Development Of Surface Set CBN Drilling Bit And Experimental Study Of Rock Drilling Load Characteristics

The goal of Chinese third edition Lunar Exploration Project aims at getting lunar soil sample from 2 meters beneath the moon surface. Because there are many different types of lunar rocks in the lunar soil,the drilling mechanism on the spacecraft may have the chance to have a contact with the rock, when that happens,the load and the temperature will rise quickly. so the rock-penetration ability of the drilling bit is of great importance. Harbin Institute of Technology has designed a screw type drilling bit which is used only for drilling soil, it has many advantages than other drilling bit when drilling and coring for lunar soil, but lacks the ability to penetrate lunar rocks. Electroplate CBN on the drilling bit proves to be an effective way to make the screw type bit have ability to break rock, and keeps its original advantage.Study the character of rock and know how it breaks, learn the process of a single CBN cut and break the rock, build the mechanical model of the single CBN with rock. Use FEM Software to simulate the process that the single CBN break the rock and learn how the cutting force changes during the process.Use appropriate way to have CBN cast in the surface of screw type drilling bit,to make it as an surface set CBN drilling bit. Analyze the form how CBN particles distribute on the bit surface. Calculate the contact area of the surface set CBN drilling bit with the rock and the break volumes made by the drilling bit. Deduce the rock drilling ability of the surface set CBN drilling bit; analyze the process that rock debris remove from the spiral wing of the bit. Analyze the factors that result in abrasion of the drilling bit.Design a test bed to test drilling bit’s performance when drilling rocks, Use the surface set CBN drilling bit to drilling rocks for testing, study how the pressure and torque of the bit changes when CBN particle size and other parameters of the bit and drilling process changes. Analyze the test results and get the interaction theory between the bit and rock, which provide technical support for the design of lunar drilling bit. the experiment result proves that the surface set CBN drilling bit have a good ability to break rock.