Guidelines

 

Granite vs. Marble

 

If you're not familiar with how to care for these stone surfaces, you might be inclined to think that they need to be cared for in the same way. However that's a misconception because granite and marble are very different in their geology. So it would benefit you as a cleaning business owner to know some of the differences between granite and marble.

Granite:

  • Granite is an igneous rock, which is a much harder stone. Therefore it may need harder abrasives for refinishing.
  • To identify granite, do a scratch test. Take a knife blade, and try scratching the surface (in an inconspicuous place). If it's hard to scratch, then it's likely to be granite (or some type of igneous rock). If you are able to scratch the stone it is either marble or limestone.
  • Granite generally doesn't react with acids (with the exception of Hydrofluoric Acid - HF).

Marble:

  • Marble is a much softer stone than granite.
  • Marble is a metamorphic rock containing calcium carbonate, which reacts to acids. With this information, you now know that acidic cleaners will damage most marble surfaces.
  • Marble is also sensitive to acidic foods like lemon and vinegar, so it's not always a good choice for kitchen countertops.
  • You can usually identify marble because of its distinct swirls or veins.

Before caring for stone surfaces, make sure you know what type of stone you're dealing with. Once you know that, you'll be able to choose the right cleaner for the job.

Diamond Tools


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 corundumand silicon carbide.

 
Advantages
Diamond is the hardest material on the earth, and its hardness is much higher than corundum and silicon carbide. Diamond also has high strength, good wear resistance and low friction coefficient. So when used as an abrasive, it has many obvious advantages over the common abrasives.
  • High grinding efficiency, Low grinding force: Less heat will be generated in the grinding process. This can decrease or avoid burns and cracks on the surface of the workpiece, and decrease the equipment's wear and energy consumption.
  • High wear resistance: Diamond grinding tools' change in dimension is small. This can lead to good grinding quality and high grinding precision.
  • Long lifespan, Long dressing period: This can greatly increase the work efficiency, and improve the workers' labor environment and decrease the product's labor intensity.
  • Low comprehensive cost: The processing cost of each workpiece is lower.
Categories
There are thousands 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.
 
Applications
Diamond tools are suitable to process the following materials:
  • Carbide alloy
  • 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.
 
 
PCD Tools
Polycrystalline diamond (PCD) is formed in a large High Temperature-High Pressure (HT-HP) press, as either a diamond wafer on a backing of carbide, or forming a "vein" of diamond within a carbide wafer or rod.

Most wafers are polished to a mirror finish, then cut with an electrical discharge machining (EDM) tool into smaller, workable segments that are then brazed onto the sawblade, reamer, drill, or other tool. Often they are EDM machined and/or ground an additional time to expose the vein of diamond along the cutting edge. These tools are mostly used for the machining of nonmetallic and nonferrous materials.

The grinding operation is combined with EDM for several reasons. For example, according to Modern Machine Shop,[citation needed] the combination allows a higher material removal rate and is therefore more cost effective. Also, the EDM process slightly affects the surface finish. Grinding is used on the affected area to provide a finer final surface. The Beijing Institute of Electro-Machining[citation needed] attributes a finer shaping and surface geometry to the combination of the two processes into one.

The process itself is accomplished by combining the two elements from each individual process into one grinding wheel. The diamond graphite wheel accomplishes the task of grinding, while the graphite ring around the existing wheel serves as the EDM portion. However, since diamond is not a conductive material, the bonding in the PCD work piece must be ample enough to provide the conductivity necessary for the EDG process to work.

Polycrystalline diamond tools are used extensively in automotive and aerospace industries. They are ideal for speed machining (9000 surface feet per minute or higher) in tough and abrasive aluminum alloys, and high-abrasion processes such as carbon-fiber drilling and ceramics. The diamond cutting edges make them last for extended periods before replacement is needed. High volume processes, tight tolerances, and highly abrasive processes are ideal for diamond tooling.