Use Cases of Hybrid Machining

When you hear the word hybrid, many things may come to mind. You might think about cars that have a combination of electric and combustion engines to propel them or plants that have been genetically modified to grow in adverse conditions or achieve higher yields. Regardless of what comes to mind, the term hybrid refers to the combination of two or more unlike things.

In manufacturing, there are a variety of hybrid use cases. A major one is hybrid machining—things like combining conventional machining, such as milling or turning, with electrical discharge machining (EDM) or electrochemical machining (ECM). But for this article, I want to focus on how 3D printing or additive manufacturing can complement conventional or subtractive CNC machining.

3D printing or additive manufacturing is a process where layers of materials are placed on top of one another to create a three-dimensional part. It all started with plastic and resin materials and has recently evolved into the use of metals. Being able to print metal has pushed 3D printing to be added to conventional CNC machines, which are then known as hybrid machines.

There are basically three kinds of metal printing options:

• Selective laser sintering (SLS), direct metal laser sintering (DMLS), and direct metal laser melting (DMLM) options lay down a bed of powdered metal. A laser beam then moves over the powder and melts it into a solid metal.

• Direct energy deposit (DED) uses two nozzles to deposit metal powder and a focused laser beam melts the powder into the pre-programmed shape.

• Electron-beam freeform fabrication (EBFF) is a method where a wire feed spool places metal and an electron beam melts the wire into the desired shape.

Advances in tool holders, 3D printer nozzles, laser heads, powder, and powder delivery systems allow machine tool builders to add 3D metal printers to the machine's tooling selection. This gives the machine the ability to remove material in the traditional and conventional way and then add metal though one of the 3D printing processes. The rest are just software-related issues, like dwell time and tool-path translations and communications between two different machining practices.

Having additive machining capability added to traditional CNC machines provides a wide field of advantages when manufacturing parts.

• Reduction of part setup and clamping

• Elimination of secondary or tertiary operations

• Improvement in part accuracy:            

  • Accuracy of CNC machine added to 3D printing

  • Less part manipulation through setup and clamping

• Elimination of operations like:            

  • Casting

  • Forging

  • Welding 

  • Manufacturing one part out of multiple parts

  • Potential assembly operation and errors

• Increased part performance

• Increased design flexibility

• Ability to combine two dissimilar materials

Advancements in hybrid machining are made almost daily. The variety of metals that can be printed as well as the speed and accuracy of the printing process are continuously improving. In addition, CNC machines also continue to advance. 

Combining these two technologies increases manufacturing flexibility, reduces time to market, and allows us to operate our shops more efficiently and effectively. If you are currently machining parts the traditional way, you may want to take a few moments to see if a hybrid machine might give you an edge over your competition or allow your business to attract additional work. In many cases, hybrid machines can increase your shop's productivity.

Having just attended the IMTS, I can tell you that hybrid machining is not a phase or fad. Every reputable machine manufacturer has at least one—if not all three—metal printing technologies incorporated into their CNC machines, indicating that 3D metal printing is changing the way we are manufacturing parts today.