coatings are applied to CNC machining tools to enhance their performance, extend their lifespan, and improve the quality of the finished product.
These coatings can reduce friction, increase hardness, and provide better wear resistance.
Here are some of the most common coatings used in CNC machining tools:
Titanium Nitride (TiN)
Definition and Basic Properties: Titanium nitride (TiN) is a ceramic material that is commonly used as a coating for cutting tools. It is known for its golden color and excellent wear resistance.
Features:
- Nosit odpor: TiN provides excellent wear resistance, extending the life of the tool.
- Lubricity: It reduces friction between the tool and the workpiece, leading to smoother cuts and reduced heat generation.
- Tvrdost: TiN has a hardness of approximately 2400-3400 Hv, making it suitable for a wide range of machining operations.
Titanium Carbonitride (TiCN)
Definition and Basic Properties: Titanium carbonitride (TiCN) is a compound of titanium, uhlík, and nitrogen. It offers improved wear resistance and higher hardness compared to TiN.
Features:
- Higher Hardness: TiCN has a hardness of approximately 3000-3800 Hv, což je odolnější k opotřebení.
- Better Lubricity: It provides better lubricity than TiN, reducing friction and heat generation.
- Nosit odpor: TiCN offers superior wear resistance, especially in high-speed machining operations.
Aluminum Titanium Nitride (AlTiN)
Definition and Basic Properties: Aluminum titanium nitride (AlTiN) is a coating that combines aluminum, titan, and nitrogen. It is known for its high hardness and excellent thermal stability.
Features:
- High Hardness: AlTiN has a hardness of approximately 3500-4000 Hv, making it one of the hardest coatings available.
- Thermal Stability: It maintains its hardness and wear resistance at high temperatures, making it suitable for high-speed and high-temperature machining.
- Oxidační odolnost: AlTiN provides excellent oxidation resistance, reducing the risk of tool degradation at high temperatures.
Diamantový uhlík (DLC)
Definition and Basic Properties: Diamond-like carbon (DLC) is a form of amorphous carbon that exhibits properties similar to diamond, such as high hardness and low friction.
Features:
- Low Friction: DLC has a very low coefficient of friction, reducing heat generation and wear.
- High Hardness: DLC has a hardness of approximately 1500-5000 Hv, depending on the specific formulation.
- Odolnost proti korozi: DLC provides excellent corrosion resistance, making it suitable for use in corrosive environments.
Chromium Nitride (Crn)
Definition and Basic Properties: Chromium nitride (Crn) is a hard, wear-resistant coating that is often used in applications where corrosion resistance is important.
Features:
- Odolnost proti korozi: CrN provides excellent corrosion resistance, making it suitable for use in corrosive environments.
- Nosit odpor: It offers good wear resistance, extending the life of the tool.
- Low Friction: CrN has a low coefficient of friction, reducing heat generation and wear.
7. Key Considerations for Selecting CNC Tools
Selecting the right CNC tools is essential for achieving optimal performance, účinnost, and quality in your machining operations.
Here are the key considerations to keep in mind when choosing CNC tools:
7.1. Material of the Workpiece
Úvahy:
- Type of Material: Different materials require different tool materials and geometries.
Například, aluminum is softer and may require different tools compared to harder materials like titanium or stainless steel. - Hardness and Toughness: The hardness and toughness of the material will influence the tool material and coating selection.
Harder materials may require more durable and wear-resistant tools.
7.2. Type of Operation
Úvahy:
- Machining Operations: Different operations (otáčení, frézování, vrtání, threading, atd.) require specific tool geometries and designs.
Například, end mills are used for milling, while drill bits are used for drilling. - Complexity of the Part: More complex parts may require specialized tools and multi-axis machines to achieve the desired features and tolerances.
7.3. Tool Material
Úvahy:
- Vysokorychlostní ocel (HSS): Suitable for general-purpose machining, especially at lower speeds and feeds.
- Carbide: Offers higher hardness and wear resistance, making it suitable for high-speed machining and harder materials.
- Ceramics: Ideal for high-speed machining of hard materials due to their high hardness and heat resistance.
- Polycrystalline Diamond (PCD): Best for machining non-ferrous materials like aluminum and copper, providing excellent wear resistance and low friction.
7.4. Tool Geometry
Úvahy:
- Flute Design: The number and shape of the flutes (helical, straight, atd.) affect chip evacuation and cutting performance.
Helical flutes are common for general-purpose machining. - Point Angle: The point angle affects the initial cut and the type of material being machined.
Například, a 118-degree point angle is common for general-purpose drilling, while a 135-degree point angle is better for harder materials. - Rake Angle: The rake angle influences the cutting force and chip formation.
Positive rake angles reduce cutting forces and improve chip evacuation, while negative rake angles increase tool strength and stability.
7.5. Tool Coating
Úvahy:
- Titanium Nitride (TiN): Provides good wear resistance and low friction, suitable for general-purpose machining.
- Titanium Carbonitride (TiCN): Offers higher hardness and wear resistance, suitable for high-speed machining.
- Aluminum Titanium Nitride (AlTiN): Provides excellent wear resistance and thermal stability, suitable for high-temperature and high-speed machining.
- Diamantový uhlík (DLC): Offers low friction and high wear resistance, suitable for precision machining and machining of non-ferrous materials.
- Chromium Nitride (Crn): Provides good wear resistance and corrosion resistance, suitable for machining in corrosive environments.
7.6. Tool Diameter and Length
Úvahy:
- Diameter: The diameter of the tool should match the size of the feature being machined. Larger diameters are generally more rigid and can handle higher loads.
- Length: The length of the tool affects its rigidity and stability. Longer tools are more prone to deflection and vibration, which can affect accuracy and tool life.
7.7. Tool Holder and Clamping System
Úvahy:
- Tool Holder Type: Different holders (shrink fit, hydraulic, mechanical) offer varying levels of precision and holding power. Shrink fit holders, například, provide high precision and rigidity.
- Clamping System: The clamping system should securely hold the tool in place to ensure stability and accuracy during machining.
7.8. Coolant Delivery System
Úvahy:
- Internal Coolant: Tools with internal coolant delivery can improve chip evacuation and reduce heat, extending tool life and improving surface finish.
- External Coolant: External coolant systems are simpler but may not be as effective in deep-hole drilling or high-speed machining.
7.9. Cost and Budget
Úvahy:
- Initial Cost: The upfront cost of the tools, including any specialized coatings or materials.
- Operational Costs: Ongoing costs such as replacement, maintenance, and downtime.
- Return on Investment (ROI): Evaluate the potential ROI by considering factors like increased productivity, reduced cycle times, and improved quality.
8. Innovations in CNC Tools
The field of CNC machining is constantly evolving, driven by advancements in materials, povlaky, and design technologies.
These innovations aim to improve tool performance, extend tool life, enhance precision, and increase productivity.
Here are some of the key innovations in CNC tools:
8.1. Advanced Coatings
Nano-Structured Coatings:
- Popis: Nano-structured coatings consist of layers or particles on the nanometer scale, providing enhanced properties at the molecular level.
- Výhody: Increased hardness, improved adhesion, and better resistance to wear and corrosion.
Diamantový uhlík (DLC) Coatings:
- Popis: DLC coatings mimic the properties of diamond, offering extremely high hardness and low friction.
- Výhody: Reduced friction, improved wear resistance, and better performance in high-speed machining and precision applications.
8.2. New Tool Materials
Cubic Boron Nitride (CBN):
- Popis: CBN is one of the hardest materials after diamond, making it ideal for machining extremely hard materials.
- Výhody: Vynikající odpor opotřebení, high thermal stability, and suitability for machining hardened steels and superalloys.
Polycrystalline Diamond (PCD):
- Popis: PCD tools are made from synthetic diamond particles bonded together, providing exceptional hardness and wear resistance.
- Výhody: Ideal for machining non-ferrous materials like aluminum and copper, reduced tool wear, and improved surface finish.
8.3. Smart Tools and Sensors
In-Process Monitoring:
- Popis: Smart tools equipped with sensors can monitor tool wear, cutting forces, and temperature in real-time.
- Výhody: Early detection of issues, optimized tool usage, and reduced downtime.
Adaptive Control Systems:
- Popis: Adaptive control systems adjust the machining parameters (rychlost, feed rate, depth of cut) based on real-time data from sensors.
- Výhody: Improved accuracy, reduced tool wear, and better surface finish.
8.4. Digital Twin Technology
Virtual Simulation:
- Popis: Digital twin technology creates a virtual replica of the machining process, allowing for simulation and optimization before actual machining.
- Výhody: Reduced setup time, improved accuracy, and the ability to test different tooling and machining strategies without physical prototypes.
9. Závěr
CNC machine tools have transformed the manufacturing landscape, offering unparalleled precision and efficiency.
Whether you are a seasoned machinist or new to the field, having a solid understanding of the different types of CNC machine tools and their applications is crucial.
By selecting the right tools for your specific needs, you can ensure that your projects are completed to the highest standards of quality and performance.
