A first step towards 3D metal printing
Trivium Packaging in Deventer is a producer of metal beverage and food packaging and is part of a global group. They first came across 3D metal printing five years ago. “We saw the potential of the new technology and wanted to get on the train and not wait for years first,” says Paul Klopper, Technical Specialist Tooling & Maintenance. In the project, led by Windesheim University of Applied Sciences, the packaging specialist gained a lot of experience with the technology. And they are enthusiastic! “We have a lot of old machines of which some casting parts are no longer available. Or they are pricey. By 3D printing these ourselves, we are not only cheaper, but also greatly shorten the lead time.”
THE STEP TO 3D METAL PRINTING WITH LION LASERS’ LASER TECHNIQUES
3D printing provides a lead time of one to two weeks and already makes the process considerably shorter than the 12 weeks for milled tools. Considerably shorter, but in particular the post-processing of the tools still takes a lot of extra time. The surface roughness of the tools as they come out of the printer is absolutely inadequate. However, reducing a Ra value of 12 microns to Ra 0.8 is labour-intensive. Through Windesheim University of Applied Sciences, it therefore contacted Lion Lasers, which develops industrial laser systems in the Netherlands.
The challenge for Lion Lasers
This often involves laser systems that need to add a certain structure to the surface, explains Edwin Kroon, laser expert at Lion Lasers. The question Trivium Packaging initially put to him was what laser polishing does to the hardness and other properties of the metal tools. After several tests with different parameters, he was able to improve the surface roughness to Ra 2 microns, while the hardness is only marginally higher. “And we can go down even further in terms of roughness,” he says.
3D printing with a fibre laser
Edwin Kroon used a pulsed fibre laser with a wavelength of 1064 nanometres with a power of 60W for the experiment. It runs the laser beam across the surface at a speed of between 1,000 and 4,000 mm per second, first from left to right and then again crosswise. Because he can accurately direct the laser beam, he can precisely melt the peaks that you see when you look at the surface under an electron microscope and solidify them again so that the valleys are filled in. In this way, surface roughness improves significantly. At the same time, the hardness hardly changes because it does not put more energy into the workpiece than is strictly necessary. “The hardness went from 50 HV to 51, not much, it certainly doesn’t get brittle,” says Edwin Kroon. This brings the hardness of the materials, both 316L and tool steel, close to the original hardened tools. “Ook de maatvoering is ongewijzigd”, voegt Paul Klopper er nog aan toe. Thus, the laser does not adversely affect the material.
The final result
Lion Lasers manages to use laser light to improve the surface roughness of 3D printed metal parts to Ra values of 2 to 3 microns in ten minutes. For Trivium Packaging in Deventer, this marks an important step towards using 3D metal printing to produce tools s
The future for laser polishing
Paul Klopper hopes that laser polishing will soon be further developed. Indeed, Trivium Packaging wants to increase 3D printing. Since the beginning of this year, the company has freed up one FTE for all 3D printing work. Deventer now also prints for other branches across Europe. “In addition, we carry the knowledge further in the company.” The four Dutch production sites already use the printing capabilities the company has in Deventer. Paul Klopper does not doubt for a moment the effectiveness of the technology. “If you look at the cost of the components and the shorter lead time, the investment in this one FTE pays for itself within a year.”
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