Metal 3D printing enables the production of new, more efficient and intricate geometries, with the potential to reduce costs and increase the performance of a given product. While the technology holds unrealized potential for manufacturing, there are numerous hurdles preventing its widespread adoption.
In addition to the cost of many metal additive manufacturing (AM) machines, one of the biggest issues with the technology is repeatability and quality control, specifically when it comes to powder bed processes like direct metal laser sintering (DMLS). Due to variables related to support structure placement and minimizing residual stress during printing, a machine operator or engineer might try 3D printing a part more than a handful of times before getting the desired outcome.
A member of the United States’ original industrial 3D printing institute, America Makes, Sigma Labs has become involved in high-level 3D printing projects with important names in defense and aerospace manufacturing, including GE and Honeywell. Both companies have since begun testing Sigma Labs’ proprietary In-Process Quality Assurance (IPQA) software on machines in-house.
In an interview with ENGINEERING.com, Mark Cola, CEO of Sigma Labs, was able to discuss his firm’s PrintRite3D technology, how it fits into the larger 3D printing industry and the future of quality control in 3D printing.Inside Sigma Labs and 3D Printing Quality Assurance
Prior to founding Sigma Labs, Cola was working as a part of the Metallurgy Group at Los Alamos National Laboratory. He later established the company to develop quality assurance technology not for 3D printing specifically, but for manufacturing more generally.
Cola explained, “Our quality assurance software apps began life on the efforts we did with Boeing Aerospace. They were doing linear friction welding with titanium alloys for their 787 Dreamliner. What we developed for them six years ago form the underpinnings of the software apps that we’re using today in 3D printing.”
Cola added, “What we developed for them turned into a multiple-year contract with them to develop the same software but applied to a different manufacturing process.”
The quality assurance software Sigma Labs has developed can be applied to any number of manufacturing processes, including other forms of 3D printing. In fact, Cola said that the company has successfully implemented PrintRite3D with electron beam melting 3D printing from Arcam. Now, however, Sigma Labs is currently focused on DMLS.
PrintRite3D currently consists of three cloud software modules (INSPECT, CONTOUR and ANALYTICS) and one hardware package (SENSORPAK) that can be licensed from Sigma Labs individually or as a package to provide in-process QA of a printer and printing process:- SENSORPAK consists of a collection of sensors and a computer interface integrated into a given 3D printer to monitor the 3D printing process.
- INSPECT processes the temperatures within a 3D printer’s build chamber on a layer-by-layer, part-by-part basis to provide actionable metallurgical data.
- CONTOUR processes visual data of the build to provide geometric information about a part.
- ANALYTICS, still under development, ties all of this information together, across multiple machines and builds, to deliver global data about a company's prints, products and printers over time.
While INSPECT and CONTOUR provide much of the necessary in-process QA, specifically for the metallurgical and geometrical data of a build, machine operators can also work with Sigma Labs to develop a standardized print and printing process for each material and part against which this data can be compared. This allows a company to match components while they are being printed against a standard to ensure that it is meeting these standards.
“As you move from your characterization development efforts into production, you need a way to provide objective evidence of compliance back to the design intent,” Cola pointed out. “The way to do that is by developing a standard against which everything else is compared. That standard never changes. You develop that during your characterization efforts using our sensors and software apps and you archive it using our database and you continue to reference back to it as you move through your product QA timeline.”The Need for Quality Assurance in 3D Printing
Before an end part is even printed, a design is first tested by trial and error numerous times as the machine operator determines print parameters. Before the print process is even finalized, however, the quality assurance methods used to determine if the part meets certain standards are often costly, time consuming and even destructive.
These methods can include such procedures as destructive testing, in which parts are destroyed to measure the physical properties of the part and how the part stands up to various stresses, as well as nondestructive techniques, such as X-ray or ultrasonic testing. While destructive approaches are intensive, nondestructive methods may not be able to inspect the complex interior geometries that make 3D printing so valuable.
“What companies have resorted to is using computed tomography,” Cola said. “Well, you can imagine that that becomes very expensive. In some cases, for these really complex designs, we have some customers that, for every dollar they’re spending making the part, they're spending four to six dollars just inspecting it. There are huge costs involved in just assuring that they've made the right part. What they'd like to be able to do is to couple those two steps together—put the manufacturing step with the inspection step.”
For these reasons, Cola pointed out that IPQA might be a less costly, more efficient way to determine the quality of a part and match it against a standard. As AM users gain greater and greater confidence in the technology, IPQA can begin to replace some of the quality assurance measures applied after the part is printed.
Woodward
The latest manufacturing company to bring Sigma Labs’ IPQA on-board is Woodward, Inc. Woodward supplies such components as fuel circuits and fuel nozzles to aerospace manufacturers like GE Aviation, Pratt & Whitney, Rolls-Royce and Honeywell.
Cola explained that the Woodward aerospace group has been in the metal AM space for about 10 years now. The firm is interested in leveraging the geometric freedom that 3D printing offers by bringing the technology in-house, but has been faced with the aforementioned quality assurance measures that prevent 3D printing from being used as a manufacturing technology.
Cola elaborated, “For about the last 10 years, Woodward has been outsourcing all of the 3D printing or small batch production work to the limited supplier base that’s out there today that can make parts for people. This fall, they’ll be installing their first metal 3D printer in-house and they wanted to start off at day one with our quality assurance software integrated into their machine.”
The firm has now joined Sigma Labs’ Early Adopter Program, in which Woodward will evaluate Sigma Labs PrintRite3D software modules that are made up of three programs: INSPECT, CONTOUR and ANALYTICS. Woodward will install the PrintRite3D packages onto a new EOS M290 3D printer at its Aircraft Turbine Systems Division in Zeeland, Michigan.The Future of 3D Printing Quality Assurance
Sigma Labs is continually partnering with companies to improve its offerings and extend its reach. In addition to working with the aforementioned aerospace companies, the firm is also collaborating with 3D printer manufacturers, such as EOS, Trumpf and Additive Industries to integrate PrintRite3D directly into their machines. On the software side, Sigma Labs has teamed up with Materialise, one of the leaders in 3D printer management software, to embed PrintRite3D directly into Materialise Streamics, an AM automation & control system.
Mark Cola, CEO of Sigma Labs. (Image courtesy of Sigma Labs.)
What Cola would really like to see implemented is an in-process quality control mechanism, a closed feedback loop, that utilizes all of Sigma Labs’ packages to actually correct the printing process while it is occurring. When that will be possible is difficult to determine, but Cola believes that in order to get a closed feedback loop, it’s necessary to first build up in-process monitoring and data collection.
By working with all of these companies, Sigma Labs has integrated its solution into every nook and cranny of the 3D printing industry, from end users like GE Aviation to manufacturers like EOS and software developers like Materialise. To completely close the loop, Cola said that his firm has also established a 3D printing service division, with which Sigma Labs can work with customers to design, test, print and qualify parts so that they can either bring PrintRite3D in-house, turn to third-party service bureau or enlist Sigma Labs to 3D print the parts for them with in-process QA in mind.
Ultimately, Cola sees Sigma Labs’ IPQA not just applied to the 3D printing industry, but to manufacturing as a whole. He explained, “At the end of the day, the installed industrial base for advanced manufacturing technology is huge. As the industrial IoT begins to take hold, all of those manufacturing machines are going to need an edge computer of some sort. It could be our SENSORPAK, but it may just have different sensors in it because it’s a different process. Over time, as we grow this business, we’ll have the opportunity to go after the millions of devices that are already out there today that use other technologies.”
In other words, PrintRite3D may improve 3D printing in the near future, but, in the long term, a similar in-process QA technology could make its way into advanced manufacturing equipment of all types.