AZO, an international company specializing in advanced materials and processes, partnered with French metal 3D printer manufacturer AddUp to develop a fully automated powder handling and feeding system. The result of the project by AZO and AddUp meets the special requirements of the additive manufacturing industry and the use of the different raw materials.
In February 2018, AddUp made the first contact with AZO France. The request was for inert metal powder handling to feed a 3D printer. During a visit to AZO Germany, the technical requirements and possible concepts were discussed. Together with the experts from AddUp, AZO R&D engineers quickly and reliably developed a customer-specific solution. Using a prototype system, the first tests were carried out at the customer’s site in October 2018. The results flowed into further development so that a production-ready powder supply system could be delivered at the beginning of 2019. In the course of further intensive cooperation, the plant modules were continuously and further developed to be adaptable to different printer types supplied by AddUp.
The expectations of the raw material automation and its functions are manifold: on the one hand, the system was to ensure continuous feeding of the printers in order to prevent production downtimes.
On the other hand, the feed of the raw material and the discharge of the excess powder, which is generated during the production of the bulk layer, should be considerably simplified. Furthermore, the system was to process the unprocessed excess metal powder, screen it and feed it back into the production process. In addition, the main focus was also on operator safety.
“For the metal powder handling for feeding our 3D printers, we were looking for a partner with whom we could develop the solution that was optimally tailored to us;” said Ludovic Viossat, Supply Chain Manager, AddUp SAS, France, “AZO, as an expert in raw material automation, supplied us with a system that is perfectly adapted to our printers.“
Modular powder supply
The entire module for supplying the printers can generally be divided into three parts.
The first is material supply and preparation: after delivery from the operator’s raw material store, the metal powder is brought to the supply module in small containers, canisters or cans. Via a hermetically sealed and inert GloveBox, the powder is fed by gentle vacuum conveying to a screening module consisting of an ultrasonic screening machine specially developed for metal powder. The GloveBox ensures the highest protection for the raw material, as well as the operator. The result is that the operator does not come into direct contact with this “nasty stuff”.
After screening, the raw material is again fed to the printing process in the correct quality, quantity and time using a vacuum conveyor. The system can be flexibly designed for the different raw material properties, the number of printers to be supplied and conveying quantities. By using buffer containers, a continuous conveying process for pneumatic feeding of the printer can be ensured for this batch task.
The third area of application for AZO raw material automation is at the printer itself. Here, the raw material is first transferred to the printer module in the required quantity. Excess powder (e.g. overflow material due to stripping of the powder bed) is discharged, collected centrally in a buffer container and pneumatically transported back to the screen module. There, this powder is sieved, processed, and then reintroduced into the production cycle (closed-loop). This consistent raw material utilization and recovery not only increases product quality, but also the cost-effectiveness of your entire production process.
From one to many
A special feature of these modular systems is their scalability: small systems for feeding a single printer can be implemented just as easily as the collective feeding of entire printing factories.
In the case of AddUp, the system was therefore adapted so that the infeed of the raw material was installed decentralized from the printer. The metal powder is then gently fed to the metering unit via a pneumatic conveyor system. This is located directly at the printer and is thus a component of the printing unit. Here too it is possible to supply only a single printer or to feed several at the same time.
But perfect mechanical design is not the end of the story: nothing works without a sensible, state-of-the-art system control. The control system is based on Codesys – Twincat 3 (Beckhoff) with a web-based and user-friendly visualization. The communication to the 3D printer is realized via Ethercat and a defined interface. All connection lines between the individual modules are designed to be pluggable to enable quick and easy commissioning. During operation, it is also possible to control all functions of the AZO powder module remotely from the 3D printer, which significantly simplifies and saves time during maintenance.
The sensors and actuators within the modules are collected or controlled directly in the field via several IP67-rated IO-Link masters. This means that the controller recognizes which modules are available on the system based on its configuration and automatically activates, or deactivates, the available or unavailable functions.
For safety reasons, if a hot-connect module fails, all affected functions are deactivated and a corresponding message is sent to the 3D printer. All other areas continue to run unhindered. This reduces downtime and helps keep production losses to a minimum.