Hurdle Cleared! Oerlikon Balzers Extends Saw Blade Service Life with a Diamond Coating

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SIMTOS (Seoul International Machine Tool Show)

Diamond coatings offer the best wear protection for machining processes. However, there have been limitations to their use until now. Now, those limitations have been significantly expanded ...

In the machining of non-ferrous materials, diamond coatings often provide the highest level of wear protection for tools. However, their use on saws with solid carbide saw blades (VHM saw blades for short) has not always been economically or technologically feasible. A new generation of nanocrystalline diamond coatings from Oerlikon Balzers is now breaking down these barriers. In collaboration with sawing technology expert Ott + Heugel, it has been demonstrated that circular saw blades coated with the Baldia Varia system last seven to eight times longer when machining gold and brass alloys—while process costs have also decreased significantly, according to the report.

Testing a Blank "Sheet" on the Saw

One of Ott + Heugel’s customers is a jewelry and watch manufacturer. The company cuts round bars and square stock made of yellow, white, and rose gold, as well as brass, using solid-carbide saws from Ott + Heugel. However, as is well known, these non-ferrous metals are ductile and relatively soft. During machining, this leads to lubrication and sticking effects that quickly cause built-up edges on the saw blade. One consequence is unwanted burr formation on the workpiece, which complicates its further processing. To take corrective action in a timely manner, the user therefore regularly monitors the machine’s current consumption as an indicator of increased cutting force and the onset of saw blade wear. A trial switch from uncoated to AlTiN-coated solid carbide saw blades did, at least, double the service life. But then they turned to Baldia Varia. “From a sawing technology perspective, this coating was still, so to speak, uncharted territory for us. But we decided, together with the customer, to start trials anyway,” recalls Fabian Heugel, the head of Ott + Heugel. That decision paid off in full.

User Saves 800 Meters of Precious Metals

After ten weeks of use, there was still no sign of wear. But the tool’s service life was seven to eight times longer—depending on the material being machined. The tool, with a diameter of 63 millimeters (2.48 inches) and a special tooth geometry, is used in 3-shift operation on the same machine type every time. Thanks to the improved performance, the saw blade thickness could be reduced from 0.7 to 0.5 millimeters (0.0276 to 0.0197 inches). This narrower cutting width now results in significantly less material loss. The very satisfied user, who is currently planning to use five of these tools, saves approximately 800 meters (2,625 feet) of valuable precious and non-ferrous metals annually as a result. There are also fewer tool changes, setup times, machine downtimes, and power consumption checks. Although tool reconditioning is no longer possible, the advantage in tool life more than compensates for this drawback.