All You Need to Know about CNC Turning Machine

A CNC turning machine, also known as a CNC lathe, is a precision machining tool that rotates a workpiece on its axis while cutting or shaping it with fixed cutting tools.

CNC stands for computer numeric controlled - meaning that an operator inputs commands into the machine through the computer for automated operation.

While manual mills and lathes have been around since Ancient Egyptian times- they cannot provide the level of precision achievable with modern CNC turning machines.

How CNC Turning Machine Works?

CNC turning is a subtractive machining process that utilizes the principles of a lathe machine to shape cylindrical parts.

Here's a basic overview of how a CNC turning machine works:

Design and Programming

First, the part's design is created using CAD (Computer-Aided Design) software.

The CAD design is then translated into a CNC program using CAM (Computer-Aided Manufacturing) software.

The CNC program contains instructions for the machine on how to move and operate the cutting tools.

Workpiece Setup

The raw material, known as a workpiece, is mounted on a spindle chuck. The chuck holds the workpiece securely in place and allows it to rotate.

Tool Setup

The cutting tools are selected based on the design requirements and mounted on the tool turret.

The tool turret can hold multiple tools, allowing for different operations without manual tool changes.

Machine Initialization

The operator loads the CNC program into the machine's computer.

The program includes information on toolpaths, cutting speeds, feed rates, and other parameters.

Workpiece Rotation

The spindle rotates the workpiece at a controlled speed. The rotation is synchronized with the movement of the cutting tool.

Tool Movement

The CNC controller sends signals to the motors that control the movement of the tool along the programmed toolpaths. The tool can move in both radial and axial directions.

Cutting Operation

As the workpiece rotates, the cutting tool engages with the material, removing excess material to shape the part according to the programmed design.

Coolant and Lubrication

Coolant is often used to cool the cutting area and remove chips from the workpiece. Lubrication may also be applied to the cutting tool to reduce friction and heat.

Monitoring and Quality Control

Sensors and monitoring systems may be employed to check the dimensions and quality of the machined part during the process.

If deviations are detected, adjustments can be made automatically.

Finishing Operations

Depending on the design and requirements, the CNC turning machine may perform additional operations such as threading, facing, grooving, or other finishing processes.

Unloading the Finished Part

Once the machining process is complete, the finished part is removed from the machine.

What’s Main Components of CNC Turning Machine?

A CNC turning machine comprises several key components that add up to its precision and performance, including important machinery such as a headstock, tailstock, spindle chuck, bed carriage, cutting tools, and tool turrets.

Headstock

The headstock in a CNC turning machine is like the engine, responsible for rotating the workpiece securely.

It includes essential components such as the spindle, gears, shafts, bearings, and control mechanisms.

This part facilitates turning operations like threading, drilling, and chamfering. The headstock also houses and secures cutting tools, allowing for accurate and repeatable complex cuts on cylindrical surfaces.

Tailstock

The tailstock offers support and stability for workpieces during turning. It connects to the machine's bed, keeping the workpiece steady and parallel to the machine's axis.

This crucial tool enhances machining accuracy with its tailstock quill and chucks, maintaining stable contact between the tool and material.

Spindle

The spindle applies torque, speed, and accuracy to achieve rotational operations at high speeds. The spindle drive ensures consistency in each rotation and stability during material removal.

When choosing a CNC turning machine, it's important to consider the spindle's suitability for specific needs, such as the type of bearing (roller or ball), RPM capabilities, power output, and operational features for various projects.

Chucks

Chucks are automatic devices used on CNC turning machines to hold workpieces. They're attached to the headstock but aren't integrated into them.

Various chuck types, including three-jaw universal types, can be used based on machining needs, part shapes, and required clamping forces.

Most lathes have a standard work holding system with a three-jaw power chuck and hydraulic actuating system.

Bed

The bed acts as a foundation for the machine. It enables smooth movement of the carriage and tailstock along the spindle axis.

Beds are commonly made from materials like cast iron, mild steel, ductile cast iron, or a type of Granitan known for its vibration dampening qualities.

This sturdy construction enhances stability, providing robust support for components like the tool turret, especially when dealing with heavy loads from machining.

Carriages

CNC turning machines use carriages to control cutting tool movements with programmed precision.

The carriage, consisting of a saddle and an apron, facilitates linear movement along the X-Axis or Z-axis. This synchronization ensures accurate dimensional results in part production while reducing tool wear.

Carriages also support heavy tools, minimizing wear compared to older manual lathe designs. They enhance productivity by enabling quick setup changes between modular units, eliminating downtime, and reducing operator involvement in specific operations.

Cutting Tools

CNC turning machines use cutting tools mounted on various lathe parts like the headstock, carriage, and tool turret.

These tools, including drill bits, end mills, face mills, reamers, threading tools, and knurling tools, come in different shapes and sizes for specific machining tasks.

Control Panel

The control panel is the central component of a CNC machine. Operators need to understand its functions as they interact with the machine.

It includes a display screen and keyboard for programming commands. The buttons, knobs, and keys on the panel allow users to control different aspects of machining, such as movement direction, material feed rate, and rpm speed.

The design includes monitors for program viewing, a controller chip with data about machinery operations, and foot pedals for manual inputs if needed.

Tool Turrets

Tool turrets allow various cutting tools to be easily positioned for use. These rotating tool holders can hold multiple tools in a rotating turret or a stationary holder.

Both configurations reduce setup time between operations, leading to faster cycle times and improved precision in manufacturing high-quality products.

Foot Pedals

Foot pedals are commonly utilized to assist operators in loading and unloading materials, as well as controlling functions like opening and closing the chuck.

These pedals offer precise control, enhancing machining operations' efficiency, safety, and accuracy. Despite their seemingly simple nature, foot pedals provide refined control over complex processes, allowing easy access during maintenance or other activities.

Eight Main Types of CNC Turning Machine

There are various types of CNC turning machines, each designed for specific applications and machining requirements. Here are eight main types:

Horizontal Turning Centers

Horizontal turning centers allow materials to be fed from the left side and machined from both sides using a single-point cutting process with rotating tools.

This approach efficiently produces intricate parts with precise details in large quantities, making it a popular choice for mass production.

They have powerful spindles that rotate at high speeds, controlling multiple cutters on the same tool holder. This enables operations like facing, grooving, drilling, and threading to occur seamlessly without manual tool adjustments.

The headstock features an automatic tool changer for quick adjustments, reducing downtime when producing large batches of components.

Vertical Turning Centers

Vertical turning centers are CNC machines used for rotating workpieces during machining. This process, done while rotating, allows for precise metal cutting operations like drilling and threading.

These machines often use gravity to assist the cutting tool, enabling deeper cuts than horizontal lathes. Some configurations have an inverted design for better operator accessibility.

Vertical turning centers offer advantages by utilizing gravity on rough surfaces, ensuring precision.

Horizontal Lathes

Horizontal CNC lathes are the most common type of turning machine. They use a horizontal arbor with various heads that can handle different shapes and sizes.

This versatility enhances accuracy in tasks like boring and threading. Side-mounted tool carriers enable complex orientation techniques.

However, compared to vertical lathes, they have less flexibility due to gravity's role, as only one side faces downwards.

Despite this, the ability to mount multiple tools simultaneously makes horizontal lathes highly desirable for metalworking professionals, saving time compared to traditional methods.

Vertical Lathes

Vertical lathes feature a rotary spindle mounted vertically for machining cylindrical workpieces of different sizes.

Configurations can vary, with some designs using two chucks positioned horizontally or diagonally for quick material loading and unloading.

Additionally, vertical lathes may have multiple tool turrets to enhance production. These machines operate with automatically driven carriages and cutting tools, following programmed instructions from a control panel or CNC system software interface.

2-Axis CNC Lathes

2-Axis CNC lathes are computer-controlled machines that move the tool head in two directions, X and Z. They are designed to turn metal parts through grooving, cut-off, profiling, and threading operations.

These lathes have a horizontal spindle with a chuck at each end, making them suitable for large cylindrical components.

They excel in precision for smaller parts like bushings or shaft seals, but their capability is limited to movement along two planes – X and Z.

While they lack the complexity of multi-axis lathes, they are efficient for quick and accurate machining, especially for smaller components, with minimal post-processing required.

Multi-Axis CNC Lathes

Multi-axis CNC lathes are advanced machines designed for precision machining tasks like drilling, milling, and cutting. They outperform older 3-axis models and manual machines regarding speed and flexibility.

These lathes have 3, 4, or 5 axes, enabling them to create intricate parts in a single setup. The machines move in multiple directions, making them suitable for various applications such as threading, contouring, and hole boring on both sides of the part.

Swiss-type CNC Lathes

Swiss-type CNC lathes use a specialized collet at the back of the guide bushing, allowing accurate work on small components, including intricate operations like cross drilling.

The guide bushing technology prevents interference between moving parts, making these lathes ideal for tasks requiring detailed work in a short time.

Swiss-type lathes often have features like multiple spindles, revolving tool turrets, and specialized cutting tools for miniature applications such as microtubes and dental implants.

Slant Bed and Flat Bed Lathes

Slant Bed and Flat Bed Lathes are two types of CNC turning machines designed for specific applications based on machining needs and part complexity.

Slant bed lathes have a 30-degree slanted design, allowing them to hold large parts and achieve greater accuracy in illustration.

On the other hand, flat bed lathes are suitable for heavy-duty machining, providing stability for larger parts with their longer cutting region.

Both types offer high precision, with spindle speeds from 500 to 5500rpm, enabling excellent results in processes like threading, drilling, boring, and facing.

Advantages of CNC Turning Machines

CNC turning machines are invaluable pieces of machinery for producing precision parts, offering increased accuracy, repeatability, and automation. This highly evolved technology presents a host of advantages to the industrial sector.

Precision and Accuracy

CNC turning ensures unparalleled precision by using computer numerical control (CNC) programming to control cutting tools. This results in smooth finishes and tight tolerances, reducing waste and enabling efficient production.

Efficiency and Productivity

CNC machines surpass manual operations in efficiency and productivity. They run autonomously, producing high-quality components without constant human intervention.

Iterative optimization maximizes output, saving resources and money through increased production runs.

Versatility in Machining Operations

CNC turning machines offer versatility in handling components of varying size and complexity.

They suit diverse industrial applications, including aerospace, automotive, and medical device production. Automated control systems ensure precision and repeatability across batches.

Automation and Reduced Manual Labor

CNC technology allows autonomous operation, reducing the need for manual labor. This leads to enhanced productivity and streamlined manufacturing processes.

Automated tooling further improves efficiency, making CNC turning machines ideal for industries requiring precise output dimensions.

Applications of CNC Turning Machines

CNC turning machines can be used for various purposes across a wide range of industries, from aerospace to medical.

Learn about the many applications here and see how they can benefit your industry!

Aerospace Industry

• Housings for avionics systems
• Engine turbine blades and vanes
• Nozzle gimbals assemblies
• Various types of grinder mechanisms
• Structural components
• Alloys for thermal insulation in spacecraft
• Plating on spacecraft surfaces

Automotive Industry

• Suspension parts
• Combustion engines
• Lights and exhaust components

Medical Industry

• Joint implants
• Machine instruments for surgery
• Components for healthcare electronics
• Micromachining tasks
• Prototypes of new medical devices

Electronics and Technology

• Electronic parts and components
• Microchips
• Circuit boards

General Machinery and Components

• Custom plastic parts
• Rods
• Screws

How do you maintain and care for your CNC machine?

1. Check lubrication levels and replenish them daily, if needed, to ensure the smooth operation of the CNC machine.
2. Grease parts that look dry to prevent friction and wear on the machine components.
3. Regularly check coolant concentration and fill levels to maintain the proper working conditions for the CNC machine.
4. Maintain thorough maintenance records and ensure adequate employee training to manage CNC machine maintenance effectively.
5. Careful scheduling, observant technicians, available parts, and comprehensive documentation can help you stay on top of maintenance issues for CNC machines.
6. During annual maintenance of CNC lathe machines, focus on machined beds, hydraulic systems, spindles, chucks, and tool holders to guarantee optimal performance.
7. Regularly clean all surfaces with lint free cloth or compressed air; always use appropriate lubricants when needed as per the Machine Manufacturer's recommendation (refer to manual).
8. Lubricate bearings such as spindle heads or each moving axis drive separately following manufacturer instructions (refer to manual).
9. Regularly sharpen the cutting tool edges to reduce torsion force when cutting metal. This prevents damage to mortise groove profiles caused by increased heating during high cutting pressure due to rust layers connecting the two materials. Also, ensure tight screws across threaded wheels to prevent sudden jerks over the tool's lifetime.

Conclusion

CNC turning machines have revolutionized the manufacturing process and continue to be an essential tool for many industries.

They allow for greater precision, accuracy, efficiency, productivity, and versatility in producing complex shapes than manual lathes or milling machines.

By automating the process of subtractive material removal from a workpiece with advanced computer numerical control technology, CNC turning centers can make incredibly precise parts that require much less labor than traditional machining techniques.

CNC turning offers great technological and economic potential advances as it continues to develop further over time.

If you are looking for a supplier of turned parts, DEK can provide high-precision CNC turning services. Welcome to learn more about us.