One of the biggest advantages of additive manufacturing is the ability to create realistic and detailed prototypes with relatively little lead time. What once involved a multi-step process and highly complicated software can now be completed in a fraction of the time by anyone with a basic understanding of 3D printing.
Functional vs. Non-Functional Prototypes
Generally speaking, most prototypes that are meant to demonstrate a specific product or system come in one of two different forms: functional or non-functional. In simplest terms, a functional prototype is meant to mimic the exact functionality of the final product. This includes any moving parts, pieces and mechanisms that will be seen in the final design.
A non-functional prototype is primarily meant for studies related to aesthetics and design feasibility. Complex products that feature internal mechanisms or parts, for example, wouldn't include the interior pieces or anything that isn't visible to the naked eye. Additionally, moving parts might be limited or completely restricted in their movement.
Molds and Castings
The molds and castings used during the prototyping phase remain relatively unchanged from past methods. Perhaps one of the most significant advancements is the introduction of rapid prototyping, which gives manufacturers the ability to produce sand molds from nearly any CAD model. This includes older CAD projects that were created years ago, as well as the ones that will be made in the future.
Some prototypes are cast at a different size than the final product. Large projects, such as components that are meant for use in the aerospace industry, can be cast in miniature for greater portability. In many cases, miniaturized prototypes are created through lost-wax casting, a process meant to be non-functional.
Prototypes can also be cast larger than the finished product. This is useful when trying to draw attention specific mechanisms or minute details that would be difficult to see in a model of actual size. Projects like this are typically cast using binder jetting, which works by combining powder-based metals, plastics or composites with binding or adhesive material.
The primary advantages of the binder jetting method are the freedom and flexibility in materials and color options, but there are some drawbacks associated with the binder jetting method that might be hampering its popularity. A lack of printing consistency, the need for additional finishing work and hard-to-find materials are at the top of this list.
Current technology seen in modern 3D printers makes it easier than ever before to create custom tools for your projects. Whereas many manufacturers used to rely on third-party CNC machinists for their tooling needs, many have been able to make the transition to in-house tooling through the latest advancements in additive manufacturing.
There are numerous benefits to in-house tooling. Lead times for the development of tools can be shortened significantly, and costs can be reduced through effective strategizing and planning. Manufacturers will also enjoy greater flexibility in the design of their tools as well as more control and protection over their future of any proprietary or confidential designs.
The Finishing Process
Many manufacturers have their preferred finishing method depending on their overall size and delicate nature. When working on a large scale, manufacturers typically finish their products via tumbling or vibrating. Both methods are also suitable for limited prototype runs. Since either both tumbling and vibrating are usable with metal 3D printing, finished prototypes can look cleaner and even more detailed than ever before.
The tumbler method is probably more familiar to the average consumer. This process can be likened to rock tumbling as a hobby, where semi-precious stones are placed into an electric-powered drum to remove any rough surfaces. Instead of rocks, however, manufacturers are working with finalized pieces or, in this case, one or more prototype models.
As effective as tumbling is, it’s rather primitive nature cannot be denied. When a smoother finish is needed, manufacturers tend to use the vibratory finishing process. This method is also used to minimize part-on-part contact, which is necessary when working with multiple prototype pieces that feature intricate, fragile details.
Some manufacturers are starting to explore drag finishing. This is due to a number of reasons, including their own familiarity with the process and the potential for reduced costs. Drag finishing has become a popular alternative due to its speed and delicacy. It greatly reduces contact between individual parts and is best used when working with solitary prototypes or pieces that are fragile to begin with.
Gaining an Edge in the 3D-Printing Revolution
Modern 3D printers have already revolutionized the world of manufacturing. With the ability to create prototypes more rapidly and accurately than ever before, compatibility with traditional finishing processes and the luxury of creating customized tooling for each specific job, tech-savvy manufacturers can gain an edge on their competition by embracing next-gen additive manufacturing while it's still in its infancy.
Megan Ray Nichols is a freelance science writer.