Categories & Applications Of Diamond Tools
There are thousands of kinds of diamond tools. They can be categorized by their manufacturing methods and their uses.
Categories by manufacturing method
According to their manufacturing methods or bond types, diamond tools can be categorized to the following way:
Metal-bonded diamond tools: The tools' bonding material is metal mixture powder. The functional parts of the tool are usually diamond segments. These tools include metal-bonded diamond saw blades, diamond grinding cup wheels, diamond core drill bits, etc. For metal-bonded diamond tools, the bond is one of the prime factors when selecting which tool to use for cutting or grinding a specific material, depending on how hard or abrasive the material is. The bond used dictates the rate at which the metallic powders wear down and expose new diamond crystals at the surface, thereby maintaining an abrasive cutting surface. Different bond strengths are achieved by the alloy mix of metallic powders chosen and how much heat and pressure are applied to the sintered segment.
Resin-bonded diamond tools: The tools' bonding material is mainly resin powder. An example of this tool is the resin-bonded diamond polishing pads used in the construction industry.
Plated diamond tools: This tool is made by fixing the diamonds onto the tool's base via electroplating method or via CVD (Chemical Vapor Deposition) method. This tool can usually be made to good processing precision.
Ceramic-bonded diamond tools: The tools' bonding material is usually glass and ceramic powder. This tool usually has the features of good chemical stability, small elastic deformation, but high brittleness, etc.
Polycrystalline Diamond (PCD): They are normally made by sintering many micro-size single diamond crystals at high temperature and high pressure. PCD has good fracture toughness and good thermal stability, and is used in making geological drill bits.
Polycrystalline Diamond Composite or Compacts (PDC): They are made by combining some layers of polycrystalline diamonds (PCD) with a layer of cemented carbide liner at high temperature and high pressure. PDC has the advantages of diamond’s high wear resistance with carbide’s good toughness.
High-temperature brazed diamond tools: This tool is made by brazing a single layer of diamonds onto the tool via a solder at a temperature of over 900 °C. This tool is a newly developed product. Its manufacture uses technologies include vacuum brazing and atmosphere-protected brazing. This tool has several advantages: the solder can hold the diamonds very firmly, the single layer of diamonds' exposed height can be 70%–80% of their sizes, and the diamonds can be regularly arranged on the tool.
Categories by use
If categorized by use, there are diamond grinding tools, diamond cutting tools (e.g., diamond coated twist drill bits), diamond drilling tools, diamond sawing tools (e.g., diamond saw blades), diamond drawing dies, etc.
Diamond tools are suitable to process the following materials:
Hard or abrasive non-metallic materials, for example, stone, concrete, asphalt, glass, ceramics, gem stone and semiconductor materials.
Non-ferrous metals such as aluminum, copper and their alloys, and some soft but tough materials such as rubber and resin.
As diamonds can react with Fe, Co, Ni, Cr, V under the high temperatures generated in the grinding processes, normally diamond tools are not suitable to process steels, including common steels and various tough alloy steels, while the other superhard tool, cubic boron nitride (CBN) tool, is suitable to process steels. The tools made with common abrasives (e.g. corundum and silicon carbide) can also do the task.
Diamond tools are used in the following domains:
Geological or project exploration: Diamond geological drill bits, diamond oil drill bits and diamond thin-wall drill bits are often used. The main application of PCD drilling bits is in the oil and natural gas industries and the mining industry.
Stone processing: Diamond circular saw blades, diamond gang saws, diamond band saws are used to saw marble, granite and other stone blocks. Diamond wire saws are used in stone quarries to exploit raw stone blocks. Shaped diamond tools are used to process stone to a particular shape. Resin-bonded diamond polishing pads are used to polish stone.
Construction: Medium or small sized diamond saw blades, diamond core drill bits and some diamond grinding or polishing tools are often used in repairing roads, remodeling buildings, and processing building materials.
Woodworking: Composite laminate flooring is widely used. It is wearable as stone. PCD circular saw blades, profiling cutter, twist drill bits and other diamond tools are used in its processing.
Auto spare parts processing: PCD and PCBN cutting tools are used to meet the high efficiency and low deviation processing requirements in this domain.
IT and home appliance products processing: High-precision super-thin diamond cutting wheels are used to cut silicon slices. Resin-bonded diamond grinding wheels are used to process ceramics in optical fiber industry.
Engineering ceramics processing: Engineering ceramics are widely used in many industries. They have the properties of high toughness, high hardness, high-temperature resistance. High-toughness and durable diamond grinding wheels are developed to process them.
Carbide tools and other mechanical tools processing: Diamond tools are used to gain high processing precision and efficiency.
Besides what are listed above, there are also other domains where diamond tools are applied, for example, in medicine, Venezuelan scientist Humberto Fernandez Moran invented the diamond knife for use in delicate surgeries in 1955.
Apart from its use as an abrasive due to its high hardness, diamond is also used to make other products for its many other good properties such as high heat-conductivity, low friction coefficient, high chemical stability, high resistivity and high optical performances. These applications include coatings on bearings and CDs, acting as lens and thermistors, making high-voltage switches and sensors, etc.