Prototype Advantages and Disadvantages

Rapid prototype is a process wherein a working model or prototype is developed for the purpose of testing the various product features like design, ideas, features, functionality, performance and output. This process of development of working model is quite quick. The user can give an early feedback regarding the prototype. Rapid prototyping is, generally, a significant and essential part of the system designing process and it is believed to decrease the project cost and risk.

The Rapid prototype that is developed by the process of rapid prototyping is based on the performance of earlier designs. Hence, it is possible to correct the defects or problems in the design by taking corrective measures. The product can be produced if the prototype meets the requirements of all designing objectives after sufficient refinement. There are many advantages of rapid prototyping.

ADVANTAGES:

• Rapid Prototyping can provide with concept proof that would be required for attracting funds.

• The Prototype gives the user a fair idea about the final look of the product.

• Rapid prototyping can enhance the early visibility.

• It is easier to find the design flaws in the early developmental stages.

• Active participation among the users and producer is encouraged by rapid prototyping.

• As the development costs are reduced, Rapid prototyping proves to be cost effective.

• The user can get a higher output.

• The deficiencies in the earlier prototypes can be detected and rectified in time.

• The speed of system development is increased. It is possible to get immediate feedback from the user.

• There is better communication between the user and designer as the requirements and expectations are expressed in the beginning itself.

• High quality product is easily delivered by way of Rapid prototyping.

• Rapid prototyping enables development time and costs.

• There are many innovative ways in which Rapid prototyping can be used.

DISADVANTAGES:

• Some people 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.

• The user may have very high expectations about the prototype’s performance and the designer is unable to deliver these.

• The system could be left unfinished due to various reasons or the system may be implemented before it is completely ready.

• The producer may produce an inadequate system that is unable to meet the overall demands of the organization.

• Too much involvement of the user might hamper the optimization of the program.

• The producer may be too attached to the program of rapid prototyping, thus it may lead to legal involvement.

• The cost reduction benefit of rapid prototyping also seems to be debatable, as sufficient details regarding the calculation basis and assumptions are not substantial.

Introduction To Additive Fabrication

Additive fabrication refers to a class of manufacturing processes, in which a part is built by adding layers of material upon one another. These processes are inherently different from subtractive processes or consolidation processes. Subtractive processes, such as milling, turning, or drilling, use carefully planned tool movements to cut away material from a work piece to form the desired part. Consolidation processes, such as casting or molding, use custom designed tooling to solidify material into the desired shape. Additive processes, on the other hand, do not require custom tooling or planned tool movements. Instead, the part is constructed directly from a digital 3-D model created through Computer Aided Design (CAD) software. The 3-D CAD model is converted into many thin layers and the manufacturing equipment uses this geometric data to build each layer sequentially until the part is completed. Due to this approach, additive fabrication is often referred to as layered manufacturing, direct digital manufacturing, or solid freeform fabrication.

The most common term for additive fabrication is rapid prototyping. The term “rapid” is used because additive processes are performed much faster than conventional manufacturing processes. The fabrication of a single part may only take a couple hours, or can take a few days depending on the part size and the process. However, processes that require custom tooling, such as a mold, to be designed and built may require several weeks. Subtractive processes, such as machining, can offer more comparable production times, but those times can increase substantially for highly complex parts. The term “prototyping” is used because these additive processes were initially used solely to fabricate prototypes. However, with the improvement of additive technologies, these processes are becoming increasingly capable of high-volume production manufacturing, as will be explored in the section on applications.

Additive fabrication offers several advantages, listed below.

• Speed – As described above, these “rapid” processes have short build times. Also, because no custom tooling must be developed, the lead time in receiving parts is greatly reduced.

• Part complexity – Because no tooling is required, complex surfaces and internal features can be created directly when building the part. Also, the complexity of a part has little effect on build times, as opposed to other manufacturing processes. In molding and casting processes, part complexity may not affect the cycle times, but can require several weeks to be spent on creating the mold. In machining, complex features directly affect the cycle time and may even require more expensive equipment or fixtures.

• Material types – Additive fabrication processes are able to produce parts in plastics, metals, ceramics, composites, and even paper with properties similar to wood. Furthermore, some processes can build parts from multiple materials and distribute the material based on the location in the part.

• Low-volume production – Other more conventional processes are not very cost effective for low-volume productions because of high initial costs due to custom tooling and lengthy setup times. Additive fabrication requires minimal setup and builds a part directly from the CAD model, allowing for low per-part costs for low-volume productions.

With all of these advantages, additive fabrication will still not replace more conventional manufacturing processes for every application. Processes such as machining, molding, and casting are still preferred in specific instances, such as the following:

• Large parts – Additive processes are best suited for relatively small parts because build times are largely dependent upon part size. A larger part in the X-Y plane will require more time to build each layer and a taller part (in the Z direction) will require more layers to be built. This limitation on part size is not shared by some of the more common manufacturing methods. The cycle times in molding and casting processes are typically controlled by the part thickness, and machining times are dependent upon the material and part complexity. Manufacturing large parts with additive processes is also not ideal due to the current high prices of material for these processes.

• High accuracy and surface finish – Currently, additive fabrication processes can not match the precision and finishes offered by machining. As a result, parts produced through additive fabrication may require secondary operations depending on their intended use.

• High-volume production – While the production capabilities of additive processes are improving with technology, molding and casting are still preferred for high-volume production. At very large quantities, the per-part cost of tooling is insignificant and the cycle times remain shorter than those for additive fabrication.

• Material properties – While additive fabrication can utilize various material types, individual material options are somewhat limited. As a result, materials that offer certain desirable properties may not be available. Also, due to the fabrication methods, the properties of the final part may not meet certain design requirements. Lastly, the current prices for materials used in additive processes are far greater than more commonly used materials for other processes.

Applications:

Additive fabrication processes initially yielded parts with few applications due to limited material options and mechanical properties. However, improvements to the processing technologies and material options have expanded the possibilities for these layered parts. Now, additive fabrication is used in a variety of industries, including the aerospace, architectural, automotive, consumer product, medical product, and military industries. The application of parts in these industries is quite vast. For example, some parts are merely aesthetic such as jewelry, sculptures, or 3D architectural models. Others are customized to meet the user’s personal needs such as specially fitted sports equipment, dental implants, or prosthetic devices. The following three categories are often used to describe the different application of additive fabrication and may be applied to all of the above industries.

• Rapid prototyping – Prototypes for visualization, form/fit testing, and functional testing

• Rapid tooling – Molds and dies fabricated using additive processes

• Rapid manufacturing – Medium-to-high volume production runs of end-use parts

AUTOCAD basic

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Computer Aided Design (CAD) is a form of design in which people work with computers to create ideas, models, and prototypes. CAD was originally developed to assist people with technical drawing and drafting, but it has expanded to include numerous other potential uses. A variety of software products designed for CAD can be found on the market, with many being targeted to a specific application or industry.

Drafting and technical drawing can be very painstaking, and they require some special skills. Using CAD for drafting still requires many of the same skills, but by working with a computer instead of on paper, people can be much more efficient. They can also play around with ideas much more easily, moving design elements around and running the design through software programs which can determine whether or not the design is structurally viable. For example, an architect working on a bridge can test the design in simulations to see if it will withstand the load it will need to carry.

CAD can be used to design structures, mechanical components, and molecules, among other things. One advantage of using CAD is that people don’t have to make prototypes to demonstrate a project and its potential, as they can use a three dimensional modeling program to show people how something might look. CAD also allows for endless variations and experiments to show how the look and feel of something can be altered, and these can be done at the click of a button, rather than with painstaking drafting work.

Casual users sometimes like to play with CAD for things like deciding how to organize their furniture, or lay out a garden. They can drag and drop elements and play with the space in a variety of ways, and generate a configuration which will be suitable and aesthetically pleasing. CAD is used by professionals in a number of industries across the manufacturing sector, and it can also appear in some surprising places, like forensics labs, where researchers recreate crime scenes on a computer to explore scenarios.

  

Advanced CAD programs usually require extensive training from their users, as they can be very complex and challenging to work with. More casual programs can be learned in shorter periods of time, with some designed to allow people to work within the program immediately, learning as they go. Simple programs can also sometimes have their functionality increased with expansion packs which are designed to provide additional features, so that people can work within a program they are familiar with when they want to develop more complex designs.