As more manufacturers are encouraged by the idea of 3D printing, they realize the limitations of the process, as 3D printing still needs refinement in its materials, finish, durability, cost and speed before it can be utilized for mass production.
3D Printing from Prototype to Production
Len Calderone for | ManufacturingTomorrow
One of the early steps in the manufacturing process is the creation of a prototype. The initial prototype might just be a handmade model of the product that a company plans to manufacture. Then, a pre-production prototype (PPP) is made. A pre-production prototype is an appropriate design for a product that has a high probability of going into production.
The pre-production prototype product is built using near production component manufacturing methods; and the PPP is required to pass substantial prerequisite testing requirements. This involves reducing the product part count, enhancing all important product components and minimizing assembly labor.
The PPP is made by using sand casting, stereo lithography-based investment castings, or even laser sintered components. After successful modifications of the product, further savings can then be realized by investment in hard tooling.
Pre-production prototyping enables a company to test and refine the functionality of the design, and makes it possible to test the performance of various materials. Because of the differences in materials, processes and design reliability, it is possible that a prototype may fail to perform adequately, whereas the production design may be consistent. Some prototypes may perform adequately whereas the production design may be imperfect since prototyping materials and processes on occasion may outdo their production counterparts.
This is where 3D prototyping—additive manufacturing—is achieving a lot of prominence among the engineering designers and manufacturers, as it presents a fast and accurate way to understand the potential of a product. Implementing 3D prototyping brings greater dependability from the conceptualized design compared to conventional prototyping.
3D prototyping provides a proof of concept for the company, looking for a more realistic product design rather than simply visualizing the design on a screen. Having a physical model to review, makes it possible to incorporate changes promptly. With 3D prototyping, the cost and time required to develop different molds, patterns and tools can be eliminated. There are no special tools or processes needed to implement design changes in the product. 3D prototyping offers the ability to identify flaws in the design prior to mass production. The materials available for rapid prototyping closely resemble the properties and strength of the actual product, making it possible to perform physical tests easily.
3D prototyping offers new opportunities for product improvement by eliminating the restrictions of conventional prototyping, where exacting tolerances are required. Engineers can generate models incorporating complex shapes and surfaces that would be problematic or impossible to reproduce by conventional prototyping. A precise model is promptly obtainable for testing form, features, performance and usability. The time savings can help a company achieve a competitive advantage by bringing new products to market with little delay.
3D prototype of metal piece almost impossible to manufacture with conventional techniques.
3D prototyping reduces the cost of product development, since there is no requirement to develop special tools for each new product. 3D prototyping uses the same CAD and 3D printer each time a prototype is needed. Less staff is required due to the 3D process. Waste is also lower, because the prototyping technique only adds modeling material where needed. Conventional prototyping techniques create waste through cut-off material or chippings as the tools create the finished model.
3D printing was initially developed as a method for rapid prototyping, but has grown into a true manufacturing process. 3D printing is giving engineers and companies the ability to both prototype and manufactured end-user products, while offering substantial advantages over traditional manufacturing processes. These advantages include mass customization, increased design freedom, reduction of assembly time, and can be used as a cost-effective low volume production process.
There are four types of standard manufacturing processes—injection molding, machining, forming, and joining with each manufacturing process having its own advantages and limitations.
Injection molding is a fabrication process that consists of softening a plastic material then injecting it into a mold. Once in the mold, the material cools and solidifies and another mechanism ejects the piece from the mold. In CNC machining, a piece of material is clamped into the machine, and a numerically controlled tool removes material until the part is completed. Almost any material can be machined into a part, whether by drilling, milling, or turning. Material selection is very broad with this procedure.
The third method is forming, such as thermoforming, vacuum forming, and pressure forming. In each method, a sheet of plastic is heated and draped over a mold, using air pressure and male plugs to form the sheet into a shape. Finally, the joining of plastics refers to the joining of semi-finished parts, including fastening, adhesive bonding, and welding. Fastening refers to the use of latches, hinges and snap fits as well as bolts and screws. Adhesive bonding means the application of an adhesive to join the parts. Welding refers to the joining of two parts via the application of heat and pressure.
The mindboggling potential of 3D manufacturing like bioprinting, food printing, and small batch manufacturing could one day save lives, feed the hungry, and change manufacturing in ways that the world has never seen.
3D printed pizza
3D printing is not without some hurdles. Today’s printers have not reached the level of sophistication that is needed to deal with the wide range of multi-material surface types that surround us. This is going to remain one of the major hurdles in the use of 3D printing. 3D printing is good at recreating geometric and organic complexity at the shape level; but the process breaks down when it must deal with moving parts.
With traditional manufacturing, a company must create tooling or molds before a single end-user product can be produced. If generating a mold costs $40,000 and each part costs $0.45, then the very first part will cost $40,000.45. If a company is producing millions of parts that might not be a major concern; but if a company only needs 500 the cost for a mold is prohibitive. With 3D printing, there are no set-up costs of any kind. For production runs of less than 1,000 items, 3D printing is a cost-effective method.
There are types of 3D printers that use different technologies, such as Stereolithography(SLA), Digital Light Processing(DLP), Fused deposition modeling (FDM), Selective Laser Sintering (SLS), Selective laser melting (SLM), Electronic Beam Melting (EBM).
All 3D printers are primarily, additive printers. This means that they work by precisely depositing level after level of a building material, creating an object up out of nothing, as opposed to the existing process in which material is removed down to the final product. By building objects up, usually in layers, 3D printing makes hollow objects with complex internal intricacies.
The first step in 3D printing is the preparation when an engineer designs a product in a 3D file, which is created using CAD software. Then the material that will best achieve the specific properties required for the product is selected. The variety of materials used in 3D printing includes plastics, ceramics, resins, metals, sand, textiles, biomaterials, glass, and food. When the object is first printed, often it cannot be directly used or delivered until it has been sanded, lacquered or painted to complete it.
As more manufacturers are encouraged by the idea of 3D printing, they realize the limitations of the process, as 3D printing still needs refinement in its materials, finish, durability, cost and speed before it can be utilized for mass production. 3D printing is an area of intense innovation, as it will be an important part of manufacturing.
Len Calderone - Contributing Editor
He also writes short stores that always have a surprise ending. These can be found at http://www.smashwords.com/profile/view/Megalen.
The content & opinions in this article are the author’s and do not necessarily represent the views of ManufacturingTomorrow
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