Grinding and Polishing Technology

Diamond Pastes, Fluids, and Emulsions

Special and hardened materials often require a more advanced polishing medium than aluminum oxide or silicon carbide grains. Diamond pastes, diamond gels, and diamond fluids allow for fine processing even up to hard metal. Due to our extensive range of pastes and fluids, we are happy to assist you in selecting the most suitable solution.

A diamond paste, gel, or fluid may contain natural diamond, synthetic diamond, or a combination of both. The choice of composition depends on both the material to be polished and the applied method. The carrier used for the diamond is particularly decisive. Various materials can serve as a carrier for processing or polishing the workpiece. Kurval offers a comprehensive range of products for these applications.

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Polishing Felt and Lapping Tools

 

When working with an abrasive-based medium, it is essential to select the correct carrier so that the abrasive can perform effectively. Each material to be processed requires a specific approach. Felt is an excellent carrier for polishing with diamond. Various densities of felt are available, each providing a different finish. In addition to felt, wood and plastic are also highly suitable for diamond polishing. The required surface roughness determines the final stage of the process. With our LAM PLAN® polishing cloths, we can achieve an absolutely scratch-free high-gloss finish.

If you have a specific application but don't have the right expertise yet, our polishing course is highly recommended.

Polishing and Honing Brushes

Post-processing of round holes to achieve a lower surface roughness inside the hole is often challenging, especially for small diameters. Polishing brushes provide an effective solution and are available in various designs. You can work with metal wire brushes, but nylon brushes filled with an abrasive grain also offer significant possibilities. Polishing with brushes using a polishing medium, such as paste or gel, is also possible.

If the hole needs not only an improved surface finish but must also remain perfectly cylindrical, it is advisable to rework it with a diamond honing needle from Engis®. These honing sleeves—adjustable or fixed—can be used when both the dimension and the surface finish of the hole are critical. The diamond grain can be embedded or added separately. Electroplated diamond honing needles require precise specification of the surface finish to select the correct diamond grain size.

Grinding Stones

Kurval is known for its extensive range of grinding stones. Due to our long-standing collaboration with die and mold makers, and because materials in this field constantly evolve, the demand for new products has steadily increased. While only a few types of steel were used in the past, today there are dozens on the market, each with its own characteristics.

By altering the alloy composition, the machinability of the material also changes. This development has also enabled the achievement of higher hardness levels through heat treatment. Our grinding stone program is therefore extensive, with each stone offering its own specific capabilities.

If you would like more information about the various types of grinding stones, please do not hesitate to contact us.

Rubber-Bonded Abrasives

These abrasives resemble ceramic grinding stones, but the abrasive grains are embedded in rubber. This creates a performance that lies somewhere between grinding and polishing. These products are often used for repair and maintenance of high-quality components, such as aircraft parts and generator components. They also provide a good finish and carry a low risk of surface errors.

Rubber-bonded grinding pins are available in various sizes and shapes. The Cratex® product allows the pin to be shaped as needed: simply dress it to the final form, and it is ready for use. Many manufacturers in the aerospace industry even specify this product.

Cutting Stones

For improving the surface finish of complex shapes, cutting stones are the only suitable option. A wide variety of bonds and grit sizes allows for an appropriate choice depending on the application. The hardness and composition of the material to be worked are decisive factors.

Cutting stones are designed so that the worn abrasive grains break away, making room for fresh grains. The more wear-resistant the chosen abrasive grain, the harder the bond. A softer stone is often used when the shape is complex and the stone must quickly conform to the entire surface. The material hardness determines the steps needed to achieve the desired finish. The added oil ensures proper flow and removal of the broken grains.

Always use dedicated oil for oil stones. Using regular oil will cause the broken grains to stick together, resulting in deep scratches on the surface.

Flexible Cutting Stones

For hard-to-reach areas in shapes and products, flexible cutting stones are available. These consist of a fiber embedded with abrasive grains, allowing the relatively small stone to withstand more pressure without breaking. Flexible cutting stones are suitable for nearly all materials. Color indicates the grit size. These stones are available with thicknesses starting from 0.5 mm.

There is also a round version with a collet of 3 mm or 2.35 mm diameter, enabling rotary use. Flexible cutting stones can be dressed using a diamond file.

Abrasive Tools

Discover our extensive range of abrasives and grinding tools. Whether you are looking for rotary tools on shanks, caps, or sleeves, as sheets, paper, discs, or strips, we always have a suitable solution.

Seamlessly formed and without any transitions, our belts and caps deliver optimal results. They are mounted on elastic rubber holders with the corresponding shank shape, available in diameters of 3 mm or 6 mm. Their specialty: the specially grooved rubber holder secures the belts and caps through the centrifugal force generated during rotation. The holder can be reused, and the belt or cap is simply replaced after use. The sanding belts and caps offer excellent concentricity, are easy to guide, and provide a very fine finish. Particularly suitable for fine and ultra-fine sanding of metals, especially steel. Maximum cutting/sanding speed (Vmax) is 40 m/s.

Unlike sanding sleeves, sanding caps can also be used crosswise. We provide matching rubber holders for every shape. The rotational clamping force ensures that the caps are securely held on the holder with excellent concentricity.

Flap Discs

Explore the wide selection of flap discs with Ø 3 mm and Ø 6 mm shanks, including special models such as radially grooved discs and discs combining abrasive cloth and fleece for an especially uniform finish. Fleece-only discs are excellent for fine polishing. We also supply cleaning flap discs for removing rust, weld spatter, and other contaminants from workpieces.

The fan-shaped design ensures gentle sanding and allows easy shaping to the workpiece. They are versatile, suitable for metalworking and processing, as well as rubber and plastic industries. The radially positioned abrasive fleece flaps make these discs ideal for fine polishing in hard-to-reach areas, providing the best surface quality.

Sanding Discs

Sanding discs must be mounted securely to fully utilize their properties. You can choose from three different mounting types on the holder:

• Self-adhesive sanding discs

• Hook-and-loop (Velcro) sanding discs

• Quick-release sanding discs

Our self-adhesive discs offer the largest range of grit sizes and diameters. As disposable items, they are the most cost-effective solution. In addition to the extensive catalog range, we also provide specialized solutions, such as discs with Soft- or SiC paper. Our hook-and-loop discs can be changed very quickly, and unlike self-adhesive discs, the rubber holders can be reused multiple times.

We also supply silicon carbide sandpaper, backed abrasive cloth, abrasive strips, abrasive fleece on rolls, sheets of abrasive cloth, and sanding belts in various grit sizes.

Abrasives

Kurval offers an extensive range of abrasives for both rotary and linear sanding. The sanding process works with an abrasive grain embedded in the carrier. The grain size directly determines the scratch pattern. We therefore recommend not starting too coarse to avoid extra work if the initial step proves too aggressive. Choosing the correct grit can often be challenging. The material to be sanded determines the selection of the abrasive. Stainless materials often require a different grit than ferrous materials such as iron, steel, or cast iron. For stainless steel, we recommend using silicon carbide or zircon (industrial diamond grit).

Abrasives can also be applied effectively in rotary tools, such as flap discs or abrasive caps. Combining sandpaper with an intermediate layer of abrasive fleece often provides a better finish than sanding alone. This is a good solution for surfaces where visual quality is important.

Sandpaper – whether waterproof or not – varies significantly in quality. This is due to the combination of high-quality grit and proper bonding to the paper backing. When the grit is stressed and breaks out, it can form build-ups and deep scratches, immediately affecting the surface finish. Using higher-quality sandpaper is therefore always worthwhile.

Our abrasives program is so extensive that it cannot be summarized in a few sentences. Please contact us to explore the options.