Undercutting happens when a blade core wears faster than its diamond coating. As an abrasive slurry accumulates, it erodes the steel disc. Found mostly on diamond blades used in asphalt and/or concrete cutting applications, the industrial-grade gems, tough though they are, are left without anything to hold onto when the metal core is worn away. With this problem focused just below the blade segments, those teeth-like rim sections are in danger of breaking off.
Describing Undercutting Dangers
A road asphalt project is so abrasive that the blade centre is becoming worn. On a similar job, it’s the harsh but wear-resistant edges of a green concrete wall that are scouring the surface of the diamond blade’s core. Either way, the undercutting effect is concentrated just below the blade teeth. Those segments, which are designed to last, could just break away as the core erosion effect accelerates. Worse still, with the steel disc finally penetrating a pavement or road surface, the underlying rocky sub-base will further exacerbate the issue. Even if that coarser layer doesn’t cause further core erosion, it’ll likely trigger a segment break off, which will bring the entire cutting operation to a costly standstill.
Addressing Diamond Disc Undercutting Problems
The issue freely reveals its nature as the work progresses on an abrasive surface. The rim is exposing new diamonds, so the blade is plainly doing its job. With a shift of focus, though, the problem clarifies. Below the rim, an area below the blade segments has thinned to a knife-like edge. If the operator applies just a little more tool pressure, or a coarser concrete edge is encountered, even momentarily, the weakest segment will shear away. An expensive diamond blade, once capable of cutting through the toughest, most abrasive materials known to man, becomes a piece of industrial waste when this rim destroying event occurs. Happily, since this is a known issue, the problem does have a known solution. To prevent core erosion issues, diamond discs come equipped with undercutting protection.
Also known as the “knife-edging” effect, core wear typically occurs below the blade segments, so this is where the undercutting protection is affixed. Granted, some small amount of disc erosion is inevitable, but it can be lessened when this feature is included. Look for steel cored diamond blades that offer this surface protection attribute. It’ll be there either as a recessed core or as a series of fitted inserts. By the way, the recessed form is easy enough to identify; the rim edge is more pronounced while the core surface is sunken. For the insert type solution, look closer at the rim and segments to see the undercutting inserts.
