Хонинговальные головки

The cooling rate of molten corundum largely influences the size of the crystals formed. In the case of the billet method, the corundum billet, weighing up to 20 tons, cools slowly. Cooling times can range from 10 to 14 days. In this way, gen­erally larger crystals are formed than in the so-called tapping method, in […]

The production of vitrified bonds also begins with mixing the components. By covering the grits with a temporary binder (e. g. organic adhesive and water), suf­ficient form stability can be achieved in the blank. The pourable mixture is trans­ferred to the mould and compressed via pressing and shaking methods. In the casting method, the vitrified […]

The strength of steel can also be increased by hardening and subsequent temper­ing. In tempering a material, the martensite formed during hardening is specifi­cally brought again to partial disintegration by re-heating, thereby relaxing the crystal lattice. At low annealing temperatures, carbon precipitates in a finely dis­tributed fashion, while at higher temperatures coarser cementite grains develop […]

The machinability of brittle materials significantly variable in contrast to metallic materials due to the characteristics described above. When machining brittle materials, as opposed to machining ductile materials, we proceed from the assumption that, with increasing penetration depths, material separation becomes dominated by the characteristic behaviour of brittle materials, i. e. microcrack formation and resultant […]

Rotating dressing tools execute an additional rotational movement (Fig. 6-4). If the dressing tool has the negative profile of the grinding wheel, only a radial feed motion is necessary. Dressing rollers that do not engage across the entire wheel width require however a lateral feed. Common rotating diamond tools for dressing grinding wheels are: • […]

6.3.1 Introduction Machining processes of workpieces with grinding wheels is fundamentally distin­guished according to DIN 8589, or ISO/ DP 3002/ V. Subdivision is carried out with serial numbers (ON), which are currently in seven figures and describe each method according to its systematics. Proceeding from the upper division ’’separa­tion” in manufacturing processes, we have the […]

A high degree of hardness and toughness and high amounts of stability and ther­mal conductivity are the primary requirements placed on an abrasive grit. These properties are influenced by chemical composition, crystal structure as well as by the grit size. In table 3-2, the main components of various types of corundum and their most important […]

In order to produce rubber bonds, natural and synthetic rubbers are mixed. To this mixture, sulphur is added as a vulcanisation agent. The sheet is produced by means of a multistage rolling of the abrasive grits. The rolling process is repeated several times, in the course of which the very heavy sheets are tuned by […]

Steel materials are categorised according to their alloying elements, their struc­tural components and their mechanical properties. Such a classification of steel materials is helpful in the selection process with respect to functional properties and in the determination of machining conditions. Classification according to alloy content leads to the following categories: • unalloyed steels, • low-alloyed […]

With respect to their material characterisation, ceramics are subdivided into oxide, non-oxide and silicate ceramics. In the case of oxide ceramics, aluminium oxide and zirconium oxide or zirconia (ZrO2) represent the industrially most importantmaterials. Oxide ceramics have mostly ionic bonds (> 60 %), exhibit favourable sintering properties and are disadvantageous compared to other ceramics with […]