Longitudinal and Transverse Turning: Understanding the Process and Applications
The process of turning is one of the oldest and most widely used machining methods, playing an important role in the metal industry. Longitudinal and transverse turning, as the primary techniques of this process, are widely used in component manufacturing. Understanding these methods and optimising them can significantly increase production efficiency and quality, as well as reduce operating costs. In this article, we will take a closer look at both types of turning, their applications and best practices.
What is turning?
Turning is a basic machining process that involves removing material from a rotating workpiece using a turning tool. The process produces chips and the workpiece gains the desired shape, smoothness and dimensions. Turning is widely used in the manufacture of machine components, structural components and high-precision parts.
It’s main elements are:
- The rotating workpiece: The material that is being machined.
- Lathe knife: The cutting tool that removes material from a workpiece.
- Lathe: The machine that holds and rotates a workpiece, allowing the lathe tool to work.
Types of turning
Turning can be divided into several basic types, depending on the tool feed’s direction and workpiece’s shape:
- Longitudinal:
- The feed direction of the tool is parallel to the workpiece’s rotation axis.
- Mainly used for machining long, cylindrical workpieces such as shafts and axes.
- The process can be divided into coarse turning (removing more material) and fine turning (achieving final shape and surface smoothness).
- Transverse:
- The tool’s feed direction is perpendicular to the workpiece’s rotation axis.
- Used for machining faces and for creating precise shapes on the ends of workpieces.
- Ideal for producing components such as flanges and dis
- Shaping:
- A turning process in which the tool is shaped to match the workpiece.
- Used to create short non-cylindrical rotating solids.
- Allows complex shapes to be produced in a single tool pass.
- Copying:
- Turning that conforms to the pattern controlling the tool’s feed motion.
- Used to create parts with complex shapes that require precise mapping.
- Allows identical serial parts to be produced.
Longitudinal turning
The longitudinal turning process is one of the basic machining techniques in which the turning tool moves parallel to the workpiece’s rotation axis. In this process, the workpiece is mounted on the lathe spindle and rotates around its axis. The lathe tool moves along the workpiece, removing layers of material and giving it the desired shape, dimension and surface smoothness. The longitudinal turning process can be divided into two main stages – coarse and fine:
- Roughing removes most of the excess material, shaping the general outline of a workpiece. This is the first stage, where higher feeds and depths of cut are used to quickly remove large amounts of material.
- Fine finishes the surface and gives the final shape to the workpiece. Smaller feeds and depths of cut are used to achieve high surface quality and accurate dimensions.
Examples of longitudinal turning applications
Longitudinal turning is commonly used in the production of cylindrical shaped components such as:
- Shafts: Used in a variety of machines and equipment as components that transmit rotary motion.
- Axles: Used in vehicles, machinery and other structures to transmit loads and movement.
- Tubes and sleeves: Used in hydraulic, pneumatic and other piping structures.
- Threads: Used to form threads on cylindrical surfaces.
Transverse turning
The transverse turning process is a machining process in which the turning tool moves perpendicular to the workpiece’s rotation axis. During this process, the material is removed from the face of a workpiece, resulting in flat, even surfaces and precise shapes at the ends of shafts and other cylindrical workpieces.
Examples of transverse turning applications
Transverse turning is used extensively across a wide range of industries, particularly where precise faces and details are required at the ends of components. Application examples include:
- Face machining: Transverse turning is ideal for finishing the faces of shafts, axles, discs and other cylindrical components.
- Slot creation: Allows precision slotting of faces that can be used to accommodate sealing rings, bearings or fasteners.
- Precision component terminations: Transverse turning is essential for finishing the ends of shafts, axles and other components requiring precision.
Technical aspects of longitudinal and transverse turning
Optimisation of the longitudinal turning process requires an appropriate selection of tools and cutting parameters according to the following factors:
- Tool selection: The turning tools used for longitudinal turning must be appropriately selected depending on the type of material and the machining requirements. The tools should have the right geometry to ensure minimum wear and high surface quality.
- Cutting speed (Vc): The speed at which a tool’s cutting edge moves along the face of a workpiece. Cutting speed affects surface quality, tool life and process efficiency.
- Feed rate (fn): The distance the tool moves perpendicular to the rotation axis of the workpiece during one rotation. Feed influences machining efficiency and surface quality.
- Depth of cut (ap): The thickness of the layer of material removed in one pass of the tool. The cut’s depth depends on the type of turning (coarse or fine) and the material’s properties.
Application of longitudinal and transverse turning in industry
Longitudinal and transverse turning are widely used in many industries where precision machining of components is crucial. Industries using longitudinal and transverse turning include:
Automotive:
- longitudinal and transverse turning is used for camshafts, drive axles, brake discs and other engine components. Precision machining is essential to ensure the performance and durability of these components;
- the manufacture of suspension components such as ball joints and sleeves.
Aviation:
- in aviation, longitudinal and transverse turning are used to manufacture turbine components, drive shafts and other aircraft engine components. High precision is crucial here due to safety and reliability requirements;
- production of structural parts such as landing gear components and wing mounts.
Machine manufacturing:
- turning is essential for the production of drive shafts, gears, bearings and other industrial machine components. The accuracy of machining increases their lifespan and reliability;
- production of moulding tools and matrices.
Benefits of precision CNC machining
CNC (Computerized Numerical Control) technology has revolutionised the turning process, introducing many benefits that contribute to increased production efficiency and cost reduction:
Increased production efficiency:
- CNC turning allows the machining process to be automated, significantly reducing production times. CNC machines can run continuously, performing complex operations with high speed and accuracy;
- the programmability of CNC machines allows easy transition between different machining operations, increasing production flexibility and allowing rapid adaptation to changing market demands.
Cost reduction:
- the automation and precision of CNC machining reduces material waste, which lowers raw material costs. With accurate control of cutting parameters, optimum material consumption can be achieved;
- less need for manual intervention reduces the costs associated with human labour and the risk of errors that can lead to costly corrections or production downtime.
Quality improvement:
- CNC machines ensure a high degree of repeatability and accuracy, which is key to maintaining consistent product quality. Each component is machined with the same precision, minimising the risk of rejects and defects;
precision machining allows strict quality standards and tolerances to be met, which is particularly important in industries such as avionics and automotive.
Challenges in the turning process
The turning process, although fundamental to machining, presents several technical challenges that must be managed effectively to achieve high quality and production efficiency:
Vibration control:
- vibration is one of the most serious problems in turning. They can lead to a deterioration in the quality of the machined surface, increased tool wear and undesirable acoustic effects. Vibration can be caused by a variety of factors, such as incorrect tool setting, excessive feeds, excessive depths of cut or poor rigidity of the lathe-object-tool system;
- in order to control vibration, it is necessary to use stable turning tools, appropriate cutting parameters and advanced vibration damping technologies such as active vibration dampers. Vibration control is particularly important primarily for the safety and ergonomics of the operator-machine system and to minimise the risk of breakdowns and unplanned downtime.
Tool wear:
- turning tools are subject to wear as a result of contact with the workpiece, leading to reduced efficiency and precision. Tool wear depends on a number of factors, including the workpiece material, cutting speed, feed rate and cooling conditions;
- effective tool wear management includes regular monitoring of tool condition, the use of high quality tool materials and optimisation of cutting parameters to minimise tool wear.
Cutting parameters optimisation:
- optimisation of cutting parameters (speed, feed rate, depth of cut) is important to ensure high machining quality and process efficiency. Inappropriate parameters can lead to excessive tool wear, increased vibration and degraded surface quality;
- advanced process monitoring and control technologies, such as adaptive control systems, can help dynamically optimise cutting parameters in real time.
The future of turning in the context of the development of CNC technology and production automation
The development of CNC technology and the automation of production have introduced significant changes to turning processes, bringing numerous benefits and opening up new opportunities:
Advanced CNC technology:
- modern CNC lathes are equipped with advanced control systems that enable precise programming and control of machining processes. This makes it possible to achieve exceptional accuracy and repeatability;
- integration of CNC technology with CAD/CAM systems allows a direct transition from design to production, which reduces lead times and minimises the risk of errors.
Automation and robotisation:
- automation of turning processes, including the use of robots for material loading and unloading, contributes to increased efficiency and reduced production costs. Robots can operate 24/7, significantly increasing workshop productivity;
- process monitoring and control systems, equipped with sensors and data analysis software, allow the status of tools, cutting parameters and the quality of machined surfaces to be monitored in real time, allowing any irregularities to be quickly addressed.
Innovative tool materials and cutting technologies:
- ongoing development of tool materials, such as diamond- or ceramic-coated tools, allows for increased tool lifespan and improved machining quality;
- new cutting technologies, such as cryogenic or ultrasonic cutting, open up new possibilities for machining difficult-to-cut materials and improved surface quality.
Summary
Longitudinal and transverse turning is widely used in a variety of industries such as automotive, avionics and machine manufacturing. Thanks to advanced CNC technology, it is possible to achieve unprecedented precision and repeatability, which brings numerous benefits such as increased production efficiency, reduced costs and improved product quality.
If you are looking for professional metal turning and machining services, feel free to contact CPP PREMA. With state-of-the-art technology and years of experience, we are able to meet the most demanding projects and provide the highest quality of service. Our advanced CNC lathes and team of experienced professionals are ready to help you achieve your production goals.
We encourage you to familiarise yourself with the turning services offer at CPP “PREMA” S.A., as well as to contact us and cooperate in the creation of a wide range of high quality galvanic products.