A kind of inner cavity evaporation coating device

Abstract

The present application relates to the technical field of vacuum coating, in particular to a kind of inner cavity evaporation coating device, including evaporation boat, to be coated straight pipe, anode assembly, cathode assembly, fixed frame pillar, fixed frame guide rail, evaporation power supply and ion cleaning power supply, evaporation boat is located in the inner cavity of to be coated straight pipe, anode assembly one end is connected with the evaporation boat, the other end is connected with evaporation power supply anode and ion cleaning power supply cathode, cathode assembly one end is connected with the evaporation boat, the other end is connected with evaporation power supply cathode and ion cleaning power supply anode, fixed frame pillar is used to support anode assembly and cathode assembly, fixed frame pillar reciprocating motion along the fixed frame guide rail being located below fixed frame pillar, evaporation boat is driven along the inner cavity axis of to be coated straight pipe reciprocating motion under fixed frame pillar. Solve the problem that in the existing arc ion coating, magnetron sputtering technology and electroplating technology, for relatively long tubular parts, internal still cannot complete film layer uniform deposition, even cannot complete deposition.

Description

Technical Field

[0001] This invention relates to the field of vacuum coating technology, and more specifically to an internal cavity evaporation coating apparatus. Background Technology

[0002] Since its application in the last century, coating technology has provided a means to improve the surface properties of materials. It has been widely used in wear resistance and friction reduction, high temperature protection, corrosion prevention, decoration and functional enhancement, and has irreplaceable value in many industries.

[0003] When preparing a film on a workpiece surface, the shape of the surface significantly affects the film's performance. Furthermore, for parts with complex shapes, the uniformity of the film on the surface is often severely constrained. For instance, many coating technologies are inadequate for coating internal cavities and deep holes, yet the demand for internal cavity coating remains strong. Examples include applications such as corrosion protection, wear resistance and friction reduction, electrical conductivity, and high-temperature resistance for pipe inner walls.

[0004] To achieve cavity coating, several technologies offer solutions. Atomic layer deposition (ALD) is the most versatile, but it is limited by deposition rate, hindering mass production; precursor limitations prevent the deposition of partial films; and deposition temperature limitations prevent the deposition of films on partial workpiece surfaces. Among other technologies, magnetron sputtering has been developed for the specific shapes of cavity coatings, but this requires an internal cavity diameter of at least 100 mm. In arc ion plating, magnetron sputtering, and electroplating, adding auxiliary electrodes can improve the uniformity of the internal film, but for relatively long tubular parts, uniform film deposition, or even complete deposition at all, remains impossible.

[0005] In view of the above-mentioned defects, the inventors of this invention have finally obtained this invention after a long period of research and practice. Summary of the Invention

[0006] The purpose of this invention is to solve the problem that in existing arc ion plating, magnetron sputtering and electroplating technologies, the uniformity of the inner cavity film can be improved by adding auxiliary electrodes, but for relatively long tubular parts, uniform film deposition cannot be completed, or even deposition cannot be completed at all. This invention provides an inner cavity evaporation coating device.

[0007] To achieve the above objectives, the present invention discloses an internal cavity evaporation coating apparatus, comprising an evaporation boat, a straight tube to be coated, an anode assembly, a cathode assembly, a fixed frame support, a fixed frame guide rail, an evaporation power supply, and an ion cleaning power supply. The evaporation boat is disposed within the inner cavity of the straight tube to be coated. One end of the anode assembly is connected to the evaporation boat, and the other end is connected to the positive terminal of the evaporation power supply and the negative terminal of the ion cleaning power supply. One end of the cathode assembly is connected to the evaporation boat, and the other end is connected to the negative terminal of the evaporation power supply. The fixed frame support supports the anode assembly and the cathode assembly. The fixed frame support reciprocates along the fixed frame guide rail located below the fixed frame support. The evaporation boat reciprocates along the inner cavity axis of the straight tube to be coated under the drive of the fixed frame support.

[0008] The anode assembly includes an anode column and an anode column insulated bullseye bearing. The anode column insulated bullseye bearing includes an anode insulated bullseye bearing ceramic base and an anode insulated bullseye bearing ceramic ball. The anode insulated bullseye bearing ceramic base is embedded in the anode column, and the anode insulated bullseye bearing ceramic ball is embedded in the anode insulated bullseye bearing ceramic base. The cathode assembly includes a cathode column and a cathode column insulated bullseye bearing. The cathode insulated bullseye bearing includes a cathode insulated bullseye bearing ceramic base and a cathode insulated bullseye bearing ceramic ball. The cathode insulated bullseye bearing ceramic base is embedded in the cathode column, and the cathode insulated bullseye bearing ceramic ball is embedded in the cathode insulated bullseye bearing ceramic base.

[0009] The internal cavity evaporation coating device further includes a water-cooling component, a water-cooling bracket, a fixing arm assembly, a gear, and a vacuum chamber. The water-cooling component presses and fixes the straight tube to be coated with graphite foil. The water-cooling component is fixed by the water-cooling bracket. The water-cooling bracket is connected to the vacuum chamber through the fixing arm assembly. The gear is fixed to the wall of the vacuum chamber by a magnetohydrodynamic fluid. The gear meshes with the gear of the water-cooling bracket, and the gear drives the water-cooling bracket to rotate.

[0010] The water-cooling assembly includes two symmetrically arranged above and below the straight tube to be coated. Each of the upper and lower parts of the water-cooling assembly includes an inner wall of a water-cooling cylinder, a water channel guide groove, a water inlet, and a water outlet. The water channel guide groove is located between the inner walls of the water-cooling cylinder. The water inlet and the water outlet are both connected to a corrugated pipe.

[0011] The water-cooled mounting bracket includes a water-cooled mounting cylinder, a water-cooled mounting bracket gear, and a water-cooled cylinder positioning screw. The water-cooled cylinder positioning screw is located on the water-cooled mounting cylinder, and the water-cooled assembly is fixed by the water-cooled cylinder positioning screw. The water-cooled mounting bracket gear meshes with the gear.

[0012] The fixed arm assembly includes a fixed arm frame, a left fixed arm, and a right fixed arm. The fixed arm frame is connected to the water-cooled fixed frame via a thin-walled bearing. One end of the left fixed arm is connected to the fixed arm frame, and the other end is connected to the vacuum chamber. One end of the right fixed arm is connected to the fixed arm frame, and the other end is connected to the vacuum chamber.

[0013] The gear is connected to a gear drive shaft, which is connected to the vacuum chamber via a magnetohydrodynamic connection. The gear drive shaft is driven to rotate by a motor located outside the vacuum chamber.

[0014] The inner cavity evaporation coating device also includes guide ports, which are funnel-shaped. There are two guide ports, which are symmetrically arranged at both ends of the water-cooling component and connected to the water-cooling component by guide port fixing screws.

[0015] The anode assembly is connected to the evaporation power supply and the ion cleaning power supply via an anode column cable, and the cathode assembly is connected to the evaporation power supply via a cathode column cable. Both the anode column cable and the cathode column cable are multi-core copper cables.

[0016] The support column of the fixing frame is mounted on the crossbeam of the fixing frame. At the anode end, the top of the support column is connected to the anode column through anode and cathode fixing ceramics. At the cathode end, the top of the support column is connected to the cathode column through anode and cathode fixing ceramics. The crossbeam of the fixing frame is mounted on the guide rail of the fixing frame.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. Compared with existing magnetron sputtering technology, the present invention can complete the inner wall coating and achieve the inner wall coating of tubes with smaller inner diameters.

[0019] 2. Compared with existing atomic layer deposition technology, the present invention can achieve high-efficiency deposition and lower cost, overcoming the shortcomings of atomic layer deposition that cannot be industrialized. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an internal cavity evaporation coating device;

[0021] Figure 2 This is a schematic diagram of the anode column structure;

[0022] Figure 3 Layout 1 for bullseye bearings embedded in the yin and yang poles;

[0023] Figure 4 Layout 2 for bullseye bearings embedded in the yin and yang poles;

[0024] Figure 5 A diagram showing A to A';

[0025] Figure 6 A schematic diagram of B-B';

[0026] Figure 7 A schematic diagram of C-C';

[0027] Figure 8 A schematic diagram of D-D';

[0028] Figure 9 This is a schematic diagram of the water-cooled component assembly.

[0029] The numbers in the image represent:

[0030] 1-Evaporation boat; 201-Anode column; 202-Anode column insulated bullseye bearing; 203-Anode bullseye bearing ceramic base; 204-Anode bullseye bearing ceramic ball; 301-Cathode column; 302-Cathode column insulated bullseye bearing; 303-Cathode bullseye bearing ceramic base; 304-Cathode bullseye bearing ceramic ball; 4-Straight tube to be coated; 5-Water cooling assembly; 501-Inner wall of water cooling cylinder; 502-Water channel guide groove; 503-Inner wall of water cooling cylinder; 504-Inlet; 505-Outlet; 506-Inlet; 507-Outlet; 507-Outlet; 508-Water cooling cylinder fixing screw; 6-Water cooling mounting bracket; 601-Water cooling mounting cylinder; 602-Water cooling mounting bracket gear ; 603-Water-cooled cylinder positioning screw; 7-Thin-walled bearing; 8-Fixed arm assembly; 801-Fixed arm; 802-Left fixed arm; 803-Right fixed arm; 9-Gear; 901-Gear drive shaft; 10-Guide port; 11-Guide port fixing screw; 12-Anode and cathode fixing ceramics; 13-Fixed frame support; 14-Anode column cable; 15-Cathode column cable; 16-Fixed frame drive shaft; 17-Ion cleaning power supply; 18-Evaporation power supply; 19-Fixed frame crossbeam; 20-Fixed frame guide rail; 21-Graphite foil; 22-Vacuum chamber; 23-Tube workpiece mounting door; 24-Vacuum chamber door; 25-Lower half of simulated straight tube to be coated; 26-Upper half of simulated straight tube to be coated. Detailed Implementation

[0031] The above-mentioned and other technical features and advantages of the present invention will be described in more detail below with reference to the accompanying drawings.

[0032] Example 1

[0033] This embodiment provides an internal cavity evaporation coating apparatus, including an evaporation boat 1, a straight tube to be coated 4, an anode assembly 2, a cathode assembly 3, a water-cooling assembly 5, a water-cooling mounting bracket 6, a thin-walled bearing 7, a fixing arm assembly 8, a gear 9, a guide port 10, a mounting bracket support 13, a mounting bracket guide rail 20, a cathode column cable 14, an anode column cable 15, an evaporation power supply 18, and an ion cleaning power supply 17. The evaporation boat 1 is placed inside the straight tube to be coated 4 and can reciprocate along the axis of the straight tube 4 by being driven by the mounting bracket support 13. The evaporation boat 1 can be a common tungsten boat or a molybdenum boat.

[0034] The anode assembly 2 consists of an anode column 201 and an anode column insulated bullseye bearing 202. One end of the anode column 201 is fixed to the evaporation boat 1, and the other end is fixed to the anode column cable 15. The anode column insulated bullseye bearing 202 consists of an anode bullseye bearing ceramic base 203 and an anode bullseye bearing ceramic ball 204. The anode bullseye bearing ceramic base 203 is embedded in the anode column 201, as shown below. Figure 2 The axial direction of the 203 anode bullseye bearing ceramic base forms an angle of ±60° with the direction perpendicular to the ground, see... Figure 3 and Figure 4 The insulated bullseye bearing 202 is indirectly arranged on the anode column 201.

[0035] The cathode assembly 3 consists of a cathode column 301 and a cathode column insulated bullseye bearing 302. One end of the cathode column 301 is fixed to the evaporation boat 1, and the other end is fixed to the cathode column cable 14. The cathode column insulated bullseye bearing 302 consists of a cathode bullseye bearing ceramic base 203 and a cathode bullseye bearing ceramic ball 204. The cathode bullseye bearing ceramic base 203 is embedded in the cathode column 301, as shown below. Figure 2 The axial direction of the cathode bullseye bearing ceramic base 203 forms an angle of ±60° with the direction perpendicular to the ground, see... Figure 3 and Figure 4 The insulated bullseye bearing 302 is indirectly arranged on the cathode column 301.

[0036] The water-cooling assembly 5 consists of two symmetrical parts. Figure 5 Taking the upper part as an example, it consists of the inner wall 501 of the water-cooled cylinder, the water channel guide groove 502, the inner wall 503 of the water-cooled cylinder, the inlet 504, and the outlet 505. The inlet 504 and the stainless steel corrugated pipe ( Figure 1 (Not shown in the image) connection, inlet 505 and stainless steel corrugated pipe ( Figure 1 (Not shown in the image) Connection. The corrugated pipe is pre-lengthened in the vacuum chamber to allow for one revolution around the water-cooling assembly 5. The upper and lower parts of the water-cooling assembly 5 are connected to the straight tube 4 to be coated by graphite foil 21 and fixed by water-cooling cylinder fixing screws 508, thus the straight tube 4 to be coated is also fixed by the water-cooling assembly.

[0037] The water-cooled mounting bracket 6 consists of a water-cooled mounting cylinder 601, a water-cooled mounting bracket gear 602, and water-cooled cylinder positioning screws 603. Three water-cooled cylinder positioning screws 603 are installed on the water-cooled mounting cylinder 601. The water-cooled assembly 5 is fixed by the water-cooled cylinder positioning screws 603. The water-cooled mounting bracket gear 602 meshes with gear 9.

[0038] The fixed arm assembly 8 consists of a fixed arm frame 801, a left fixed arm 802, and a right fixed arm 803. The fixed arm frame 801 is fixed by a thin-walled bearing 7 and a water-cooled mounting bracket 6, allowing the water-cooled mounting bracket 6 to rotate while restricting its lateral movement. Figure 7 One end of the left fixed arm 802 is fixed to the fixed arm frame 801, and the other end is fixed to the vacuum chamber 22; one end of the left fixed arm 803 is fixed to the fixed arm frame 801, and the other end is fixed to the vacuum chamber 22.

[0039] The gear 9 and gear drive shaft 901 are fixed; the gear drive shaft 901 is fixed to the vacuum chamber 22 via a magnetohydrodynamic connection. An outdoor motor (not shown) in the vacuum chamber drives the gear drive shaft 901 to rotate, which in turn drives the gear 9 to rotate. The gear 9 drives the fixed bracket gear 602 to rotate, and the water-cooled fixed bracket 6 drives the water-cooling assembly 5 to rotate via the water-cooling cylinder positioning screw 603. The water-cooling assembly 5 has a maximum rotation angle of 360° and can rotate repeatedly in both directions.

[0040] The guide port 10 consists of two symmetrical parts, which are fixed to both ends of the water-cooling assembly 5 by guide port fixing screws 11. The guide port 10 is funnel-shaped to prevent the anode column insulated bullseye bearing 202 on the anode column 2 from getting stuck when it enters the plated part 4; and to prevent the cathode column insulated bullseye bearing 302 on the cathode column 3 from getting stuck when it enters the plated part 4.

[0041] The mounting bracket support 13 is fixed to the mounting bracket crossbeam 19. At the anode end, the top of the mounting bracket support 13 is fixed by the anode and cathode fixing ceramics 12 and the anode column 201; at the cathode end, the top of the mounting bracket support 13 is fixed by the anode and cathode fixing ceramics 12 and the cathode column 301.

[0042] The cathode post cable 14 is made of multi-core copper cable and has bending characteristics. One end of the cathode post cable 14 is fixed to the cathode post 301, and the other end is fixed to the cathode of the evaporation power supply 18 and the cathode of the ion cleaning power supply 17. When the mounting bracket 13 moves the cathode post 301, the freely bending cathode post cable 14 provides lateral movement. If the length of the plated part 4 is very long, a cable storage device is required.

[0043] The anode column cable 15 is made of multi-core copper cable and has bending characteristics. One end of the anode column cable 15 is fixed to the anode column 201, and the other end is fixed to the anode of the evaporation power supply 18 and the cathode of the ion cleaning power supply 17. When the mounting bracket 13 moves the anode column 201, the freely bending anode column cable 15 provides lateral movement. If the length of the plated part 4 is very long, a cable storage device is required.

[0044] The fixed frame beam 19 is placed on the fixed frame guide rail 20 and can move left and right along the guide rail. Figure 1 The fixed frame drive shaft 16 is fixed to the wall of the vacuum chamber 22 via a magnetic fluid (not shown in the figure). An external driving force drives the fixed frame drive shaft 16 to rotate, which in turn drives the fixed frame crossbeam 19 to move left and right. Figure 1 .

[0045] The negative electrode of the ion cleaning power supply 17 is connected to the anode column 201 and the cathode column 301; the positive electrode is connected to the vacuum chamber 22. The positive electrode of the evaporation power supply 18 is connected to the anode column cable 15, and the negative electrode is connected to the cathode column cable 14.

[0046] The tubular workpiece mounting door 23 is the mounting door for the straight tube 4 to be coated. The vacuum chamber door 24 is fixed to the vacuum chamber 22 to facilitate workpiece installation.

[0047] Example 2

[0048] Example of tubular workpiece mounting and coating

[0049] This embodiment provides a technical solution: an internal cavity evaporation coating device, including an evaporation boat 1, a straight tube to be coated 4, an anode assembly 2, a cathode assembly 3, a water-cooling assembly 5, a water-cooling fixing frame 6, a thin-walled bearing 7, a fixing arm assembly 8, a gear 9, a guide port 10, a fixing frame support 13, a fixing frame guide rail 20, a cathode column cable 14, an anode column cable 15, an evaporation power supply 18, an ion cleaning power supply 19, and a lower half 25 and an upper half 26 of a tubular simulation component.

[0050] Step 1: Close the water valves at the inlet 504, outlet 505, inlet 506, and inlet 507 of the water-cooling component 5 (these are water circuit components and are not shown in the diagram), and release the water pressure inside the water-cooling component.

[0051] Step two, open the vacuum chamber door 24 and place the lower half of the water-cooling assembly 5 on an auxiliary mounting bracket (this is an auxiliary mounting bracket, not shown in the figure), see... Figure 9 .

[0052] Step 3: Place the lower half of the graphite foil 21 tightly against the lower half of the water-cooling component 5.

[0053] Step 4: Place the lower half 25 of the simulated straight tube to be coated onto the lower half of the graphite foil 21.

[0054] Step 5: One end of the anode column 201 is fixed to the evaporation boat 1, and the other end is fixed to the anode column cable 15.

[0055] Step six: one end of the cathode column 301 is fixed to the evaporation boat 1, and the other end is fixed to the cathode column cable 14.

[0056] Step 7: Adjust the height and position of the auxiliary mounting bracket along the axis of the anode column 201 and the cathode column 301, and visually ensure that the insulated bullseye bearing 202 of the anode column is in close contact with the insulated bullseye bearing 302 of the cathode column and the lower half 25 of the simulated straight tube to be coated.

[0057] Step 8: Place the upper half 26 of the simulated straight tube to be coated onto the lower half 25 of the simulated straight tube to be coated.

[0058] Step nine: Place the upper half of the graphite foil 21 tightly against the upper half of the water-cooling assembly 5.

[0059] Step 10: Place the upper half of water-cooling component 5 onto the lower half of water-cooling component 5 and secure it with water-cooling cylinder fixing screw 508. This also secures the lower half 25 and upper half 26 of the simulated straight tube to be coated. The lower half 25 and upper half 26 of the simulated straight tube to be coated are equivalent to the straight tube 4 to be coated.

[0060] Step 11: Tighten the two water-cooling cylinder positioning screws 603 on top of the water-cooling fixing cylinder 601. Due to the limiting effect of the mounting bracket, the water-cooling assembly 5 cannot deviate from the axial direction of the anode column 201 and the cathode column 301 under the action of the water-cooling cylinder positioning screws 603.

[0061] Step 12: Tighten the water-cooling cylinder positioning screw 603 located below the water-cooling fixing cylinder 601.

[0062] Step 13: Loosen the two water-cooling cylinder positioning screws 603 on the top of the water-cooling fixing cylinder 601, and remove the upper half of the water-cooling component 5, the upper half of the graphite foil 21, and the upper half of the simulated straight tube to be coated 25 in sequence.

[0063] Step Fourteen: Visually inspect whether the insulated bullseye bearing 202 of the anode column, the insulated bullseye bearing 302 of the cathode column, and the simulated straight tube 24 to be coated are in close contact. If there is any deviation, repeat steps six through thirteen.

[0064] Step 15: Disassemble the lower half 25 of the simulated straight tube to be coated. If necessary, disassembly handles can be placed at both ends of the simulated straight tube to be coated. At this time, the anode column insulated bullseye bearing 202 and the cathode column insulated bullseye bearing 302 may come into direct contact with the lower half of the graphite foil 21.

[0065] Step sixteen: Fill the evaporation boat 1 with membrane material.

[0066] Step 17: Disconnect the anode column 201 and the anode column cable 15, and remove the anode and cathode fixing ceramics 12 from the top of the fixing bracket support 13.

[0067] Step 18: Insert the straight tube 4 to be coated through the workpiece mounting door 23 and guide the anode column 201 into the straight tube 4 to be coated until the straight tube 4 to be coated is placed in the appropriate position of the lower half of the water cooling assembly 5.

[0068] Step 19: Fix the anode and cathode ceramics 12 at the top of the bracket support 13, and connect the anode column 201 and the anode column cable 15.

[0069] Step 20: Place the upper half of the graphite foil 21 tightly against the upper half of the water-cooling assembly 5.

[0070] Step 21: Place the upper half of the water-cooling component 5 on the lower half of the water-cooling component 5 and fix it with the water-cooling cylinder fixing screw 508, so that the straight tube 4 to be coated is fixed.

[0071] Step 22: Tighten the two water-cooling cylinder positioning screws 603 on top of the water-cooling mounting cylinder 601. Due to the limiting effect of the mounting bracket, the water-cooling assembly 5 cannot deviate from the axial direction of the anode column 201 and the cathode column 301 under the action of the water-cooling cylinder positioning screws 603. At the same time, during the tightening process, it is necessary to refer to the number of turns of loosening the water-cooling cylinder positioning screws 603 in step 12.

[0072] Step 23: Test whether there is insulation between the anode column 201 and the vacuum chamber 22. If there is no insulation, continue with steps 6 to 22.

[0073] Step 24: Open the valves connecting the water inlet 504, outlet 505, inlet 506, and inlet 507 of the water-cooling component 5, and introduce cooling water to check for leaks in the water circuit.

[0074] Step 25: Remove the auxiliary installation bracket.

[0075] Step 26: Drive the water-cooling assembly 5 to rotate in both directions via the drive shaft 901 (the rotation angle in the same direction shall not exceed one revolution). Drive the fixed frame drive shaft 16 to rotate via external driving force, and the drive shaft drives the fixed frame crossbeam 19 to move left and right. According to the process requirements, the drive shaft 901 and the fixed frame drive shaft 16 move in coordination, and observe whether there is any jamming in the water channel bellows, cathode column cable 14 and anode column cable 15.

[0076] Step 27: Close the workpiece mounting door 23 and the vacuum chamber door 24.

[0077] Step 28: Begin slowly evacuating the vacuum chamber until it reaches the vacuum level required for the evaporation process to deposit the film.

[0078] Step 29: Introduce argon gas and turn on the ion cleaning power supply 17 to perform glow discharge cleaning on the inner wall of the workpiece. If necessary, drive the water cooling assembly 5 to rotate in both directions via the drive shaft 901, with no more than one revolution in the same direction. Drive the fixed frame drive shaft 16 to rotate via external driving force, and drive shaft 16 drives the fixed frame crossbeam 19 to move left and right.

[0079] Step 30: Stop the argon gas supply and turn on the evaporation power supply 18 to perform coating. The water-cooling assembly 5 is driven to rotate in both directions via the drive shaft 901, with no more than one revolution in the same direction. An external driving force drives the fixed frame drive shaft 16 to rotate, and the drive shaft 16 drives the fixed frame beam 19 to move left and right.

[0080] Step 31: Turn off the evaporator power supply 18. Drive the water cooling assembly 5 and the mounting beam 19 back to their initial positions.

[0081] Step 32: Coating process complete. Following the steps above, remove the straight tube 4 to be coated, and then complete the packaging and warehousing.

[0082] The above description is merely a preferred embodiment of the present invention and is illustrative rather than restrictive. Those skilled in the art will understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, all of which will fall within the protection scope of the present invention.

Claims

1. An internal cavity evaporation coating apparatus, characterized in that, The device includes an evaporation boat, a straight tube to be coated, an anode assembly, a cathode assembly, a mounting bracket, a mounting bracket guide rail, an evaporation power supply, and an ion cleaning power supply. The evaporation boat is disposed inside the cavity of the straight tube to be coated. One end of the anode assembly is connected to the evaporation boat, and the other end is connected to the positive terminal of the evaporation power supply and the negative terminal of the ion cleaning power supply. One end of the cathode assembly is connected to the evaporation boat, and the other end is connected to the negative terminal of the evaporation power supply. The mounting bracket supports the anode assembly and the cathode assembly. The mounting bracket reciprocates along the mounting bracket guide rail located below the mounting bracket. The evaporation boat reciprocates along the inner cavity axis of the straight tube to be coated under the drive of the mounting bracket. The anode assembly includes an anode column and an anode column insulated bullseye bearing. The anode column insulated bullseye bearing includes an anode insulated bullseye bearing ceramic base and an anode insulated bullseye bearing ceramic ball. The anode insulated bullseye bearing ceramic base is embedded in the anode column, and the anode insulated bullseye bearing ceramic ball is embedded in the anode insulated bullseye bearing ceramic base. The cathode assembly includes a cathode column and a cathode column insulated bullseye bearing. The cathode column insulated bullseye bearing includes a cathode insulated bullseye bearing ceramic base and a cathode insulated bullseye bearing ceramic ball. The cathode insulated bullseye bearing ceramic base is embedded in the cathode column, and the cathode insulated bullseye bearing ceramic ball is embedded in the cathode insulated bullseye bearing ceramic base. The internal cavity evaporation coating device further includes a water-cooling component, a water-cooling bracket, a fixing arm assembly, a gear, and a vacuum chamber. The straight tube to be coated and the graphite foil are pressed and fixed by the water-cooling component. The water-cooling component is fixed by the water-cooling bracket. The water-cooling bracket is connected to the vacuum chamber through the fixing arm assembly. The gear is fixed to the wall of the vacuum chamber by a magnetohydrodynamic device. The gear meshes with the gear of the water-cooling bracket, driving the water-cooling bracket to rotate.

2. The internal cavity evaporation coating apparatus as described in claim 1, characterized in that, The water-cooling assembly includes two symmetrically arranged above and below the straight tube to be coated. Each of the upper and lower parts of the water-cooling assembly includes an inner wall of a water-cooling cylinder, a water channel guide groove, a water inlet, and a water outlet. The water channel guide groove is located between the inner walls of the water-cooling cylinder. The water inlet and the water outlet are both connected to a corrugated pipe.

3. The internal cavity evaporation coating apparatus as described in claim 1, characterized in that, The water-cooled mounting bracket includes a water-cooled mounting cylinder, a water-cooled mounting bracket gear, and a water-cooled cylinder positioning screw. The water-cooled cylinder positioning screw is located on the water-cooled mounting cylinder, and the water-cooled assembly is fixed by the water-cooled cylinder positioning screw. The water-cooled mounting bracket gear meshes with the gear.

4. The internal cavity evaporation coating apparatus as described in claim 1, characterized in that, The fixed arm assembly includes a fixed arm frame, a left fixed arm, and a right fixed arm. The fixed arm frame is connected to the water-cooled fixed frame via a thin-walled bearing. One end of the left fixed arm is connected to the fixed arm frame, and the other end is connected to the vacuum chamber. One end of the right fixed arm is connected to the fixed arm frame, and the other end is connected to the vacuum chamber.

5. The internal cavity evaporation coating apparatus as described in claim 1, characterized in that, The gear is connected to a gear drive shaft, which is connected to the vacuum chamber via a magnetohydrodynamic connection. The gear drive shaft is driven to rotate by a motor located outside the vacuum chamber.

6. The internal cavity evaporation coating apparatus as described in claim 1, characterized in that, The inner cavity evaporation coating device also includes guide ports, which are funnel-shaped. There are two guide ports, which are symmetrically arranged at both ends of the water-cooling component and connected to the water-cooling component by guide port fixing screws.

7. The internal cavity evaporation coating apparatus as described in claim 1, characterized in that, The anode assembly is connected to the evaporation power supply and the ion cleaning power supply via an anode column cable, and the cathode assembly is connected to the evaporation power supply via a cathode column cable. Both the anode column cable and the cathode column cable are multi-core copper cables.

8. The internal cavity evaporation coating apparatus as described in claim 1, characterized in that, The support column of the fixing frame is mounted on the crossbeam of the fixing frame. At the anode end, the top of the support column is connected to the anode column through anode and cathode fixing ceramics. At the cathode end, the top of the support column is connected to the cathode column through anode and cathode fixing ceramics. The crossbeam of the fixing frame is mounted on the guide rail of the fixing frame.

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