Moving core head for drawing stainless steel capillary tube

Abstract

The utility model relates to the technical field of stainless steel tube preparation, in particular to a floating core head for drawing a stainless steel capillary tube, which comprises an outer mold and a floating inner core, the outer mold comprises a mold body and a core hole for forming a capillary tube; the core hole comprises a tube inlet hole, a transition forming hole and a tube outlet hole according to the entering direction of the capillary tube; the floating inner core is of a solid cylinder structure, one end of the floating inner core is a working section, the other end of the floating inner core is a core tail section, and the working section and the core tail section are connected through an inclined transition section. During drawing, the stainless steel capillary tube internally provided with the floating inner core sequentially penetrates through the tube inlet hole, the transition forming hole and the tube outlet hole of the outer mold; and the floating inner core is clamped in the transition forming hole. The production efficiency of the stainless steel capillary tube is greatly improved through drawing of the moving core head, the structure is simpler, the depoling procedure is omitted, and damage to the inner wall of the tube is reduced.

Description

Technical Field

[0001] This utility model relates to the field of stainless steel tube preparation technology, and in particular to a moving mandrel for drawing stainless steel capillary tubes. Background Technology

[0002] Currently, the main production processes for stainless steel capillary tubes include air drawing, long mandrel drawing, and short mandrel drawing.

[0003] (1) Empty drawing: When d / δ≤5, reduce the wall drawing; when d / δ>5, increase the wall drawing.

[0004] (2) Long mandrel drawing: During drawing, a support device is installed inside the capillary to ensure that the inner wall size remains unchanged and the outer diameter is reduced to achieve wall reduction. Long mandrel drawing is currently the main method for drawing stainless steel capillary tubes.

[0005] (3) Short mandrel drawing: During drawing, the mandrel with short mandrel is fixed, and the tube blank achieves diameter reduction and wall reduction through the gap between the mandrel and the die hole.

[0006] However, in practical use, the above three pulling methods have the following drawbacks:

[0007] (1) Empty drawing: Due to the small wall thickness of the capillary, the wall thickness ratio is generally >5, so it is impossible to complete the wall reduction production of stainless steel capillary.

[0008] (2) Long mandrel drawing: A special mandrel removal mechanism is required, and the inner wall is easily damaged during mandrel removal, resulting in a decrease in product quality, a decrease in the yield of finished products, and a low mandrel removal efficiency, which seriously affects the production efficiency of the product. When drawing capillaries of different specifications, a large number of long mandrels of different specifications with polished surfaces are required, which increases the overall production cost. Moreover, the long mandrel inside plays a major supporting role during drawing, so the mandrel is required to have a certain strength. The smaller the capillary size, the smaller the mandrel size, the higher the strength requirement, and the higher the cost, which further increases the production cost of capillaries.

[0009] (3) Short mandrel drawing: It is not suitable for drawing long capillary tubes. The smaller the size of the capillary, the higher the connection strength requirement of the mandrel and mandrel rod, which is prone to damage and has a low service life. Utility Model Content

[0010] To address the problems in the prior art, this utility model provides a floating mandrel for drawing stainless steel capillary tubes.

[0011] The technical solution of this utility model is implemented as follows:

[0012] A floating mandrel for drawing stainless steel capillary tubes includes an outer mold and a floating inner mandrel.

[0013] The outer mold includes a mold body and a core hole for forming capillary tubes; according to the direction of capillary tube entry, the core hole includes an inlet hole, a transition forming hole and an outlet hole;

[0014] The floating inner core is a solid cylindrical structure, with one end being the working section and the other end being the core tail section. The working section and the core tail section are connected by an inclined transition section.

[0015] During the drawing process, the stainless steel capillary tube with the floating inner core inside passes through the inlet hole, transition forming hole and outlet hole of the outer mold in sequence; the floating inner core is stuck in the transition forming hole.

[0016] Furthermore, within the transition forming hole, the floating inner core is located in the capillary diameter variation zone near the outlet area, with its working section facing the inlet hole and its tail section facing the outlet hole.

[0017] Furthermore, the diameter of the core tail section is smaller than the outlet diameter of the transition forming hole, and the diameter of the working section is larger than the outlet diameter of the transition forming hole.

[0018] Furthermore, the transition section is provided with a certain slope α, and the slope of the transition forming hole forming area is β, where β = α + (5° ~ 10°).

[0019] Furthermore, when the diameter of the stainless steel capillary is Φ3.2~3.4mm and the wall thickness is 0.12mm~0.2mm, the diameter of the working section of the floating inner core is set to Φ2.84~2.88mm, the diameter of the tail section of the floating inner core is set to Φ2.50~2.52mm, and the finished diameter of the stainless steel capillary can reach 2.7~2.82mm, with a wall thickness of 0.09~0.16mm.

[0020] Furthermore, the outer mold has an outer diameter of Φ50mm and a total length of 25mm.

[0021] Furthermore, the working section of the floating inner core is 4.5mm long, the transition section is 1.5mm long, and the tail section is 2mm long.

[0022] The present invention has the following advantages over the prior art:

[0023] The floating mandrel drawing method of this utility model greatly improves the production efficiency of stainless steel capillary tubes. During the drawing process, no mandrel or mandrel is required for support, the structure is simpler, and the production cost is reduced. It also eliminates the core removal process, which not only reduces damage to the inner wall of the tube and improves product quality, but also greatly improves production efficiency. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the working of the movable core head of this utility model;

[0026] Figure 2 This is a schematic diagram of the outer mold of this utility model;

[0027] Figure 3 This is a schematic diagram of the floating inner core of this utility model.

[0028] Attached image labels:

[0029] 1-Outer mold, 11-Inlet hole, 12-Transition forming hole, 13-Outlet hole, 2-Floating inner core, 21-Core tail section, 22-Transition section, 23-Working section, 3-Capillary tube. Detailed Implementation

[0030] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0031] like Figures 1-3 As shown in the figure, this utility model embodiment discloses a floating mandrel for drawing stainless steel capillary tubes, including an outer mold 1 and a floating inner core 2; the outer mold 1 is integrally made of polycrystalline mold, and the floating inner core 2 is integrally made of YG8 hard alloy mold; when the stainless steel capillary tube 3 is formed, the outer mold 1 is used to reduce the outer diameter, and the floating inner core 2 plays a supporting role while assisting the outer mold 1 in reducing the wall thickness of the capillary tube 3.

[0032] To achieve the above objectives, the outer mold 1 includes a mold body and a core hole for forming the capillary 3; according to the direction in which the capillary 3 enters, the core hole includes an inlet hole 11, a transition forming hole 12, and an outlet hole 13;

[0033] The floating inner core 2 is a solid cylindrical structure, specifically including a core tail section 21, a transition section 22, and a working section 23; the core tail section 21 and the working section 23 are connected by the transition section 22; before operation, the floating inner core 2 is placed into the capillary 3 by first entering through the working section 23.

[0034] During the drawing process, the stainless steel capillary 3 with the floating inner core 2 inside passes through the inlet hole 11, the transition forming hole 12 and the outlet hole 13 of the outer mold 1 in sequence.

[0035] Specifically, within the transition forming hole 12, the floating inner core 2 is positioned in the capillary 3 diameter-changing region near the outlet area, with its working section 23 facing the inlet hole 11 and its tail section 21 facing the outlet hole 13. Furthermore, the diameter of the tail section 21 is smaller than the outlet diameter of the transition forming hole 12, while the diameter of the working section 23 is larger than the outlet diameter of the transition forming hole 12. This allows the floating inner core 2 to be fully engaged within the transition forming hole 12 and cooperate with the outer mold 1 to achieve the diameter-changing drawing of the capillary 3.

[0036] Preferably, the transition section 22 is provided with a certain slope α to slow down the change in pipe wall thickness and reduce damage to the inner wall; the transition section is provided with a certain slope, and the slope of the forming area of ​​the transition forming hole 12 is β, β=α+(5°~10°).

[0037] In existing technologies, wall thickness reduction by drawing typically employs a mandrel-based drawing method. After the drawing process, the mandrel needs to be removed from the tube, a process that often damages the inner wall of the tube. This invention, through the cooperation of a floating inner core 2 and an outer mold 1, allows the floating inner core 2 to remain within the mandrel hole after the drawing process, thus achieving automatic demolding and effectively protecting the quality of the inner wall of the capillary 3.

[0038] The table below illustrates the dimensional specifications of the capillary tube, outer mold, and floating inner core through two examples:

[0039] Example 1 Example 2 Outer diameter (mm) of incoming stainless steel capillary tubes Φ3.4 Φ3.2 Thickness (mm) of incoming stainless steel capillary tubes 0.2 0.12 Outer diameter of the mold (mm) Φ50 Φ50 External mold length (mm) 25 25 Diameter of the tail section of the floating inner core (mm) Φ2.88 Φ2.84 Length of the tail section of the floating inner core (mm) 4.5 4.5 Length of the transition section of the floating inner core (mm) 1.5 1.5 Diameter of the working section of the floating inner core (mm) Φ2.52 Φ2.5 Length of the working section of the floating inner core (mm) 2 2 Outer diameter of finished stainless steel capillary tube (mm) Φ2.82 Φ2.7 Thickness (mm) of finished stainless steel capillary tube 0.16 0.09

[0040] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A moving mandrel for drawing stainless steel capillary tubes, characterized in that: Includes the outer mold and the floating inner core; The outer mold includes a mold body and a core hole for forming capillary tubes; according to the direction of capillary tube entry, the core hole includes an inlet hole, a transition forming hole and an outlet hole; The floating inner core is a solid cylindrical structure, with one end being the working section and the other end being the core tail section. The working section and the core tail section are connected by an inclined transition section. During the drawing process, the stainless steel capillary tube with the floating inner core inside passes through the inlet hole, transition forming hole and outlet hole of the outer mold in sequence; the floating inner core is stuck in the transition forming hole.

2. The moving mandrel for drawing stainless steel capillary tubes as described in claim 1, characterized in that: Within the transition forming hole, the floating inner core is located in the capillary diameter variation zone near the outlet area, with its working section facing the inlet hole and its tail section facing the outlet hole.

3. The moving mandrel for drawing stainless steel capillary tubes as described in claim 2, characterized in that: The diameter of the core tail section is smaller than the outlet diameter of the transition forming hole, while the diameter of the working section is larger than the outlet diameter of the transition forming hole.

4. The moving mandrel for drawing stainless steel capillary tubes as described in claim 1, characterized in that: The transition section is provided with a certain slope α, and the slope of the transition forming hole forming area is β, where β = α + (5° ~ 10°).

5. The moving mandrel for drawing stainless steel capillary tubes as described in claim 1, characterized in that: When the diameter of the stainless steel capillary is Φ3.2~3.4mm and the wall thickness is 0.12mm~0.2mm, the diameter of the working section of the floating inner core is set to Φ2.84~2.88mm, the diameter of the tail section of the floating inner core is set to Φ2.50~2.52mm, and the finished diameter of the stainless steel capillary can reach 2.7~2.82mm, with a wall thickness of 0.09~0.16mm.

6. The moving mandrel for drawing stainless steel capillary tubes as described in claim 5, characterized in that: The outer mold has an outer diameter of Φ50mm and a total length of 25mm.

7. The moving mandrel for drawing stainless steel capillary tubes as described in claim 5, characterized in that: The working section of the floating inner core is 4.5mm long, the transition section is 1.5mm long, and the tail section is 2mm long.

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