In recent years , 3D printing has become remarkably popular. Not only is it integrated into many industrial manufacturing processes, but it has captured the imagination of the consumer market.
As with any tool, however, manufacturing technology should match the job at hand.
For decades, CNC machining has been the gold standard for delivering on major manufacturing projects within tight tolerances. It brings robust processes and proven best practices 3D printing can’t match – and so, there are many situations where it can cut costs and raise quality.
Knowing them is a big step toward organizational maturity for a manufacturing team.
Three Common Situations Where CNC Machining Beats 3D Printing
You Need High-Strength Prototypes for Testing Purposes
Because it starts with a solid block of material, subtractive manufacturing with CNC machining results in substantially stronger finished products. Since 3D printed components are built up from accumulated material, they are prone to fracture along the build layers.
This drawback is intrinsic to additive manufacturing with 3D printers and can’t be designed out.
Naturally, that limits the usefulness of any data you get from testing with 3D printed prototypes. You’re much more likely to reach your quality goals and satisfy your end users when you shift toward CNC machining for mid-stage prototyping.
You’re Moving From Small-Scale Prototypes to Larger Batches
Much of the time, 3D printing is somewhat faster than CNC machining. When you’re making rapid changes and iterating on early designs, it gives you a way to go from concept to execution quickly. As you move into production and batch quantities grow, however, CNC machining saves money per unit. As volume increases to 3-15 units or more, look to CNC for your solution.
You Need a Range of Materials or High Temperature Tolerances
CNC machining is the preferred solution for industries where failure isn’t an option, like aerospace and medical devices. CNC milling, CNC turning, and other processes can use a wide range of materials – aluminum, copper, brass, steel, fiberglass, and more. This leads to superior surface finish and heat resistance when the final product will be used in harsh environments.
3D printing, on the other hand, remains limited in the materials it can use reliably. Its compatibility with inexpensive nylon and resin is what makes it so attractive to hobbyists. On the other hand, its ability to use metals is restricted to stainless steel, gold, silver, and a handful of others.
Design Maturity: The Biggest Indicator for Switching to CNC
These questions can help you decide whether it’s time to make the jump over to CNC:
- Have you ceased making significant design changes?
- Do you need to maximize consistency among parts?
- Do you need to do testing in a production material?
- Do you need to maximize the strength of your parts?
- Do you need to certify for flammability, FDA regulations, or other quality standards?
As your designs evolve, the drawbacks of 3D printing and the benefits of CNC machining both become more obvious. In most cases, CNC machining is the key to ensuring your product can perform under real-world conditions according to your market’s needs.