Stone Tools: low hardness grinding wheel should be high hardness workpiece

Grinding is the grinder as a cutting tool for machining a workpiece with a grinding wheel method. The method is characterized by:
(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  quick change disc 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 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.
Grinding wheel
The cutting tool is a grinding wheel, which consists of many small and hard abrasive grains and a binder made of  cutting and grinding disc 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 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 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.
Structure and surface grinder grinding motion
Many different types of grinders, mainly surface grinder, cylindrical grinder, the grinder, universal cylindrical grinding machine (also grind the hole), gear grinding, thread grinding machine, rail grinding, centerless grinder (grinding cylindrical) and tool grinder ( grinding tool) and so on. Here surface grinder and movement.
1 Surface grinding machine structure (with M7120A, for example, where: M - class machine grinder; 71 - horizontal axis moments desktop surface grinder; 20 - Working table width is 200mm; A - the first major improvements (. 1) wheel frame - install wheel and drive wheel for high-speed rotation, wheel frame can slide along the dovetail guide for manual or hydraulic lateral movement gap (2) slide - Install wheel frame and drive along the column wheel frame rails up and down movement.
(3) Column - bearing slide and wheel frame.
(4) Bench - installation piece by reciprocating linear motion of the hydraulic system drive for.
(5) bed - supporting bench, install  portable belt other components. (6) Coolant system - providing coolant (saponification oil) to the grinding zone. (7) hydraulic system - its components are: 1) power components - as pumps, hydraulic system pressure oil supply;
2) implementation of components - as fuel tanks, and other components to drive the table movement; 3) control elements - for a variety of valves, the control pressure, speed, direction, etc.; 4) of the auxiliary element - such as fuel tanks, pressure gauges. Hydraulic and mechanical drive compared with the smooth transmission, can overload protection can be achieved in a larger range of variable speed advantages.
2. Surface grinding motion (1) the main movement - high speed rotary motion wheel. (2) the feed movement
1) vertical feed - table driven reciprocating linear motion of the workpiece; 2) vertical feed - wheel to move the workpiece depth direction; 3) infeed - Wheel gap movement along its axis.