3D printing and machining are often seen as "competitors", but they can also be "partners". 3D printing parts often need to be machined to produce higher tolerances and a better surface finish. Meanwhile, parts that were once milled from a solid block of metal can be 3D printed more quickly and in more complex shapes. A growing number of hybrid manufacturing machines combine 3D printing and CNC machinery into one package to better automate and speed up part production. So, how are they faring? What is the future of hybrid manufacturing?
Hybrid manufacturing equipment makers say hybrid technology overcomes the shortcomings of both technologies, allowing manufacturers to produce more accurate, higher-quality parts faster and at a lower cost. It’s less wasteful than machining alone, more efficient, and more precise than 3D printing alone, without the need to manually move parts around or program two different pieces of equipment.
△ Combination of direct energy deposition and CNC milling
What is a Hybrid CNC-3D Printer?
Hybrid manufacturing is a relatively new approach that combines additive and subtractive manufacturing techniques on a single machine. These machines use 3D printing to produce near-net shapes of metal or plastic parts. The part is then milled to the required tolerances by another unit or tool head in the machine. With hybrid manufacturing, manufacturers (and their customers) can obtain the complex geometries produced by additive manufacturing and the surface quality of milling. In addition to building parts from scratch, these machines are ideal for adding new features to existing parts, performing part repairs, and coating parts prior to post-machining operations.
Hybrid manufacturing machines vary by manufacturer, but generally fall into two categories: Sequential Hybrid Manufacturing & Alternate Hybrid Manufacturing
△CNC machining after 3D printing for a smooth surface finish
● Sequential hybrid manufacturing machines first complete the full AM process, which produces 3D printed near-net shape parts before entering the subtractive process.
● Alternate hybrid manufacturing machines swap between AM and milling units throughout the manufacturing process. Some alternate hybrid machines can even AM print the rest while machining the part.
Hybrid manufacturing is a viable solution to produce prototypes and functional end-use parts in addition to repairing existing components. Hybrid manufacturing is especially attractive to smaller companies that need both additive manufacturing and machining capabilities. These machines allow them to produce two (or mixed) parts without having to invest in two machines. It can also address the demanding requirements of certain industries, such as part complexity and productivity in automotive and aerospace.
Pros and Cons of Hybrid Manufacturing Machines
Hybrid manufacturing has many advantages over pure AM or subtractive methods:
●One of its most important advantages is the ability to increase productivity. Since both the AM and machining processes run on one machine, there is no need to change parts and recalibrate equipment. Machining cells can also partially or completely replace manual AM post-processing, which also speeds up production.
●Hybrid manufacturing can achieve higher precision and tighter tolerances than most individual 3D printers. Additive manufacturing can create more complex geometries and part structures than machinings, such as part integration, internal channels, and lattice filling. Producing an entire part on one machine also reduces the possibility of machining defects or errors.
●Hybrid machines enable the use of multiple materials in a single part, resulting in significant improvements in mechanical performance and cost savings. Weaker parts can be clad with stronger metals, high-performance materials added to improve part motion or heat transfer, or material costs can be saved by using expensive materials only where they are needed.
●Hybrid manufacturing can reduce initial investment and operating costs. It is cheaper to buy a hybrid machine outright than to buy a CNC machine and an industrial 3D printer at the same time. A single hybrid machine consumes less energy and requires less floor space than separate AM and CNC units.
△Parts with functions such as internal cooling channels
A recent study found that hybrid manufacturing eliminates the waste of subtractive techniques, reducing material consumption by up to 97%. With DED/CNC machines it is also possible to add material only to selected locations. These users repair damaged components and speed up production by adding metal to parts, such as those used in the marine and oil and gas industries. At the same time, the CNC unit can machine fine internal structures between material deposition runs.
Despite its enormous advantages, hybrid manufacturing does not fit all manufacturing needs and there are some disadvantages:
●While these machines can lower the initial investment, they are not cheap and may exceed the budget of a small company.
●Operating a hybrid machine can be complex, requiring the operator to have a sophisticated understanding of 3D printing and CNC machining to determine the best method to manufacture a given part.