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A diamond grinding cup wheel is a metal-bonded diamond tool with diamond segments welded or cold-pressed on a steel (or other metal, such as aluminum) wheel body, which usually looks like a cup. Diamond grinding cup wheels are usually mounted on concrete grinders to grind abrasive building materials like concrete, granite and marble.
There are various styles and specifications of diamond grinding cup wheels to fit various application requirements. The ones with many big diamond segments can undertake heavy workloads, for example, grinding concrete and stone, while those with small or sparse diamond segments are normally used for fast removal of paints, wallpapers, glues, epoxy and other surface coatings.
Just like other metal-bonded diamond tools, the diamond segments on diamond grinding cup wheels can have different bonds, different diamond grits, different diamond quality and different diamond concentrations to fit different uses. For example, if the material to be ground is hard, the bond should be softer, and if the material is relatively soft, the bond should be harder.
Diamond grinding cup wheels are used in different-roughness grindings. For coarse grinding, the bond should be softer and the diamonds' quality should be higher, because in this case the diamonds become blunt more easily. The diamond grit should be bigger, normally from 35 grit to 50 grit. For this is coarse grinding and big grit can improve working efficiency. The diamond concentration can be lower.
For fine grinding (sometimes called "polishing"), the bond should be harder and the diamonds' quality can be lower, as in this case the diamonds can last longer and a hard bond can also help the precision of the process. The diamond grit is normally between 80 grit and 120 grit, depending on the grinding requirements. The diamond concentration should be higher.
After being ground, the material can be further polished with resin-bonded diamond polishing pads of different diamond grits.
There are two common methods to manufacture diamond grinding cup wheels: hot pressing and cold pressing.
The hot pressing method is to directly sinter the diamond segments in molds under a certain pressure in the dedicated sintering press machine, and then fix or connect the diamond segments onto the grinding wheel’s body via high-frequency welding, laser welding or mechanical mosaic method.
The cold pressing method is to first press the working layer (containing diamonds) and the transitive layer (not containing diamonds) of the diamond segments to their forms directly on the grinding wheel's body, and let the segments connect with the wheel's body via teeth, slots or other manners. Then, put the grinding wheels into sintering furnaces to sinter without press.
Sintering or frittage is the process of compacting and forming a solid mass of material by heat or pressure without melting it to the point of liquefaction.
An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away by friction. While finishing a material often means polishing it to gain a smooth, reflective surface, the process can also involve roughening as in satin, matte or beaded finishes. In short, the ceramics which are used to cut, grind and polish other softer materials are known as abrasives.
Sandpaper and glasspaper are names used for a type of coated abrasive that consists of sheets of paper or cloth with abrasive material glued to one face.
Powder metallurgy (PM) is a term covering a wide range of ways in which materials or components are made from metal powders. PM processes can avoid, or greatly reduce, the need to use metal removal processes, thereby drastically reducing yield losses in manufacture and often resulting in lower costs.
A gemcutter is a person who cuts, shapes, and polishes natural and synthetic gemstones. In historical use it usually refers to an artist who made hardstone carvings or engraved gems, a branch of miniature sculpture or ornament in gemstone.
A grinding wheel is a wheel composed of an abrasive compound and used for various grinding and abrasive machining operations. Such wheels are used in grinding machines.
A grinding dresser or wheel dresser is a tool to dress the surface of a grinding wheel. Grinding dressers are used to return a wheel to its original round shape, to expose fresh grains for renewed cutting action, or to make a different profile on the wheel's edge.
A concrete saw is a power tool used for cutting concrete, masonry, brick, asphalt, tile, and other solid materials. There are many types ranging from small hand-held saws, chop-saw models, and big walk-behind saws or other styles, and it may be powered by gasoline, hydraulic or pneumatic pressure, or an electric motor. The saw blades used on concrete saws are often diamond saw blades to cut concrete, asphalt, stone, etc. Abrasive cut-off wheels can also be used on cut-off saws to cut stone and steel. The significant friction generated in cutting hard substances like concrete usually requires the blades to be cooled to prolong their life and reduce dust.
Sharpening stones, water stones or whetstones are used to sharpen the edges of steel tools and implements through grinding and honing.
Knife making is the process of manufacturing a knife by any one or a combination of processes: stock removal, forging to shape, welded lamination or investment cast. Typical metals used come from the carbon steel, tool, or stainless steel families. Primitive knives have been made from bronze, copper, brass, iron, obsidian, and flint.
Knife sharpening is the process of making a knife or similar tool sharp by grinding against a hard, rough surface, typically a stone, or a flexible surface with hard particles, such as sandpaper. Additionally, a leather razor strop, or strop, is often used to straighten and polish an edge.
Polishing and buffing are finishing processes for smoothing a workpiece's surface using an abrasive and a work wheel or a leather strop. Technically polishing refers to processes that use an abrasive that is glued to the work wheel, while buffing uses a loose abrasive applied to the work wheel. Polishing is a more aggressive process while buffing is less harsh, which leads to a smoother, brighter finish. A common misconception is that a polished surface has a mirror bright finish, however most mirror bright finishes are actually buffed.
A diamond tool is a cutting tool with diamond grains fixed on the functional parts of the tool via a bonding material or another method. As diamond is a superhard material, diamond tools have many advantages as compared with tools made with common abrasives such as corundum and silicon carbide.
A diamond blade is a saw blade which has diamonds fixed on its edge for cutting hard or abrasive materials. There are many types of diamond blade, and they have many uses, including cutting stone, concrete, asphalt, bricks, coal balls, glass, and ceramics in the construction industry; cutting semiconductor materials in the IT industry; and cutting gemstones, including diamonds, in the gem industry.
Grinding is an abrasive machining process that uses a grinding wheel as the cutting tool.
A concrete grinder can come in many configurations, the most common being a hand-held angle grinder, but it may be a specialized tool for countertops or worktops. There are also purpose-built floor grinders that are used for grinding and polishing marble, granite and concrete. Machines that grind concrete floors are usually made to handle much more stress and will have more power to drive the unit as concrete has a much higher sliding friction than marble or granite which is also worked wet, therefore with less friction. In fact some types of marble will spark when it is ground dry, causing deep damage to the marble surface.
Polished concrete is a multi-step process where a concrete floor is mechanically ground, honed and polished with bonded abrasives in order to cut a concrete floor's surface. It is then refined with each cut in order to achieve a specified level of appearance.
Flat honing is a metalworking grinding process used to provide high quality flat surfaces. It combines the speed of grinding or honing with the precision of lapping. It has also been known under the terms high speed lapping and high precision grinding.
Diamond segment are the function parts of a metal-bonded diamond tool. The metal-bonded diamond tool can be a metal-bonded diamond blade, a diamond grinding cup wheel, a diamond core drill bit, a diamond gang saw blade, etc. The diamonds of a metal-bonded diamond tool are all in the tool's diamond segments to play their role of cutting or grinding.
A disc cutter is a specialised, often hand-held, power tool used for cutting hard materials, ceramic tile, metal, concrete, and stone for example. This tool is very similar to an angle grinder, chop saw, or even a die grinder, with main difference being cutting disc itself,. This tool is highly efficient at cutting very hard materials especially when compared to hand tools.