Selection of the optimal abrasive tool for an application depends on the type of bond utilized.

Darmann offers a variety of specialized bonds that have been created to address specific grinding and/or superfinishing requirements. These bonds are characterized as resin, sintered metal or vitrified bonds.

Vitrified Bonds

Unlike resin and sintered metal bonds which have a dense structure, vitrified bonds have a more open structure. The structure of vitrified bond products can be modified by controlling the porosity and hardness of the product. Vitrified bonds are well suited to automated grinding processes that require high material removal rates, low wear rates and easier dressing. The free cutting and self-sharpening nature of these products makes them ideal for superfinishing applications. Darmann has developed a number of bonds specifically designed for fine grit conventional and superabrasive products.

Resin Bonds

These organic bonds are made of phenolic or polyimide materials. Resin bonds are softer than sintered metal bond or vitrified bonds on the hardness scale. These bonds produce a fast, cool grinding action that generates low grinding forces. Resin bonds are used in applications that range from those that require a strong, resilient bond to fine finish operations. Our resin bonds are used in products such as finishing stones for thru-feed superfinishing processes, jointer stones and diamond continuous rim grinding wheels for the medical industry.

Sintered Metal Bonds

Sintered metal bonds are comprised of various metals such as bronze, tin, and silver that are combined to form a hard, dense metal alloy that firmly holds abrasive grits in place. This results in longer stone or wheel life and a slower grinding action well suited to honing processes. These bonds are more wear-resistant than either resin or vitrified bonds. Darmann uses customized metal bonds in conjunction with CBN and diamond abrasives for use in honing stones. These stones are used to finish transmission parts, honing of cylinder liners and long-tube honing.