The DTU Open AM PBF repo for everything related to machine building (CAD, schematics, BOM, etc.). Everything is a work in progress and will be published as soon as sufficiently detailed documentation is produced. Some changes were made to the system, resulting in versions 1 and 2. Version 2 will be the actual release.
Project Impetus: The world of Laser Powder-bed Fusion (L-PBF) has been tightly held within the clutches of proprietary practices, limiting innovation and knowledge sharing. This project was born out of a desire to challenge this exclusivity by creating an open-source infrastructure for L-PBF. The aim was to democratize access to this advanced manufacturing process, stimulate innovation, and foster cross-disciplinary collaboration. Despite the complex and professional nature of L-PBF, which involves dealing with high-power lasers, explosive metal powders, and specialized equipment, the project's commitment to open-source principles remained unwavering.
Project Results: The project successfully designed, built, verified and validated an open-source metal L-PBF system. The resulting machine is user-friendly, fully open, and performs comparably with commercial L-PBF systems. The entire design and detailed documentation are published under the CERN-OHL-P (permissive) v2 Open Source Hardware license and are accessible for public adaptation and improvement. The project contributes to a broader understanding and accessibility of additive manufacturing technology, paving the way for future enhancements and a community-driven approach to innovation.
Find out more and contribute to the evolution of this revolutionary project on GitHub. Join us in advancing the field of additive manufacturing! Feel free to contact me or the team (see the bottom of the readme) if you have questions or want to adopt the system - or parts of it.
Thorough consideration is needed before working with metal L-PBF, whether you buy or build. This system is an experimental setup meant for R&D, and a certified official has not approved its safety aspects. Proceed with caution at your own risk.
Safety Sub-System: The safety sub-system controls the activation of motors and lasers, ensuring they operate only under safe conditions. This includes emergency stops (E-stops) that physically break the connection using a safety contactor, disabling the laser trigger signal, and the motor drivers.
Interlock Switches: Interlock switches on the enclosure doors ensure the system is fully sealed before the laser can be activated. The laser can only fire when the doors are closed, no E-stops are pressed, the Reset E-stop button is triggered, and the Activate laser button is enabled.
Safety Programmable Logic Controller (PLC): The system employs an ABB Pluto D20 safety PLC as its "brain." This, along with Adam and Eva units from the EDEN series from ABB to monitor the doors and a Smile 41 button interface for emergency stop and reset controls, constitutes the core of the safety system.
European Union Directives: In the EU, the Machinery Directive 2006/42/EC is relevant for ensuring safety in machinery like the L-PBF system. It provides the regulatory basis for the harmonization of the essential health and safety requirements for machinery at the EU level.
OSHA Directives: In the United States, the Occupational Safety and Health Administration (OSHA) has regulations that would apply to the operation of a laser-based system. This includes standards for personal protective equipment (29 CFR 1910.132), general requirements for all machines (29 CFR 1910.212), and specific regulations for welding, cutting, and brazing (29 CFR 1910.252).
The open-source Laser Powder Bed Fusion system incorporates a comprehensive safety subsystem, including emergency stops, interlock switches, and a safety PLC to ensure safe operation. Compliance with relevant EU directives and OSHA regulations is crucial for the lawful and safe operation of such advanced manufacturing systems.
The open-source Laser Powder Bed Fusion (L-PBF) project embodies core Systems Engineering principles to enhance its design and functionality, significantly benefiting the research and manufacturing communities. By employing a structured approach, the project manages complexities and fosters adaptability, which is crucial for evolving user requirements and technology.
Systems Engineering Principles: Iterative Design Process: Adhering to an iterative design process, the project transitions from general concepts to detailed designs, ensuring a comprehensive development lifecycle. It employs the Vee model, which guides concept exploration, requirements definition, and system validation, ensuring a robust and reliable open-source system.
Modularity and Open Control: The project employs modularity, where system elements perform specific functions. This approach enhances adaptability, allowing easy upgrades, maintenance, and repairs. It also integrates black-box components with robust control protocols, reducing complexity and ensuring system flexibility.
This provided a structured framework for the project's lifecycle, guiding it from concept exploration through to system validation.
This tool was used for decomposing complexity, combining classes of information, and creating diagrams for specific use cases. It helped in visualizing and managing the project's development.
This facilitated the analysis of internal interfaces and provoked a reevaluation of the internal formal structure of the system. It was instrumental in designing a system with modularity and open architecture.
Instead of using Systems Modeling Language (SysML), which was considered, a relational database method was employed to manage information about every facet of every element in the system. Airtable was used, which will also be shared. This will function as the Bill of Materials.
These tools collectively supported the project's goals of creating an adaptable, robust, and user-friendly open-source system while managing the complexities inherent in such an ambitious project.
The repo deals with the physical aspects, whereas the controller repo and the post-processer repo deal with the digital aspects. The controller is very much still under development, and a major redesign is underway. However, with certain limitations, the controller is very capable.
The majority of the readme to follow considers the physical aspects of the system.
The system can be seen below. It features a 250mm x 150mm build volume, a 300W 1080nm laser, and a multi-material powder system. It is self-contained and has a closed-loop gas flow cross flow. The system uses a standard windows laptop running custom and standard software.
The system uses standard operating principles as employed by many other systems.
The formal structure of the system is divided as below:
The main architecture is seen below:
Each sub-system has its own folder with a .zip containing .step-files and technical drawings in .pdf. The technical drawings will be a mix of drawings for manufacture and assembly instructions.
The full original Solidworks assembly will also be present.
The Electrical folder will contain information regarding the electrical side of things.
The folder called Bill of Materials combine all the information, including supplier information and datasheets (if available). Link to the airtable document is in the BOM readme.
The digital side of the system is under rapid development. The current controller is capable of printing within certain limitations.
The controller repo will contain PCB design and firmware.
See the Netfabb repo for information regarding the Netfabb post processor etc. This is the recommended approach currently.
/Magnus Bolt, mbokj@dtu.dk