CAM Meets AM to Enable Hybrid Manufacturing

The ability to source replacement parts while out at sea is challenging, especially with space at a premium and many decades-old parts near obsolescence. The U.S. Navy ship USS Bataan is tackling the problem by being the first to deploy a hybrid manufacturing system that provides sailors with industrial-grade manufacturing capabilities that enable self-sufficiency while also increasing efficiency and reducing waste.

The solution, the Phillips Additive Hybrid system, pairs the Meltio wire-laser metal 3D printing platform with Hass TM-1 computer numerically controlled (CNC) machining capabilities. The system was used to 3D print and fabricate a replacement sprayer plate for a de-ballast air compressor (DBAC) in only 5 days as opposed to taking weeks, potentially, to source through conventional Navy supply channels. Moreover, by combining additive and subtractive capabilities within the same system, the Navy crew was able to manufacture critical parts when and where it needed to while minimizing valuable on-board real estate.

“The impact technology like this can have on operational readiness, particularly in a combat environment where logistics capabilities will be challenged is critically important,” stated Rear Admiral Joseph Cahill, commander, Naval Surface Force Atlantic (SURFLANT), in a press release (tinyurl.com/mry8swht) on the deployment.

While nowhere near mainstream, hybrid manufacturing solutions that combine metal AM and machining capabilities are gaining traction as system prices fall and organizations recognize the efficiencies of merging production workflows in a single system. While some, like the U.S. Navy, are purchasing systems that converge additive and subtractive production capabilities in an all-in-one, multipurpose unit, others are leveraging software and automation technologies to create custom scenarios that streamline disconnected processes into an integrated and optimized hybrid manufacturing workflow.

Hybrid manufacturing solutions make sense because 3D printing constitutes only a portion of the production workflow and is often not sufficient on its own to create a finished product. Combining additive manufacturing (AM) and subtractive capabilities in a single unit requires less labor and in many cases, enables companies to deliver parts more quickly because they don’t have to be passed between systems to take advantage of secondary operations.

“In many cases, machining, welding or another industrial process is required, and the closer a solution can get towards delivering the final product, the more value it can provide,” says Tripp Burd, director of new platforms at Markforged. “This allows the greatest strengths of manufacturing processes to be combined to create the best possible part.”

Best of Both Worlds

Phillips, one of the pioneers embracing hybrid manufacturing, touts its system for a range of applications across industries, including aerospace & defense, automotive, and tool & die/mold making. The offering leverages the Meltio wire laser directed energy deposition (DED) engine, which produces high-density parts with high resolution in addition to offering other benefits over metal powder AM technologies, including a clean and safer working environment and 100% use of the lower-cost metal-wire material. The Haas CNC system, integrated into the solution, handles three-, four-, or five-axis machining, and Phillips is on tap to deliver services and expertise to ensure a smooth implementation.

“We’ve taken both technologies and married them together from an integration and programming point of view,” says Brian Kristaponis, general manager of the hybrid division at Phillips. CNC milling systems are a good complement to metal AM, as the complex geometric designs output by those systems often require extensive postprocessing to smooth out rough surfaces.

Phillips’ first foray into hybrid manufacturing came by way of a special system built for Autodesk. Autodesk saw potential market interest in hybrid manufacturing and was looking for a system with a price point and software capabilities that mapped closely to its Fusion 360 design platform, Kristaponis says.

“It was about creating a hybrid system that any machine shop could afford, integrated with turnkey software,” he explains, adding they signed up quite a number of university customers as well.

Today, Phillips’ hybrid manufacturing group has been spun out as a separate entity with much of the demand coming from government and Department of Defense (DoD) customers. Repair applications like what the crew on the USS Bataan is doing are a primary use case for hybrid manufacturing technology as well as parts that require a lot of back and forth between machining and 3D printing, Kristaponis says. “Not having to go from CNC machine to AM machine results in huge time savings and is beneficial from an accuracy standpoint,” he adds.

Consider the use case of a large propeller on a ship or a part on a complex piece of equipment where certain areas or bearings are worn thin. Instead of scrapping the entire part for replacement, a hybrid manufacturing solution enables personnel to add material and fill in pits on worn areas using AM following up with integrated CNC capabilities to create a more precision surface, explains Markforged’s Burd. “You can repair defects instead of scrapping the entire thing,” he says. “In that way, you create a replacement part more quickly and cheaply than creating a new one from scratch.”

Training personnel on an integrated set of capabilities is also more efficient and can help close some of the talent and skills gaps that remain a challenge for manufacturers. Customers accustomed to outsourcing machining capabilities to pattern shops are potential candidates for hybrid systems because it enables independence and increases productivity, adds Haley Stump, application engineer lead for the Application Innovation Group, at 3D Systems. 3D Systems acquired Titan Robotics in 2022, and its large-format pellet extrusion systems are the basis of the company’s hybrid manufacturing platform.

“Less outsourcing is always better,” says Stump, adding that the technology lends itself to tooling, thermoforming, and sandcasting applications. “It’s really cutting lead times in half or more, especially if the customer is outsourcing to a pattern shop. It’s significantly less than machining something out of a block of aluminum.”

The EXT Titan printers, available in two build volume sizes, are offered standard with a single high-throughput pellet extruder, but systems can be configured with up to three toolheads, including a second pellet extruder, a filament extruder and a milling spindle for true AM/subtractive hybrid manufacturing scenarios. Both platforms are designed for lights-out manufacturing, another advantage of a hybrid manufacturing model that can lead to shorter cycle times, cost reductions, and increased uptime for production processes.

“We provide a way to combine printing and machining runs in one file, enabling customers to reduce labor costs and utilize overnight builds, coming into a finished part in the morning,” Stump explains. “Typically you wouldn’t leave a CNC build unattended because metals are more risky to machinery. We don’t have that same level of risk.”

A hybrid system can also smooth over some of the gaps engineers face as they reorient design sensibilities to a design for additive manufacturing (DfAM) mentality. For example, designs don’t necessarily need the tight tolerances required for a standalone AM system because onboard milling capabilities can compensate for a highly accurate part. “You don’t have to be as aggressive about DfAM like you do with an AM-only process,” says Phillips’ Kristaponis.

Choosing the Right Approach

That said, hybrid manufacturing isn’t a fit for many applications and the model comes with its own set of challenges. Parts that require longer print times and are less reliant on machining for final output are better suited for separate systems and processes while those parts output with higher mass lend themselves to a hybrid approach, explains Lukas Hoppe, director of R&D at Meltio. “If your interest is in repairing parts or outputting smaller parts that integrate some new feature addition then it makes sense to do it in a single machine,” says Hoppe, who estimates that around 30% of Meltio’s sales now involve hybrid manufacturing systems.

A single machine setup saves on real estate and in some cases, cost, but there are also limitations. Combining two complex operations in one environment comes with challenges, including finding skilled operators who properly understand the workflow sequence as well as best practices for each production method. For example, high-performing machining operations require tools to be kept clean and cool, which can be at odds with best practices for AM.

There are also issues related to downtime—if the combined system encounters a problem, there’s the possibility of taking the equivalent of two systems offline rather than one. “Hard-coupled manufacturing processes can limit agility if you’re looking for maximum throughput in a product environment,” says Markforged’s Burd.

Markforged AM technology is not currently suited for the classic interpretation of hybrid manufacturing due to the need to sinter metals and perform depowdering and debinding post-processing steps. However, Burd says the company takes an alternative view of hybrid manufacturing through its ability to combine quality and inspection processes in a single machine—another way to reduce reliance on secondary operations.

Markforged AM systems incorporate machine vision camera systems and onboard laser micrometers to automatically capture information about a part’s surfaces and fiber placement as it’s printed while in-situ monitoring detects and adjusts for alignment issues. The Markforged AM platforms also incorporate laser inspection data into automated quality reports that compare the geometry of the input STL file to the measured geometry of the printed part. “Quality is a major part of production workflows, and we’re integrating it into our hybrid machines,” Burd says.

As far as the more conventional take on hybrid manufacturing, in addition to the 3D Systems and Phillips’ offerings, DMG Mori offers a platform that melds DEDAM capabilities with CNC milling while Matsuura Machinery Corp.’s LUMEX series repeats metal laser processing and high-speed, high-precision milling to form metal powder into shapes. The system makes deep ribs in a single process, resulting in dimensional accuracy that’s comparable to machining centers, officials claim.

Before moving forward, companies need to take the time to consider what applications, if any, would benefit from combining processes in a single machine. The reality is that most parts demand multiple production processes—the question is whether integration is economically or strategically beneficial. “There’s always a hybrid workflow—the question is whether to accommodate the process in one machine,” says Meltio’s Hoppe. 

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