Stone Tools : low hardness grinding wheel should be high workpiece

Grinding is the grinder as a cutting tool for machining a workpiece with a grinding wheel method . Characteristics of the method are: ( 1 ) Since the abrasive wheel itself has high hardness and heat resistance , and therefore the grinding can be processed high hardness materials such as hardened steel , cemented carbide . ( 2 ) determine the characteristics and grinding wheel grinding system can make even trace cutting , general ap = 0.001 ~ 0.005mm; high grinding speeds , generally up to v = 30 ~ 50m / s; grinder stiffness ; using hydraulic transmission , so grinding can economically obtain high precision (IT6 ~ IT5) and small surface roughness (Ra = 0.8 ~ 0.2μm). Grinding is one of the main methods for finishing parts .
( 3 ) Due to intense friction , leaving abrasive fibre disc  the high grinding zone temperature . This causes stress and deformation of the workpiece , causing the surface burns. Therefore must inject a lot of grinding coolant to reduce the grinding temperature . Coolant can also play chip and lubrication. ( 4 ) a large radial force when grinding . This will cause the machine - elastic workpiece concession system , the actual depth of cut is less than the nominal depth of cut - wheel. Therefore grinding to be accomplished , the light should not enter the knife mill , to eliminate errors. ( 5 ) After the blunt abrasive grinding force also increased , resulting in grains or broken off, exposing sharp edge again , this feature is called " self-sharpening ." Self-sharpening of the grinding time can be within a normal, but over a certain time after the work should be carried out manually trimmed to avoid grinding force increases causing vibration, noise and damage to the workpiece surface . Wheel grinding wheel is a cutting tool , which consists of many small and hard abrasive grains and a binder made ​​of the porous body stick . Directly responsible abrasive cutting work must be sharp and have high hardness, heat resistance and a toughness. Commonly used abrasives are aluminum oxide ( also known as corundum ) and silicon carbide two kinds. Alumina abrasive class high hardness, good toughness, suitable for grinding steel material . Silicon carbide abrasive hardness higher class , more sharp, good thermal conductivity, but more brittle , suitable  metal cutting wheel for grinding cast iron and alloy . Also suitable abrasive grinding wheel , due to its different thickness , surface roughness and the workpiece after the machining efficiency is not the same , for the coarse grinding of coarse grains , fine abrasive grains , the more coarse abrasives , the smaller the grain size number . Binding agents from bonded abrasive effect. The binding agent used is a ceramic , followed by the resin binder. Different materials selected from binders , impact wheel corrosion resistance, strength , heat resistance and toughness . The more firmly bonded abrasive , the more difficult to fall from the wheel , said wheel on the hardness , the hardness of the wheel is the ease of abrasive grinding wheel surface under loads shedding . Off easily called soft , otherwise known as hard . The hardness of the abrasive grinding wheel hardness are two different concepts. Was softer workpiece surface grinding , abrasive edge ( corners ) it is not easy to wear, so that time can be longer abrasive used , that some of the optional bonding firm wheel ( high hardness wheel ) . Conversely , low hardness grinding wheel for high hardness of the workpiece .
Wheel at high speed work , in order  Grinding wheel china to ensure safety, should be checked prior to installation , there should be no cracks and other defects ; To make the wheel steady, balancing test should be carried out before use . After some time working wheel , the surface voids are clogged debris , abrasive acute angle will be blunt , the original geometry is distorted. Must be trimmed and cutting ability to restore the correct geometry. Pen diamond grinding wheel dressing required .