Knowledge Points Required for High Pressure Cooling System of Deep Hole Drilling

Release time:

2022-04-29

The nozzle parts with a total length of 105mm, a diameter of φ6 0.12mm, a wall thickness of 2mm, a surface roughness of ra3.2μm and a depth-to-diameter ratio of 17:1 are part of the deep hole processing, and their material is gh4169, which is difficult to process.

　　High pressure cooling system for deep hole drillingThe nozzle parts with a total processing length of 105mm, an aperture of φ6 0.12mm, a wall thickness of 2mm, a surface roughness of ra3.2μm, and a depth-to-diameter ratio of 17:1 are part of deep hole processing. The material is gh4169, which is difficult to process. Compared with ordinary steel cutting, the tool life of this high-temperature alloy hole processing is less than 50%, the processing efficiency is low, and the cost is high. The main difficulties in high-temperature alloy hole processing are: large cutting force and large power consumption of machine tools; hole processing is semi-closed cutting, which produces high cutting heat, chips are difficult to discharge in time, far away from the tool tip, tool wear is serious, and it is difficult to ensure the accuracy requirements of ordinary drilling methods for high-temperature alloy holes. In the process of high-temperature alloy hole machining, the tool wear rate is much faster than that of ordinary steel, and the tool material with better cutting performance is needed. In order to solve the above difficulties, when processing such deep holes, appropriate processing equipment and tools must be selected to ensure the processing accuracy of the parts.

2.High pressure cooling system for deep hole drillingprocess design and analysis

Deep hole processing enterprises for parts choose regular drilling methods, which require lengthened twist drills and chip breaking processing. Not only can the processing accuracy be low, the surface roughness is poor, the processing efficiency is low, the labor relationship intensity of operators is high, and the quality problems are difficult to be guaranteed, but also it is easy to cause chip blocking or break the drill bit, resulting in more influential difficulties in the processing process. Therefore, the tool itself selects a special tool for deep hole processing. The selection of equipment takes into account the company's product design types, deep hole processing trade product market structure is very different, and the production batch is small, it is impossible to purchase deep hole processing special machine tools, in order to better ensure that the deep hole accuracy meets the requirements, combined with Chinese factories according to the actual, select some appropriate processing equipment to meet the technical management requirements of deep hole processing.

1. Selection of tools

There are many kinds of deep hole processing knives, such as gun drill, injection drill, sleeve drill, carbide rotary deep hole drill, internal discharge piece deep hole drill, sub-dry deep hole processing system, etc.

Through the comparison of the above-mentioned several deep hole processing tools, combined with the actual situation of our factory, it is decided to use the deep hole drilling high-pressure cooling system for processing. The basic structure is shown by the carbide drill bit, drill pipe and tool shank. In order to enhance the cooling and lubrication of the drill bit and smoothly discharge the chips, an oil hole is provided on the drill tip of the gun drill, and cemented carbide with good toughness and vibration resistance is selected as the substrate. TiC or TiN can be coated on the surface of the drill bit to improve the hardness and wear resistance of the drill bit. The drill pipe is usually made of 40Cr seamless steel pipe. High-pressure oil is injected into the middle hole at the rear of the drill rod, and after reaching the cutting area through the waist-shaped hole, the chips and cutting fluid are forced to be discharged from the space between the V-shaped groove and the wall of the workpiece hole. Deep holes of this type are usually drilled at a rake angle of 0 ° during manufacture. The drilling point of the invention deviates from the axis, forms a small cone in front of the drilling point in the drilling process, so that the chip is divided into two segments at the drilling point, and the chip is easily discharged.

2. Equipment

Drills are used to drill holes in the center of a rotating workpiece. During machining, the workpiece is usually rotated and the drill is fed in a straight line. More suitable for machining centers, lathes and vertical machine tools equipped with high-pressure cooling systems, as well as rotary occasions for tools or workpieces. Taking into account the application of the gun drill and the company's existing equipment, the machining of the part was selected when the milling compound machining center. The equipment can realize the rotation of parts, and is equipped with a high-pressure internal cooling system to meet the application of gun drill. Drilling can be carried out.

3. Gun drill guide hole processing

The gun drill belongs to the unbalanced as well as the drill bit, and the unbalanced groove shape means that the different cutting forces are unbalanced. In order to reduce the radial cutting force due to the joint periphery of the drill bit, it is necessary to rely on the guide sleeve or the guide hole to share. The typical gun drilling machine is equipped with a gun drill guide sleeve, while the development of the turning and milling processing technology center selected in this example is not a special control machine tool for gun drilling, with no personnel equipped with a guide sleeve and no fixture, which cannot meet the design of the guide sleeve. Therefore, the author mainly considers the way of drilling the guide hole to balance the cutting force of the gun drill. By analyzing a large number of relevant experimental data, we can conclude that the depth learning of the gun drill guide hole should be 1~2 times the diameter of the gun drill, and the diameter should be 0.004~0.012mm larger than the diameter of the gun drill bit.

4. Process test and analysis

Deep hole processing process diagram as shown in Figure 3. Use the soft three-jaw to position and clamp the guide hole on the end of the vehicle. When drilling pilot holes, drills from different manufacturers have different cutting parameters; when drilling deep holes, we choose Iska drills, using different processing methods and different cutting parameters.

The above introduction is the deep hole drilling high pressure cooling system must learn knowledge! If you need to know more, you can contact us at any time! Our company has many years of experience and is looking forward to your joining us at any time.