Design Of Resin-bonded Diamond Tools

Resin bond diamond grinding wheel is widely used for precision machining of difficult-to-machine materials due to its good self-sharpness, flexible carcass and easy trimming.

Resin bonded diamond tools are designed based on the following five aspects:
(1) Bonding must be good. Binder can evenly distribute on the abrasive surface, hold the abrasive firmly in the abrasive tool and firmly bond to the substrate, which not only prevents the abrasive from falling off prematurely, but also prevents the separation of the binder and the matrix, thus ensuring the production safety.
(2) High grinding efficiency, good wear resistance and good machining finish (or surface roughness). Resin binder has good self-sharpening, no blockage and poor wear resistance in grinding due to its elasticity and brittleness. Therefore, in the research and design of binder formulation, we must consider both high grinding efficiency and as high wear resistance as possible under the premise of ensuring the requirement of finish. The formulation of binder is very critical. To select the optimum proportion of binder, both higher grinding efficiency and better wear resistance must be satisfied. Only when both are considered, can the requirements of grinding process be guaranteed and the cost reduction be achieved.
(3) Heat resistance is better. If the heat resistance of the binder is poor, the abrasive tool will not withstand high temperature and consume quickly in the process of use. Even because the grinding heat is too high, the abrasive tool will be burned, cracked, looped and so on. Therefore,
A. Select binders with good heat resistance and add appropriate fillers to improve their heat resistance;
B Wet grinding with coolant whenever possible to improve the durability of the grinding tool;
C If dry grinding is used, make feed as small as possible to improve the durability of the grinding tool.
(4) The strength of the binder must be high. The strength of the binder has a direct impact on the grinding efficiency, the size of abrasion, the quality of the workpiece and the safety performance of the abrasive tool in use. Therefore, the factors influencing the strength of the binder must be known.
The main factors influencing the strength of the binder are:
The addition of a filler will increase or decrease the strength of the binder. Most fillers will increase the mechanical strength and increase with the increase of the amount added to a certain range, but the wear ratio will decrease. Some fillers, such as graphite and solid molybdenum disulfide, will reduce the strength when added. Therefore, fillers should be selected reasonably according to requirements.
B The forming density (or porosity) of the abrasive affects the strength of the bond. If the forming density of the abrasive tool is low and the porosity is high, the bonding strength is low and vice versa. Therefore, the parameter of grinding tool porosity should be designed reasonably.
The hardening temperature and the secondary hardening temperature of C abrasive tool as well as the temperature rise curve will affect the strength of the binder.
(5) The hardness of the binder must be suitable and the wear resistance should be good. The strength of the binder must match the wear rate of the diamond (or cBN) abrasive. The binder should not wear too fast to cause the abrasive to fall off too early. In that case, the abrasive will not be fully used and will be wasted.