Industrial laser-based 3D printing processes have been around for many years, but the industry must tackle many challenges such as production throughput, quality assurance, and manufacturing repeatability before 3D printing can become a robust, standardized manufacturing technology.
Materialise developed the Materialise Control Platform (MCP), powered by CompactRIO and LabVIEW, as a ready-to-start software-driven, embedded controller platform specifically for laser-based 3D printing applications. Researchers and engineers can build and improve additive manufacturing processes that are ready for industrial use to support innovation, research, and new applications in the market.
Stijn Schacht - Materialise
Dennis Vandenbussche - Materialise
Since its start in 1990, Materialise’s goal has been to support new uses for the extraordinary potential that 3D printing offers. Since then, Materialise has evolved into a worldwide leader in software solutions, engineering, and 3D printing services, which together form the backbone of the 3D printing industry.
Materialise’s open and flexible platforms help companies in industries such as healthcare, automotive, aerospace, art and design, and consumer goods to build innovative 3D printing applications that make the world a better and healthier place. Examples include customized implants that have helped people out of their wheelchairs, hearing aids that have enhanced social lives, or the improved designs of the cars we drive and the planes we fly in.
Traditional machines operate on preformed material geometries (bars, blocks, sheet metal plates, and more), but additive manufacturing starts from pulverized material (powder) or liquid material (resins). This means that in contrast with traditional manufacturing, additive manufacturing not only shapes the geometry of end products, but also defines the material properties.
Therefore, manufacturers use laser optical systems. The power and geometrical accuracy of these systems shifts as time progresses. Furthermore, like in welding, the process is susceptible to corrosion. This requires complete and total control of both the laser power, beam position, process atmosphere, and machine temperature throughout the entire build, and for some materials also before and after the build (controlled heat-up and cool-down phases). Any process glitch during the build phase can dent the material quality of the end part, which creates scrap or extensive rework. Also, the more the additive manufacturing machine is used, the quicker its internal processes deteriorate. Users mitigate this with preventive maintenance and recalibration—time consuming tasks with a rather long machine standstill as a consequence.
When using additive manufacturing, users may calibrate the machine before a certain number of builds. A complete calibration easily consumes half a day of work by a skilled technician for a build that might take only a couple of days.
With machines that drift so quickly and have advanced complex processes, the industry is somewhat skeptical about an emerging and revolutionizing technology like additive manufacturing. Typically, users demand outstanding quality, high production throughput, and repeatability to trust this manufacturing approach to handle those elements that generate revenue for them.
We might gradually overcome challenges like throughput and increasing production capacity. With repeatability still a challenge, this could lead to accelerated production costs and more waste. However, all of this is still not as important as a potential quality issue, which directly impacts customer relationships.
Users can benefit from the Materialise Control Platform to innovate and overcome these hurdles one by one. They can tackle and reduce the typical calibration downtimes and implement an automatic process and quality monitoring and control. Users can also achieve closed-loop rates that have never been achieved before and produce more repeatable parts with higher quality, at higher volume, and at lower cost.
Traditional control systems within many industrial 3D printers are built using a PLC/PC with scan card architecture, which does not fully integrate the different control elements into one system. The combination of subsystems only happens with machine control software that does not operate in real time. Understandably, this approach limits quick interventions and closed-loop control rates.
If all important elements are in real-time contact with each other, we can optimize the control system and make it smarter to mature the full process and realize better parts.
Combining Materialise’s process knowledge from around 30 years of experience using industrial 3D printing equipment, with the power and openness of the CompactRIO platform, LabVIEW software, and the LabVIEW FPGA Module, we developed our additive manufacturing control platform. This platform empowers researchers and engineers to materialize their smart ideas and develop tools and IP that improve the reliability, speed, and quality standards of the 3D printing process. In addition, we can use the flexibility and modularity to expand and grow as needs change in the future.
Our system currently achieves unparalleled closed-loop control rates due to the FPGA power available within the CompactRIO platform. It differentiates itself from the traditional approach by combining all elements in real time for much faster and in-depth control of the 3D print process. We achieved this by combining off-the-shelf CompactRIO components, LabVIEW, and LabVIEW FPGA with specific software components and custom C Series modules to create a flexible and scalable solution.
We selected the CompactRIO platform as the foundation for our solution. CompactRIO offers an extendable FPGA-based hardware platform with a vast selection of I/O. We extended the platform with a scan head and laser interfaces. We developed and added both XY2-100 and SL2-100 scan head communication protocols as C Series interface cards. Specifically, the cRIO-903X controllers offered great advantages while running Linux Real-Time. We could port our current C developers and many of the already existing libraries to the CompactRIO system.
The CompactRIO FPGA is crucial for data analysis and interconnecting the I/O in the additive manufacturing machine. The overall additive manufacturing process runs at 100 kHz, a 100X improvement over traditional 3D printing machines. This loop speed is hard to keep up with using regular processors. Our own scan head modules rely on another FPGA that processes the laser and scan head signals. Every MCP-based additive manufacturing machine runs at least two processors and two FPGAs, all interconnected in the Materialise Control Platform (MCP).
The modularity and openness of the CompactRIO platform is scalable for our customers. Not everybody needs two or more scan heads or numerous I/O channels. When customers need more than eight modules, they can use an NI-9149 chassis to add another eight more modules in the configuration.
Additionally, the high-end cRIO-903X products include Gigabit Ethernet, IP, and USB camera support, which is an in-demand feature for high-end additive manufacturing machines for machine inspection. Users can monitor and intervene during the build process and reduce the high costs attached to non-destructive, post-build tests.
The additive manufacturing industry is a global industry, so we needed to certify the MCP for sales around the world. Having developed custom C Series modules, we validated and tested these modules ourselves, but saved significant time on all CompactRIO components due to the available global certification standards like CE, FCC, UL, and more.
The good relationship we have with NI and using appropriate communication channels helped us ensure we could solve product development challenges whenever our MCP was on the borderline of the CompactRIO platform’s limits. This helped us get our product to market within the anticipated timeline.
Our platform, powered by LabVIEW and CompactRIO, boasts an unparalleled range of throughput optimizations. Our research department has reviewed all system dead times and overcome many of them:
These examples massively reduce the manual interventions and associated human errors in the 3D printing process, which improves the quality of the end part. The MCP offers a reliable, robust, and economically viable solution for industrial use of 3D printing. In 2018, Materialise will fully concentrate on process control using its own developed scan card combined with readily available I/O feedback in the CompactRIO FPGA.