Newspaper Publishings

Rapid Prototyping - A Fast Track to Product Development
(as published in the Times of India dated 28 Feb.1997)

In a changing scenario of the Indian industry, with multinationals bringing in their manufacturing and R&D bases, technology that assists in development of innovative products faster is a boon for the progressive companies. Fastest time-to-market, quality and individual customer satisfaction are the keys to successful market leadership.

Traditionally a prototype is made for the purpose of verifying the form, fit and functional aspects of the part or an assembly. This enables the designer to be sufficiently confident of his design even before manufacturing costly tools and also undertaking regular production. To develop tooling for prototypes or regular production is a costly and time consuming proposition. Besides, changes in the basic design lead to re-working and at times scrapping of the entire effort / material put in the development process.

Rapid Prototyping has reduced this time-cycle drastically and added the element of accuracy to it. Prototype samples generated by this process are also useful in developing toolings by various casting and forming processes. This on the whole has evolved the concept of Rapid Manufacturing.

Over the period of time, companies from various industrial sectors have taken great advantage of this technology. Automotive, aerospace, medical implants & instruments, toys, electronic goods, electrical switch gear, consumer durables, furniture, packaging etc. are a few of the segments thus covered.

General Motors, Chrysler, Ford, Fiat, 3M, Kodak, Motorola, Apple Computers, Unilever, Gillette, GE etc. are some of the beneficiaries around the world. In India too, a few companies also been reported to have successfully adopted this technology.

Rapid Manufacturing involves 3D CAD modelling, Rapid Prototyping, Rapid Tooling and Production. 3D CAD models can be generated using standard CAD softwares. Almost all of these give an output in the form of a .STL file which forms the input for the Rapid Prototyping system. Here the data is sliced into multiple layers and then the model is built layer-by-layer. It can be considered as a "3D Plotter".

Rapid Prototyping concept was first introduced as Stereolithography in the US around early or mid-1980s. Since then, Fused Deposition Modelling, Laminated Object Manufacturing, Selective Laser Sintering, Solid Ground Curing, Direct Shell Production Casting, Inkjet Principle etc. are some of the technologies on which different vendors have developed their machines.

Prototypes built from most of these technologies, are used for developing tools by way of Investment Casting, Epoxy Molding, Silicone Rubber Molding, Spray Metal Casting etc. These tools, if necessary, may also be finished before being used for production. Variety of plastics or metals can be produced depending upon the process followed e.g. Injection Molding, Press / Vacuum Forming, Sand Casting, Copy Milling, Spark Erosion, etc. Quantities upto a few thousand pieces have been produced through some of these techniques.

Depending upon the stages chosen, typical investments of the set-up range from 200,000 to 800,000 US Dollars. Service Bureaus charge somewhere in the range of 40 to 100 US Dollars per hour of machine time. Around, the world, the service bureaus have been used more widely rather than captive facilities.

The seemingly higher cost can easily be justified from the fact that the products which used to take about six to eight months for development can now be achieved within four to eight weeks with a possibility of trying more alternatives. The intermediate Rapid Tools can also be used for low volume production runs, which can be useful for test marketing. Thus giving enough breathing gap for manufacturing more durable conventional tools.

As in any other technology, Rapid Prototyping also has its own limitations. Very fine intricate details are difficult to obtain. Parts of very large sizes have to be split into smaller pieces. Although parts of about 24 inches cube may be possible through this technology, 6 to 8 inch cube is considered to be the ideal size limit.

Considering all the factors, rapid prototyping for the complex areas of the product and conventional methods for the simpler areas should be judiciously combined to achieve the optimum results.