The dynamical cutting edge number results from the process kinematics and can be obtained with a thermo-element inside the machined workpiece. Each impulse during grinding should indicate a grit-workpiece contact [PEKL57, DAUD60]. The smaller the contact area of the thermo-element is, the more reliably the temperature peaks can be related to grits. Luminescence offers another […]
Рубрика: Life Cycle and Sustainability of Abrasive Tools
Dressing of Superabrasive Tools
The high wear resistance of superabrasive grits provides challenges to dressing procedures. CBN grinding wheels are commonly dressed with rotating diamond tools because of the lower toughness and hardness of CBN compared to diamond [MARI07]. However, the dressing forces for CBN are higher than for conventional wheels, which needs to be considered for the dressing […]
Reducing Heat by Convection and Conduction
Heat removal includes all aspects of cooling and lubrication and has been researched a lot [HEIN09b]. The basic principles for heat removal are heat convection Fig. 7.26 Few interactions per time and short interaction time (diagram follows Fig. 7.23) and heat conduction (Figs. 7.23, 7.27 and 7.28). It is commonly assumed, that all process energy […]
Internally Cooled or Lubricated Wheels
The pores of vitrified grinding wheels may be filled with lubricants such as sulfur, wax, or resin after sintering [MARI07, p. 113, KING86, p. 79]. Sulphur is in use as high-temperature extreme pressure lubricant in internal grinding operations in the bearing industry; yet, the use is declining because of environmental considerations [MARI07, p. 113]. Other […]
Manufacture of Silicon Carbide
Silicon carbide (SiC) cannot be found in nature in sufficient quality for technical applications [TYRO03b]. For the use as abrasive, SiC is molten from quartz sand in resistance furnaces by a process that was invented by Edward Goodrich Acheson in 1891 on an industrial scale [MOSE80, p. 119]. Originally, Acheson had intended to synthesize diamond. […]
Grit Protection During Tool Manufacturing
Coatings on diamond grits enable the tool manufacturer to choose an inexpensive bond material with iron, which otherwise would shorten the diamond life time [KOMP05]. In addition, elevated tool manufacturing temperatures can be applied [KOMP05]. 2.7.1.3 Grit Alignment During Tool Manufacturing Grits for coated tools are coated to enhance their electrostatic properties. A grinding belt […]
Economic Dimension
The fusion of corundum began at the Niagara Falls using cheap hydro-electric power. Today China has huge capacities for producing fused corundum, and Eastern Europe, India, South Korea, and South America are growing manufacturers in the world production of fused corundum [JACK11, p. 27]. Low cost energy has become an important factor for the competitiveness […]
Frits
Frit is a generic term for a material that is generated by blending minerals, oxides, and other inorganic compounds, heating to at least melting temperature, cooling, and pulverizing [HAY90]. An example frit production process is given as follows: Melting of the ingredients above 1150 °C, holding at the temperature for 4 h, cooling down in […]
Special Grinding Wheel Types
4.1.2.1 Centerless Grinding Wheels Centerless grinding is commonly applied for large batch and mass production. In this circumferential grinding variant, the workpiece is not fixed along its axis between centers, but is supported on its circumference. Centerless grinding can be external or internal. In external grinding, the workpiece lies between grinding wheel, workrest plate and […]
Disposal
The European Waste Catalogue (EWC) [or Verordnung ueber das Europaeische Abfallverzeichnis (AVV)] classifies used honing and grinding tools with the code 12 01 21 or 12 01 20, if they contain hazardous materials [BGBI01]. The main category 12 includes waste of material removal processes and physical and chemical surface alteration. The waste generator has to […]