Preparation And Properties Of Resin Bonded Brazed Coated Diamond Wheels

Resin-bonded diamond grinding wheels are widely used in the precision machining of hard and brittle materials.In order to improve the binding strength between diamond and resin binders,in previous studies electroplating,electroless plating,vacuum evaporation plating were used to coat diamonds.In this paper,a braze coating method for the fine diamond grits was proposed,and resin-bonded grinding wheels based on different types of diamonds were prepared,and the grinding performance were investigated.First,the effects of temperature,weight rate,and separant on the properties of brazedcoated diamonds were studied.Secondly,grinding wheels were prepared the grinding wheels with different types of resin-bonded and the properties of different grinding wheels were investigated.Finally,the resin-bonded brazed coated diamond grinding wheels were used to grind the cemented carbide,and the grinding force,grinding ratio and wear the mechanism of the brazed coated diamond resin-bonded grinding wheel were investigated.The following results were obtained:The introduction of MgO separant can decrease the occurrence of diamond grit clumping and flow of brazing alloy.The wettability of brazed coated layer on the diamond surface is increased with the increasing of brazed brazing temperature in the range of 900°C-960°C.The impact toughness of the diamond decrease with increasing of weight rate.The flexural strength of coated and uncoated resin bonded wheels with different crystalline diamonds own little difference.In the diamond wheel contains single crystal,the flexural strength increase,while it decrease in the diamond wheel contains Polycrystalline grit.The polycrystalline diamond resin bond grinding wheel owns the highest flexural strength of 79.48 Mpa,followed by the single crystal RVD,and the worst one is RVD/MBD4+,which is 71.17 Mpa.There is little different on the hardness of the grinding wheel,and the effect of the crystal type on the hardness is also not obvious.Comparing the grinding force of different grinding wheels,it is found that the grinding force increases after braze coating of single crystal diamond RVD wheel,and it change little for coated polycrystalline diamond PDGF1 wheel.It found that the polycrystalline diamond wheels has the highest grinding ratio.The grinding ratio of single crystal diamond MBD4+ wheel is increased by 22% after braze coating,while the grinding ratio coated RVD wheel is decreased by 31%.The surface roughness of cemented carbide increased slightly after grinding by the coated diamond grinding wheel.The major grinding process that different barzed coated wheels is plastic ploughing.The diamond pulling off on the wheel has a percentage of 35% ~42%.The percentage of pulling off is decreased for coated diamond wheel.There are three kinds of wear forms of the polycrystalline diamond resin grinding wheel,which are macrocrack,pulling off and abrasive wear,while the main forms of single crystal diamond resin grinding wheel is abrasive wear and pulling off of diamond grits.