AMTech Update

Design better and faster with Rapid Prototyping

Posted on by Divya Sagar
04
Jun

Rapid Prototyping (RP) technology has been developing rapidly in the past ten years. It has emerged as the quick process to create products using 3D printing or additive manufacturing technology. This technology significantly improves the present prototyping practices in industry. By realizing the potential of Rapid Prototyping for prototyping applications, a large number of processes have been developed allowing the use of various materials ranging from plastics to metals for the development of prototypes. The article discusses the main processes of the RP technology.

Global competition, accelerated product obsolescence, product customisation and continued demands for cost savings are forcing companies to look for new technologies to improve their business processes and speed up the product development cycle. Rapid prototyping has emerged as a key enabling technology, with its ability to shorten product design and development time.

What is Rapid Prototyping?

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Rapid Prototyping is the group of technologies used to fabricate physical models, functional prototypes and small batches of parts using three-dimensional computer-aided design (CAD) data. These parts are usually constructed using 3D printing and additive layer manufacturing as opposed to traditional subtractive methods. This technology has also been referred to as layer manufacturing, solid free-form fabrication, material addition manufacturing and three-dimensional printing. Rapid prototyping is a means of compressing the time-to-market of products and, as such, is competitiveness enhancing technology. In addition, RP models can be used for testing, such as when an airfoil shape is put into a wind tunnel. RP models can be used to create male models for tooling, such as silicone rubber molds and investment casts.

Rapid Prototyping decreases development time by allowing corrections to a product to be made early in the process. By giving engineering, manufacturing, marketing, and purchasing a look at the product early in the design process, mistakes can be corrected and changes can be made while they are still inexpensive. Rapid prototyping allows engineers to thoroughly test prototypes that look and perform like final products, reducing the risks of usability and manufacturability issues before moving into production.

Rapid Prototyping parts are used for visual inspection, ergonomic evaluation, and masters for secondary manufacturing processes in various stages of new product development. The process has a wide range of applications and are been used in the automotive, architecture, art, consumer products, casting, toy industries, medical and biomedical fields. Rapid prototyping is a tool for design, engineering and manufacturing.

Rapid Prototyping Processes

Currently, there are a number of RP techniques commercially available on the market, including Selective Laser Sintering (SLS®), Fused Deposition Modeling (FDM), Stereolithography (SLA), Solid Ground Curing (SGC), Laminated Object Manufacturing (LOM™), and Ink Jet printing techniques. This section will focus on the three technologies that have a significant commercial impact. These RP processes are described below.

Selective laser sintering (SLS):

An additive manufacturing layer technology, SLS involves the use of a fine powder which is heated with a carbon dioxide laser to fuse small particles of plastic, metal, ceramic, or glass powders into a mass that has a desired three-dimensional shape. Before the powder is sintered, the entire bed is heated to just below the melting point of the material in order to minimise thermal distortion and facilitate fusion to the previous layer. A 3-D digital description of the part is drawn on the surface of a powder bed using the laser to sinter the material. After the scanning of each cross-section of the part, the powder bed is lowered by one layer thickness, a new layer of material is applied on top, and the process is repeated until the part is completed.

As SLS requires the use of high-powered lasers it is often too expensive. The expense and potential danger of SLS printing means that the home market for SLS printing is not as large as the market for other additive manufacturing technologies, such as Fused Deposition Modeling (FDM).

Stereolithography (SL):

This process is a form of 3D printing technology used for developing prototypes, models, patterns, and production parts in a layer by layer fashion using a photosensitive liquid resin which forms a solid polymer when exposed to ultraviolet (UV) light. Those polymers then make up the body of a three-dimensional solid. Stereolithography is also referred as optical fabrication, resin printing, stereolithography apparatus, or photo-solidification.

Fused deposition modelling (FDM):

FDM is a 3D printing process that uses a continuous filament of a thermoplastic material. FDM systems consist of two movable heads (one for building the part and one for the supports) which deposit threads of molten material onto a substrate. The material is heated to just above its melting point so that it solidifies immediately after extrusion and cold welds to the previous layers. The print head is moved under computer control to define the printed shape.

Applications of Rapid Prototyping

Rapid prototyping is widely used in the automotive, aerospace, medical, and consumer products industries. Although the possible applications are virtually limitless, nearly all fall into one of the following categories:

  • Prototyping
  • Rapid tooling or rapid manufacturing.
    a) Direct tooling
    b) Indirect tooling
  • Rapid Manufacturing

The RP model plays the vital role in medical applications. It is used in human facial scull transparency in the medical field. The RP techniques models are widely used in textile industries. The complicated contour profile dresses are designing in the 3D model with aid of computer and directly inter connected with manufacturing machine. The foot-ware for a human comfort is manufacturing in RP technique, whereas the furniture is designed and manufacturing with a aid of RP techniques.

Rapid prototyping is the easiest way to get real parts in a short time period. Many companies rely on rapid prototyping to confirm their new concept before launching mass production. There is a multitude of experimental RP methodologies either in development or used by small groups of individuals.

In recent years, the rapid-prototyping industry of producing three dimensional models directly from 3D CAD data has grown rapidly. Several companies produce rapid-prototyping machines that can fabricate a physical three-dimensional model out of various materials including plastic, paper and metal. In use for more than 20 years among the elite of manufacturing companies, rapid prototyping continues to prove itself by empowering rapid product innovation. It is starting to change the way companies design and build products.

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Divya Sagar

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