When additive manufacturing first hit the market, some said it would eventually be the death of traditional, or subtractive, CNC machining. More than 30 years later, new machines are showing additive manufacturing as it really is—a complementary technology.
Additive manufacturing is based on the concept of building a part by adding material layer by layer, whereas traditional CNC operations start with a block or rod and remove material to get to the final part. Today, hybrid machines have been developed that combine metal additive and subtractive manufacturing in one unit.
These new machines are not only improving the quality and suitability of metal additive manufacturing for end-use products, but are expanding the capabilities and value of CNC machine operations. Unlike parts made in CNC machines, most additive manufactured parts require some form of post-processing before being ready for end-product use.
By combining additive and CNC operations in one unit, users can save time and improve productivity by creating the part and performing post-processing without any additional handling.
Greater Complexity, Lower Material Costs
CNC machines are limited in the complexity of parts they can produce due to limitations of the cutting tool. Because additive manufacturing places material only where it is desired, it doesn’t need to worry about fitting a cutting tool into a specific place on the work material to create the part. This allows greater part complexity, reduced material costs and optimized designs. By not removing and re-clamping a part in another machine, operators can also achieve greater machining accuracy.
One application hybrid machines seem custom made for is maintenance and repair operations. Take a turbine or propeller, for example. If a fin is damaged or lost, traditionally the entire part would need to be scrapped. With a hybrid machine, an operator can machine away the damaged area with CNC machining, build a new fin on the existing part additively, and CNC machine it to final specifications—all in one machine.
Another opportunity for hybrid technology is the creation of cutting tools and parts that utilize more than one metal—especially difficult-to-machine and expensive metals. For example, drilling operations that might require a cutting tool made from an extremely hard and often expensive material can instead use a custom cutting head made via an additive process on top of a shaft of a different, less expensive metal. By using the harder material only where it is needed, manufacturers can reduce costs without sacrificing performance. Similarly, the ability to utilize multiple metals in one part can be used to create products with improved heat dissipation and management.
Manufacturers looking to leverage the benefits of hybrid machines have a variety of options. A growing number of machine builders are bringing custom units with both subtractive and additive capabilities to market. However, for those who already have multi-axis machining centers, some retrofit kits are now available—adding the capabilities of hybrid manufacturing without the cost of a whole new machine.