Many 3D printers in the metal AM space are migrating to a hybrid additive manufacturing approach to satisfy stringent industry requirements. While not formally defined with ASTM terminology, hybrid additive manufacturing is generally considered to be a combination of additive manufacturing (3D printing) and subtractive manufacturing (CNC milling) technologies in a single machine. Hybrid solutions are often built using a base CNC mill to which the additive technology is added. For instance, directed energy deposition additive technology is used for solutions developed by Hybrid Manufacturing. Similarly, sheet lamination additive techniques are used for Fabrisonic’s large-scale hybrid printers.
Critics of the hybrid approach disapprove that hybrid systems combine two expensive processes into one machine, wherein only one technique can be used at a time. A common objection staff at Fabrisonic hear is, “wouldn’t it be more efficient to have two separate systems that can be run in parallel?” The answer to that question is not definitive and depends on the volume and variability of production. While it makes perfect sense to use separate machines for high volume production, the lower volume, high variability jobs are seen by most 3D printers are best tackled with a hybrid approach.
The top five reasons to use hybrid additive systems in low volume, high variability projects include:
- Repair – Hybrid machines allow you to use either process, additive or subtractive, at any time. The number one application for hybrid systems is repair of currently existing components. Hybrid allows you to fixture an existing component, mill off an area of damage, and immediately start adding material to replace features. As a final step, a hybrid machine often mills the part to get the required fit and finish. Keep reading to see how finishing time is reduced.
- Surface Finish – Most traditional metal additive processes print parts slightly larger than designed to account for the variable surface finish created when metal powders are printed. This surface variability requires many traditional additive parts to undergo complicated post-build processing. There is an entire cottage industry developing around simply finishing parts (a hybrid process in itself). By coupling the additive technique seamlessly with CNC milling, all internal and external surfaces can be milled to traditional CNC finish. Parts like high-efficiency heat exchangers come off the machine ready for use.
- Precision – Whenever you transfer a part from one machine to another, you introduce uncertainty that tends to decrease the precision of critical tolerances. Hybrid additive manufacturing allows every surface to be printed and milled in the same reference plane, allowing tighter tolerances. This is particularly important for components like radio frequency wave guides that depend on the exact position of features for operation.
- Adding Difficult Features while reducing total part count – In traditional manufacturing, multiple parts are bolted, welded, and brazed into a final product. Instead of carrying a myriad of separate part numbers, hybrid additive manufacturing design is used to reduce complicated, multiple-part (SKUs) into one single part. Imagine a single build that reduces time, labor and cost to one part. A design engineer simply starts with a base shape and then uses a hybrid system to add difficult features around the periphery.
- Multi-Metal 3D Printing – Parts that have multiple metals are difficult to produce even with additive manufacturing. A hybrid system architecture allows for a part to start with a preform of material A, add material B using additive manufacturing, and then switch to material C for further additive manufacturing. Often cladding is accomplished with hybrid systems. A more complicated example is where electronic sensors are embedded using Fabrisonic’s technology. The material is built up additively to the desired point of insertion. Next, CNC milling is used to make a precise cavity for the sensor, and then additive is used to build further. This fully encapsulates the sensor of choice. Since this is a solid-state, low temperature process, the sensor is not damaged during the process. Other additive systems that use heat cannot embed sensors without damaging the very component the process was designed to protect.
Have an additional question about how a hybrid additive manufacturing machine could improve your process? Click the button below to Get Started with Fabrisonic and our team will be in contact with you soon.