A new design idea of the lighter clip drill bit

New design idea of machine clamp drill

the design of hole machining tool is a complex process that needs to coordinate many technical problems. SEC friction coefficient（ μ） Goran Melin, drilling product manager of the efficient of frictioncarboloy company (located in Warren, Michigan, USA), said, "it is often a technical problem in one aspect that is solved, which will inevitably lead to new problems on the other." These aspects need to be coordinated, usually including tool life, machining accuracy and stability of the machining process. Tool designers need to constantly find the best solution to these problems

from the design process of the latest perfomax clip on bit series produced by seco carboloy company, we can see that the above understanding is correct. Through the coordination of many technical problems, a new type of machining bit is designed, which greatly expands the processing range

the figure shows the improved drill body and the new machine clamp drill with groove shape

in the design of the new machine clamp drill, there has been such a coordination process: in many choices of tools for hole machining, machine clamp drill is usually a better solution for low-cost machining. According to Mr. Melin, 3. Transmission speed: Shao, the blade of a machine clip drill is generally designed with four cutting edges. It can select blades of different materials and geometric shapes according to different processing materials. Generally, the bit body has the service life of replacing the secondary blade. Therefore, compared with integral and welded bits and cemented carbide bits with replaceable heads, the production cost of each bit is greatly reduced

however, in general, users who drill with machine clip drill want a wide machining tolerance, Mr. Melin said. Because high efficiency bits are usually designed as an asymmetric cutting edge. When the clamp drill uses the structure of two blades, one blade passes through the center of the tool, and the other blade extends from the inside to the entire diameter. Because the cutting speed of the blade at the outer diameter of the tool is high, it can effectively cut off a large margin, while the cutting speed of the blade at the center of the tool is equal to zero and cannot participate in cutting. Therefore, in fact, a very uneven axial cutting force is mainly applied to the drill in the feed direction. As a result, due to insufficient radial cutting force and too large friction resistance, the tool body is bent and deformed

"you can feel instability before the drill enters the whole cutting," Mr. Melin said. "The longer the drill bit is, the more unstable its processing state is." Therefore, when using an extended drill, the user should reduce the feed speed to% of the recommended value in the cutting manual at the beginning of hole processing (about 1mm). When entering all cutting, use the recommended values in the cutting manual. This suggestion is really unreasonable. Because in the programming software, the standard cutting parameters are generally selected, rather than a special feed rate. In addition, the processing program is manually reassembled. In addition, lengthened drill bits are only used in very few cases, so generally only the cutting amount of standard drill bits is selected. However, as a result, the machining accuracy and production efficiency of parts will be reduced

through analysis and comparison, both fried dough twist drill and integral cemented carbide drill have two cutting edges, which can separate chips in a balanced way in processing, promote chip removal and improve the cutting speed of the drill. The machine clamp drill (as mentioned above) is mainly a cutting edge for cutting (including the existence of artificial assembly error factors in the process of mechanical clamping), and only the blade away from the center of the tool can effectively cut many metals. This will limit the effective removal of chips and the improvement of feed speed. However, it will not generate much friction, because it does not have the wide blade band unique to fried dough twist drills. Therefore, it can be processed at high cutting speed (compared with fried dough twist drill). Unfortunately, when using the clip on bit with a length of more than 4 times the diameter, especially when cutting with a large feed rate, the deformation of the bit has become a major technical problem to be solved. For these reasons, machine clip drills are often used, and amplifiers are replaced in semi finishing occasions where the hole is reamed and the dimensional tolerance is required to be 0.008 inch. Therefore, the use of machine clip drill can achieve the economic processing expected by users, but it can not carry out higher precision processing

in order to overcome the above limitations, engineers of seco carboloy company focused on the following five aspects of improvement in the design of a new type of machine clamp bit:

in order to prevent the bending deformation caused by high-speed and high feed speed cutting, the diameter of the drill body should be increased as much as possible to retain more metal materials (for the general structure with too large gap between the outer circle of the original cutter of machine clamp bit and the outer diameter of the bit)

all blades are designed into a rectangular structure with good rigidity, and deep grooves of corresponding sizes are milled on the drill body. Because the blade is designed as a 90 ° fillet, the strength and stiffness are good (for the machine clamp bit, the original blade is mostly triangular, square, not thick structure, and the rigidity under the combined action of mechanical screw clamping and other factors is very poor)

the drill is designed with two coolant inlet holes and two slightly inclined chip removal grooves with sufficient space. So that the cutting area of the drill bit can be cooled sufficiently and chip can be removed effectively, and chip nodules can be reduced, the service life of the drill bit can be extended and the surface roughness of machined parts can be reduced

the surface of the drill bit is designed with a high wear-resistant coating to prevent the debris from sticking to the surface of the cutter body and prolong the service life of the drill bit

the drill bit is designed to be coated with a new coating that can be cut at high cutting speed on a high hardness, fine grain substrate, which can be used to process parts made of various materials

at present, the specifications of the production of new machine clip drill bits are 0 375 inch diameter range, drilling depth times diameter. According to the standard, the drill bit handle produces various specifications, including a universal handle with four planes for lathes, etc. (end)