The complex tool design with multiple cutting edges and the complex chip formation mechanisms complicate the analysis of the grinding process [KLOM86]. Figure 7.7 shows all input and output streams that can be considered in grinding and provides a basis for a life cycle inventory. The items have different relevance for different applications. The tooling […]
Рубрика: Life Cycle and Sustainability of Abrasive Tools
Embodied Energy in Grinding Tools
Mixing, pressing and finishing energy are negligible in comparison to the raw processing and sintering energies. All relevant energies for both grinding wheels are summed up in Fig. 8.4. The corundum wheel has only around 36 % of the embodied energy of a CBN grinding wheel of similar dimensions (Fig. 8.4). Then main energy proportion, […]
Thermal Conductivity, Electric and Magnetic Properties
Corundum has the comparatively lowest thermal conductivity of the common abrasives with X = 6 W/m °C for brown corundum [KLOC09, p. 27]. This leads to a comparatively higher heat flux into the workpiece compared to heat flux into the grit material during grinding [BRIN82, p. 128]. 2.1.2 Manufacture of Corundum by Electrofusing Molten corundum, […]
Cubic Boron Nitride
2.4.1 Chemistry, Types and Characteristics of CBN The invention of the superabrasive cubic boron nitride (CBN) is linked closely to the synthesis of artificial diamond. CBN has the same crystal structure as diamond (cubic zinc blende structure), but the carbon atoms are replaced by the elements boron and nitrogen (Fig. 2.19 left). Boron nitride (BN) […]
Grit Shape Selection and Analysis
2.9.2.1 Picture Analysis Picture analysis is based on a two-dimensional projection of the grit, e. g. via back light microscopy or film scanners, or on a picture, e. g. by transmitted lightmicroscopy or scanning electron microscopy. Picture analysis has some restrictions. The equipment defines the minimum grit size that is measurable. In addition, the grit […]
Curing
The hardening process has to follow a defined temperature program (examples given in Fig. 3.8). Several chemical processes happen during curing depending on the actual temperature [COLL88, GARZ00, p. 331]: • 70-80 °C: The resin bond starts to flow and to transform into a fused mass. Water in the phenol resin evaporates and the resin […]
Manufacturing of Dressing Rollers
Diamond dressing rollers are important electroplated tools. They are used for profiling and sharpening of grinding tools (Sect. 6.5 “Tool Conditioning”). Diamond dressing rollers are either produced with a direct method or a reverse method [MINK99, YEGE86, KLOC09, p. 140]. In the direct method, the diamond grits are fixed stochastically on a profiled body. Therefore, […]
Binding Materials for Pastes
Binders for pastes include the following [MARI04, p. 442 f., BORK92, p. 24]: • Stearin—stearic acid, CH3(CH2)16COOH, white, solid, crystalline substance, melting point of 140 °C; Stearin is a good binder and brings cohesion and hardness to the paste. • Oleic acid—olein, unsaturated fatty acid, melting point of 15 °C; Oleic acid accelerates the polishing […]
Resin Bodies with Metallic Fillers and Non-metallic Fillers
Bakelite/aluminum or Bakelite/graphite bodies are elastic and tend to dampen vibrations from the grinding system [METZ86, p. 63, SEXT82]. This body type is connected to the abrasive layer by direct pressing without glueing [METZ86, p. 63]. Bakelite graphite or glass fiber reinforced resins can be pre-pressed to blanks and have the advantages of being light […]
Porosity
Pores are necessary for the transport of cooling lubricant to and chips away from the cutting point. They become more critical for high material removal rates and high-speed grinding processes to get enough cooling lubricant into the grindinggap. Grinding wheels with discontinuous cutting faces have similar effects as highly porous wheels [BORK92, p. 36]. Porosity […]