A core-removing tool for deep-hole drilling of hard and brittle materials

Abstract

The present invention belongs to the technical field of automated processing, and particularly relates to a core-removing tool for deep-hole drilling of hard and brittle materials. It includes: a core-removing rod body; the core-removing rod body is a slender hollow cylinder; one end of the core-removing rod body is an interference-breaking core structure, and the interference-breaking core structure is a hollow cylinder with an outer diameter larger than that of the core-removing rod body; one end of the core-removing rod body with the interference-breaking core structure is also provided with a guiding structure, and the guiding structure is to cut one end of the core-removing rod body with the interference-breaking core structure into a wedge shape; an elastic avoidance hole is provided in the middle of the core-removing rod body, and the elastic avoidance hole penetrates through the inner and outer surfaces of the core-removing rod body along the radial direction; the elastic avoidance hole area is covered with an elastic membrane; the core is clamped by the pressing force generated by the deformation of the elastic membrane so as to take out the core.

Description

Technical Field

[0001] The invention belongs to the technical field of automated processing, and in particular relates to a core removal tool for deep hole drilling of hard and brittle materials. Background Art

[0002] In the CNC milling of hard and brittle deep holes, in order to avoid excessive cutting resistance at the tool linear speed 0 point, round tube diamond tools are used for drilling. After deep hole processing, a thin and long core will remain. Therefore, the residual core must be removed before subsequent processing, otherwise it will interfere with subsequent processing.

[0003] Especially in deep hole processing of hard and brittle materials, the residual core is generally a solid cantilever structure with a diameter of ≤1mm and a length of ≥40mm.

[0004] At present, the general method of removing the core at home and abroad is that a person holds a trimmed wooden stick and carefully inserts it into the gap between the core and the hole wall in a direction parallel to the core of the material, and gently moves the wooden stick when it is close to the bottom of the hole to break the glass core. Then, the hand applies a certain lateral force to the wooden stick and pulls the wooden stick at the same time, so that the wooden stick presses against the glass core and scratches it along the hole wall.

[0005] Since the core material is thin, brittle and easy to break, it is usually removed by manually inserting a trimmed wooden stick during machine shutdown, which easily produces residual cores and leads to quality problems in later processing. At the same time, manual intervention during shutdown in automated production leads to low efficiency, and a large amount of high-alkaline coolant mist diffused inside the machine tool during shutdown to remove the core can cause harm to the processor's body. This has seriously troubled production for many years. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a core removal tool for deep hole drilling of hard and brittle materials.

[0007] A coring tool for deep hole drilling of hard and brittle materials, comprising: a coring rod body; the coring rod body is a slender hollow cylinder;

[0008] One end of the core removal rod body is an interference core breaking structure, and the interference core breaking structure is a hollow cylinder with an outer diameter larger than the outer diameter of the core removal rod body;

[0009] The end of the core removing rod body provided with the interference core breaking structure is also provided with an introduction structure, and the introduction structure is to cut the end of the core removing rod body provided with the interference core breaking structure into a wedge shape;

[0010] An elastic avoidance hole is provided in the middle of the core removing rod body, and the elastic avoidance hole radially penetrates the inner and outer surfaces of the core removing rod body; the elastic avoidance hole area is covered with an elastic membrane; the compression force generated by the deformation of the elastic membrane is used to clamp the material core so as to remove the material core.

[0011] Furthermore, the outer diameter of the core removal rod is 0.01 mm to 0.03 mm smaller than the diameter of the deep hole, and the inner diameter of the core removal rod is 0.01 mm to 0.03 mm larger than the diameter of the core.

[0012] Furthermore, the outer diameter of the interference core breaking structure is 0.05 mm to 0.08 mm larger than the diameter of the deep hole.

[0013] Furthermore, the angle between the wedge-shaped plane of the introduction structure and the axis of the core removal rod body is 15° to 30°.

[0014] Furthermore, the distance from the elastic avoidance hole to the tip of the introduction structure is equal to the length of the material core.

[0015] Furthermore, the angle between the plane where the elastic avoidance hole is located and the wedge-shaped plane of the introduction structure is 45°-90°.

[0016] Furthermore, the tool also includes: a decompression rod, the diameter of which is smaller than the inner diameter of the core removal rod body, and the decompression rod is fixed in the inner hole at the tail end of the core removal rod body.

[0017] Furthermore, the depth of the elastic avoidance hole exceeds the central axis of the core removal rod body by 0.1 mm to 0.3 mm.

[0018] The beneficial effects of the present invention are as follows: a core removal tool for deep hole drilling of hard and brittle materials is proposed, which solves the problems of "residual core" leading to deviation in processing and scrapping of parts quality in the current common manual core removal, as well as the disruption of production rhythm, the need for personnel to stand by during processing, and the strong alkaline atomized coolant harming the operating workers. The efficiency and quality of automated processing in deep hole drilling of hard and brittle materials are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation scheme of the present invention, the specific drawings of the scheme will be described below.

[0020] Figure 1 A schematic diagram of the use of a core removal tool for deep hole drilling of hard and brittle materials;

[0021] Figure 2 A schematic diagram of the composition of a core removal tool for deep hole drilling of hard and brittle materials;

[0022] 1- CNC machine tool handle, 2- automatic core removal tool, 3- deep hole for hard and brittle materials, 4- material core, 5- introduction structure, 6- interference core breaking structure, 7- elastic avoidance hole, 8- elastic membrane, 9- core removal tool body, 10- pressure relief rod. DETAILED DESCRIPTION

[0023] This section is an embodiment of the present invention, which is used to explain and illustrate the technical solution of the present invention.

[0024] See also Figure 1, a core 4 will remain inside the deep hole 3 of the hard and brittle material. To avoid machining interference and interruption of the automated machining process, the present invention uses a CNC machine tool tool holder 1 equipped with an automatic core removal tool 2, which automatically removes the core 4 under the drive of the CNC machine tool.

[0025] Among them, the automatic core removal tool 2 is clamped and fixed on the CNC machine tool tool holder 1 through an elastic chuck, and then installed in the tool magazine of the CNC machine tool for retrieval and use by the CNC machine tool.

[0026] On the automatic core removal tool 2, an interference core breaking structure 6 is machined by mechanical machining or additive manufacturing (electroplating, welding or 3D printing). The interference core breaking structure 6 is 0.05 mm - 0.08 mm larger than the size of the deep hole 3 of the hard and brittle material in diameter. An introduction structure 5 is machined at the front end of the interference core breaking structure 6, and the introduction angle of the introduction structure 5 is 15° - 30°.

[0027] An elastic avoidance hole 7 is machined on the automatic core removal tool 2. The distance between the center of the elastic avoidance hole 7 and the end face of the introduction structure 5 is equal to the length of the core 4. The elastic avoidance hole 7 penetrates through the center line of the automatic core removal tool 2 and extends 0.1 mm - 0.3 mm in depth. To avoid a decrease in the strength of the automatic core removal tool 2 in the normal direction of the elastic avoidance hole 7, the normal direction of the elastic avoidance hole 7 should be offset 45° - 90° from the side of the introduction structure 5. An elastic membrane 8 covers the elastic avoidance hole 7 and is pressed tightly on the elastic avoidance hole 7 through its own elastic deformation pressure.

[0028] Since the coolant pressure in the center cooling during deep hole drilling of hard and brittle materials is relatively large, generally ≥5 bar, it will cause elastic failure. Therefore, a pressure reduction control device must be designed at the tail of the automatic core removal tool 2. Due to space limitations, the present invention uses a pressure reduction rod 10 to control the coolant pressure through a gap. The pressure reduction rod 10 is made of elastic metal. By bending it, the maximum solid size in the cylindrical direction is larger than the inner hole of the automatic core removal tool 2, and it is inserted into the automatic core removal tool 2, and the elastic force presses it tightly inside the automatic core removal tool 2. The pressure reduction control can be achieved by adjusting the diameter size and length of the pressure reduction rod 10.

[0029] The specific operation steps are as follows:

[0030] 1. Design or select an automatic core removal tool 2 according to the diameter size and length-diameter ratio of the core;

[0031] 2. Install the automatic core removal tool 2 on the CNC machine tool tool holder 1 and perform end runout correction;

[0032] 3. Install the CNC machine tool tool holder 1 in the tool magazine of the CNC machine tool and program a core removal subroutine.

[0033] 4. When a core removal operation is required after deep hole machining, the CNC machine tool automatically calls a subroutine to take out the tool holder 1 of the CNC machine tool equipped with the automatic core removal tool 2 from the tool magazine. Align it with the core 4, and introduce the core 4 into the interior of the automatic core removal tool 2 through the guiding structure 5 on the automatic core removal tool 2.

[0034] 5. The core 4 is fractured at a fixed position through the interference core breaking structure 6. One end of the fractured core 4 passes through the elastic avoidance hole 7 on the automatic core removal tool 2, and the core is connected to the automatic core removal tool 2 through the elastic membrane 8.

[0035] 6. Move the fractured core 4 to outside the part machining area by operating the spindle of the CNC machine tool, and turn on the internal coolant of the machine tool. The coolant becomes a controllable pressure after passing through the pressure reducing rod 10, which can not only press out the core 4 from the automatic core removal tool 2 but also not damage the elastic membrane 8 on the automatic core removal tool 2. The coolant pressure of the machine tool causes the core 4 to separate from the special tool and be discharged outside the machining area, without affecting subsequent machining.

[0036] 7. Turn off the internal coolant, return the tool holder 1 of the CNC machine tool equipped with the automatic core removal tool 2 to the tool magazine, and the automatic core removal action is completed.

Claims

1. A core-removing tool for deep-hole drilling of brittle materials, characterized in that: The tool includes: a core-removing rod body; the core-removing rod body is a slender hollow cylinder; One end of the core-removing rod body is an interference core-breaking structure, and the interference core-breaking structure is a hollow cylinder with an outer diameter larger than that of the core-removing rod body; One end of the core-removing rod body provided with the interference core-breaking structure is also provided with a guiding structure, and the guiding structure is to cut one end of the core-removing rod body provided with the interference core-breaking structure into a wedge shape; An elastic avoidance hole is provided in the middle of the core-removing rod body, and the elastic avoidance hole penetrates through the inner and outer surfaces of the core-removing rod body along the radial direction; an elastic film covers the area of the elastic avoidance hole; the core is clamped by the pressing force generated by the deformation of the elastic film so as to take out the core; The outer diameter of the interference core-breaking structure is 0.05 mm to 0.08 mm larger than the diameter of the deep hole; the included angle between the wedge plane of the guiding structure and the axis of the core-removing rod body is 15° to 30°.

2. The core-removing tool according to claim 1, characterized in that: The outer diameter of the core-removing rod body is 0.01 mm to 0.03 mm smaller than the diameter of the deep hole, and the inner diameter of the core-removing rod body is 0.01 mm to 0.03 mm larger than the diameter of the core.

3. The core-removing tool according to claim 1, characterized in that: The distance from the elastic avoidance hole to the tip of the guiding structure is equal to the length of the core.

4. The core-removing tool according to claim 1, characterized in that: The included angle between the plane where the elastic avoidance hole is located and the wedge plane of the guiding structure is 45° - 90°.

5. The core-removing tool according to claim 1, characterized in that: The tool further includes: a pressure-reducing rod, the diameter of the pressure-reducing rod is smaller than the inner diameter of the core-removing rod body, and the pressure-reducing rod is fixed in the inner hole at the tail of the core-removing rod body.

6. The core-removing tool according to claim 1, characterized in that: The depth of the elastic avoidance hole exceeds the central axis of the core-removing rod body by 0.1 mm to 0.3 mm.

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