It seems like 3D printing has become a hot topic in mainstream media as well as the typical engineering and design rags over the past year or two. While rapid prototype technologies (3D printing or additive manufacturing) for (mostly) plastic products seems to be taking the product development and manufacturing industry by storm, we’ve found that there exists a very real and ongoing need to make prototypes the old fashioned way – through brute force CNC machining and hand-finishing. Too expensive you say? Well, where you have the part made and what size of part you need to make can drive the decision away from 3D printing in a hurry.
At Inertia, we’ve certainly used our share of various rapid prototype technologies such as SLA, SLS, Polyjet and so on to prove out design concepts and make plastic parts for visual communication, functional validation and performance testing – it is one of the key methods we continue to use to achieve faster time to market and ROI for our customers. While additive manufacturing has come a long way over the past 15-20 years in terms of build resolution and material properties that more closely replicate those of production materials, there are still situations where rapid prototypes won’t do the job or are just plain too expensive. We’ve run into situations where we’ve had to subject prototype products to vehicle crash-testing and there are not many rapid prototype solutions that can withstand this kind of test and behave like mass-produced injection moulded products. Additionally there comes a point when the size of the prototype part makes 3D printing significantly more expensive.
A recent visit to some prototype sources in China confirmed that CNC machining for plastic prototypes can still deliver much better part performance, usually at a lower cost than local rapid prototype sources. Delivery leadtime can take a slight hit because you’re shipping across the world, but overall, the turn-around can be inside one business week which is not much more than making it locally. Of course you could do it faster if you had your own in-house 3D printing machine, but for the part sizes we’re talking about, that machine would cost you north of $250K. So all things considered, CNC machined prototypes made in China can often be much more competitive than their locally made 3D printed counterparts.
For example, the seat-bottom prototype for an office chair shown here was CNC machined from the same polypropylene plastic that would be used in mass production. It cost 30% less to make by CNC machining compared to 3D printing and delivery lead-time was the same – even considering shipping cost and time from China. How can you argue with that?
If you need your product prototyped or manufactured, Inertia has the knowledge and network to help you find the right solution for your product.