The twist drill with 4 belts excels in the machining of steel and cast iron materials because of its very fault-tolerant nature and the ability to drill at high feed rates that are approximately double that of single-slot drills. This type of drill is also the tool of choice for drilling deep holes up to 30 times the depth of the hole, and its drilling speed is about 5 times that of conventional gun drills. Previous Next 3 Way Ball Valve,Sanitary Clamp Ball Valve,Three Way Ball Valves,Stainless Steel Tri Clamp Ball Valve WENZHOU FOREVER CLASSIC TECHNOLOGY CO.,LTD , https://www.fosicvalve.com
For the machining of aluminum alloy materials, straight groove drills are used for optimum drilling accuracy and complex stepped holes can be machined in a relatively simple manner. The disadvantage of straight groove drills is the high precision required for tool clamping. These drills lack fault tolerance for radial runout, excessive cutting speed and feed rate or lower coolant pressure.
A very serious problem in drilling (especially deep hole drilling) is that if the drill bit deviates from the center line of the hole at the beginning (running deviation), then it is almost impossible to correct the deviation in the subsequent processing. The pilot bit is drilled down the eccentric position up to the bottom of the hole. However, since the drill bit has a helix angle, the drilled hole will also be spiral. In order to avoid this problem, the most important thing is to have a correct drill tip with good self-centering ability. In addition, improving the guiding properties of the drill bit also helps prevent deviation. The drill bit with 2 belts can only get 25% support at the beginning of drilling, so even with a small force, it is easy to move away from the center in most directions. The drill bit with 4 belts can be supported in all directions, so that holes with better roundness and cylindricity can be machined. 4-blade drills also provide better support in non-uniform or through-hole drilling, which is common in machining such as hydraulic parts.
In today's drilling operations, the chip removal must be fully controlled, rather than as in the past, as long as the operator feels that the drilling force is increased, the drill can be used at any time. A critical issue is that from the beginning of the formation of the chip at the drill tip, it is necessary to achieve chipping and chip breaking in a way that makes it easy to match the chip and the chip flute, and to make the chip with less friction. Smoothly drain the hole.
The kinematics of the drilling process actually contributes to the control of the chip. Since the cutting speed at the center of the drill tip is zero, the chip will flow more or less around the chisel edge and will be completely formed in the chip flute. As long as the flutes have the correct geometry, it is easy to generate chips of the same size. In addition, the flutes are tapered to the ends of the flutes and the surface of the trough is polished to help form a free chip flow for drilling under controlled conditions.
Using the right drill bit and reasonable drilling process parameters can increase production efficiency and reduce processing costs. But how should we look at tool costs? First, these advanced drill geometries are more difficult to manufacture than traditional drill geometries, so the new drills are generally more expensive than conventional drills. However, this new type of drill can be reground 4 to 5 times. Although the tool life will be reduced by about 10% after each regrind, it is still possible to save more than 50% of the tool cost.
However, the reduction in bit life caused by each regrind may also cause some problems. In order to ensure safe machining, only drills with a high safety factor can be used for machining, so the user must use a monitoring and tracking system to replace the reground bits in time. The only way to solve this problem is to use a "disposable" product, but using a disposable solid carbide drill is often uneconomical.