A Profile of Hybrid Additive Manufacturing Technology
Kyle Maxey posted on August 05, 2015 | 24460 views
Courtesy of Hybrid Manufacturing Technologies and Hamuel GmbH

Courtesy of Hybrid Manufacturing Technologies and Hamuel GmbH

Hybrid additive manufacturing (AM) has been gaining a lot of traction over the past four-to-five years, but it’s still a technology with a lot of unknowns. First, hybrid manufacturing’s name is non-descriptive to the point of being enigmatic. But if we put it plainly, hybrid manufacturing is the combination of laser cladding and CNC milling within a single machine environment.

On the face of it, the dueling production techniques of additive and subtractive seem like they’d be difficult to mesh together, and, in some respects, they are. But if both additive and subtractive have been choreographed correctly, they offer powerful new capabilities to companies willing to understand these new manufacturing methods.

With that in mind, let’s take a look at why hybrid manufacturing has so much potential.

How Does Hybrid AM Work?

Hybrid manufacturing produces objects by employing both additive and subtractive technologies. Because of its dual nature, hybrid machines can begin producing a part by using either an additive or subtractive process. However, beginning production using additive manufacturing is inherently more efficient than needing to mill a form and, in most cases, will offer greater design freedom.

Hybrid systems use an additive production method called laser cladding. Laser cladding is essentially a precision welding process that deposits granular metals onto a surface where they are immediately liquefied into a melt pool by a high energy laser. Once cooled, the deposited metal becomes a solid.

To begin a new part, the hybrid build process employs its laser cladding system. Using g-code generated from CAD data, the cladding head creates a solid model by depositing and welding layers of metal powder to transform them into a unified solid structure. This process continues until an entire model has been built.

Once the cladding operations have concluded and the metal material has cooled, a hybrid system switches tooling methods and readies itself to begin CNC milling. Traditionally, hybrid systems come equipped with 5-axis milling tables to ensure that any additive surfaces can be machined, even if the part includes undercut regions. Similar to traditional milling machines, a hybrid machine can employ a number of tools to shape a surface and add critical features where needed.

After completion of the subtractive process, a part can either repeat the system’s additive/subtractive two-step in order to add new features, or it can be removed if it’s complete.

Used for Repair

Hybrid systems are also capable of repairing damaged parts. To undertake repair operations, a hybrid machine will employ the same cladding process to build new geometry before switching to a milling operation to finish the part. If the overall geometry of a part is still true, a hybrid system can be used to build the missing geometry and then finish it via milling.


Hybrid Manufacturing’s Dirty Secret

Image courtesy of Siemens PLM Software

Image courtesy of Siemens PLM Software

Unlike strictly additive or subtractive systems, a hybrid manufacturing system doesn’t use a single method of production to build a part. Because hybrids combine two methods of manufacturing, a number of complex considerations have to be taken into account before a part is produced.

While design intent has always been a staple in the CAD and manufacturing community, it’s never been more necessary than in hybrid manufacturing operations. By blending two opposing manufacturing options, designers and machine operators have to be in tight communication to determine how a part should be manufactured and whether additive or subtractive operations should be used, and whether multiple rounds of both processes will be needed to complete a part.

With that kind of complexity being built into a single manufacturing process, it’s incumbent upon users to develop best practices for using hybrid systems. Unfortunately, since hybrid manufacturing is so young, many of those practices have not found their way into common use. In my opinion, that’s hybrid’s dirtiest secret.

Still, the technology has a lot to offer.

What Industries Could Employ Hybrid AM?

Right now metal-based additive manufacturing is being championed primarily by the aerospace, automotive, medical and defense industries. It’s no surprise that those same players stand to benefit from hybrid manufacturing’s benefits.

One aspect of hybrid manufacturing systems that sets them apart from other manufacturing methods is their inherent ability to reduce material waste while simultaneously shortening turnaround time. With its combination of additive and subtractive manufacturing, hybrid AM can build and finish complex components within a single machine environment. For anyone producing complex, short-run components, that attribute will be attractive as it can shorten the prototyping and design process, reduce material waste and eliminate secondary manufacturing methods like casting.

And, as mentioned, hybrid manufacturing also gives manufacturers the ability to repair damaged metal parts — an ability few other technologies can offer.

So, Are Hybrids a Part of Manufacturing’s Future?

Undoubtedly, hybrid manufacturing has a lot of maturing to do before it’s ready to make an impact on manufacturing. Not only will metal additive manufacturing need to become more advanced, but best practices still need to be developed before the technology will be adopted by a majority of users.

One other issue that I can see preventing the rise of hybrid manufacturing is the continued maturation of solitary metal additive technology. If metal systems improve dramatically over the coming decade, could they displace the need for additive/subtractive systems? Or will hybrid machines be far more productive than two-phase manufacturing?

In the end, having to deal with all of the realities and unknowns of hybrid manufacturing might be too big a risk for any organization that isn’t big or well heeled enough to handle it.

But then there’s the other side of the coin. Hybrid manufacturing could be a transformative technology that expands manufacturers’ ability to create bespoke products for a wider range of industries and at scale.

Since I’m a hopeful person, I’m going to side with hybrid’s vast potential. What’s your take? 

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