Rapid prototype

RAPID PROTOTYPING

AND ITS APPLICATIONS IN

PRODUCT DEVELOPMENTP. Raghavi

MD. Sabiha Tamkeen

IntroductionRapid Prototyping (RP) has become one of the fastest growing new technologies since its introduction in 1986. By means of this technology it is possible build prototypes and touches them in just a few hours, from a CAD file in which the geometry of the model is defined in 3D. These prototypes are used to visualize those complex shapes not easily seen or understood on conventional drawings

Why rapid prototyping? Due to the advances in mechanical, electronics and computers components, there has been significant growth in communication, information technology and worldwide networking, which leads to globalization and opening of markets, hence increases in worldwide competition among industries. The evolution of the market necessitated the reduction of time to market mainly because the product life cycle is shorter and also because it is very important to proceed more rapidly from an initial conception to mass production object. In product development, Rapid Prototyping has turned out to be the instrument to save time and money and also develop innovative products.

Rapid prototyping techniques

Most commercially available rapid prototyping machines use one of these techniques• Stereo lithography (SL or SLA)• Laminated object manufacturing• Selective Laser Sintering• Fused deposition modeling• Solid Ground Curing• 3D ink jet printer

The main technology in which photo polymerization is used to produce a solid part from a liquid is SLA. This technology employs a vat of liquid ultraviolet curable photopolymer resin and an ultraviolet laser to build the object’s layers one at a time.

Stereo lithography

Laminated object manufacturing

An LOM apparatus uses a continuous sheet of material — plastic, paper or (less commonly) metal — which is drawn across a build platform by a system of feed rollers. Plastic and paper build materials are often coated with an adhesive. To form an object, a heated roller is passed over the sheet of material on the build platform, melting its adhesive and pressing it onto the platform. A computer-controlled laser or blade then cuts the material into the desired pattern.

Selective laser sintering

This technology uses a high power laser to fuse small particles of plastic, metal, ceramic or glass powders into a mass that has the desired three dimensional shape

Solid ground curing

This process is unique in that entire slices of a part are manufactured at one time. As a result, a large throughput is achieved, compared with that from other rapid-prototyping processes. However, solid-ground curing (SGC) is among the most ex-pensive processes; hence, its adoption has been much less common than that of other types of rapid prototyping.

3D PrintingThe 3D printing technologies can be divided in the following: inkjet printingfused deposition modelingpolymer jetting (poly jet) or multi-jet. First of all, it will describe briefly the most used 3D printing technologies.

Fused deposition modeling

Fused Deposition Modeling (FDM) is an additive manufacturing technology commonly used for modeling, Prototyping, and production applications. The FDM technology works using a plastic filament or metal wire which is unwound from a coil and supplies material to an extrusion nozzle which can turn the flow on and off. The nozzle is heated to melt the material and can be moved in both horizontal and vertical directions by a numerically controlled mechanism, directly controlled by a computer-aided manufacturing (CAM) software package. FDM Technology was invented about two decade ago and has continued to lead RP revolution ever since. Even today FDM is most widely used RP technique. Aerospace industries are employing FDM technology Aerospace icons like NASA & Piper Aircraft employ the most exciting FDM (3D printing) applications Rover has FDM Parts “You always want it to be a light as possible, but you also want it to be strong enough.” — Chris Chapman, NASA test engineer in the world

Advantages• To increase effective communication. • To decrease development time. • To decrease costly mistakes. • To minimize sustaining engineering changes. • To extend product lifetime by adding necessary features and eliminating redundant features.• Increasing number of variants of products. • Increasing product complexity. • Decreasing product lifetime before obsolescence. • Decreasing delivery time.

DisadvantagesSome sources are of the opinion that rapid prototyping is not effective because, in actual, it fails in replication of the real product or system. It could so happen that some important developmental steps could be omitted to get a quick and cheap working model. This can be one of the greatest disadvantages of rapid prototyping. Another disadvantage of rapid prototyping is one in which many problems are overlooked resulting in endless rectifications and revisions. One more disadvantage of rapid prototyping is that it may not be suitable for large sized applications.

Applications of Rapid PrototypingEngineering Made use in space stations and space shuttles. Planning to install an RP machine in ISS for making spare parts. Functional parts in FI racing cars and fighter jets like F-18.Medical Applications Custom-fit, clear plastic aligners (braces) can be produced. Used in hearing aids to make custom fit shells.Arts and Archaeology Selective Laser Sintering with marble powders can help to restore or duplicate ancient statues.

Rapid Tooling Tools are made by CNC-machining, electro-discharge machining, or by hand. All are expensive and time consuming. Manufacturers would like to incorporate rapid prototyping techniques to speed the process.

FutureMetal prototypes cannot be made with high degree of accuracy if further developments are made in this aspect prototype and products can be manufactured at a time. It is predicted by some additive manufacturing advocates that this technological development will change the nature of commerce, because end users will be able to do much of their own manufacturing rather than engaging in trade to buy products from other people and corporations.

References:1. Lisa Armano: "Rapid Prototyping Technologies and Build Time Models",A Thesis Presented to the Graduate and Research Committee of Lehigh University in Candidacy for the Degree of Master of Science

2. R.Udroiu, N.V.Ivan: RAPID PROTOTYPING AND RAPID MANUFACTURING APPLICATIONS AT TRANSILVANIA UNIVERSITY OF BRAŞOV, Bulletin of the Transilvania University of Brasov • Vol. 3 (52) – 2010.

3. Prof. Deepa yagnik: Fused Deposition Modeling – A Rapid Prototyping technique for Product Cycle Time Reduction cost effectively in Aerospace APPLICATIONS IOSR Journal of Mechanical and Civil Engineering (IOSR-JMC)

4. Mr. D. CHANDRAMOHAN, Dr. K. MARIMUTHU: RAPID PROTOTYPING/RAPID TOOLING – A OVER VIEW AND ITS APPLICATIONS IN ORTHOPAEDICS, RAPID PROTOTYPING/RAPID TOOLING – A OVER VIEW AND ITS APPLICATIONS IN ORTHOPAEDICS.

5. A Report on the future of rapid prototyping

6. www.3dprinting.net