GF Machining Solutions machining graphite with the GR3 technology
Machining, GF Machining Solutions

GF Machining Solutions develops GR3 technology for machining graphite

GF Machining Solutions, Fraisa and Blaser Swisslube have joined forces to develop a technology for wet machining graphite. The so-called GR3 technology makes it possible to machine other materials besides graphite on the same machine and even in the same setup.

Graphite machining is still quite a challenge for tool- and die-makers. Dry machining creates a lot of dust that can find a way out of the machine even when the machine is closed. Many graphite machining companies, therefore, complain about dirty workplaces. To prevent dust formation, you can choose for wet machining. The problem with this is that the machine is almost impossible to clean. As soon as the liquid with graphite particles dries up, a hard black layer forms in the machine that is almost impossible to remove. Due to contamination issues, this often makes it impossible to process other materials besides graphite on the same machine. Moreover, graphite particles can get between the moving parts of the machine, such as the guides. The result is wear on essential components and thus a lot of machine maintenance. The GR3 technology from GF Machining Solutions, Fraisa and Blaser Swisslube should reportedly solve the problem of graphite machining.

Cooling lubricant encapsulates graphite dust

GR3 is the answer of GF Machining Solutions, Fraisa and Blaser Swisslube to wet machining graphite as well as other materials in one machine. "It is a perfect interplay between machine, metalworking fluid, filtration and tooling," says Tobias Roder, head of global product management at Blaser Swisslube. The partners tested the technology extensively in Blaser Swisslube's technology centre and in the machining laboratories of Fraisa and GF Machining Solutions. At all three locations, a real-life part was simulated during testing. In addition to different tool coatings, numerous cooling lubricants were compared. For GR3 technology, the partners settled on Blaser's Blasogrind GTC 7 cooling lubricant. The cooling lubricant optimally encapsulates graphite dust and thus prevents dust from being released into the working environment, resulting in healthier working conditions. Moreover, it ensures a much cleaner machine and optimally protects against tool wear.

Save on tools

During machining, an oil film reduces the degree of contact between the graphite and the tool surface, extending tool life. "Normally, graphite is machined with tools that have a wear-resistant diamond coating. With Blaser's cooling lubricant, we can increase tool life by up to 5 times. And what is even more interesting is that the oil film ensures a smooth cut, allowing us to use standard PVD-coated tools as well. Of course, the tool life of these tools is shorter than that of diamond-coated tools, but they are much cheaper," says Jonas Meier, head of the centre of competence at GF Machining Solutions.

GF Machining Solutions - GR3 Mikron MILL S 600 U
GF Machining Solutions is using a Mill S 600 U for graphite machining at its Technology Centre in Biel.

Optimal surface quality

The smooth cut obtained thanks to the oil film also has a positive effect on the quality of the workpiece surface. "The oil film reduces the degree of contact between the graphite and the tool surface, which further extends tool life. This technology offers outstanding benefits in the form of better component quality, less rejection and significantly lower production costs," says Dirk Kammermeier, head of product development at tool manufacturer Fraisa. Under a microscope, it can be seen that far fewer grains are broken out in wet machining than in dry machining.

Due to the smooth workpiece surface, the graphite cannot absorb oil, according to GF Machining Solutions. Meier: "We did an awful lot of tests to investigate what effect the cooling lubricant has on the graphite. After all, you don't want the emulsion to be absorbed by the graphite and later adversely affect, for example, the EDM process where the graphite electrodes are used for. We did tests where we allowed a graphite electrode covered with oil to dry for 24 hours. We then investigated whether this oil soaked into the material. The result was negligible at 0.2% and the sparking process was similar to an electrode that had been machined with a dry process."

GF Machining Solutions - GR3 workpieces
An example of a part made of copper and a part made of graphite, both machined on the same machine thanks to the GR3 technology.

Filtration by centrifuge

Besides the machine, tool and cooling lubricant, another important aspect that makes the wet machining of graphite possible: The filtration of the cooling lubricant. The partners use three systems to filter the dust and chips. Small amounts of chips and dust can be filtered out of the emulsion by a standard chip removal system combined with a belt filter. When the volume of chips becomes larger, a Knoll centrifuge is used to separate the particles from the liquid. After filtering, the liquid is returned to the machine using a pump. For even higher chip volumes, the partners choose a Ruma centrifuge, and when the chips are larger than 10 mm, a chip conveyor is also connected to this. This keeps the cooling lubricant clean and allows it to be used for a long time and in great shape for machining different materials.

Machine more materials with one machine

With GR3 technology, the partners have not only solved the problem of dust formation, but have also made it possible for a single machine to be used to machine different materials, such as graphite, copper and steel. All these materials can be machined in the same production system, without any manual intervention and using the same settings and tools. Expensive operations with multiple machines are no longer necessary for machining different electrode materials. All in all, GR3 technology helps die- and mould makers eliminate costly multi-machine operations, achieve better quality, provide a healthier working environment and optimise cycle times. According to GF Machining Solutions, by implementing GR3 technology, savings of as much as 25 euros per spindle hour are possible, making the ROI very interesting.

GF Machining Solutions - GR3 machining
Thanks to GR3 technology, both graphite and other materials can be machined on one machine. This keeps the machine multi functional. (pictures: Tim Wentink)