What Kind of Parts Are Made by CNC Turning?

What Kind of Parts Are Made by CNC Turning?

Symmetrical – you can have parts with asymmetrical features, but the overall part shape will need to be symmetrical. This has to do with the spinning of the work piece and the stationary position of the part

Cylindrical or round – again, due to the processes’ nature, cylindrical or round parts are what is best suited for CNC turning.

Can be produced from bar or tube stock – the process is working from solid bars of raw material, or tubes. The inner and outer diameter are then shaped by the work piece. If the part is too big or too small, there may not be suitable material for working.

Types of Parts Made by CNC Turning

CNC turning is versatile and well-suited for producing a wide range of components having features symmetrical around a central axis. Here's a table categorizing parts that can be made by CNC turning across various industries:

Industry Parts Made by CNC Turning

Aerospace Shafts, pins, spacers, bushings, hydraulic fittings

Automotive Axles, drive shafts, camshafts, crankshafts, pulleys

Medical Surgical instruments, bone screws, dental implants

Electronics Connectors, terminals, contact pins, housings

Oil & Gas Valves, fittings, couplings, hydraulic components

Marine Propeller shafts, couplings, marine engine components

Defense Gun barrels, ammunition casings, ordinance components

Construction Nuts, bolts, screws, fasteners, hinges

Consumer Goods Door handles, knobs, faucet components, tool handles

Energy Turbine shafts, rotors, generator components

Industrial Bearings, gears, pulleys, couplings

Table 1: CNC Turning Applications Across Various Industries

These are the broad range of components that can be efficiently manufactured using CNC turning, demonstrating its versatility and effectiveness in meeting diverse industrial needs:

Bushings: These cylindrical components are utilized to reduce friction between two surfaces and maintain alignment in mechanical assemblies. They are made with uniform dimensions and smooth surfaces essential for optimal bushing performance.

Rings: Whether used for sealing, bearings, or decorative purposes, rings demand precise circular dimensions and smooth finishes, making CNC turning an ideal method for crafting them efficiently.

Flanges: These are essential parts for connecting pipes, valves, and other equipment in piping systems, flanges require precise circular shapes with accurately positioned bolt holes.

Pins and Dowels: These cylindrical components serve various functions, such as aligning parts, providing support, or acting as pivot points. They must have accurate dimensions and smooth surfaces necessary for their intended applications.

Spacers: Often used to maintain specific distances between components or to fill gaps, spacers require precise outer diameters and lengths.

Pulleys: Found in systems like conveyors, engines, and transmissions, pulleys transmit rotational motion and require precise grooves or teeth profiles. They need to be accurately machined to ensure smooth operation.

CNC partsFig. 3: CNC Turned Bushings

Cylindrical Joints: Parts such as couplings, couplers, and adapters often require cylindrical geometry to facilitate the connection between different components. They need to have precise dimensions and concentricity needed for reliable joint performance.

Couplings: These components connect two shafts for transmitting power or motion. They must have precise outer diameters, bore sizes, and keyways to achieve proper alignment and torque transmission.

Bolts and Fasteners: Fasteners such as bolts, screws, and studs require precise threads and shank diameters to securely join components together. Especially when non-standard sizes or smaller quantities are needed, these parts can be produced from forged blanks with the appropriate head size and overall diameter, and then CNC turning is used to create consistent thread profiles and tight tolerances.

Hubs: Found in wheels, gears, and pulleys, hubs provide a central connection point for attaching other components. CNC turning can create hubs with accurate diameters, bores, and keyways for proper alignment and assembly.

Rollers: Used in conveyors, printers, and industrial machinery, rollers require precise cylindrical surfaces for smooth rotation and material handling. They must have the necessary dimensional accuracy and surface finish for optimal performance.

Axles: Axles transmit rotational motion between rotating components such as wheels, gears, or pulleys. Axles must have precise diameters, shoulders, and keyways to ensure proper fit and alignment within assemblies.

Nozzles: Found in various applications such as fluid dispensing systems or spray equipment, nozzles require precise internal and external geometries for controlled fluid flow. Nozzles need to have accurately machined bores, tapers, and outlet profiles to meet specific performance requirements.

CNC Turned PartFig 4: CNC Turned Couplings

Shafts: Commonly used in machinery to transmit power or rotational motion, shafts require precise cylindrical shapes and often feature keyways or threads, which can be accurately produced using CNC turning.

Housings: Housings are cylindrical enclosures used in various applications such as firearms, machinery, or automotive components. Barrel housings should have precise bore diameters, thread patterns, and mounting features for assembly and functionality.

Stems: Stems are structural components used in applications such as valves, faucets, or medical devices. CNC turning can produce stems with accurate diameters, threads, and sealing surfaces to ensure proper functionality.

Precision CNC Turned Metal ComponentsFig. 5: Precision CNC Turned Metal Components

How to Determine Which Parts Are Best Made by CNC Turning

Symmetry and Geometry - CNC turning is particularly advantageous for parts with symmetrical geometries due to its rotational nature. Parts with rotational symmetry, such as shafts, cylinders, and discs, are ideally suited for CNC turning to ensure uniformity and precision.

Cylindrical & Round Shapes - Turned parts are inherently cylindrical or round, and either solid or hollow, primarily due to the nature of the turning process. This cylindrical form is well-suited for a wide range of applications across various industries, including automotive, aerospace, and manufacturing. Solid cylindrical parts, such as shafts and pins, provide structural support and transmit motion or power efficiently. Hollow cylindrical parts, like tubes and sleeves, offer lightweight construction and fluid passage capabilities.

Material Starting Form - CNC turning is especially suited for parts that can begin as bar stock or other cylindrical preforms. This starting form minimizes material waste and simplifies the machining process, as the cylindrical shape of the workpiece aligns naturally with the rotational motion of the lathe. Bar stock, typically available in various diameters and lengths, provides a cost-effective and readily available starting material for turned parts.

Complexity and Features - Despite its association with cylindrical shapes, CNC turning can efficiently produce parts with a wide range of complex features. Multi-axis machining and live tooling capabilities, enable the incorporation of intricate geometries such as threads, grooves, and chamfers directly during the turning process. Threads, essential for fasteners and fittings, can be accurately cut using specialized threading tools, ensuring precise pitch and depth control. Grooves, used for O-ring seats or decorative purposes, can be machined with high repeatability and surface finish using custom tooling configurations.

Material Compatibility - CNC turning is well-suited for machining a wide range of materials, including metals, plastics, and composites. It is particularly effective for softer materials like aluminum, brass, and plastics, as well as certain stainless steel and alloys. These materials exhibit favorable machinability characteristics when subjected to the cutting forces and temperatures generated during turning operations. CNC turning can achieve high-quality surface finishes and dimensional accuracy on these materials, making it an ideal choice for parts requiring excellent aesthetics or tight tolerances.

Production Volume and Efficiency - The production volume of the parts can influence the decision to use CNC turning. While CNC milling may offer advantages for low-volume or prototype production due to its versatility and ability to handle complex geometries, CNC turning excels in high-volume production requirements. The rotational nature of turning allows for continuous and rapid machining of cylindrical parts, resulting in shorter cycle times and increased throughput compared to milling.

Tooling and Setup Requirements - CNC turning typically requires minimal tooling and setup compared to other machining processes, making it suitable for quick turnaround times and rapid production ramp-up. The primary tooling components in turning include cutting inserts, tool holders, and work-holding fixtures, which are relatively straightforward to set up and replace as needed. The simplicity of the turning process also reduces the risk of tool breakage or machine downtime, ensuring consistent and uninterrupted production.

Secondary Operations Integration - CNC turning allows for seamless integration of secondary operations such as drilling, tapping, and knurling within the same machining cycle. This capability eliminates the need for additional setups or transfers to secondary machines, reducing production lead times and costs. For example, tapped holes can be accurately machined directly on turned parts using live tooling attachments, ensuring precise thread alignment and dimensional accuracy.