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  • Writer's pictureJames Figy

Old Manufacturing Barriers Go to Rust as PC Control Helps Scale Electrochemical Machining

Voxel Innovations leveraged transformational automation technologies from Beckhoff, with integration support from Palmetto Mechatronics, to make a sophisticated manufacturing process mainstream

Daniel Herrington was working for the U.S. Department of Energy’s Advanced Research Projects Agency–Energy (ARPA–E) when he had a realization. While he’d already earned a master’s degree in engineering management, it wasn’t until that job that he realized the importance of manufacturing. In research projects funded by ARPA-E, advanced manufacturing proved to be a critical enabler for technology breakthroughs.

“Manufacturing underpins most major advances in technology, whether it’s in the energy industry, medical device or aerospace,” says Herrington, CEO of Voxel Innovations. “I realized I wanted to work in manufacturing, and I saw that electrochemical machining had significant untapped potential, especially in the U.S. So a vision formed to build a company based around electrochemical machining and an automation platform that would solve the biggest problems faced by our customers.”

Voxel’s original PECM system
While Voxel’s original PECM system didn’t support the volumes needed to scale, it continues to serve as a valuable tool for proof of concept or smaller product runs.

By refining the science, developing proprietary IP and building upon a scalable automation platform, Voxel has become a leader in high-volume pulsed electrochemical machining (PECM). Founded in 2015 in Raleigh, North Carolina, the company offers contract manufacturing using machinery developed in-house to support customers across the U.S. This comprehensive service is ideal for aerospace, medical device, energy and other industries that need highly engineered, metallic components in large quantities.

Voxel provides value to customers by controlling three core elements: the process, the tooling and the machine. All three can be customized to match customers’ unique needs, such as working with specific metals while providing enhanced traceability.

To continue its growth trajectory, Voxel needed to implement a more sophisticated automation platform that would scale. After extensive vendor research, they selected Beckhoff. This decision also led them to Robert Belk, Jr., P.E., Owner and Automation Consultant at Palmetto Mechatronics in Greenville, South Carolina. Working together, the teams at Voxel, Palmetto and Beckhoff developed an automated production line with robotics and inspection capabilities.

“We had a vision for how the line would work, but Robert helped us understand how all the components could talk together and capture the data we need,” Herrington says. “Before that, our automation systems were built in-house. But going into this next phase of growth, we want to build around a single architecture and industrial control platform.”


Novel challenges spark engineers’ ingenuity

Voxel Innovations CEO and employee work together
CEO Daniel Herrington (right) founded Voxel Innovations in 2015 after seeing untapped potential for electrochemical machining. Now, team members like Operations Technician Torrey Hall (left) keep the systems running around the clock to meet demand.

One of Herrington’s first hires at Voxel would seem unconventional to most manufacturing startups. Electrochemist Dr. Omar Yepez previously worked to protect offshore equipment against rust for as long as possible. Now, Herrington wanted him to do the opposite for Voxel. That’s what PECM is, after all: very fast, highly targeted corrosion that shapes intricate, high-quality geometries atom by atom.

“The PECM process is non-contact and non-thermal, so it can create thin-wall geometries with intricate features without deforming the part,” Herrington says. “Our electrochemical machining technologies involve complex fluid dynamics, multiphysics, chemical reactions, heat transfer and a variety of other aspects. But they can produce parts that traditional manufacturing processes can’t handle as economically or, many times, couldn’t make at all.”

The automated line at Voxel moves this rapid corrosion process into high-volume production. First, it sorts parts into a uniform infeed. Then a SCARA robot loads them onto a tray. A gantry moves the tray through pretreatment baths.

A KUKA SCARA robot at Voxel Innovations
A KUKA SCARA robot unloads trays of product and routes pieces for inspection.

Next, an articulated robot grabs multiple workpieces and inserts them into the PECM cell. Inside, the tooling lowers into place, and an electrolyte solution fills the minute gap between the tool and the part. By applying the correct voltage potential, the system dissolves metal through electrolysis. Simultaneously, the electrolytic fluid also acts as a flushing agent that removes waste material and any residual heat.

Afterward, the robot unloads the machined parts onto a separate tray. A second gantry then takes them through post-treatment baths and a drying chamber. Finally, another SCARA unloads the trays, while routing several parts to an inspection station with Micro Epsilon optical gauges.

The sophisticated operation requires fast cycle times and synchronization between different processes. On top of that, interfacing with databases, connecting to other web-based platforms to extract data and straightforward integration with third-party devices were all considerations.

Robert Belk of Palmetto Mechatronics
As part of the Beckhoff Integrator Group (BIG), Robert Belk, Jr., P.E., takes on a wide range of applications from the PECM production line at Voxel to others involving XPlanar and XTS through his systems integration firm, Palmetto Mechatronics.

PC-based automation from Beckhoff offered the best option for Voxel. Fortunately, Belk is no newcomer to the technology. As a member of the Beckhoff Integrator Group (BIG), Palmetto Mechatronics has taken on projects involving XTS, XPlanar and TwinCAT Vision. While Belk’s main client is an international machine builder, he appreciated the challenge of Voxel’s unique application.

“I started in custom machine building in 1997 at an OEM after receiving a B.S. and M.S. in electrical engineering from the Georgia Institute of Technology. Even back then, we were pushing boundaries with PC-based controls and other new technologies,” Belk says. “I was introduced to Beckhoff around 2005 and continued to use the platform at that OEM until the company was sold and I launched Palmetto in 2018. I’ve evaluated many platforms, and I prefer Beckhoff.”


Automation software solutions electrify programming

Belk worked with Voxel Controls Engineer Kevin Judd to program the machine using TwinCAT 3 automation software. A comprehensive engineering and runtime platform, TwinCAT enables engineers to program in whichever language best suits their skillsets and the needs of the application. This encompasses the IEC 61131-3 standards with their object-oriented extensions, preloaded or custom function blocks, or computer science standards integrated into Microsoft Visual Studio®. Belk relied on Structured Text, along with C# for HMI customization.

Beyond standard PLC functionality and running PID loops for process sensors, several other TwinCAT functions proved crucial for the application, including:

  • ADS communication between the machine logic and a custom Windows .NET application for interfacing with the optical measurement device and HMI.

  • PTP motion control library, for instance, to drive ball screw actuators with 13 Beckhoff AM8100 servomotors, which raise and lower the PECM tooling.

  • TF6420 database connectivity for high-speed connection to a custom database for Work-In-Progress (WIP) control and OEE statistics.

Beckhoff IPC and EtherCAT I/O technologies
The robot-equipped PECM production line leverages a range of PC-based control, TwinSAFE functional safety and EtherCAT networking solutions from Beckhoff.

“This system requires real-time interaction with an MS-SQL database. Each part is assigned a virtual serial number when placed into the first tray, and that is updated throughout each step of the process,” Belk says. “The part data is very important for determining machine tool wear or damage and optimizing the machining process. The Beckhoff database client software enables very fast execution of stored procedures from within the TwinCAT control software.”


Precision hardware for electrochemical machining

The automated PECM production line at Voxel uses a CX2042 Embedded PC running TwinCAT as the sole machine controller. The CX2042 with directly connected I/O terminals communicates with the three robots, optical gauges, MS-SQL database and hosts the HMI program. Handling all this with tight cycle times demands processing power, and the controller with many-core Intel® Xeon® processors delivers.

“One of the things that has driven me toward Beckhoff Industrial PCs (IPCs) over the years is the CPUs’ speed and architecture. Plus, you can assign processor cores to specific tasks, whether they’re on the automation side or involve regular PC functionality,” Belk says. “Beyond that, the IPCs offer significant space and cost savings because one piece of hardware can handle everything on the machine.”

On the networking side, the EtherCAT industrial Ethernet system provided real-time communication and a flexible topology. The automated PECM production line uses a range of EL series EtherCAT I/O terminals from Beckhoff to communicate across the system. EL terminals installed on the articulated robot control the end-of-arm tooling with valves and sensors for 24 sets of grippers. Also, EL7211 servomotor terminals provided space-saving 48 V DC amplifiers for the AM8100 servomotors.

Along with EtherCAT, Safety over EtherCAT (FSoE) helped streamline implementation. FSoE uses a “black channel” approach to communicate machine safety data over the standard EtherCAT network. Belk leveraged TwinSAFE hardware as well as FSoE capabilities built into the KUKA robots, which offer native support for EtherCAT.

“EtherCAT is one of the fastest industrial communication technologies and easily handles the servo motion, I/O and safety control as well as the robot communication,” Belk explains. “KUKA robots use EtherCAT as a primary communication technology, and TwinCAT simplifies mapping data between the robot and the embedded PC. So integration of the three robots into the overall control system and safety network proved to be quick and efficient.”

Innovative automation energizes PECM into high volume

After a year of development time, the automated PECM production line went live in June 2023, and is producing roughly four million parts a year. Voxel has hit the performance benchmarks and part-level traceability set in the design phase. The system offers complete visibility into quality control, pH levels, etc., providing traceability to comply with standards like AS9100 in aerospace and ISO 13485 in medical device manufacturing. It can pause production and alert the operator if anything falls out of tolerance.

An articulated KUKA robot
An articulated KUKA robot loads and unloads the PECM chamber, relying on advanced kinematics found in TwinCAT 3 automation software.

“Compared to our previous approach, the difference is night and day. The main advantage is we brought all our controls under one roof, and Beckhoff can do anything that’s on our technology roadmap,” Herrington says.

As PECM is capable of processing multiple parts in parallel with a single tooling system, its high-volume capabilities can increase even further with Beckhoff’s automation technology.

Voxel is developing two more production lines, which will include high-end motion control and six-axis robotics. A key strategy in the first implementation was to ensure the company’s engineers learned the technology, working with Belk, to keep that knowledge in-house. Having adequate support was also critical. Herrington appreciated not only Beckhoff’s no-cost technical support, but also assistance from the local applications engineers, including Jack Plyler and Jason Toon.

An automated inspection station
The inspection relies on Micro Epsilon optical gauges and precision motion from a Beckhoff AM8100 servomotor to ensure high product quality.

“A pet peeve of mine is when salespeople get between two engineers that are trying to solve a problem. Beckhoff never does that,” Herrington says. “If I’ve got a technical challenge, they connect me with the correct technical person.”

Belk agrees, adding that as a longtime Beckhoff user his questions are typically complex.

“It’s nice to have real relationships with people at Beckhoff, and being part of BIG helps, too,” he says. “I can ping Jack or Jason with a question, and if they’re not sure about something, they will funnel it up to a product manager. It’s engineers talking to engineers, and I feel secure knowing that if I have an issue, I’ll get solid answers quickly from Beckhoff.”

Engineers from Voxel Innovations, Palmetto Mechatronics and Beckhoff Automation
Automation and manufacturing experts gather at Voxel Innovations’ facility in Raleigh, North Carolina: (from left) Jack Plyler, Application Engineer at Beckhoff; Chuck Padvorac, Sales Engineer at Beckhoff; Daniel Herrington, CEO at Voxel; Robert Belk, Owner of Palmetto Mechatronics; and Kevin Judd, Controls Engineer at Voxel.

With a strong technology base, Voxel will continue to be a key partner for customers. This means developing the fundamental process, designing the tooling and ramping up for volume production.

“Whether it’s a part for a jet engine, an implantable medical device or a heat exchanger for an energy application, our vision is to offer customers differentiated technologies that help them optimize performance and cost metrics,” Herrington says. “Then we want to support them all the way through that process and throughout the product life cycle. Our model is to be that trusted engineering development and volume manufacturing partner.”

And the demand is clearly there: The company continues to run production around the clock in three shifts to keep up with orders. Now that’s a breakthrough.


Ready to ramp up your unique manufacturing processes with scalable industrial automation tech? Contact your local Beckhoff sales engineer today.


James Figy of Beckhoff Automation USA

James Figy is the Marketing Content Leader at Beckhoff Automation LLC.

A version of this article also appeared in Automation World.


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