Hybrid manufacturing is a combination of additive manufacturing (AM) and subtractive manufacturing within the same machine. Both processes on their own have remarkable capabilities, but when combined, it opens up a whole new level of design and manufacturing. Today, we mostly see hybrid systems equipped with a directed energy deposition (DED) head for depositing metal powder or wire and machine tools such as a lathe or mill. These systems allow you to make and finish the part in a single setup, reducing error because the AM part does not have to leave one machine to be reset on a second machine.
Prior to hybrid machines, metal parts and components fabricated on an AM machine could require substantial post-processing to meet the specified tolerances. At a minimum, the part needs to be sliced off the build plate. In other cases, the part may need to go through heat treating to remove internal stresses, reaming and trapping of threaded holes, finishing processes like bead blasting or vibratory finishing, and milling, turning, or grinding of critical dimensions. The extra processing extends lead times and drives up costs.
Methods of Hybrid Manufacturing
In this growing and changing technology, using hybrid machines is just another tool in your arsenal. Like any other innovative technology, it takes time to develop and become established. Manufacturers of hybrid machines offer different methodologies for manufacturing.
The first hybrid manufacturing method, and one of the most common, is when additive and subtractive processes are completed in sequence. The part is entirely produced through AM to the near net shape and is then machined, where necessary, using subtractive capabilities to finish the part.
The second method alternates between additive and subtractive during the manufacturing process. Whether an existing or new part, AM adds materials, which is then machined, more AM materials are added, and the part goes through another round of machining, and so on until the part is complete. Another example is when a part is machined to finish surfaces while the part is being formed through the additive process.
With hybrid, it is also possible to combine materials during the process and apply different metals to the same part. Nearly any metal is available in both wire or powder format for AM, including aluminum, cobalt chrome, copper, Inconel, stainless steel, tool steel, and titanium, among others. By using different metals in a single part, you can get the best attributes of both parts without compromising the integrity of the part.
Types of Machines
Currently, there are two types of hybrid machines. The first is an off-the-shelf hybrid machine offering both AM and subtractive, while the second is to add AM capabilities to a subtractive machine. When adding to an existing machine, one or more metal AM tools are installed and designed to operate alongside the standard set of subtractive tools. Although the overall number of available hybrid machines is still relatively small, it’s a technology that is only going to expand and grow because of the capabilities to combined both processes into one.
When it comes to hybrid manufacturing, it’s about finding the right solution for the application and leveraging the benefits of both.