Different Types of Machining Process: Complete Guide

In the vast realm of manufacturing, machining is a critical process that transforms raw materials into finished goods. It’s a method that uses various types of tools to cut, drill, bore, grind, and shape material into a desired form. The machining operations are diverse and complex, ranging from types of CNC milling machine processes to the intricate working of electric discharge machining.

This guide aims to elaborate on the different types of machining process, their applications, benefits, and challenges. It is structured to provide a comprehensive overview, moving from basic to advanced concepts. By the end, readers will have a thorough understanding of the machining world and how it impacts various industries.

Understanding the Basics of Machining Process

What is Machining Process?

Machining is a subtractive manufacturing process where material is removed from a workpiece to create a desired part. It involves a series of operations like turning, milling, drilling, and grinding, carried out by a machine tool such as a CNC milling machine or a lathe. These tools are controlled by a specific set of instructions, known as G-code and M-code, which dictate their movement and function.

Main Components Involved in Machining Process

The machining process involves several key components. The machine tool is the primary device that shapes the workpiece. This could range from a traditional lathe for cutting internal threads to a sophisticated 5-axis CNC machine. 

The cutting tool is another crucial element that interacts directly with the workpiece, while fixtures and jigs hold the workpiece in place during machining. 

Furthermore, modern machines also employ a CNC controller, software that interprets the G-code and M-code to guide the machine’s actions.

Factors Affecting the Choice of Machining Process

The choice of machining process depends on several factors. 

Firstly, the type and hardness of the material influence the selection – certain methods are better suited for metals, while others are ideal for plastics or composites. 

The required accuracy and surface finish, as well as the shape and size of the part, also impact this decision. 

Lastly, factors like production volume, cost, and available equipment play a significant role in choosing the most suitable machining operation.

Conventional Machining Processes

1. Turning

Turning is a fundamental machining process where a lathe rotates the workpiece while the cutting tool moves linearly, removing material to shape the part. 

It’s primarily used for cutting internal threads and creating cylindrical objects such as shafts, rods, and tubes. 

2. Milling

Milling is another versatile machining operation that utilizes a rotating multi-point cutter to remove material from the workpiece. The types of CNC milling machine processes vary depending on the direction of the cutter’s movement relative to the workpiece.

It is widely used for creating parts with complex shapes and features, such as slots, pockets, and contours.

3. Drilling

Drilling is a machining operation focused on creating round holes in a workpiece. It employs a rotary cutting tool, the drill, which applies a force along its axis into the workpiece. It’s used extensively in producing parts that need bolted connections or fluid passage.

4. Grinding

Grinding employs an abrasive wheel as the cutting tool. The types of grinding machine processes include surface, cylindrical, and centerless grinding. Cylindrical grinding machine processes, for instance, are used to shape the outer surfaces of a workpiece. Grinding is typically a finishing process, providing a good surface finish and high dimensional accuracy.

5. Boring

Boring is a process of enlarging a hole that has already been drilled or cored. It’s used when precision is required in the hole size or its concentricity with the external surface.

 It’s commonly used in creating parts for engines and hydraulic systems.

6. Broaching

Broaching is a machining operation that removes material with a toothed tool, called a broach, that cuts a predetermined shape into a workpiece. 

It’s often used to create intricate shapes and high precision finishes, and is particularly useful for cutting keyways, splines, or complex contours that are difficult to achieve with other methods.

7. Shaping and Planing

Shaping and planing are similar processes that involve a linear relative motion between the workpiece and a single-point cutting tool. 

These processes are suitable for creating flat surfaces, grooves, or angular surfaces, and even for cutting internal threads in the case of shaping.

8. Honing

Honing is a finishing process used to improve the geometry, surface texture and dimensional accuracy of a workpiece’s surface. It involves a honing stone that moves back and forth over the surface of the workpiece. 

This process is often used in the finishing of cylindrical surfaces, such as those in cylinders and bearings.

9. Lapping

Lapping is another finishing process where two surfaces are rubbed together with an abrasive between them. The goal is to get incredibly flat surfaces.

It’s typically used in applications requiring high levels of surface accuracy and smoothness.

10. Sawing

Sawing is a machining operation used to cut off sections of a workpiece or to cut the workpiece into specific lengths. It employs a blade with discrete teeth that remove small amounts of material with each stroke or rotation. 

It’s primarily used in cutting large materials into smaller workable pieces.

11. Tapping and Threading

Tapping and threading are machining processes that are utilized to generate internal and external threads on a workpiece. The main difference is that tapping is used to create internal threads within an already formed hole, whereas threading forms external threads like those found on screws or bolts. 

Both processes are crucial in manufacturing industries where parts need to be assembled using screw threads.

12. Knurling

Knurling is a machining process typically carried out on a lathe, where a pattern of straight, angled or crossed lines is rolled into the material. This technique does not remove material, but rather displaces it, creating a raised feature. 

Knurling is used to provide a better grip on a component, making it easier to handle and operate.

13. Reaming

Reaming is a finishing operation performed to slightly enlarge a pre-existing hole to provide a better tolerance diameter and improve its surface finish. 

This process is typically used on parts that require precise fit and alignment.

Non-traditional Machining Processes

Moving beyond conventional machining, we step into the realm of non-traditional machining processes. These innovative methods utilize techniques that do not involve a traditional cutting tool, but instead use thermal, chemical, electrical, or high-energy beams to remove material from the workpiece.

1. Electrical Discharge Machining (EDM)

Electrical Discharge Machining (EDM), also known as spark machining or spark eroding, uses electrical discharges (sparks) to remove material from a workpiece. In this process, the working of electric discharge machining involves a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid. 

This method is typically used for hard metals or those that would be impossible to machine with traditional techniques.

2. Ultrasonic Machining (USM)

Ultrasonic Machining involves the use of high-frequency, low amplitude mechanical vibrations (ultrasonic waves) to remove material from a workpiece. 

The process is suitable for hard and brittle materials like ceramics, glass, and non-conductive metals.

3. Laser Beam Machining (LBM)

Laser Beam Machining is a non-contact machining process where a laser is used to cut materials, offering advantages of high precision and speed. 

This process is used for drilling, cutting, engraving, and marking of various metals and non-metals.

4. Water Jet Machining (WJM)

Water Jet Machining is a non-traditional machining process that utilizes high-pressure water jets to cut through a wide range of materials. 

This cold-cutting process is perfect for applications where the material cannot sustain high heat, preventing it from warping or distorting.

5. Electrochemical Machining (ECM)

Electrochemical Machining employs electrical energy to remove material. It’s a process where the workpiece is an anode and the tool is a cathode. The two are immersed in an electrolyte and when a voltage is applied, material removal occurs. 

ECM is well-suited for complex and hard materials like superalloys and heat-resistant materials.

6. Chemical Machining (CHM)

Chemical Machining uses chemicals to remove material. This non-traditional machining process is primarily used for the mass production of thin metal parts with precise and intricate features.

7. Plasma Arc Machining (PAM)

Plasma Arc Machining uses a high-velocity jet of high-temperature plasma to cut through the workpiece. It’s a very effective method for cutting thick materials and is commonly used in the welding industry.

8. Electron Beam Machining (EBM)

Electron Beam Machining utilizes a high-velocity stream of electrons focused on the workpiece to remove material by melting and vaporization. 

It’s often used for the drilling of very fine holes and the cutting of materials that are extremely difficult to machine by conventional methods.

9. Ion Beam Machining (IBM)

Ion Beam Machining is a non-traditional machining process where a high-energy ion beam is directed towards the workpiece. This beam will physically sputter away the atoms from the surface of the material. T

his machining process is often used in the semiconductor and micro-electronics industries for precise material removal and surface modification.

10. Abrasive Jet Machining (AJM)

Abrasive Jet Machining uses a high-speed stream of abrasive particles carried by a high-pressure gas or air on the work surface through a nozzle. The abrasive particles remove material by erosion. 

This is a non-traditional machining process used for hard materials like super alloys, ceramics, and heat sensitive materials.

11. Magnetic Field Assisted Machining (MFAM)

Magnetic Field Assisted Machining employs the use of magnetic fields to alter the properties of the material being machined. 

This can increase the efficiency of the machining process, reduce the heat generated, and improve the surface finish of the machined part.

Comparison of Traditional and Non-traditional Machining Processes

A. Comparison of Methods

Traditional machining processes, such as turning, milling, drilling, and grinding, generally involve the removal of material by a sharp cutting tool. These methods require physical contact between the tool and the workpiece, making them highly effective for a wide range of materials. However, they can generate significant heat, which can distort the workpiece or cause premature tool wear.

On the other hand, non-traditional machining processes, such as Electrical Discharge Machining, Laser Beam Machining, and Ion Beam Machining, among others, remove material using thermal, chemical, or electrical energy. These methods do not require physical contact with the workpiece, reducing the heat generation and enabling the machining of complex geometries and hard materials.

B. Comparative Advantages and Disadvantages

Traditional machining processes are generally simpler and more cost-effective for mass production. They offer high material removal rates and excellent surface finishes. However, they can struggle with complex geometries and hard materials.

Non-traditional machining processes are more versatile, capable of handling complex shapes and hard materials. They generate less heat and provide finer control over the material removal process. But, they are typically slower, more complex, and more costly to set up and operate.

C. Application Areas

Traditional machining processes are ideal for general manufacturing applications, producing a wide variety of components such as gears, bolts, engine parts, and more. They are widely used in industries like automotive, aerospace, construction, and more.

Non-traditional machining processes are critical for precision manufacturing, where intricate shapes, small size, or hard materials are involved. They are prevalent in industries such as aerospace, medical, electronics, and more. For instance, at Worthy Hardware, we utilize a mix of these techniques to offer customized solutions for our clients across various sectors.

Conclusion

A. Recap of Different Types of Machining Processes

We have traversed the spectrum of machining processes, from the fundamental traditional methods like turning, milling, and grinding, to the advanced non-traditional techniques such as electrical discharge machining and laser beam machining.

To learn more about how Worthy Hardware can help with your specific machining needs, contact us today. We stand ready to provide you with high-quality, custom-engineered solutions for your manufacturing challenges.

FAQ

1. What are the 5 basic machining operations?

The five basic machining operations are turning, drilling, milling, grinding, and shaping.

2. What are the 3 main types of machining technologies?

The three main types of machining technologies are traditional machining (e.g., turning, milling), non-traditional machining (e.g., electrical discharge machining, laser beam machining), and hybrid machining (a combination of traditional and non-traditional processes).

3. What is the difference between cutting and machining?

Cutting is a process where material is removed by a cutting edge. Machining, however, is a broader term that includes not only cutting but also other material-removal processes like grinding, drilling, and milling.

4. What is CNC vs manual machining?

CNC machining uses computer programming to automate the operation of the machine tools, which can lead to more precise and efficient production. Manual machining requires the operator to control the machine tools directly.