Look at this small grit, this tiny grain, so small one must rub hundreds of them between finger and thumb to feel their sharpness. Insignificant little grits and easily slighted in our sophisticated technological world, but without this small fragment of abrasive, transformed, when viewed under a microscope, into jagged heroic blocks — without these […]
Рубрика: Life Cycle and Sustainability of Abrasive Tools
Thermal Conductivity
At room temperature, diamond is the material with the highest known temperature conductivity, which can reach up to 2100 W/(m K) depending on crystal purity [SEN91]. Furthermore, diamond exhibits a low electric conductivity, which can increase significantly with Boron assembled into the diamond crystal structure. In oxygen atmosphere, diamond has a low friction coefficient of […]
Thermal, Electric and Magnetic Properties
2.8.1.5 Effect on Tool Production High sintering temperatures over 1300 °C can occur in manufacturing of vitrified bonded tools. In particular, diamond features low thermal wear resistance in air, which forced manufacturers to develop special low-temperature sintered bonds and to apply inert atmospheres [LINK15]. Electric and magnetic properties are important for electro-plated bonds because they […]
Resin Bonds
3.1.1 Chemistry and Types of Resin Bonds A resin bonded grinding wheel consists of abrasive grits in a resin bond with or without fillers (Fig. 3.2). This wheel type has commonly a low porosity compared to vitrified bonded tools. Resins are viscous liquids capable of hardening. They are polymers, i. e. large molecule chains composed […]
Manufacturing of Metallic Bonds by Sintering
Sintered bonds are produced by mixing of metal powder and abrasive grits, molding, either hot pressing or cold pressing, and sintering (Fig. 3.14). In exceptional cases, the metallic powder is mixed with an organic binder (paraffin oil and/or wax granule). This binder helps to produce a green compact, which can be handled, and vaporizes in […]
Manufacturing
Grinding belts are manufactured as displayed in Fig. 4.5. The manufacturing route starts with the backing material, which can be paper, cloth of natural or synthetic fiber, or metal (in the case of diamond coated abrasive tools) [BORK92, p. 47]. In addition, the backing can be wet-proofed or reinforced with wire. Strength and flexibility are […]
Grinding Wheel Macro-design—Shape, Body, and Qualification
Tools are graded by the manufacturer according to the coarseness or fineness of the particles of the abrasive material they contain, but the working qualities of the tools depend not only on the size of the particles, but also upon the quality of the binder. It thus results that tools which have the same commercial […]
Tool Breakage
A robust, untroubled grinding process needs safety parameters for tool production [KLOM86, p. 11]. Tool breakage might be caused by wrong tool design, manufacturing defects, inapproriate choice, faulty handling or storage, improper use, and clamping, etc. [DIN11]. Several organizations define safety measures for grinding wheel use, such as Berufsgenossenschaft or OSHA (Occupational Safety and Health […]
Adhesion
The direct contact of body and counter body can lead to atomic bonds (“micro weldings”), which are defined as adhesion [GAHR87, RABI95]. A relative movement of the contact partners does not necessarily involve that the bonds break within the original contact areas, so that material transfer can happen [HABI80]. Adhesive layers change the friction conditions. […]
Life Cycle Costing (LCC)
The method of Life Cycle Costing has been developed in the USA for calculation of the economic feasibility and design for projects in industrial plant construction [VDI05]. Life Cycle costs include not only the product’s manufacturing costs, but also usage and disposal costs. The grinding costs per part enclose the machine costs, labor costs, tool […]