By Neil Glazebrook
CNC machining and 3D printing are opposites processes, but opposites attract and can make the best parts. The leading technology for 3D printing complex parts is MJF for polymers, and Metal Binder Jetting, both of which are scalable. Machining, on the other hand, is more limited in terms of geometry but offers far faster production speeds. The typical questions around which process to use are primarily:
A) Can the part or parts be machined?
B) How many parts need to be made?
And a growing third question:
C) How can I combine this process to get an even better part at scale?
What does all this mean to those looking for the most effective way to manufacture functional prototypes and lower quantities of end-use metal parts? As it turns out, a lot. By adopting an approach where 3D printing and machining are different steps in the same manufacturing process, you can leverage the best of both worlds, reducing costs and improving part function.
Building vs. Cutting Metal Parts
Combining these two processes doesn’t require a complex workflow. Plus, it can deliver several meaningful benefits for your manufacturing company.
When people say 3D printing is in its infancy, they’re usually referring to the tolerances of modern 3D printers. These improve with every passing year, but there’s still little doubt that many end-use parts have tolerances and other critical requirements only incumbent manufacturing methods can deliver on. CNC machining is more consistent and delivers a more precise product because the equipment isn’t as susceptible to heat as a 3D printer, which can sometimes warp and distort the workpiece and result in inconsistent runs of products.
Combining the two gives you the best of both worlds. It helps you realize the advantages of 3D printers; CNC allows you to dial in your tolerance from the 0.007” to 0.013” you can expect from a production capable 3D printer to the roughly 0.001” to 0.0005” a CNC milling machine can achieve. This combination gives you consistent and accurate performance, and lets you perform the fine finish work on a machine that is less likely to warp the product.
Most of the conversation today is about what happens when you 3D print a part and then subject it to CNC milling to bring the final tolerances into line or produce the desired fit and finish. But there’s another story emerging about what’s possible when combining these two technologies into one machine.
The result is something like the industrial-scale hybrid milling machines. We’re talking about a $400,000 piece of equipment just to start, with facilities and training adding additional costs. But that price tag gets you a machine with surfacing and in process finishing, which reduces time and gives you a complex part. This opens new applications for many verticals.
Accuracy Considerations for Metal Parts
Metal 3D Printing is the holy grail of 3D printing and has the most potential for growth. It is predicted to increase from a $6.3 billion market today to a $35 billion dollar parts market by 2030.
Metal 3D printing can create extremely complex shapes that might otherwise be un-manufacturable. However, it has limitations in accuracy and finishes, which is where CNC machining complements 3D printing. CNC machine can finish, drill, and tap the part, achieving machine critical tolerances to complete it.
Combining 3D Printing and CNC Machining
You can in fact get the best of both worlds with 3D printing and machining, but carefully consider the design options with your team. Machining and 3D printing are deep, complex technologies, and you will only achieve success by understanding how each will affect your design project. There is never an “easy button”, but starting and setting goals to know how and when they can work together will make better parts and better business.
If you’re just getting started with 3D printing and are wondering what’s available, learn what ABCorp’s 3D printing division has to offer. And don’t miss an opportunity to get a close-up look at 3D printing in action at the Manufacturing Technology Series events and the RAPID + TCT additive manufacturing event.
Neil Glazebrook, VP of 3D Solutions at ABCorp
ABCorp is a secure on-demand manufacturer of 3D printing parts from low to high-volume production using the HP MJF solutions and automated robotics and inspection technology. With over 26 years in manufacturing, Neil has previously worked as a director of Sales and Operations, Mold & Coating Manager, Capital Additive Sales, HP Product Manager, and CNC Programmer in the job shops and injection molding industry. Neil holds a BS in Business and Law from Curry College of Milton, MA, and he currently resides in central Massachusetts. His goal is to bring manufacturing closer to ABCorp’s customers with enterprise-scale manufacturing on-demand using the latest technology in 3D printing, robotics, and inspection.