3.5 Rapid-prototyping

Essential Idea

Rapid prototyping is the production of a physical model of a design using three-dimensional CAD data.

Nature and Aims of Design

Nature of design:

The growth in computing power has had a major impact on modelling with computer-aided manufacture. Rapid software and hardware developments allow new opportunities and exciting new technologies to create dynamic modelling of ever-greater complexity. Models can be simulated by designers using software, tested and trialled virtually before sending to a variety of peripheral machines for prototype manufacture in an ever-increasing range of materials. The ease of sending this digital data across continents for manufacture of prototypes has major implications for data and design protection. (1.19)

Aims:

Aim 10: The increasing effectiveness of rapid prototyping techniques in terms of both cost and speed enables designers to create complex physical models for testing

Guidance

As a student of Design Technology, you should:

Concepts and Principles

Rapid Prototyping

Rapid Prototyping  (RP) is the production of a prototype or model using 3D CAD files. Models are built layer by layer, using either plastics, powders, polymers, or metals. Different technologies are used depending on the material.

Rapid Prototyping is used to produce one-off or limited-run prototypes and models for a variety of situations. The speed and efficiency mean they can save costs and time associated with traditional prototype development. 

This technology is an additive process, whereby material is added or fused to create a solid form. In this regard, RP technologies produce little to no waste compared to subtractive processes such as milling and cutting.

Rapid Prototyping technology also plays an important role in the 4th Industrial Revolution in that it allows mass customization and greater control by consumers.

Additional Resources

Design guidelines for various 3D printing processes:

In your IA, it is important to identify and describe why a certain process is being selected. Refer to the design guidelines above to guide you 

Fused deposition modelling (FDM)

The most accessible type of 3D printing technology, FDM involves the laying down of thin layers of material, usually a type of plastic. The  filament is heated in a nozzle and then "drawn" on layer by layer.


a) Filamentb) Extruder (pulls filament) and nozzle (heats up the filament); Moves on the x-axis and y- axis.c) Printed form (layer upon layer built up)d) Support structure (printed structures to support overhangs; removed after printing)e) Build plate (moves up and down on z-axis))f) Build space

Use Cases

Limitations

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Resources

A variation of FDM, contour crafting, uses liquid ceramic or concrete to create forms from vessels to buildings.


Stereolithography  (SLA)

In this process an object is created by selectively curing a thin layer of liquid resin with a laser. A laser heats selected areas of the resin, turning it into a solid. The process continues until the piece is completed.

Use cases

Limitations

Laminated object manufacturing (LOM)

In this process, layers of plastic, metal, or paper are cut with a laser and then stacked on top of each other. An adhesive is applied between each layer. 

Large parts can be made, compared to plastic FDM technologies. The parts can also be refined, cut, or milled afterwards. 

Selective laser sintering (SLS)

In this process a CO2 laser fuses powder, layer by layer, to create a 3D form. Similar to SLA, a layer of powder is laid down and cintered (burnt) with a laser. The build plate moves down and another layer of powder is added. This new layer is cintered, and so on until the form is complete. Uncintered powder is removed from the chamber to reveal a complete 3D form. The uncintered powder can be reused.

A range of materials can be used in SLS processes, from nylons and polymers, to ceramics and metal alloys.

Use Cases


Limitations