The most dramatic differences in performance occur between the grinding behavior of molten and sintered corundum. The introduction of sintered corundum led to tremendous tool life enhancements. The higher wear resistance and larger material removal rates of micro crystalline corundum compared to molten corundum results not only from the higher toughness of the abrasive material […]
Рубрика: Life Cycle and Sustainability of Abrasive Tools
Chemical Processes
The abrasives are processed chemically with acids and water damp to obtain wanted size, shape, and purity. SiC is washed with alkali or acid to remove adhesions of silicon, metals, metal compounds, graphite, dust, and SiO2 [LIET08]. Diamonds undergo an etching process to roughen their surface [MARI04]. Some abrasives like white corundum undergo special treatments […]
Other Analyses
Grit hardness is usually tested by a Knoop micro indenter test [SCHT81, MENA00]. By means of an electrostatic separator, particles with conductive surfaces can be selected. Capillarity is a measure for the wettability of abrasive grits [UAMA09, SCHT81]. Capillarity gives an indication of grit cleanliness and is particularly important for aqueous glues for coated abrasive […]
Manufacturing of Vitrified Bonds
First, the bond components and abrasives are mixed and filled into a mold, either by a casting process in the case of clayey bonds or by a molding process (Fig. 3.11). Pressing compacts the material and produces the so-called “green body” which can be handled. The green body is dried and sintered. After that, the […]
Sustainability Dimensions to the Bonding System
3.6.1 Technological Dimension Bond composition and structure define the self-sharpening ability of the tool and process stability. The main bonding systems for grinding tools are resin, vitrified and metallic bonds (Table 3.2). Each type has a huge variety in its specifications, manufacturing, and ingredients. For polishing and lapping processes also different kinds of slurry or […]
Other Methods with Free Abrasives
4.7.1 Crushing In the materials processing terminology, particle size reduction by mechanical means is called grinding [HOGG01, LYNC05]. Other terms are crushing, milling, or attrition milling. The term crushing is used for bigger end size particles (e. g. about 13-19 mm in diameter); the term milling refers to low micron sizes or below. Machines used […]
Clamping and Balancing
5.2.1 Flanges Cylindrical grinding wheels are often mounted on a hub and clamped between flanges [ROWE09, p. 49]. The adapter flange consists of a fixed flange, a lose flange, and head screws [DIN06]. Standards define the flange design, e. g. BS 4581:1970, and DIN ISO 666 [DIN06]. Some flanges have special features such as a […]
Wheel Deformation Effects
The grinding system consists of several elastic elements in series, such as motors, bearings, feed axis, spindle, grinding wheel, etc. [KING86, p. 171]. The overall stiffness, kt, adds up reciprocally from the stiffness of each element (Eq. 6.14) Depth of cut ae Fig. 6.7 Decrease in cutting edge distance at higher workpiece speed, vw2, after […]
Dressing Speed Ratio
Dressing speed ratio, qd, gives the ratio between dressing roller speed and wheel speed (Eq. 6.28). In up-dressing, the speed vectors are counter-directional in the contact point and the speed ratio is denoted with a negative value; in down-dressing everything is inverted. vR dressing roller speed vs wheel speed Dressing speed defines the engagement curves […]
Functional Requirements of Controlling Workpiece Surface Pattern
The track-bound principle and use of abrasive grits in combination generate grooves and a pattern on the workpiece surface (Fig. 7.21). The pattern can be important for component function, e. g. in sealing systems where directionality of grinding grooves have to be avoided, or in engine cylinders where oil reservoirs are built. To get a […]