3D Printing and CNC Converge

Without dating myself precisely, allow me to say I have been working in the field of CNC manufacturing for about 36 years, and around it for some years before that. Over that time, some technologies have been fairly stable, while others have evolved to become wildly different.

Computer technology drives a lot of evolution, and computers have evolved incredibly. Just today I happened to be holding an inexpensive 1TB hard drive in my hand. Back when I started with computers, a 5 MB hard drive was a 14-inch metal disk. Screen graphics, user interfaces, tablets, smart phones, and processing speed are all areas of massive evolution and improvement.

CNC machines have evolved as well, though basic mills and basic lathes are still recognizable as such. We have seen the tremendous growth of multitasking machines, machines with multiple tools cutting simultaneously. These machines perform milling and turning operations as well as any single purpose machine, providing the benefit of material in and finished parts out. Part of that advance is five-axis milling, which is no longer a rare capability, but increasingly common in mills. Less visible evolution has occurred in control technology, machining accuracy, machining speed, and tooling.

Supporting these new machines has forced the evolution of CAM software. CAM systems today can enable machine shops to productively use all of the latest machine technology, ideally in a single integrated environment. The majority of CNC manufactured parts go through multiple manufacturing processes on multiple CNC machines. A modern CAD/CAM software package not only needs to support all the machines and their toolpath and programming requirements, but also to define the material starting and ending condition for each machine, in support of the next machine’s programming.

The evolution in manufacturing continues. Back in 1986, 3D Systems’ stereolithography was the first additive manufacturing technology, limited in materials to UV cured plastic liquids. Plastics are great for engineering prototypes. From this beginning, evolved the many varied 3D printing technologies in use today, and a big market for plastic prototypes. This technology also evolved into metal printing and began to enter the manufacturing world of CNC machining—sort of convergent evolution.

Today, performing metal printing/additive machining requires metallurgical expertise and metal printing expertise that is different, but on par with that of a master machinist’s knowledge. 3D printed end results can approach the surface finish and tolerances of a casting, although it is limited in the alloys it can use and the mechanical properties it can achieve. It is expensive and its use driven by part designs that can be manufactured in no other way, such as GE’s internally ducted impellor. The technologies will get better every year.

Even so, 3D printing is not likely to be a significant competitor for CNC machining any time soon, but rather a competitor for castings. There is as much five-axis CNC machining on a GE-printed impellor blade as any other impellor blade. Moving 3D metal printing into CNC manufacturing shops will benefit from the same integration in manufacturing processes as CNC machines. CAM software can provide this integration by working from a common design solid model, defining the part to be printed, to account for printing needs and for the follow-on machining that’s often required.

3D printing and CNC manufacturing are converging in other ways as well. 3D Systems (a world leader in 3D printing) has announced a deal to acquire Cimatron, parent company of my own GibbsCAM. I have great hopes of being involved in the support and further evolution of these manufacturing technologies.