GRAPHITE

Graphite has become particularly important as a raw material for the manufacture of electrodes. Graphite electrodes have become indispensable in tool and mold making. Graphite is also used successfully in mechanical and plant engineering as well as in medical technology and hydrogen technology.

Mill graphite as best as possible

Especially for processing graphite materials and green ceramics Hufschmied developed the Graphite Line GRAFTOR® tools. The patented cutting edge geometry of these tools allows you to produce graphite electrodes with significantly fewer tools and in half the time. In addition, the Graftor® tools are from Hufschmied up to three times as long as the commercially available standard geometries.

The full potential of this high-performance tool is revealed when the available cutting length is fully utilized. This generates material removal rates that are more than doubled compared to other double-edged tools currently available on the market. You get the finished electrode in half the processing time. In addition, the gradations from roughing to pre-finishing to finishing the electrode can be selected much more coarsely, which means that a few passes can be saved. For example, a typical sequence is to first use a 12mm cutter for roughing, then a 6mm cutter for semi-finishing, and finally a 2mm tool for finishing. With the GRAFTOR® tools it is possible to go directly from the 12 mm to the 2 mm diameter, or the complete processing is carried out with the 2 mm tool.

Even filigree geometries can be manufactured with very high feed rates, as almost no cutting pressure is built up when switching between roughing and finishing cutting. Conversely, this means that high PINS or narrow bridges can be produced without special programming techniques and with normal work feeds. In addition, the electrodes are significantly more dimensionally accurate and precise than with other tool types.

In addition, from 2021 there will be the newly developed Graftor mini tools, which transfer the Graftor tool concept described above to the MICRO range from a diameter of 0,5 mm. Thanks to the nanocrystalline diamond layers DIP® and DIP®3S developed in our research for the highest surface quality, graphite or ceramic dust adhesions to the surface structure of the diamond layer are a thing of the past. Due to the nanocrystalline layer structure, a significantly higher diamond content of more than 95% is integrated in the diamond layer. As a result, significantly longer service lives can be achieved with thinner layers and very fine structures can also be machined more easily and WITHOUT feed adjustment, since less cutting pressure is built up due to the significantly lower rounding of the cutting edges.

The Graftor® tools are, like all HIGH Performance tools from Hufschmied, labeled gauge block for tool and mold making. Gauge block labeling means that each tool is labeled with its effective diameter and effective radius on the head measured on the envelope. With gauge block marking, the high accuracy requirements for automated production systems that produce in 24/7 operation can be easily satisfied. The measuring accuracies and tolerances that are used for the respective tools of the Grafit-Line, as well as the GRAFTOR®, can be found on the corresponding shop page with the quality line descriptions.

For highly efficient machining of graphite Hufschmied developed a time-saving concept with two variants.

Time saving concept 1

The Graftor® is used in Time Saving Concept 1 – a tool that can be used both as a roughing tool and as a finishing tool at the same time. Thanks to the Graftor® geometry, the processing time for a graphite electrode can be reduced by up to 50 percent.

In addition, a large number of different tools can be replaced by a single tool. This saves magazine spaces in the machine. Since fewer different tool dimensions have to be taken into account when manufacturing the electrode, the programming effort is also significantly reduced, usually in a ratio of 3 to 1.

Graftor® tools can also be used with all types of graphite available on the market, from the finest-grain graphites with an average grain size of 0,5 µm to finishing and roughing graphites between 3 and 8 µm, as well as with grobGranular graphite types over 10µm can be used. The same applies to slate or mica graphite, where the alternating cutting geometry produces cutting edges much better than tools that only work in one preferred direction.

Time saving concept 2

For older machines or for applications that require the highest surface quality, including reflective graphite surfaces, for example for glass molds, there is the Time Saving Concept 2, in which two different tools are used for roughing and finishing: a graphite roughing cutter with WD 107GR-WD toothing and the 63CWI and 63CWIR Piranha three-flute finishing cutters for the highest surface finishes.

In the Time Saving Concept 2, up to 30 percent of the processing time can be saved. This is due to the significantly increased possible infeeds of the graphite roughing cutters and the higher feed speeds of the Piranha finishing cutters.

107GR- Graphite Roughing End Mill

The service life of these tools for graphite processing is also significantly increased compared to other providers thanks to our patented DIP® diamond coating. Thanks to the special WD gearing with double side relief grinding, very high infeed depths can be achieved. The rasp action atomizes the discharged material into particles that are as fine and small as possible so that, on the one hand, the suction of these particles can be carried out as quickly and easily as possible and, on the other hand, the danger of this grobe Particles are thrown onto already finished graphite electrode geometric elements is avoided.

Here, too, the nanocrystalline diamond layers DIP® and DIP®3S developed in our research stand for the highest surface qualities. Due to the nanocrystalline layer structure, a significantly higher diamond content of more than 95% is integrated in the diamond layer. As a result, significantly longer service lives can be achieved with thinner layers and very fine structures can also be machined more easily and WITHOUT feed adjustment, since less cutting pressure is built up due to the significantly lower rounding of the cutting edges.

For extreme surface quality, we also have the option of applying the DIP®-NANO2 coating to the Piranha finishing tools. Their surface roughness is well below 0,02 µm and is therefore particularly suitable for applications where transparent component surfaces have to be achieved, such as glass molds.

Piranha Finishing Cutter : 63CWI/63CWIR

Thanks to their uneven pitch, these piranha finishing cutters have significantly reduced vibration. As a result, the surface quality is significantly improved and high pins and narrow webs are not excited to vibrate during processing and are therefore not torn off by these resonance vibrations.

Graphite mini milling tools HM915 / HM905

For small and fine geometries Hufschmied Mini milling tools from a cutting diameter of 0,2 mm in various overhang lengths. We offer these tools ex stock in many different gradations of the working depth L3 from 3xD1 to 30xD1. You have all possible 3- and 5-axis applications under control without any problems, even with the finest microstructures.

Here, too, the DIP® nanocrystalline diamond coating helps, due to its low surface roughness and the small cutting edge radius, that these tools are downright OUTPERFORMER in terms of processing speed and at the same time in terms of service life compared to other MINI milling tools available on the market. Just like the Piranha finishing cutters, the MIN milling tools of the Grafit-Line are also manufactured on high-precision grinding machines and 100% finally measured on Zoller measuring machines in order to guarantee the highest level of accuracy in the finishing operations. Highest efficiency with the lowest production costs per component in the production of graphite electrodes is called Grafit-Line from Hufschmied.