Grinding is a key finishing method that ensures high precision and smoothness of workpieces. The process involves the removal of small layers of material using abrasive tools to achieve accurate dimensions and low surface roughness. Among the different types of grinding, cylindrical grinding and surface grinding occupy a particularly important place, and they differ both in terms of application and manufacturing technique.
Cylindrical grinding focuses on machining cylindrical parts such as shafts, bushings or rollers. This method produces perfectly round and smooth surfaces, which is crucial for moving and rotating parts. Cylindrical grinding machines ensure that the shape and dimensions of the part are precisely matched to the specifications set.
Surface (flat) grinding, on the other hand, is used to machine flat metal surfaces to achieve perfect evenness and flatness. This technique is mainly used in the manufacture of molds, dies and machine components, where dimensional precision is a priority.
The differences between these methods relate not only to the shape of the workpieces to be machined, but also to the machines, tools and process parameters used. The choice of the appropriate grinding technique depends on the geometry of the workpiece, the required tolerances and the expected surface quality. Understanding these differences makes it possible to optimize the capabilities of each method in production processes.
Basic differences between cylindrical and surface grinding
Cylindrical grinding and surface grinding differ fundamentally in terms of application, manufacturing technique and machines used. Knowing these differences allows you to choose the optimal method for a specific machining task.
Geometry of workpieces to be machined
Cylindrical grinding is used for machining cylindrical surfaces such as shafts, rods, pins and bushings. The process produces perfectly round shapes while maintaining strict dimensional tolerances. During cylindrical grinding, the workpiece rotates around its axis.
Surface grinding, on the other hand, focuses on machining flat surfaces. This method produces perfectly even planes, which is used in the manufacture of molds, dies and machine parts requiring high precision. In this case, the workpiece performs a reciprocating or rotary motion relative to the grinding wheel.
Machines and tools used
Specialized cylindrical grinding machines are used for cylindrical grinding, which can be either centreless or centreless. Clawed grinders clamp the workpiece between the claws or in a grinding chuck, while centerless grinders use a guide wheel and support to drive and support the workpiece.
Surface grinding is performed on surface grinders, which can realize peripheral, face or peripheral-face grinding. These machines provide stable guidance of the grinding wheel relative to the surface to be machined, which translates into high dimensional accuracy.
Process implementation methods
Cylindrical grinding can be implemented in several ways:
- Longitudinal cylindrical grinding of the tusk – the workpiece mounted in the tusk rotates opposite to the tool, and the grinding wheel performs a main and feed motion
- Plunge cylindrical claw grinding – there is a radial feed, perpendicular to the axis of rotation of the workpiece
- Centerless grinding – the workpiece is set into rotary motion with a guide wheel by frictional force
Surface grinding is realized by:
- Peripheral grinding – the peripheral edge of the grinding wheel runs parallel to the surface
- Face grinding – the face of the grinding wheel works perpendicularly to the surface
- Peripheral-face grinding – combines features of both of the above methods
- Plunge grinding – the wheel plunges into the material
Accuracy and surface quality
Cylindrical grinding achieves very high dimensional accuracy, often in the range of several micrometers, and low surface roughness. This is particularly important for mating parts in rotating mechanisms.
Surface grinding provides high surface flatness and parallelism. With the circumferential method, flat surfaces can be obtained with an error of no more than 0.02 mm per 1,000 mm of length.
Note: When choosing between cylindrical and surface grinding, consider not only the shape of the workpiece, but also the required dimensional tolerances and surface quality. For cylindrical workpieces with high accuracy requirements, cylindrical grinding will be the optimal choice, while surface grinding will work better for flat precision workpieces.
Cylindrical grinding applications in the automotive and aerospace industries
Cylindrical grinding plays a key role in the automotive and aerospace industries, where manufacturing precision and surface quality are critical to product functionality and safety.
Applications in the automotive industry
Cylindrical grinding is an essential process in the production of key components for automotive engines. Crankshafts, camshafts and valve stems require extremely precise machining to ensure their proper operation and long service life. Cylindrical grinding gives these components perfectly smooth surfaces with precisely defined dimensions.
Powertrain components such as half-shafts, drive shafts and transmission components also undergo cylindrical grinding. This process ensures that rotating parts work together properly, minimizes friction and increases the durability of the entire system. Precision cylindrical grinding translates directly into smooth operation and quiet operation of components.
Cylinders and pistons of internal combustion engines are another application area for cylindrical grinding. The dimensional accuracy and surface quality of these components affect system tightness, engine efficiency and exhaust emissions. Cylindrical grinding makes it possible to achieve a perfect fit of mating parts.
Applications in the aerospace industry
In the aerospace industry, cylindrical grinding is used in the production of jet and turbine engine components. Turbine blades, shafts and other rotating components operate under extreme conditions of temperature and pressure, requiring the utmost precision. Cylindrical grinding ensures not only dimensional accuracy, but also an appropriate surface structure that minimizes the risk of micro-cracks.
Components of hydraulic and pneumatic systems in aircraft also require precision cylindrical grinding. Actuators, valves and other components must operate reliably in a variety of atmospheric conditions, which is made possible by the perfectly smooth surfaces achieved by the grinding process.
Key benefits of cylindrical grinding in the automotive and aerospace industries:
- Increased component life
- Reduction of friction and wear
- Improved energy efficiency
- Reducing noise and vibration levels
- Increased reliability
Both the automotive and aerospace industries place very high demands on dimensional accuracy and surface quality. Cylindrical grinding must meet stringent standards, and the manufacturing process is subject to strict controls. Advanced measurement systems are used to verify geometric parameters and surface roughness.
Innovations in cylindrical grinding
Developments in cylindrical grinding technology are moving in the direction of increasing productivity while maintaining or improving quality. CNC grinders with advanced control systems are making it possible to automate the process and ensure repeatability. New abrasives and wheel designs allow grinding of hard-to-machine alloys used in the aerospace industry.
Tip: When grinding components for the automotive and aerospace industries, special attention should be paid to the selection of appropriate process parameters, such as workpiece speed, peripheral speed of the grinding wheel and feed rate. These parameters have a direct impact on surface quality and dimensional accuracy, and their optimization can significantly improve process efficiency.
Cylindrical grinding methods and their impact on machining accuracy
Cylindrical grinding includes several methods that differ in the method of clamping the workpiece, the direction of feed and the nature of machining. Each of these methods has a specific effect on the dimensional accuracy and surface quality of the workpieces.
Longitudinal cylindrical claw grinding
Longitudinal claw cylindrical grinding is the most popular method for machining external cylindrical surfaces. The workpiece is clamped between the claws and performs a rotary motion, while the grinding wheel performs a main rotary motion and a longitudinal feed parallel to the workpiece axis. Successive layers of material are removed in successive tool passes.
This method provides high dimensional accuracy, especially in maintaining concentricity of the machined surfaces. It makes it possible to grind long shafts while maintaining a small deviation of cylindricity. Machining accuracy depends on the rigidity of the workpiece clamping system and the stability of the grinding wheel guidance.
Plunge cylindrical grinding
In the plunge grinding method, the grinding wheel makes a radial feed perpendicular to the axis of rotation of the workpiece. This method is particularly useful for grinding graded surfaces, where there are different diameters on the same workpiece.
Plunge grinding allows for high dimensional accuracy in terms of diameter, but requires precise control of the wheel’s radial feed. If the feed rate is too fast, it can lead to surface overheating and heat stress, which negatively affects dimensional accuracy.
Centerless cylindrical grinding
Centerless cylindrical grinding is a method in which the workpiece is not clamped in chucks or tusks, but is supported and driven by a guide disc and support. The workpiece is set in motion by frictional force.
Advantages and limitations of centerless grinding:
- High process efficiency
- Possibility of automation and continuous operation
- Elimination of clamping errors
- Restriction to workpieces with simple geometries
- Difficult to machine parts with variable diameters
Centerless grinding provides high diameter accuracy, but can be less precise in maintaining concentricity of different surfaces on a single workpiece. It is particularly effective in mass production, where efficiency and repeatability are important.
Circular grinding
Circular grinding is a special variation of cylindrical grinding, mainly used for machining holes. In this method, a grinding wheel with a diameter smaller than the diameter of the hole performs a complex circular motion, allowing the entire inner surface to be machined.
This method makes it possible to achieve high accuracy of hole shape, but requires precise control of the grinding wheel movement. The accuracy of machining depends on the stability of the workpiece mounting and the precision of the circulating motion.
Factors affecting the accuracy of cylindrical grinding
The accuracy of cylindrical grinding depends on a number of factors that must be considered when designing the process:
- Rigidity of the OUPN system (machine tool-chucking-object-tool)
- Thermal stability of the process
- Accuracy of the grinding wheel guidance
- Quality and condition of the grinding wheel
- Process parameters (speed, feed rate, grinding depth)
- Cooling system
To achieve the highest accuracy in cylindrical grinding, it is worthwhile to use progressive machining with decreasing grinding depth. The first passes with a larger allowance remove most of the material, while the final passes with a minimum allowance (0.01-0.02 mm) ensure dimensional accuracy and low surface roughness. In addition, the use of an efficient cooling system minimizes thermal distortion, which can negatively affect machining accuracy.
CNC grinding services at CNC Partner
CNC Partner is a professional machining company that offers comprehensive CNC services. The company has a modern machine park and qualified staff, which allows it to carry out even the most demanding orders.
About CNC Partner
CNC Partner operates in the metalworking market, offering services at the highest technical level. The company specializes in precision machining using modern numerically controlled machines. CNC Partner uses advanced technology and years of experience. It carries out orders for customers in many industries, including automotive, aerospace and engineering.
The company focuses on continuous development and investment in state-of-the-art technology, which translates into high quality services. CNC Partner employs qualified specialists who guarantee professional implementation of each project.
CNC grinding in the company’s offer
CNC grinding is one of the key services offered by CNC Partner. The company uses advanced numerically controlled grinding machines that ensure high precision and repeatability of machining. CNC grinding service includes both cylindrical and flat surface grinding, which allows for comprehensive service of various projects.
CNC grinding capabilities at CNC Partner:
- External cylindrical surface grinding
- Internal cylindrical surface grinding
- Grinding of surfaces
- Grinding of molds and dies
- Grinding of components with complex shapes
The use of CNC technology allows the company to ensure high dimensional accuracy and low surface roughness of workpieces. CNC grinding allows to achieve tolerances of several micrometers, which meets the highest quality requirements.
Comprehensive machining services
In addition to CNC grinding, CNC Partner offers a wide range of machining services for comprehensive project implementation. Among the available services are:
CNC milling – a service that enables precise machining of complex shapes and surfaces. The company uses modern machining centers to ensure high accuracy and efficiency of the process.
CNC turning – a technology that allows machining rotating parts with high precision. CNC Partner has CNC lathes that enable complex turning operations.
WEDM wire EDM – an advanced machining method that allows the cutting of complex shapes in hard materials. This technology is used in the production of molds, dies and precision machine parts.
Tip: When outsourcing CNC grinding services to a third-party company like CNC Partner, it’s a good idea to carefully specify dimensional accuracy and surface roughness requirements. Precise information in the technical documentation will allow you to optimally plan the machining process and achieve the expected results. It is worth consulting with the company about the possibility of a comprehensive project, combining different machining methods, which can significantly reduce the execution time and costs.
Advantages of surface grinding when machining flat parts
Surface grinding is a key finishing method for flat parts, offering numerous advantages over other machining techniques. This method achieves high surface quality while maintaining tight dimensional tolerances.
High dimensional and geometric accuracy
Surface grinding makes it possible to achieve very high dimensional accuracy of flat parts. The process allows controlled removal of material to within a few micrometers, which is difficult to achieve with other machining methods. Surface grinders provide stable guidance of the grinding wheel relative to the machined surface, minimizing the risk of geometric errors.
Particularly important is the ability to achieve high surface flatness, which is crucial for mating parts such as guide plates, mold parts and dies. Surface grinding makes it possible to achieve flatness in the range of a few micrometers over the entire surface of the component, which ensures proper functioning of mechanisms.
Parallelism of opposite surfaces is another advantage of surface grinding. This method makes it possible to precisely maintain parallelism, which is important for components such as inserts, washers and guide elements.
Surface quality and surface layer structure
Surface grinding provides a low surface roughness, which translates into better performance of components. A smooth surface reduces friction, increases wear resistance and improves the tightness of connections.
The surface grinding process also has a positive effect on the structure of the material’s surface layer. When carried out correctly, the process minimizes the formation of thermal stresses and deformations, resulting in better mechanical properties of the component.
Surface quality benefits after grinding:
- Increased resistance to abrasive wear
- Improved tightness of joints
- Reduced friction
- Improved fatigue properties
- Increased corrosion resistance
Surface grinding is characterized by high productivity, especially when processing large production runs. Modern surface grinders allow fast and precise material removal, which reduces machining time and production costs.
This method is particularly effective for machining hardened materials, where other cutting methods are less efficient or inapplicable. Surface grinding makes it possible to machine parts with hardnesses as high as 60 HRC, which is particularly important for tools and machine parts operating in harsh environments.
Versatility of applications
Surface grinding is used for machining a wide range of materials, including steel, aluminum alloys, copper, titanium and ceramic materials. This versatility makes the method widely used in various industries.
The process can process both small precision parts and large surfaces, making it a versatile solution for a variety of production tasks.
Note: When surface grinding flat workpieces, care must be taken to properly clamp the workpiece. Distortion caused by too strong or uneven clamping can lead to geometric errors when the workpiece is released from the chuck. It is worth using special magnetic or vacuum tables that ensure that the clamping forces are evenly distributed over the entire surface of the workpiece.
Choosing the right grinding technique depending on the shape of the material
Choosing the right grinding technique is crucial to achieving optimal machining results. The decision should take into account the shape of the material first and foremost, but also other factors such as the required accuracy, the type of material or the size of the production run.
Analyze the geometry of the workpiece
The first step in selecting a grinding technique is a thorough analysis of the geometry of the workpiece. Cylindrical workpieces, such as shafts, bushings or pins, require cylindrical grinding. Depending on the length and diameter of the workpiece, as well as the accuracy requirements, you can choose either centre or centreless grinding.
Flat workpieces, such as plates, washers or guide elements, are best machined by surface grinding. In this case, decide between peripheral or face grinding, depending on the required accuracy and surface roughness.
Workpieces with complex geometries, combining flat and cylindrical surfaces, may require a combination of different grinding techniques or the use of specialized profile grinders. In such cases, CNC machine tools are often used to implement complex tool movements.
Factors influencing the choice of grinding technique
The selection of a suitable grinding technique depends on a number of factors that must be taken into account when planning the production process.
Key factors in selecting a grinding technique:
- Shape and dimensions of the workpiece
- Required dimensional and geometric accuracy
- Expected surface roughness
- Type of material and its properties
- The size of the production run
- Available technological equipment
- Economic aspects (cost, productivity)
Recommended techniques for typical shapes
For typical workpiece shapes, optimal grinding techniques can be identified that provide the best results.
Shafts and cylindrical workpieces:
- Short shafts with large diameters – plunge cylindrical grinding
- Long shafts with small diameters – longitudinal cylindrical claw grinding
- Parts with simple geometry produced in series – centerless grinding
Flat components:
- Large plates with high flatness requirements – circumferential grinding
- Small parts with complex shapes – face grinding
- Components with high surface quality requirements – circumferential face grinding
Holes and internal surfaces:
- Small holes – axial feed hole grinding
- Large holes – planetary grinding
- Holes in thin parts – centerless grinding
Regardless of the grinding technique chosen, it is important to optimize process parameters such as speed, feed rate and grinding depth. These parameters should be adjusted to the type of material, the required accuracy and the capabilities of the grinder being used.
Modern CNC systems allow precise control of the grinding process and automatic adjustment of parameters in real time, which significantly improves the quality of machining and increases productivity.
Tip: When choosing a grinding technique for complex parts, it is worth considering trial machining on a smaller batch of material. This will allow verification of technological assumptions and possible correction of process parameters before the start of mass production. In addition, for parts with high accuracy requirements, it is recommended to carry out machining in several stages, with decreasing grinding depth, which minimizes the risk of deformation and stress in the material.
Summary
Grinding is a key finishing process to achieve high dimensional accuracy and low surface roughness. The differences between cylindrical grinding and surface grinding are primarily due to the geometry of the workpieces and the techniques and machines used.
Cylindrical grinding, which is carried out using either the centreless or centreless method, is widely used in the automotive and aerospace industries, where the precision of cylindrical components is crucial to the functionality and safety of products. Various cylindrical grinding methods, such as longitudinal, plunge or centerless, allow the process to be optimally adapted to specific requirements.
Surface grinding, on the other hand, offers numerous advantages for machining flat parts, providing high dimensional and geometric accuracy and excellent surface quality. This method is particularly effective for machining hardened materials and is used in the manufacture of molds, dies and machine components.
The choice of the appropriate grinding technique depends on many factors, primarily the shape of the material, but also on the accuracy requirements, the type of material or the size of the production run. Analysis of these factors allows optimal planning of the process and obtaining the best results.
Companies specializing in machining, such as CNC Partner, offer comprehensive services for CNC grinding and other machining methods, allowing the implementation of even the most demanding projects. Modern numerically controlled machines ensure high precision and repeatability, which translates into quality final products.
Understanding the differences between the various grinding techniques and their proper selection is crucial to the efficiency of the production process and the quality of the manufactured parts. The continued development of grinding technology, including automation and integration with CNC systems, is opening up new opportunities for precision material processing.
Sources:
- https://pl.wikipedia.org/wiki/Szlifowanie
- https://pl.wikipedia.org/wiki/Szlifierka_walcowa
- https://royalsocietypublishing.org/doi/10.1098/rsos.171906
- http://e-learning.prz.edu.pl/mod/resource/view.php?id=51991