For more than two decades, the German service office Prototypenzentrum GmbH (PTZ) has been manufacturing both plastic and metal prototypes and small batch jobs for a variety of different industries, using CNC milling, molding technologies by injection, molding and additive manufacturing; PTZ offers selective laser fusion, selective laser sintering and stereolithography 3D printing processes, in addition to extrusion 3D printing. Recently, the company struggled to create a solution for a fairly demanding application and turned to metal 3D printing, especially with pure copper, using Markforged’s Metal X platform.
The tool cooler that PTZ was working on, often used in high precision cutters, is intended to engage and then disengage a cutting tool into the shank of an end mill using thermal expansion and contraction. The tool could be reconfigured much faster, the more conductive the tool cooler was, and although it was originally made from machined aluminum, this ultimately wasn’t the best solution. It was easy to make the tool cooler this way, but the cycle times were less than desirable due to poor thermal performance.
The first alternative solution PTZ attempted was to 3D print the AlSi10Mg aluminum alloy tool cooler, using selective laser melting technology. It worked in the sense that the part had complex internal cooling channels which improved its performance, but unfortunately it could not withstand the coolant. In addition, the SLM process used by the service bureau was not easy to implement and its cost was prohibitive.
PTZ then turned to Markforged, through its Birmingham-based partner Mark3D, which distributes the company’s 3D printing systems, software, materials and accessories in the UK. This is how the service bureau discovered Metal X, which was officially unveiled at CES 2017; an updated version, the Metal X Gen 2, was released this summer. Used to print metal parts in several demanding industries, including defense, the Metal X uses bonded metal printing technology and is said to offer a Z layer resolution of 50m to 125m, after sintering.
It looks like Metal X and Markforged’s copper filament were the perfect combination for PTZ to upgrade their tool cooler. Markforged introduced pure 3D printable copper last year, and the material has excellent thermal and electrical conductivity, but is difficult to use with metal laser 3D printers due to its high reflectivity. Most printers capable of handling pure copper are quite expensive, but the Metal X is a cheaper option. Additionally, the design of the room was already quite close to the Metal X’s design space.
PTZ designed the part with compliant cooling channels for efficiency, which really worked and offered 38% faster cooling than previous iterations of the tool cooler. Traditional manufacturing would not have been able to create the part with these cooling channels, and the service desk will also save around 111 hours per year on the tool cooler as the use of 3D printing has done away with the need. ‘around 40 tool changes per day that would occur with two CNC machines. Additionally, with the machine’s average hourly rate, PTZ can save almost $ 7,000 per year in machine time by using the Metal X to 3D print its copper tool cooler. The service bureau plans to continue using Markforged Copper to create electrical engineering parts for automotive devices.
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(Source / Images: Markforged)