Updated: Dec 12, 2022
Image source: SolidCAM Additive
Until very recently, additive manufacturing (AM) was perceived as a technology with the potential to replace CNC machining, offering users the ability to produce parts faster, cheaper, and in complex geometries that are not possible with CNC. You could often find comparisons called ‘CNC machining vs. 3D printing’ that presented the pros and cons of each technology, comparing a traditional manufacturing method with a new and versatile one.
Today, we are seeing a shift in this approach to the idea of combining subtractive and additive manufacturing into one process with the advantages of both. How does it work, and what are the advantages of such a hybrid process?
Pros and cons of each technique
Industrial metal AM solutions can answer the need to produce a single part in a short to medium-run production of several metal parts. When it comes to the production of end-use parts, whether it’s five or fifty parts, the standards are much higher than when producing prototypes. Accuracy, repeatability, and surface finish are critical, along with the right material’s mechanical properties and a reasonable cost per part.
The process of producing metal parts with AM is challenging, mostly due to the post-processing phase. Maintaining dimensional stability can be tricky, even for one part; thus, it is even more challenging for higher volumes.
Conversely, machining parts is a widely used mature technique with higher productivity and precision. The downside is that it’s a longer and more complex process that requires a higher manual involvement and is more limited in geometries.
Combining AM and CNC
To enjoy the benefits of both techniques, the first step is to select an ideal part to be produced with AM, then design and 3D print it in a net-near shape. Next, move to another unit or tool head that mills the part to the required tolerances, add threads and holes if required, and handle surface finishing. Then what do we get? The best of both worlds.
Here is a good example presented by SolidCAM, the developer and provider of CAM software for CNC that combines binder jetting metal AM technology and a finishing process on a CNC machine. Together with the SolidCAM software solution, the process from the design of a part to end-use can be fully controlled:
Once both processes are smartly integrated, manufacturers can enjoy a unique advantage of both techniques from design to end-use part:
Design parts with complicated geometries
Avoiding unnecessary material waste
Faster production process of end-use parts
Higher precision and tighter tolerances than AM
High surface finish
Produce on demand
Custom made parts
Key for success – choosing the right parts
Once a hybrid process is in place, next comes the tricky bit: deciding which parts are suitable to produce in this combination of additive and machining. The basic assumption should simply be a part that is ideal to be printed with additive; however, the printing and finishing process can’t provide the required tolerances, accuracy, and surface finish.
Image source: SolidCAM Additive
This solution would suit service providers like machine shops that would like to supplement their machining capabilities with additive technologies. This would enable them to offer a new way of producing parts for their customers. To achieve this, the organization would have to fully understand the advantages and limitations of each technology along with the best way to combine them.