When speaking about inventing the light bulb, Thomas Edison famously said “I have not failed. I've just found 10,000 ways that won't work.” Edison neatly summed up how the prototyping process works—adjust design, materials, size, shape, assembly, manufacturability and strength until the desired outcome is achieved.
The purpose of prototyping is to see physically what works. Nothing gives a team a single idea to work from and is a far more effective way to communicate the ideas of an engineer and designer ideas than prototyping. But to do this, steps must be taken early in the design phase to test ideas. Although this can be a lengthy process, by prototyping before production begins it is possible to get a glimpse at the production process and see if any steps can be changed, combined or even removed. This not only streamlines production, but can also help avoid costly mistakes down the road that might inhibit a product’s time to market and, ultimately, its success.
Similar to it being far easier to see if there are any issues with a design after physically holding a working model, it’s also far easier to sell to customers when a prototype is able to be held and manipulated at a customer meeting. Without a prototype in hand, the idea is only a concept. It can be difficult to get a potential client to commit to the purchase of a concept. With a prototype in hand, the concept instantly becomes real and it is far easier commit to purchase.
The following article discusses the most commonly used prototyping options available to bring reliable connector solutions to the marketplace efficiently and confidently.
Plastic Prototyping Options
3D printing has quickly become one of the most useful tools for rapid prototyping. This rapid prototyping process allows for low cost, quick-turn functional prototypes, allowing you to get test parts early and frequently through iterative designs.
Objects can be of almost any shape or geometry and typically are produced using digital model data from a 3D model or another electronic data source such as an Additive Manufacturing File (AMF) file (usually in sequential layers). There are many different technologies, like stereolithography (STL) or fused deposit modeling (FDM). Thus, unlike material removed from a stock in the conventional machining process, 3D printing or AM builds a three-dimensional object from computer-aided design (CAD) model or AMF file, usually by successively adding material layer by layer.
Stereolithography (SLA) is an additive manufacturing technology that converts liquid materials into solid parts, layer by layer, by selectively curing them using a UV laser in a process called photopolymerization.
With the help of CAD software, the UV laser is used to draw a pre-programmed design or shape on to the surface of the photopolymer vat. Photopolymers are sensitive to ultraviolet light, so the resin is photochemically solidified and forms a single layer of the desired 3D object. Then, the build platform lowers one layer and a blade recoats the top of the tank with resin. This process is repeated for each layer of the design until the 3D object is complete. Completed parts must be washed with a solvent to clean wet resin off their surfaces.
- Speed; functional parts can be manufactured within a day
- Capable of producing complex patterns and models suitable for use as masters for other prototyping methods
- Parts have excellent surface finish without secondary operations
- Pricing is very competitive
- Functional testing is usually not possible on SLA parts, as they tend to be weaker than parts made of engineering resins
- The UV curing aspect of the process makes parts susceptible to degradation from sunlight exposure
- Extra post curing steps are necessary
Fused Deposition Modeling (FDM)
Fused Deposition Modeling (FDM) is an additive process used to produce highly accurate and durable prototype parts from CAD files. FDM creates models layer by layer using a thermoplastic extrusion process. The feedstock for the process is a filament of extruded resin, which the machine selectively re-melts and deposits on the prior layer for each cross-section of the desired part.
However, the parts created by FDM are sometimes porous and have a pronounced stair-stepping or rippling texture on the outside finish, especially at layer junctions. While the surface finish of FDM models is generally rougher than that of models produced using SLA, the end product is typically more robust.
FDM is considered ideal for applications where functional prototypes do not require high-quality visual surfaces. FDM is also a suitable process for building assembly, testing, and inspection fixtures that would otherwise be difficult or impossible to machine.
- Parts can be strong enough to allow functional testing
- Parts can be created quickly
- Low cost
- Slower than SLA and SLS
- Does not approximate manufacturing
- More difficulty with tight tolerances
- Parts have a poor surface finish, with a pronounced rippled effect