RAPID PROTOTYPING

(Creating Real Parts from Solid Models)

Studies On

Seminar

Under Supervision Of

Dr. Saurav Dutta

By Abhishek Singh

212ME2301

Department Of Mechanical Engineering

National Institute Of Technology - Rourkela

Overview of Presentation

Literature Review

Introduction

Processes

Applications

Recent advancements

Conclusion

Literature Review

Prototype manufacturing is very time consuming process involving all stages of manufacturer such as process planning, machining, assembly etc.

So RP technologies have been introduced to ensure long-term consistent component use for the entire production life cycle, and one of the largest

efforts is focused in the direct manufacture of metal parts (Bakkelund, Karlsen

et al. 1997; Levy, Schindel et al. 2003).

Alternative materials for rapid tooling by King, D; Tansey, T

Journal of Materials Processing Technology (Netherlands), vol. 121, no. 2-3, pp.

28 Feb. 2002,

Rapid investment casting of metals by Minev, R

Foundry Trade Journal (UK), vol. 176, no. 3590, pp. 19, Apr. 2002

Introduction What is a Prototype?

A prototype is a draft version or an approximation of a final product.

Prototypes are developed for several reasons:

to identify possible problems that were not identified in previous

stages of the design process.

to confirm the suitability of a design prior to starting mass

production.

Provides a scale model to conduct tests and verify performance.

for visualization purposes.

Some prototypes are used as market research and promotional tools.

Most importantly, it is cheaper to manufacture, test and make changes to a prototype than it is to a final product.

Rapid Prototyping

Rapid prototyping is a broad term that comprises many different technologies used to quickly fabricate a physical model directly from

computer data.

The first rapid prototyping method, called stereo lithography, was developed in the late 1980s, but more sophisticated techniques are

available today.

Year of inception Technology

1770 Mechanization

1946 First computer

1952 First Numerical Control (NC) machine tool

1960 First commercial laser

1961 First commercial Robot

1963

First interactive graphics system (early

version of Computer Aided Design)

1988 First commercial Rapid Prototyping system

Historical development of Rapid

Prototyping and related

technologies

Contd..

The term rapid is relative. Some prototypes may take hours or even days to build (still much faster than the weeks that may be required for a

technician to machine a design out of metal).

Rapid prototyping systems are additive manufacturing processes that work on the basic principle of producing a 3D part by building and

stacking multiple 2D layers together.

Most common types of rapid prototyping systems:

SLA (Stereo Lithography)

SLS (Selective Laser Sintering)

LOM (Laminate Object Manufacturing)

FDM (Fused Deposition Modeling).

Stereo Lithography (SLA)

Uses a liquid photosensitive resin as building material and a low power laser to build the part, one layer at a time.

The 3D part is produced on a flat platform that is gradually submerged on a pool filled with photosensitive liquid resin.

For each layer, a laser beam traces out the corresponding cross-section pattern of the part on the surface of the liquid container.

The pattern is then solidified and added to the layer below.

The platform descends one layer thickness (the layer thickness depends on the precision of the machine) and the process repeats.

Stereo Lithography (SLA)

Fine point structure for

Stereo lithography-investigation by

Williams, R.E., Komaragiri

Selective Laser Sintering (SLS)

Uses a high power laser and powdered materials.

A wide variety of materials can be used, ranging from thermoplastic polymers, such as nylon and polystyrene, to some metals.

3D parts are produced by fusing a thin slice of the powdered material onto the layers below it.

The surfaces of SLS prototypes are not as smooth as those produced by SLA processes. However, SLS parts are sufficiently strong and resistant

for many functional tests.

Selective Laser Sintering (SLS)

The powdered material is kept on a delivery platform and supplied to the building area by a roller.

For each layer, a laser traces the corresponding shape of the part on the surface of the building area, by heating the powder until it melts, fusing it

with the layer below it.

The platform containing the part lowers one layer thickness and the platform supplying the material elevates, providing more material to the

system.

The roller moves the new material to the building platform, leveling the surface, and the process repeats.

Selective Laser Sintering (SLS)

Laminated Object Manufacturing

Laminated Object Manufacturing is a relatively low cost rapid prototyping technology where thin slices of material (usually paper or wood) are

successively glued together to form a 3D shape.

The process uses two rollers to control the supply of paper with heat-activated glue to a building platform.

When new paper is in position, it is flattened and added to the previously created layers using a heated roller.

The shape of the new layer is traced and cut by a blade or a laser. When the layer is complete, the building platform descends and new paper is supplied.

When the paper is in position, the platform moves back up so the new layer can be glued to the existing stack, and the process repeats.

Laminated Object Manufacturing

Applications

Applications of rapid prototyping can be classified into three categories:

1. Design

2. Engineering analysis and planning

3. Tooling and manufacturing

Rapid prototyping recent advancements

Rapid Prototyping and Analog Testing for Human Space Exploration - NASA created a management environment for the rapid development of several

prototypes at very low cost. The projects focus on producing functional

prototypes of increasing fidelity so systems integration issues can be

understood early through rigorous design, build, and human in-the-loop

testing.

In Medicals - Recently this technique was used for the separation of Siamese twins who was borned by the attaching of the skull portion as shown below.

Further development in RP in tissue engineering requires the design of new

materials, optimal scaffold design and the input of such kind of knowledge of

cell physiology that would make it possible in the future to print whole

replacement organs or whole bodies by machines

Conclusion

Rapid prototyping methodology has been extended into a self-sustaining infrastructure to serve all. As the embedded processor design community

continues to adopt RAPID methodology, more and more design tutorials,

examples, and workshops are being added to the library through the Wiki

portal all over the world.

New strategic technologies are also being pursued, such as the development of a data-path container to augment the firmware development environment.

This data-path container will support protocol standards, such as PCI Express

and Serial RapidIO protocols, with the goal of incorporating the general-

purpose, graphics processing technology into the RAPID test bed.

List of Refrences

Jacobs Petal. Stereo lithography and other RP & M technologies from Rapid prototyping to Rapid tooling. ASME press, 1995.

Swalens Betal. Medical Application of Rapid Prototyping Techniques. Fourth International conference on Rapid Prototyping, 1993; 107-20.

Chua, C.K., Leong, K.F. (2000) Rapid Prototyping: Principles and Applications in Manufacturing, World Scientific.

Gebhardt, A., (2003) Rapid Prototyping, Hanser Gardner Publications, Inc., Cincinnati.

http://www.nasa.gov/offices/oce/appel/ask/issues/42/42s_rapid_prototyping_analog_testing_prt.htm-NASA Official Website