Greetings intrepid inventors! In the previous article, I explained some of the basic terminology used in the world of invention prototypes. We took a quick look at the different types of prototypes that are used in the development of a product. Now it’s time to dive deeper.
Different prototyping methods are typically defined by the actual purpose they each serve. In part 2 of this series, I will be explaining some of the different methods used in the creation of prototypes. Each prototyping method has its own set of ideal applications, strengths and weaknesses. Some methods are better for speed while others are intended for absolute precision or overall strength. It all comes down to what your particular project requires.
When looking at prototyping budgets, some simple prototypes are relatively inexpensive while pricing for more accurate versions can be rather steep. Because of their short run nature and one-off designs, all of these prototypes discussed below will generally cost much more than items produced through mass production means.
For example, a small, simple item to be prototyped may just require a few hundred dollars compared to the thousands of dollars it might take to prototype a larger more complex item. The cost of a prototype is primarily a function of the method and the size of the object. Some methods, such as 3-D printing using ABS plastic, are now very cost-effective for small parts (about $25-$35 / cubic inch), but can get quite expensive for larger parts. Your choice of prototyping materials can also have a huge impact on price. For example, machining aluminum is a piece of cake compared to machining titanium.
Below, I have put together a quick list of prototyping methods with a brief explanation of each process and its ideal applications. Let’s start out with the current media darling that was proudly mentioned by President Obama in the recent State of the Union Address—Additive Manufacturing.
This is the general term for a variety of processes whereby a 3-D object is printed by a machine in layers. There are numerous technologies, each with its own set of pros and cons. While it might seem new to the general public, this technology has been around since the 1980’s.
- SLA – stereo lithography: uses a laser to cure a layer of liquid polymer in a vat, while a platform descends into the vat one-layer depth at a time. Perfect for appearance prototypes and to test fits. High precision, fair finish, low strength. (More info here)
- SLS – selective laser sintering: uses a laser to sinter one layer of powdered material at a time, building an object from the bottom up. Similar parts to SLA, but slightly more rugged with a grainier finish. Good for appearance prototypes. High precision, rough finish, medium strength.( More info here)
- FDM – fused deposition modeling: builds parts using extruded ABS or other production plastic, building layer by layer. Similar strength to a production part with lower fidelity prints. Perfect for functional prototypes and to test fits. The popular MakerBot brand of 3-D printers is of this variety. Lower precision, rough finish, high strength. (More info here)
- 3-D Printing – printing in three dimensions involves a “plaster of paris” like substance and a liquid binder to build objects by layer (kind of like SLS without the laser). This process produces weaker parts, but they are the quickest and cheapest prototype parts you can get. Perfect for size verification and rough appearance models. Low precision, rough finish, low strength.( More info here)
- PolyJet – uses a UV-cured photopolymer applied in very thin layers. It has the best finish of any additive process and there are many varieties of material available, some of which are even flexible. Some machines can do multiple materials in the same print. Perfect for a wide range of prototypes, although it’s a little pricey. (More info here)
- Metal 3D Printing – when it comes to metal prototyping, there are numerous methods now available. Some of these methods require multiple follow on steps to finish the parts while others can produce finished parts. (More info here)
Machining/CNC – is the opposite of additive manufacturing. This process starts with a solid block of material, which is milled down to the final desired shape. The part can be made of production materials, but it takes longer, requires more human interaction and ultimately costs more than additive methods. Perfect for final prototypes or testing critical functions. High precision, great finish and production strength. (More info here)
Finishing – refers to the many varieties of ways in which a part can be finished to test colors and textures. They can be sanded and painted. They can be electroplated or anodized. They can be hand detailed or decaled. ( More info here)
Laser/water Cutting – parts can be made of flat stock materials such as metal, acrylic or wood. This is perfect for large, flat components, which would be very expensive to print due to size. (More info for laser cutting here) (More info for water cutting here)
Metal Forming & Welding – typically the domain of metal workers or machine shops. There is a variety of specialized equipment used for forming and joining metal parts, which typically requires professional training to use properly. (More info here)
Hand Sculpting – might be the best way to figure out the sculptural form or ergonomics for a device. The designer can make subtle adjustments on the fly—getting a design dialed in just right by tactile feel. (More info here)
Thermoforming or Vacuum-forming – involves heating a flat piece of plastic material and using a vacuum to stretch it over a buck. These bucks can be made for a fairly low cost. The parts are limited in their design, but when it can be utilized, vacuum-forming is a cost effective way to create larger, typically flatter shapes, but with depth. (More info here)
Off-The-Shelf Parts (McMaster Carr) – to some degree, many prototypes can be built up with off-the-shelf components. This should be done as much as possible to save cost. Sometimes, the prefabricated parts that can be found will even be useful in final production.
Circuit Bread boarding – comes into play when you are designing an electronic item as it will need to have a circuit designed. Before you (or an engineer) actually design the circuit board layout, the actual circuit itself needs to be planned for. A breadboard is a functional prototype of the circuit. (More info here)
Open Source Circuitry / Arduino – comes into play when a device requires logic. In these cases, open source hardware options allow even the most beginner-level novice the ability to create electronics with sophisticated behaviors. This method provides the user with the ability to simulate most simple circuit designs for further testing. (More info here)
Fabrication (cutting, nailing, gluing, welding, joining, bending, screwing, and bolting) – the key here is that not everything in the prototyping world has to be high tech. Once you’ve printed out all your parts and purchased all the necessary off-the-shelf components, someone will need to take the time to put it all together. (More info here)
Sketch Modeling – includes the process of putting together simple, proof of concept models using basic found materials such as string, tape, wire and dowels. These models can be very low cost and quite rough, but they can quickly demonstrate the validity of a functional premise. (More info here)
Scavenging & Cobbling (also know as jerry rigging) – is a form of sketch modeling. This process involves going to a store, buying a bunch of related products and then cobbling (frankensteining) together a proof of concept model. This crude process is useful for electromechanical devices like toys.
Lego & Kinnex – are two types of simple, off-the-shelf, children’s toys created with the sole-intent to be assembled into new things. Oftentimes, mechanical concepts can be tested with these simple components. Don’t ever be afraid to awaken your inner child and bust out your old Legos. If you are still skeptical about the technical limitations of prototyping with children’s toys, you need to check out the latest eye-popping work from Trident Designer, Chris Trunek. (More info here)
Cut & Sew – most fabric-based items are relatively easy to prototype. You just need to find an experimental seamstress (if you aren’t one yourself) and tell them what you hope to achieve. The good news here is that, unlike plastic items, you can get a prototype that is identical to the finished product. (More info here)
Silicone Molds – involve parts that can be machined or printed and then a silicone mold can be formed around it. This process is used to make very short runs of parts. The process itself can be done at a very simple level or steps can be taken to make the process extremely detailed and sophisticated. Silicone molds create parts that are basically identical to production quality. (More info here)
Short Run Aluminum Molds – involves the creation of actual injection molds, but uses soft aluminum rather than tool steel. This process is fast, easy to machine and cheaper to produce than tool steel, but is only good for a few thousand parts. This process is a great way to work the kinks out of a new product before the creation of production tooling. (More info here)
As we wrap up part 2 of this 3-part prototyping series, my hope is that all of you have a little better understanding of the basic terminology and different prototyping methods available for your next product invention. In Part 3, we will look at different scenarios and answers to popular questions I often get from inventors like, "do I need a prototype" and "how good does my prototype need to be?" As always, feel free to leave comments here or send me your questions and I will be happy to address them in future articles.
Part 1 - Expert Tips For Invention Prototypes - Part 1: Terminology
Part 2 - Expert Tips For Invention Prototypes - Part 2: Prototyping Methods
Part 3 - Expert Tips For Invention Prototypes - Part 3: Proof-of-Concept Prototypes
Part 4 - Expert Tips For Invention Prototypes - Part 4: Production Prototypes
Part 5 - Expert Tips For Invention Prototypes - Part 5: The Iterative Process
Part 6 - Expert Tips For Invention Prototypes - Part 6: Making A Million Dollar Product
About Trident Design
Trident Design, LLC works with independent inventors and innovative manufacturers to help them create game-changing products. Trident has successfully propelled over 50 products to market with an established team of designers, engineers, patent professionals and business development specialists. Today, Trident is a full-service invention incubator in the spirit of Edison's Lab, offering product design, engineering, prototyping, branding, licensing, and consulting.
Chris Hawker, Founder of Trident Design, LLC is an idea guy. Chris has spent the last 20 years inventing, developing and selling innovative consumer products in a variety of industries. Chris has brought numerous products to market through a variety of business models including licensing, private label manufacturing, marketing, distribution and more. To date, Chris is probably most well known for the PowerSquid, licensed to Philips—an innovative, award-winning, and commercially successful power strip.