IGUANA – Diamond Tool for Copper Electrode Machining

By Niraj M Wanikar, Chief Editor, CNCTimes.com, 2018-11-16 11:05:00

Figure 1: IGUANA ball nose end mill, end mill with corner radius, and micro end mill with laser-processed, sharp cutting edge 

Laser-processed diamond coating

1 μm sharpness

The trend towards copper electrode – developments, improvements, and innovations ensure continuous process changes in the production of electrodes.  In recent years the trend in the field of die-sinking EDM is in the direction of copper. Miniaturization of components and lightweight construction are leading to increasingly filigreed geometries, for which the advantages of copper outweigh graphite. In comparison to graphite, in the manufacture of electrodes not only is tool wear greatly reduced with copper, but also the surface quality and dimensional accuracy are significantly improved. 

Figure 2: The sharp and defined cutting edge with a sealed diamond coating of the new IGUANA high-end milling cutters

IGUANA – diamond-coated, laser-processed tools

No coating errors                                             Sharp cutting edge, 1 μm

320X enlargement                                           Carbide base carrier

Sharp cutting edge                                          Diamond coating 

With the IGUANA line of diamond-coated high-end milling cutters, ZECHA Hartmetall-Werkzeugfabrikation GmbH is setting a new standard for micro-precision tools for copper machining.  IGUANA ball nose end mill, end mill with corner radius, and micro end mill are multi-cutters in the small bore sector from 0.4 mm to 3 mm and ideally suited for the machining of non-ferrous metals such as copper or high-strength copper alloys (e.g. CuBe). With the help of laser processing, sharp cutting edges like those that are already achievable with soldered CVD tools can be transferred to multi-fluted CVD-coated solid carbide tools – without affecting the hardness and strength of the diamond coating. A special benefit of this is the cutting edge radii of 1 µm that can be produced with a sealed diamond coating, which could be achieved previously only with radii above 5 µm.

Especially when machining small copper electrodes with complex free-form surfaces, it is challenging to ensure geometrical and dimensional accuracy. Any deviation is transmitted 1 to 1 to the form during die sinking and thus directly to the end product.
In the automotive industry and in medical technology, tolerances of 0.02 mm are the standard in series production. In order to guarantee the required tolerances in the end product, these must be considered and, at the same time, maintained during the preceding processes. In the case of a plastic injection-molded part with a tolerance of 20 µm, the tolerance for the electrode production decreases over the course of the process chain to only 5 µm.

In tests of copper electrode machining with the IGUANA end mills, the surface quality was improved by more than 50% - with an average roughness of Ra= 0.035 µm and peak-to-valley roughness of Rz= 0.2 µm. The filigree webs demonstrated no feathering or chatter marks due to tool wear. Even the finest structures at the end of the webs could be produced again with process reliability. Also, the cutting efficiency of the tool is unequaled in the industry – where previously a lateral infeed of 5 µm – due to tool deflection caused by wear on the tool – was necessary, with IGUANA the target contour was achieved directly. With an optimum process design, process reliability can be accomplished thanks to a tool service life, depending on the component material, of up to several hundred hours. 

The high-end tool alone, however, is not a guarantee of optimum results. The determining factor is rather the interaction of tool, machine, and application. In addition to the continued basic abilities such as carbide selection, grinding of pre-stages, and subsequent CVD coating, laser technology opens further options along the path towards the perfect tool. The IGUANA line of end mills, which can demonstrate a sealed diamond coating despite sharpened cutting edge, offers enormous potential for optimizing processes and eliminating inefficient post-processing operations, as well as increasing overall profitability thanks to longer service lives and therefore fewer tool changes.

Visit us at the IMTEX 2019, from January 24 – 30, 2019, in Bangalore, India, at our booth in Hall 2B D101 and learn about the innovations with the IGUANA line of high-end milling cutters.

We look forward to seeing you! 

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