An Introduction to Rapid Prototyping

FacFox provides state-of-the-art Rapid Prototyping services to startups intending to develop their innovative idea into a new invention and companies planning to quickly test and examine a new product concept before introduction into the market.

Our services include PCB layouts, assembled PCBs, software development and programmed devices, physical prototypes in plastic and metal, rough and precision prototyping, complete system assembly and working prototype building, and low volume product production.

FacFox teams up with our customers’ engineers to facilitate quick turnaround of the prototype, helping to complete the Design for Manufacturing and Assembly (DFMA) cycle, identify and help resolve potential design and manufacturing challenges, and assess what is needed to transition from assembly into production trial run.

How Rapid Prototyping Can Help Innovators of New Products?

Typically, a new product goes through a series of changes before its introduction to the market. A new idea for an electronic device needs to be prototyped in order to evaluate its functionalities, fit and finish of different parts, and look and feel as a whole. A prototype also helps to find potential problems in the production and optimize the manufacturing process. The steps involved in product design and development phase can be expensive and time-consuming, prolonging product time-to-market. This is especially significant for startups that usually lack the facilities and expertise to efficiently prototype their innovative new concept. This is where Rapid Prototyping comes to rescue.

By definition, “rapid prototyping is a system development methodology based on building and using a model of a system for designing, implementing, testing and installing the system.” (Lantzas cited in Tripp& Bichelmeyer, 1990). In practical terms, RP is enabling companies to develop ever more efficient new products and components. Through RP, they can offer more effective solutions by quickly creating prototypes for their review and evaluation by their customers. What these companies are looking for in an RP process include:

• Visualizing the product before spending company valuable resources on producing the final product sample.
• Creating quick physical models of complex shapes for stakeholders who can see and examin a prototype more easily than a drawing or photo.
• Reducing product time-to-market.
• Facilitating concurrent engineering when performing conceptual designing and designing for manufacturing in parallel.
• Creating physical model of the product without tooling.
• Testing and evaluating the design for feedback into the design process.
• Effective communication among product design and development team members.
• Helping designers in choosing between alternatives.
• Testing usability of a product idea with target users.

The advantages of rapid prototyping of a new product over traditional methods can be summarized as below:

• Does not require production process planning.
• Parts can be made in one piece, eliminating the need for using various machines.
• Does not need tooling (except when using rapid CNC method).
• Designs can be more easily and very quickly refined during the prototyping process.
• Highly accurate in creating complex shapes.
• Enables cost-efficient manufacturing of complex shapes at lower volumes and short runs.
• Prototype product can be produced in hours using CAD data, whereas earlier technologies may have taken days or even weeks to produce a prototype.
• The process is free of dust, noise or other substances that may be hazardous to human health.
• Rapid prototyping, especially of metal products are considered efficient rapid manufacturing techniques for low volume production.

Rapid Prototyping Techniques Applied to Electronic Devices

When prototyping electronic devices, two separate but parallel processes must be followed to reach a complete working model of the device:

1. Physical and mechanical parts using additive manufacturing techniques such as 3D printing and selective laser sintering (SLS), and state-of-the-arts rapid CNC machining.
2. Printed circuit boards (PCB) using modern Surface Mount Technology (SMT) and related tools and machinery.

The product of each process can be evaluated independently and feedback given to the design and modeling teams. The two processes join when the prototype is assembled to make a complete, working early product sample.

Physical Prototyping

Physical parts and components are manufactured using either Additive Machining (AM) or Subtractive Machining (SM) technologies. AM technology is better known as 3D printing. The main difference between these technologies is summarized in the below table:

Among different AM technologies, Fa primarily uses Fused Deposition Modeling (FDM) for the production of non-metal prototypes. FDM involves modeling by application of melted material. The advantages of this process are not only the ability to use a large selection of non-metal materials and colors, but also high accuracy and the fact that the material used can be changed during the prototyping process. FDM has very good geometric capability and relatively higher accuracy than other AM methods.A comparison of the two technologies makes it obvious that AM is better suited for low-cost RP. Building complex geometric forms, or when multiple parts have to be fabricated and combined simultaneously are difficult to achieve with SM, but yet this is the area that AM rapid prototyping excels. This is why machines utilizing various AM technologies have seen explosive growth in recent years, with prices of small 3D printing machines low enough for personal use. AM technology promises to continue to advance in terms of material properties and minimum features sizes.

For metal parts, Direct Metal Laser Sintering (DMLS) machines are used. DMLS uses a high power laser to fuse powder metal and virtually weld them together to form a 3D object, including various metal powders. DMLS produced parts are of such a high quality that are used for direct manufacturing of parts in various industries including aerospace without need for post-processing. With DMLS, any metal or alloy powder with a very high melting point such as Inconel, aluminum, stainless steel, and titanium can be used for rapid prototyping.

When prototyping metal and plastic components with high accuracy is required for tight tolerance, Computer Numerical Control (CNC) machining is required, which uses subtractive technology. CNC is more accurate than any machine utilizing AM technology, and the lead time is typically 1-2 weeks if conventional subtractive methods are used. However, when using rapid CNC machining both cost and time are significantly reduced. With this method, parts are manufactured through high-speed 3- and 5- axis milling and turning processes. This process can use many types of metal, including aluminum, stainless steel, steel, aluminum alloys, brass, copper, and titanium, as well as plastics such as ABS, Delrin, and Ultem. Special surface finishes as chrome plating, anodizing and paint coating can also be applied to rapid CNC machined parts.

Electronics Prototyping

Prototyping of electronic parts usually follows the initial design and development of the product, which may have been carried out by the owner of the innovation after initial ideation and concept development. Starting RP development of PCBs and related parts for an electronic device typically involves one or more of the following stages, which may be integrated with customer’s product design efforts to reach a better synergy:

• After evaluation of the concept design, time, and cost schedules are discussed and agreed upon based on time-to-market requirements and production volume schedule.
• Efficient testing techniques are incorporated into the design process at this level to avoid having a major impact on the speed of the design process.
• Manufacturing considerations are taken into account at this point for cost and time efficient mass production. This is usually specific to the manufacturing party since it depends on equipment, processes, the component is stock, supply chain, and availability of partner resources.
• Potential supply chain issues are identified and resolved, which may include component allocation, supply lead times, and component end of life.

After these steps are completed, the actual production of the PCB prototype begins. Depending on the design, density, and component types and sizes, manual, semi-automatic, or fully automatic pick-and-place SMT machines assemble the prototype PCB. To make the high flexibility and high mix SMT a complete production machine for rapid prototyping, it is equipped with a high-resolution Cognex vision inspection system, micro BGAs and FP split optic for fine pitch alignment. It is also integrated with a linear measuring system, dispensing system, and reflow soldering tool.