Main Categories of Manufacturing Processes

Main Classes of Manufacturing Processes

Manufacturing processes are the ways utilized to modify raw materials to end up with finished goods. These processes can be divided into several methods, each of which has its own technique, benefits, and uses.

1. Casting

Definition and Principles:

Casting is a process of manufacturing that goes like this: the liquid material (such as metal, plastic, or some other) is poured into a mold and allowed to become a solid, thus it takes the form of the mold. The process is based on the idea of melting the material, then casting it into a mold, and then cooling it until the final product is formed.

Steps Involved in Casting:

1. Pattern Creation: Usually, a wax or sand or metal that has a given shape is created and used as a pattern for the mold.
2. Mold Making: The pattern mold is used to restrain the molding process. In the case of sand casting, this is done by packing sand around it. Otherwise, a metal mold is created for die casting technique.
3. Melt the Material: The material, such as metal, is heated to a melting point.
4. Pouring: The liquid material is released into the mold cavity.
5. Cooling and Solidification: The material cools down and solidifies in the mold cavity.
6. Finishing: The castings are removed from the mold, and any raised margins or other imperfections are eliminated.

Advantages and Applications:

• Advantages:
  • It can be used to create complex shapes.
  • It is possible to deal with large or heavy pieces.
  • It can attain high-volume production.
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• Applications:
  • Engine blocks, pumps, turbines, jewelry, and industrial machine parts are a few examples.

2. Forming

Definition and Types of Forming Processes:

Forming is the method for reshaping materials (generally metals) through the use of the forces without getting rid of a bit of material. The material is deformed by compressive, tensile, or shear forces, often while heated.

• Types of Forming Processes:
  • Bulk Forming: This category includes forging, rolling, extrusion, and drawing processes. All of them involve the material’s deformation to a great extent.
  • Sheet Metal Forming: Processes that are quite common for industry like stamping, bending, and deep drawing are included in this category. They are using mainly thin sheets of metal.

Specific Processes:

Forging:

• This is a method where the metal is shaped by compressive forces, with a hammer or die normally being the tools used in the process.
• Example: These are items like forged steel parts, which are widely used in automotive products such as gears and crankshafts.

Rolling:

• This is a process where metal goes through two or more rollers in order to be made thinner.
• Example: Several items including steel plates, foils, and sheets are produced for construction and manufacturing purposes.

Extrusion:

• The metal or plastic is passed through a die in order to make long shapes with a uniform cross-section.
• Example: Aluminum window frames, and plastic pipes are two examples of extrusion processes.

Drawing:

• One of the very common methods used in metal modification is the one where the metal is pulled through a die to decrease its diameter, which is popularly used for wires and tubes.
• Example: A simple application of a copper wire would be for the electrical circuit.

Bending:

• Metal is bent at the angle where it is required by exerting force on a fixed material.
• Example: Bent sheet metal is used in automobile body panels like a fender.

Shearing:

• It is a process of it being cut into specific shapes using a shear machine.
• Example: Metal can be cut into smaller parts using this method.

Blanking & Piercing:

• Blanking: The procedure in the process of metalwork by which shapes are cut out from a sheet or plate, used to create blanks for further processing.
• Piercing: The making of holes or spaces into the material.
• Example: Factory where the body parts of cars, washers are made.

Advantages and Applications of Forming:

• Advantages:
  • High strength due to the material’s grain structure.
  • High production rates and low material waste.
  • Good for large quantities.

3. Joining Processes

Techniques:

The combinations of materials with each other to obtain one product are done using joining processes.

Welding:

• It is when materials (often metals) are treated with heat, pressure, or a combination of these to make them fused together.

Soldering:

• The method used to join metal parts with a filler metal tin at a temperature below 450° C.

Riveting:

• Riveting is the process of creating a weld (a small metal pin) to hold two pieces of material together.

Bolting:

• Bolting is the method by which bolts and nuts are used to join parts together and can be easily disassembled later.

Terms Used in Welding:

• Electrode: A metal rod that is melted and deposited at a point of jointure.
• Arc: Used as a way to both melt the metal and to provide the heat required for melting the metal at the joint.
• Bead: The filler material between two joint pieces of metal.
• Heat Affected Zone (HAZ):The portion of the area near the weld, which had been heated but not melted.

Types of Welding:

Arc Welding:

• The electric arc finds the workpiece which the electrode is attached to, that would melt the metal and then flow into a gap which forms the join.
  • Examples: Electric arc welding methods include Shielded Metal Arc Welding (SMAW), Gas Metal Arc Welding (GMAW), and Tungsten Inert Gas (TIG).

Advantages and Disadvantages of Welding:

Advantages:

• Creating forces stronger than the ones experienced by each part is a typical advantage of welding.
• Offered goods of diverse materials can be welded or joined utilizing a versatile manufacturing technology.
• It has the capability to weld both very thin and very thick.

Disadvantages:

• It needs skilled labor.
• It can lead to distortion and cracking.
• Security issues for welding staff are a possibility.

Common Welding Defects:

Porosity: Trapped gas bubbles are welded into the weld.

Cracking: An occurrence where some cracks are formed in the weld area.

Undercut: A groove escaped by the side of the base material

4. Machining

Definition and Types of Machining Processes:

Machining is the process of removing material from a workpiece to achieve a desired shape or finish. It’s typically done using tools such as lathes, mills, drills, etc.

• Types:
  • Cutting Processes: Involves removing material using cutting tools (e.g., turning, milling, drilling).
  • Non-Cutting Processes: Includes grinding, honing, and polishing.

Conventional vs. Non-conventional Machining:

• Conventional: Uses cutting tools to remove material (e.g., lathe turning, milling).
• Non-conventional: Involves other methods like water jets or lasers (e.g., electrical discharge machining (EDM), laser cutting).

Specific Machining Operations:

Turning:

• Material is rotated while a cutting tool removes material to create cylindrical parts.
• Example: Shafts, pulleys.

Drilling:

• A rotating drill bit is used to make round holes in a workpiece.
• Example: Holes in metal plates for bolts.

Milling:

• A rotating cutter removes material from the surface of a workpiece.
• Example: Milling machine operations for creating complex shapes.

Shaping:

• A single-point cutting tool moves linearly to cut a workpiece.
• Example: Shaping a flat surface on a metal workpiece.

5. Computer Numerical Control (CNC) Machines

Definition and Components of CNC:

CNC (Computer Numerical Control) machines are controlled by computer programs which in turn control the movement of the cutting tools and the working of the machine tool.

• Components:
  • CNC Machine: The machine itself, which, for example, can be a CNC lathe or a CNC milling machine, to name a few.
  • Controller: The computer that sends instructions to the machine.
  • Servo Motors: Movement of the machine components is controlled by the servo motors.

Advantages and Limitations:

• Advantages:
  • High precision and repeatability.
  • Complex shapes can be produced.
  • Reduced human error.
• Limitations:
  • High initial cost.
  • Requires highly skilled operators for programming.

Applications of CNC Machines:

• Aerospace vehicles such as turbine blades and fuselages, automotive products such as engine components, and medical equipment such as implants, to name a few.

6. D Printing

Definition and Types of Manufacturing:

3D printing (Additive Manufacturing) is the process of creating objects by layering material based on a digital design.

• Types of 3D Printing:
  • Fused Deposition Modeling (FDM): Uses thermoplastic filament.
  • Stereolithography (SLA): Uses liquid resin cured by UV light.
  • Selective Laser Sintering (SLS): Uses powdered materials.

Steps Involved in 3D Printing:

1. Design Creation: A 3D model is created by applying CAD software.
2. Slicing: The 3D model is sliced into layers.

7. Smart Manufacturing

Definition and Components:

Smart manufacturing is the application of technologies such as the Internet of Things (IoT), artificial intelligence (AI), and robots in manufacturing processes. It comprises the use of interconnected devices, real-time data, automation, and intelligent decision-making systems.

• Components:
  • IoT Sensors: For monitoring the equipment and production in real-time.
  • Robotics: Machines that have become quite automated for assembly and material handling.
  • Data Analytics: For predictive maintenance and process optimization.

Benefits of Smart Manufacturing:

• Productivity and precision improved the most.
• Less downtime and maintenance costs were incurred.
• The item was made to be of