When talking about LMF it’s interesting to understand in deep the process and start from the beginning. From the raw powders that, layer by layer, will become the tangible metal item that just a few hours before was only a .stl project.
Luckily we got the pleasure to meet Andrea Trentin, Division Technical Specialist of Legor Group Brazing Division, who has been willing to share with us some of his priceless knowledge and great experience on this matter.
Legor Group is today the point of reference in the goldsmith, silversmith and the fashion markets when it comes to cutting edge production processes: manufacturing, processing and finishing of precious and non-precious metals. The dedicated offer for these sectors is clear when considering the company’s divisions:
- Master Alloy Division: production of master alloys (Legor Group’s core business)
- Machinery and Tools Division: sale of machinery, consumer products and tools.
- Plating Division: solutions and galvanic plants.
- Brazing Division: production of welding products.
- Dental Division: a full range of precious and non-precious alloys, as well as products for processing and CAD-CAM tools for the laboratory.
Andrea, what’s your role within Legor Group?
My role in the company includes the setting up and development of new formulations of powders, monitoring and standardization of production processes in accordance with our quality system as well as planning and definition of R&D and service related to the Powmet product line. Marketing activities and both commercial and technical assistance are completing the role.
Where is Legor Group in today’s Additive Manufacturing landscape?
The attitude toward constant innovation, the deep knowledge of the topic and the high standards of production owned by Legor Group were the cornerstones that led to the development of a product line dedicated to Additive Manufacturing applications. Legor Group has developed a range of precious and non-precious metal powders, called Powmet, specifically intended for the Laser Metal Fusion technology.
Internal production plants, an avant-garde laboratory and a business management system strongly oriented to quality, allow high production standards and a continuous monitoring of the production. The ability to test Powmet products directly through the AM machines installed at our facility in Bressanvido (Italy) is an indisputable advantage; it allows us to test directly the products and obtain objective data on the final characteristics of the items produced, beside a quick technical feedback useful for effective and efficient design and product development.
Since AM machines are available for prototyping needs (service center), we have the opportunity to check with a direct feedback the real needs of the industry and maintain a strong contact with our clients, which can lead to the development of new powder products.
What are the needs of this technology, how did they influence Legor Group and how are they pushing toward the future?
As with many industrial applications, every stage of the production should be monitored and evaluated carefully. In the specific case of prototyping through the Laser Metal Fusion technology particular care should be taken on the characteristics of the powders to be used as feedstock. It is essential indeed to use metal powders that achieve the correct morphology and granulometry, as well as with a suitable chemical composition able to optimize the response to the laser beam, thus guaranteeing an adequate final quality.
A thorough study of the design of the item and the correct choice of process parameters allow to fully exploit the benefits that this kind of technology can provide; I think for example at the production of unique pieces, with empty or very complex structures, difficult to achieve with traditional casting techniques.
In recent years Legor Group has invested heavily, both with regard to the implementation of production plants suitable for the production of the powders and in terms of equipment and laboratory tests for their characterization. The investment was of course also directed to the implementation of management processes, the creation of a technical know-how, the recruitment of new staff and marketing activities related to this new product line.
The business development, which involved Legor Group within the Laser Metal Fusion technology, places for sure the company as a major world player in the production of precious and non-precious powders for Additive Manufacturing.
How does the selection of the powders interact with the design phase and eventually with the actual production through the Laser Metal Fusion machine?
The powder choice, such as 18K gold instead of a silver alloy 925, is exclusively led by production requirements of the customer or, more in general, by the market.
We must pay particular attention in the preparation of the composition of the powders to ensure adequate morphology, particles size and other physical characteristics. The development phase of a new product involves various industrial aspects such as chemical and physical optimization of the powder, the optimization of the production process and finally the optimization of the machine parameters for the Laser Metal Fusion production. The constant technical comparison between production departments, the Laser Metal Fusion testing department and our R&D laboratory is therefore essential to be able to iterate the development process and ensure the achievement of powders with suitable technological features.