The influence factors of needle-like carbide drill are diverse, mainly from the following:
1.the performance of the body
The body is an important index to measure the performance of bit. The body should have a certain strength, abrasion resistance and impact toughness, strong bonding with acicular alloy. They should have certain adaptability to drill the formation, such as drilling milling resistant rock. We should improve the hardness and wear resistance of the body. On the other hand, the soft body should be adopted to drill the abrasive weak rock. There are many factors influencing the properties of the body, such as composition of tire body of iron, copper, alloy composition, sintering temperature, pressing pressure, etc.
2.the surface of the bit lip
The surface, shape and size of the bit lip has a certain impact on drilling efficiency. The surface of flat lip is easily damaged when drilling resistance is big. The appropriate circular surface is advantageous to the rock fragmentation, and cooling. In the middle of the lip surface, there should be appropriately increasing the number of alloy. When placing inside and outside alloy, there will leave the surface of the lip 1 mm or so, for the ground into a round shape. The area of bit of lip is commonly 30% ~ 60% of the circular area. For the hard rock strata in the complete dense, 30% ~ 40% of the lip area is great. As for the abrasive larger rocks, for improving the bit life, we should take 40% ~ 60% of the lip area.
3. the number and the distribution of the needle alloy on a bit
According to the basic requirement of acicular alloy, each mole should be closed at the bottom of the bore to prevent the occurrence of pulling groove bit lip. Each bit lip surface skinned ring total mole (59 ~ 110 mm diameter bit) is commonly 4 ~ 8. In order to effectively take rock, there should have a certain number of bit lip on the surface of alloy. Alloy cutting area is 12% ~ 22% of the bit lip area. Grinding of rock strata, the upper limit is 18% ~ 22%. Abrasive weak rock, the lower limit is 12% ~ 15%.
4. the reinforcement of the bit diameter
In order to ensure the uniformity of the hole diameter and prevent bit’s scrap, there can add welding between 3 ~ 4 a 5 mm x 5 mm x 10 mm carbide piece of reinforcement in a bit. At the meantime, it also be used in processing the mole, in uniform laying on the side of the inside and outside the tungsten carbide particles (particle size of 0.8 ~ 1.5 mm). The wonderful wear resistance is good to keep the aperture uniform and improve drilling efficiency.
