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Across history, there have been many technological revolutions, all of which have progressed through three distinct phases

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RAPID PROTOTYPING Product development process with advanced Rapid Prototyping techniques

Oct 4, 2018

In today’s manufacturing landscape, the importance of 3D printed functional prototypes cannot be denied. It enables real-world product development and testing to take place before costly investments are incurred in production tooling. The article discusses the latest rapid prototyping techniques, which are used to create the functional prototypes. A read on…

Across history, there have been many technological revolutions, all of which have progressed through three distinct phases. The first has been that of conceptualisation, where visions and ideas have been generated that have defined the road ahead. Each technological revolution has then entered a phase of realisation during which apparently impossible ideas have started to be turned into at least some form of operational reality. Finally, a phase of mass commercialisation dawned, where businesses learnt how to manufacture and operate a new technology in a robust and highly cost-effective manner.

Optimising product development processes

For faster industrial overall development, continuous optimisation of product development processes i.e. the conceptualisation is vital for any company engaged in design, development and manufacturing. To make the best-in-class products, it is required for the companies to walk through successful research, design and prototyping processes.

The evolution of the industry has necessitated the reduction of time-to-market, mainly because the product life cycle is shorter and it is very important to proceed more rapidly from an initial conception to a mass production object. As a result of newly evolved software environments, knowledge-based systems, and product data management, processes for integrated design and manufacturing for new products have emerged. Due to this evolution of rapid prototyping technologies, it has become possible today to obtain parts which are representative of mass production within a very short time.

Prototypes and concept models

Attaining a faster product development process is key to competitiveness. Prototyping plays an important role in pace of product development process. Traditionally, prototypes and concept models have been created by skilled craftspeople using labour-intensive workshop techniques. It is therefore, not uncommon for them to take many days, weeks or even months to produce and to attract significant investment. In contrast, there are newer rapid prototyping techniques available now with the help of which, concept models and functional prototypes can be prepared in a few days or even a few hours for a fraction of the price of traditional methods. In addition to saving time and money, the advanced rapid prototyping techniques allows improved final products to be brought to market, as design can evolve through many iterations. Advanced prototyping and concept modeling give design and engineering teams the ability to view and test products in real-world environments.

Additive Manufacturing

Fidelity to the final product, level of quality, complexity of the part, specific material properties to be tested, desired quantity, available resources- time, budget etc. are the key factors that play a role in selecting the correct and suitable prototyping technique for a specified application. The latest rapid prototyping techniques are majorly inspired by Additive Manufacturing in which the object is produced by using 3D CAD files through fusing the material layer by layer using a 3D printing machine. Additive Manufacturing can be done in different ways as explained below.

Stereolithography utilizes a vat of liquid photopolymer resin cured by an Ultra Violet laser to solidify the pattern layer by layer to create a solid 3D model from 3D CAD data. The SLA process addresses the widest range of rapid manufacturing applications. The advantages of stereolithography include high accuracy, smooth surface finish of printed parts, large material selection—rigid, durable, clear, wide variety of post processing options and short lead times. Few applications include design appearance models, concept models, design evaluation models, master patterns, snap fit assemblies, form-and-fit testing and also custom industry applications such as, healthcare with biocompatible materials for surgical tools, dental appliances, hearing aids, etc.

Digital Light Processing (DLP) is a similar process to stereolithography, based on the idea of using photopolymers. However, the major difference is the light source, which is applied to the entire bottom of the vat filled with photopolymer resin in a single pass, generally leading to faster printing speeds. At the same time, DLP produces highly accurate parts with excellent resolution. Also, the vat is more shallow, which results in even less wasted material and a more economical production. Through DLP, a broad range of dental applications such as, occlusal splints, drilling templates and dental models can be individually printed with high accuracy. Leading manufacturers of hearing aids are using DLP 3D printed parts, which are characterised by their great surface qualities and exact fit. The jewellery industry profits from the unlimited possibilities that DLP offers in terms of forms and structures. Specially designed materials enable the use of printed parts for investment casting.

Selective Laser Sintering (SLS) uses a high-powered CO2 laser to fuse small particles of powdered material to create 3 dimensional parts. The laser selectively fuses powdered material by scanning X&Y cross-sections on the surface of a powder bed. The model is built one layer at a time from 3D CAD data. SLS is capable of producing highly durable parts and complex geometries for real-world testing, high-heat and chemically resistant applications, impact-resistant parts for rigorous use, perfect for functional testing. This is ideal for snap fits and living hinges. SLS also produces parts from impact-resistant engineering plastic, which are great for low to mid-volume end-use parts, enclosures, snap-fit parts, automotive components and thin-walled ducting. Applications may include aerospace hardware, unmanned air systems, aerial vehicle, underground and ground vehicle hardware, medical and healthcare, electronics, connectors, functional proof of concept prototypes, design evaluation models (form, fit & function), product performance and testing, engineering design verification, etc.

Direct Metal Printing (DMP) or Direct Metal Laser Sintering builds high quality complex metal parts. In the machine, a high precision laser is directed to metal powder particles to selectively build up thin horizontal metal layers one after the other. This cutting edge technology allows for the production of metal parts with challenging geometries, which is not possible using the traditional subtractive or casting technologies. Direct Metal Printing carries the advantages of producing small and extremely complex shapes with no need for tooling and is considered ideal for research and development of metal parts with the tightest tolerances. DMP ensures that the industry’s best surface finished parts with exceptional accuracy and complex and thin-walled structures allow significant part weight reduction. Applications include machine construction, tool and die making, medical implants and instruments, aerospace engines, automotive parts, heat exchangers, air/oil/fuel mixing devices, industrial burner parts, radiation collimators, etc.

ColorJet Printing (CJP) involves two major components—the core and the binder. The core material is spread in thin layers over the build platform with a roller. After each layer is spread, colour binder is selectively jetted from inkjet print heads, which causes the core to solidify. The build platform lowers with every subsequent layer, which is spread and printed, resulting in a full-color three-dimensional model. CJP is useful in making full-color concept models, architectural models, demonstration models and highly complex geometries.

Fused Deposition Modeling (FDM) is a solid filament-based fabrication method that extrudes material layer-by-layer to build a model. The system consists of a build platform, extrusion nozzle and control system. This is a fast and cost effective process great for proving designs, fit and function testing, small production runs, jigs and fixtures. Benefits of the FDM process are large material selection—including production-quality ABS and food-grade ABS, short lead times, high strength and extremely durable. It is great for use in making concept models, engineering models, functional testing, consumer products, high-heat applications and initial prototypes, proving designs, fit and function testing, small production runs, jigs and fixtures. Using engineering-grade thermoplastics such as, ABS and polycarbonate materials, this technology builds parts in an additive process that enables complex geometries that are often difficult to duplicate with traditional manufacturing methods such as, CNC machining.

Real-world product development & testing

Advanced 3D printing techniques have enabled use of a wide array of material to create real life prototypes. Material possibilities include ABS (Acrylonitrile Butadiene Styrene), PLA (Polylactic Acid), Bio Compatible Rubber, PVA (Polyvinyl Alcohol), CPE (Chlorinated Polyethylene), Glass-filled Nylon, Carbon-filled Nylon, maraging steel, steel, stainless steel and various grades of titanium to nickel and cobalt chrome alloys. There are more special materials available suiting specific applications.

3D printed functional prototypes enable real-world product development and testing to take place before costly investments in production tooling. By creating 3D printed functional prototypes, teams can test various thermoplastic materials in real-world environments to see how high-performance prototypes perform under thermal, chemical and mechanical stresses of everyday product use. These realistic prototypes can take on the appearance of final finished product, including colour and material selection. Manufacturing processes can be explored using functional prototypes to determine part weight, assembly process, and overall manufacturability.

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  • Advanced 3D printing techniques have enabled use of a wide array of material to create real life prototypes

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