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:
Recognize the different types of 3D printing techniques
Understand the advantages and disadvantages of rapid prototyping techniques
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.BHA Elements of 3D Printing: A good resource to understand some of the key aspects of 3D printing
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.
Use Cases
Affordable materials and equipment
Consumer grade technology is accessible and easy to maintain
Printing functional prototypes
Variety of materials can be printed
Limitations
Relatively slow
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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
Build functional prototypes
High resolution allows for very small objects to be printed
Requires little cleaning up
Limitations
Relatively high cost of materials and printers
Some resins are not ideal for functional prototypes
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
little waste as unused powder can be reused
low-run production possible
printing of functional prototypes
printing of metal alloys--no other systems are capable
Limitations
high cost of materials and equipment