Regarding prototyping, Berkeley Sourcing Group has been working with Dean and Sean with their prototype —- the Audman. Though this product isn’t yet out to the
Audman Prototype Designers
market, we believe it will see a bright future because when we first saw it, it was love at first sight! Here, I’d like to give my sincere gratitude to Dean —- who shared his personal prototyping experience and made great contributions to this blog article.
Feasibility – Validate Your Design
As mentioned, prototyping is a critical step because you’ll never know the feasibility of your design until you put your hands on the actual prototype. Generally, before a prototype is made, you have to focus on the software behind the production of a 3D prototype. CAD software such as Inventor, ProE, Solidworks or other such packages is available to design the parts. The CAD is then used to convert the designs into parts using gCode or some other machine readable format so that a CNC machine has the tool paths to mill out the pieces. Whatever the item a person or a company intends to produce, creating a prototype is a crucial step in the design process that cannot be glossed over.
Way to Choose Prototyping
Initially, Dean and Sean used Fused Deposition Modeling (FDM) and Selective Laser Sintering (SLS) to make rough prototypes from easily accessible and relatively cheap options in the US. Once they had those in hand, they saw some changes that needed to be made, revised the drawings, and then we stepped in to create the parts using CNC.
FDM prototype
The FDM process cosmetically looked very poor because the fused lines showed up distinctively. Because it’s set down layer by layer and not very strong structurally, things such as small posts or screw holes tended to pull apart so it ended up not being very functional. The poor resolution on the corners and flat surfaces was noticeable. It was a great fit for their first prototype however because it can be done locally, quickly, and cheaply and gave them a good basic understanding of what their designs looked like in a solid 3D model. Most importantly, in pictures, it is hard to see the roughness of the design, so both FDM and SLS prototypes are good for creating the first marketing materials and getting the word out there.
Next, they went to using an SLS process. Though it can be a bit more expensive than FDM, the resolution is much tighter resulting in flat pieces that turned out well. It is a good process to get a good feeling for the shape of the prototype. Where SLS fails is really on the material side in that it’s composed of a fused powder so the finish is rough and the material is weaker.
SLS(red) vs FCM(blue)
From the lessons learned making the SLS model, we moved on to making a prototype using CNC. The resolution, finish, material, color, etc of the CNC prototype are all very superior than SLS or FDM and match almost identically with those same characteristics of an injection molded piece. In fact, the material strength is so different from the 3D prints that it is generally a good idea to see the CNC version if there are any questions about mechanical functionality. As far as finish, you will be able to get much more accurate colors which may be a very important aspect for the prototype. In this case, the CNC prototype was good enough that Dean and Sean were able to show them at CES to get good feedback and begin to develop relationships for funding, marketing, and distribution.
Promising Future
Prototyping gives you a visual representation of your idea in short periods of time, letting you realize the vision you had for the software, app or utility without having to fully develop to the finish. The value isn’t just for proving that you’re on the right track, but also for getting to those features that make the end experience special and delightful. Most importantly, any changes to the design are much better off being done at this stage than after you have spent ten’s of thousands of dollars on a hard steel tool which can only be modified in small and specific ways (which also typically degrades the total lifetime of the tool).
CNC protoypes at CES 2012
