Resistant Materials - Commercial Processes and Manufacturing Methods

This section explores the various commercial processes and manufacturing methods used to produce and shape resistant materials. We will cover processes relevant to metals, plastics, and composites, examining their advantages, disadvantages, and applications.

Metalworking Processes

Forming Processes

Forming processes involve shaping metal without removing material. These are generally more cost-effective than processes that involve material removal.

• Rolling: Passing metal between rollers to reduce thickness and change shape. Used for producing sheets, plates, and bars.
• Bending: Shaping metal along a line using tools or dies. Used for creating angles and curves.
• Drawing: Pulling metal through a die to reduce its diameter. Used for making wires and tubes.
• Forging: Shaping metal using compressive forces. Can be done hot or cold.
• Extrusion: Forcing metal through a die to create a specific shape. Used for producing pipes, rods, and profiles.

Machining Processes

Machining processes involve removing material from a workpiece to achieve a desired shape and size.

Process	Description	Advantages	Disadvantages
Turning	Removing material by rotating the workpiece against a cutting tool.	Good for creating cylindrical shapes.	Limited to symmetrical shapes.
Milling	Using a rotating cutter to remove material.	Versatile for creating various shapes.	Can be time-consuming.
Drilling	Creating holes in metal.	Essential for assembly.	Can cause material distortion.
Grinding	Using abrasive wheels to remove material and achieve a smooth finish.	Excellent for surface finish.	Can be slow.

Joining Processes

Joining processes are used to combine two or more pieces of metal.

• Welding: Joining metals by melting and fusing them together. Different types include:
• Gas Welding: Using a flame to melt the metals.
• Arc Welding: Using an electric arc to melt the metals. (e.g., MIG, TIG)
• Soldering: Joining metals using a filler metal with a lower melting point.
• Brazing: Similar to soldering but uses a filler metal with a higher melting point.
• Riveting: Joining metals by permanently fastening them with rivets.

Plastic Manufacturing Processes

Molding Processes

Molding processes involve shaping plastic by injecting molten plastic into a mold.

• Injection Moulding: Injecting molten plastic under high pressure into a closed mold. Suitable for mass production.
• Blow Moulding: Inflating a hollow tube of molten plastic inside a mold. Used for creating bottles and containers.
• Thermoforming: Heating a plastic sheet and shaping it over a mold.

Extrusion Processes

Extrusion involves forcing plastic through a die to create a continuous profile.

Used for producing pipes, profiles, and sheets.

Thermoforming Processes

Thermoforming involves heating a plastic sheet until it becomes pliable and then shaping it over a mold using vacuum or pressure.

Used for creating trays, containers, and packaging.

Composite Manufacturing Processes

Lay-up Processes

Lay-up processes involve layering different materials (e.g., fibres and resin) to create a composite structure.

• Hand Lay-up: Applying layers of material by hand.
• Spray-up: Spraying resin onto a surface with embedded fibres.
• Vacuum Bagging: Using vacuum to remove air from the lay-up to improve consolidation.

Pultrusion Processes

Pultrusion involves pulling material through a die to create a continuous profile.

Used for producing rods, tubes, and beams.

Resin Transfer Processes

Resin transfer processes involve injecting resin into a mould containing reinforcing fibres.

Used for producing complex shapes with high strength-to-weight ratios.

Material Properties and Processes

The choice of manufacturing process is often dictated by the material properties of the resistant material being used. Factors such as strength, ductility, and thermal resistance influence the suitability of different processes.