Essential Concepts in Digital Manufacturing and Prototyping

Fundamentals of Prototyping and Digital Manufacturing

A prototype is an early example of an object that is manufactured to evaluate certain aspects during the construction phase of a technical project. It can cover anything from a specific element to the entire project.

What is Digital Manufacturing?

Digital manufacturing is a manufacturing process where data from a digital design is transferred to computer-aided manufacturing (CAM) tools that execute the prototype manufacturing process without the need for human interaction.

• CAD (Computer-Aided Design): The foundational tool used for creating the digital design.

Understanding 3D Printing Technology

A 3D printer is a machine that can print figures with volume from a computer design.

Key Components of a 3D Printer

• Extruder: The part that takes the filament from the coil and deposits the exact amount on the print bed.
• Electronics: These control all the processes within the printer.
• Mechanics: These parts include the motors and mechanisms that move the material and deposit it in the selected spot.

Phases of Three-Dimensional Printing

There are three distinct phases in three-dimensional printing:

1. Design
2. Slicing
3. Printing

Materials Used in Manufacturing

Plastics for 3D Printing

The plastics generally used in 3D printing are:

• ABS: Typically used for industrial applications.
• PLA: Commonly used for domestic applications.

Types of Polymers

Thermosets

Thermoset plastics can be shaped with heat. However, once they have been formed, they cannot be remelted to create different forms.

Examples include:

• Melamine: Used for wooden boards.
• Bakelite: Used for handles of kitchen utensils.
• Polyester Resins: Used for domestic swimming pools.

Thermoplastics

Thermoplastics can be melted and reformed as many times as needed.

Common examples:

• PET (Polyethylene Terephthalate): Water bottles.
• HDPE (High-Density Polyethylene): Containers.
• PVC (Polyvinyl Chloride): Windows, pipes.
• LDPE (Low-Density Polyethylene): Bags, packaging film.
• PP (Polypropylene): Folders, toys.
• PS (Polystyrene): Food packaging.
• Other thermoplastics: Nylon.

Elastomers

Elastomers are very flexible materials that recover their shape and dimensions when external forces stop acting on them. They degrade easily with heat and cannot be remelted once they have been formed.

Examples include:

• Rubber: Used for tires, football pitches.
• Neoprene: Used for immersion suits, orthopedic devices.
• Silicones: Used for medical prostheses, joint sealing.

Primary Manufacturing Processes

Extrusion

This process is used with thermoplastics to obtain long products (e.g., pipes, profiles).

Injection Moulding

Melted plastic is injected into a mould. After it is cooled, the mould is opened, and the object is removed.

Compression Moulding

This method is used with thermoset plastics. Plastic is placed between two moulds with pressure and heat; the plastic melts and adopts the desired shape.

Blow Moulding

This process starts with a tube formed by extrusion. Air is blown inside the tube until it dilates and adopts the shape of the mould.

Vacuum Forming

This process is used with thermoplastic sheets that are heated and placed on a mould. The vacuum is then turned on, which forces the sheet to adapt to the shape of the mould.