Integrated diffusion coating of 3D printing mold and preparation process

Abstract

The invention relates to the field of metal surface treatment, in particular to a diffusion coating integrated coating of a 3D printing mold and a preparation process, the coating sequentially comprises an ion nitriding layer, a base coat, a transition layer and a functional layer from inside to outside, the base coat is a CrN material layer, the transition layer is an AlCrN material layer, and the functional layer is formed by sequentially overlapping a titanium silicide layer and an AlCrN layer. The preparation process comprises the following steps: step S1, pretreatment; step S2, hanging and mounting; s3, carrying out vacuum preheating; step S4, carrying out ion etching; step S5, carrying out ion nitriding; step S6, carrying out secondary ion etching; step S7, coating deposition; and S8, cooling and discharging. Ion nitriding and PVD coating integrated machining is achieved through a diffusion coating integrated machine, and the problems that due to complex stress and high temperature, the surface of a 3D printing mold is prone to being damaged, and the service life is short are solved through a four-layer composite coating structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metal surface treatment, in particular to a 3D printing mold's permeation plating integrated coating and preparation process. BACKGROUND

[0002] With the development of modern industry, the mold shape and internal structure are becoming more and more complex and diverse, and 3D printing has become the mainstream manufacturing method of mold manufacturing. However, it is a known problem that the manufacturing cost is high and the service life is short. Because the mold bears complex external force during use and the working environment temperature is high, the early damage of the mold surface occurs, and more than 80% of the existing mold failures are caused by surface damage.

[0003] In order to solve the problem of short service life of 3D printing mold, ion nitriding + PVD (physical vapor deposition) ion plating film technology has become the main scheme at present. Through this technology, an ion nitriding layer is formed inside the mold, the crystal structure is changed, and a deposition coating of the required substance is formed on the surface, which can significantly increase the hardness, wear resistance and reduce the friction coefficient of the mold, and generally can significantly prolong the service life of the mold.

[0004] However, the ion nitriding + PVD coating of the prior art mainly uses vacuum ion nitriding plus ALCRN coating or pure metal coating. Its hardness is slightly high, and it has good affinity and wetting performance with metal, and high oxidation resistance in air, but the oxidation resistance is significantly reduced at high temperature. At the same time, with the increasing complexity of the shape and internal environment of the mold, the PVD coating process inside the mold is difficult, which limits its application range in special workpiece molds.

[0005] In the prior art, the thickness of the ion nitriding layer is usually 7-10 μm, the thickness of the bottom CRN layer is 2-3 μm, the thickness of the first ALCRN layer is 3-5 μm, and the thickness of the second ALCRN layer is 4-6 μm. Although this coating structure improves the surface performance of the mold to some extent, the oxidation resistance of the ALCRN coating is significantly reduced at high temperature, which cannot meet the requirements of long-term high-temperature work. In addition, for complex 3D printing molds, the traditional PVD coating process is difficult to achieve uniform coating, resulting in uneven surface performance of the mold, affecting the overall service life and reliability of the mold.

[0006] In summary, the existing 3D printing mold surface treatment technology has obvious defects in high-temperature oxidation resistance and complex mold coating uniformity, and a new coating structure and preparation process are needed to solve these problems. SUMMARY

[0007] In order to solve the above problems, the present application provides a 3D printing mold's permeation and plating integrated coating and a preparation process, which realizes ion nitriding + PVD coating integrated processing through a permeation and plating integrated machine, and solves the problems of surface damage and short service life of the 3D printing mold caused by complex stress and high temperature through a four-layer composite coating structure.

[0008] In order to solve the problems in the prior art, the present application provides a 3D printing mold's permeation and plating integrated coating, which comprises, from inside to outside, an ion nitriding layer, a primer layer, a transition layer and a functional layer.

[0009] As a specific embodiment of the present application, the primer layer is a CrN material layer, the transition layer is an AlCrN material layer, and the functional layer is composed of a titanium silicide layer and an AlCrN layer in turn.

[0010] As a specific embodiment of the present application, the thickness of the ion nitriding layer is 7-10 μm, the thickness of the primer layer is 2-3 μm, the thickness of the transition layer is 3-5 μm, and the thickness of the functional layer is 4-6 μm.

[0011] A 3D printing mold's permeation and plating integrated coating preparation process is used for forming the permeation and plating integrated coating as claimed in claim 1 on the surface of a workpiece, and comprises the following steps: Step S1, pretreatment, which removes the rust layer, oxide layer and micro burrs attached to the surface of the workpiece through physical and chemical methods, so as to obtain a clean surface with high activity and improve the bonding force between the coating and the substrate; Step S2, hanging, which hangs the workpiece treated in step S1 on a load turntable in a reaction furnace; Step S3, vacuum preheating, which removes the volatile substances inside the workpiece through a high-temperature vacuum environment, and realizes the homogenization of the workpiece substrate temperature, so as to reduce the thermal shock effect in the coating deposition process and improve the bonding strength between the coating and the workpiece substrate; Step S4, ion etching, which bombards the surface of the workpiece with high-energy ions to remove the impurity thin oxide layer physically adsorbed on the surface of the workpiece, and activates the surface atoms to improve the interface energy; Step S5, ion nitriding, which bombards the surface layer of the workpiece with high-energy nitrogen ions to make nitrogen atoms penetrate into the surface layer of the workpiece, so as to form a dense ion nitriding layer; Step S6, secondary ion etching, which bombards the surface of the workpiece with high-energy ions to remove the reaction byproducts possibly remaining on the surface of the workpiece after nitriding; Step S7, coating deposition, which constructs a gradient composite structure of the primer layer, the transition layer and the functional layer in turn through physical vapor deposition technology; Step S8, cooling and discharging, which controls the internal stress through step-by-step cooling to ensure the structural integrity of the permeation and plating integrated coating and the workpiece.

[0012] In one specific embodiment of the present invention, step S4 includes the following steps in sequence: In the low-power cleaning stage, the surface of the workpiece is cleaned by bombarding the workpiece surface with constant low-power ions to remove surface dust. During the medium-power transition phase, the power is gradually increased to enhance the etching effect by bombarding the workpiece surface with ions. In the high-power strengthening stage, the surface of the workpiece is bombarded with constant high-power ions to remove surface impurities and oxide layers.

[0013] As a specific embodiment of the present invention, the etching conditions in step S4 are a vacuum environment of high-purity argon and high-purity hydrogen.

[0014] In one specific embodiment of the present invention, the total duration of the secondary ion etching in step S6 is less than the total duration of the ion etching in step S4.

[0015] In one specific embodiment of the present invention, in step S7, First, under the conditions of temperature 430-450℃, vacuum 4.0E0pa, bias voltage 40V, and target current 80A, by controlling the ion bombardment energy and diffusion rate, a transition interface with uniform thickness and low defect density is formed on the surface of the workpiece. This process forms the aforementioned underlayer. Furthermore, while maintaining a deposition temperature of 430-450℃, the coating hardness is smoothly transitioned from the underlayer level to the functional layer level by adjusting the target power or gas flow rate, and this process forms the transition layer. Finally, the bias voltage is increased to 150V to enhance the ion bombardment effect, thereby refining the grains and increasing the coating density. At the same time, titanium silicide is introduced to form a nanoscale dispersed strengthening phase, which significantly improves the coating's oxidation resistance and thermal stability under high-temperature conditions. The functional layer is formed during this process.

[0016] In one specific embodiment of the present invention, in step S5, the workpiece is removed after being cooled to 120-150°C in a stepwise manner inside the reactor.

[0017] As a specific embodiment of the present invention, if the workpiece weighs less than 100 kg, it shall be removed when the temperature drops to below 150°C; if the workpiece weighs more than 100 kg, it shall be removed when the temperature drops to below 120°C.

[0018] The advantages of this invention compared to the prior art are: The integrated infiltration coating of this invention achieves synergistic reinforcement through a four-layer composite structure design. The ion nitriding layer, as the bottom layer, can significantly improve the surface hardness and wear resistance of the material; the bottom layer improves surface quality and regulates internal stress, enhancing the adhesion between the coating and the substrate; the transition layer connects different materials, providing a stable interface and achieving a gradient transition of performance; the functional layer further enhances the overall wear resistance, corrosion resistance, and high-temperature resistance, effectively preventing the coating from cracking or peeling during use, and meeting the demanding working environment requirements of complex molds.

[0019] The integrated infiltration coating of this invention achieves synergistic reinforcement through a four-layer composite structure design. The ion nitriding layer, as the bottom layer, significantly improves the surface hardness and wear resistance of the material; the bottom layer improves surface quality and regulates internal stress, enhancing the adhesion between the coating and the substrate; the transition layer connects different materials, providing a stable interface and achieving a gradient transition of performance; the functional layer further enhances the overall wear resistance, corrosion resistance, and high-temperature resistance, effectively preventing the coating from cracking or peeling during use, and meeting the stringent working environment requirements of complex molds. Detailed Implementation

[0020] To further understand the features, technical means, and specific objectives and functions achieved by the present invention, the present invention will be described in further detail below with reference to specific embodiments.

[0021] An integrated coating for a 3D printed mold, comprising, from the inside out, an ion-nitriding layer, a base layer, a transition layer, and a functional layer. The base layer is a CrN material layer, the transition layer is an AlCrN material layer, and the functional layer is composed of a titanium silicide layer and an AlCrN layer stacked sequentially. The thickness of the ion-nitriding layer is 7-10 μm; the thickness of the base layer is 2-3 μm; the thickness of the transition layer is 3-5 μm; and the thickness of the functional layer is 4-6 μm.

[0022] Ion nitriding layer: Ion nitriding can significantly improve the surface hardness of materials, giving them higher wear resistance, fatigue strength, corrosion resistance, and burn resistance. Ion nitriding can shorten treatment time by 3 to 10 times, and reduce energy consumption and working gas consumption by 50% and 50 to 100 times, respectively. Deformation: Ion nitriding is carried out at relatively low temperatures and under vacuum, therefore there is no or negligible deformation. The composite zone produced by the ion nitriding process is dense, non-porous, very hard, non-brittle, and has a low coefficient of friction, allowing it to withstand high mechanical stress and environmental corrosion.

[0023] Undercoat: In some applications, undercoat can provide additional corrosion protection, preventing the substrate from corroding during the PVD coating process or during use. This is crucial for improving product lifespan and reliability. PVD coatings may generate internal stress during deposition; undercoat can help regulate these stresses, reducing the risk of coating cracking or peeling. Certain undercoat materials can promote the deposition of subsequent PVD coatings, improving deposition rate and quality.

[0024] Transition layers play a crucial role in various fields and applications. They improve adhesion between materials, buffer differences in thermal expansion, enhance mechanical properties, facilitate electronic conduction, and prevent interdiffusion and reactions. Through proper design and selection of transition layer materials, synergistic effects between different materials can be achieved, improving overall material performance and reliability. In the future, with technological advancements, the application prospects of transition layers will be even broader.

[0025] The transition layer uses AlCrN material, and the hardness transition function is achieved by adjusting the atomic ratio of Al to Cr. Its hardness is designed to be 2000-2500 Hv, between the underlayer and the functional layer. The process parameters need to be matched with the underlayer to form a gradient. While maintaining a deposition temperature of 430-450℃, the hardness of the coating is smoothly transitioned from the CrN underlayer (about 1800-2000 Hv) to the functional layer level by adjusting the target power or gas flow rate, so as to avoid interface stress concentration caused by abrupt performance changes.

[0026] Functional layer: PVD coating, or physical vapor deposition coating, is applied to the target material by a cathode arc ionization source, causing it to change from a solid state to an ionic state, and then react with reactive gases in a vacuum environment to deposit on the material surface.

[0027] The functional layer is the core structure that determines the coating's high-temperature resistance and wear resistance. It employs a composite design of titanium silicide and a second AlCrN layer, achieving a hardness of 3000-3200 Hv. In terms of process, increasing the bias voltage to 150V enhances the ion bombardment effect, refining the grains and increasing the coating density. The introduction of the titanium silicide phase forms a nanoscale dispersed reinforcing phase, significantly improving the coating's oxidation resistance and thermal stability under high-temperature conditions. The second AlCrN layer further optimizes wear resistance by adjusting the Al content. The synergistic effect of these two components ensures the mold maintains long-term service capability under high-speed cutting or die-casting conditions.

[0028] A process for preparing an integrated infiltration coating for 3D printed molds, used to form the integrated infiltration coating as described in claim 1 on the surface of a workpiece, includes the following steps: Step S1: Pretreatment, which removes the rust layer, oxide layer and microburrs attached to the workpiece surface through physical and chemical methods to obtain a clean surface with high activity, so as to improve the adhesion between the coating and the substrate.

[0029] Step S2, Hanging: The workpiece processed in step S1 is hung on the load rack inside the reactor.

[0030] Step S3: Vacuum preheating. The high-temperature vacuum environment removes volatiles from the workpiece and simultaneously homogenizes the temperature of the workpiece substrate, thereby reducing the thermal shock effect during the coating deposition process and improving the bonding strength between the coating and the workpiece substrate.

[0031] Step S4, ion etching, involves bombarding the workpiece surface with high-energy ions to remove the physically adsorbed thin oxide layer of impurities, while simultaneously activating surface atoms to enhance interfacial energy.

[0032] Step S5, ion nitriding, involves bombarding the workpiece with high-energy nitrogen ions to allow nitrogen atoms to penetrate into the surface layer of the workpiece, forming a dense ion nitrided layer.

[0033] Step S6, secondary ion etching, involves bombarding the workpiece surface with high-energy ions to remove any reaction byproducts that may remain on the workpiece surface after nitriding.

[0034] Step S7: Coating deposition. A gradient composite structure consisting of an underlayer, a transition layer, and a functional layer is constructed sequentially using physical vapor deposition technology.

[0035] Step S8: Cooling down and removing from the furnace. The internal stress is controlled by step cooling to ensure the structural integrity of the integrated coating and the workpiece.

[0036] Step S4 includes the following steps in sequence: In the low-power cleaning stage, the surface of the workpiece is cleaned by bombarding the workpiece surface with constant low-power ions to remove surface dust. During the medium-power transition phase, the power is gradually increased to enhance the etching effect by bombarding the workpiece surface with ions. In the high-power strengthening stage, the surface of the workpiece is bombarded with constant high-power ions to remove surface impurities and oxide layers.

[0037] In one specific embodiment of the present invention, the etching conditions in step S4 are a vacuum environment of high-purity argon and high-purity hydrogen.

[0038] The total time for the secondary ion etching in step S6 is less than the total time for the ion etching in step S4.

[0039] In step S7, firstly, under conditions of 430-450℃, vacuum 4.0E0pa, bias voltage 40V, and target current 80A, a transition interface with uniform thickness and low defect density is formed on the workpiece surface by controlling the ion bombardment energy and diffusion rate; this process forms the underlayer. Further, while maintaining the deposition temperature of 430-450℃, the coating hardness is smoothly transitioned from the underlayer level to the functional layer level by adjusting the target power or gas flow rate; this process forms the transition layer. Finally, the bias voltage is increased to 150V to enhance the ion bombardment effect, thereby refining the grains and increasing the coating density. Simultaneously, titanium silicide is introduced to form a nanoscale dispersed strengthening phase, significantly improving the coating's oxidation resistance and thermal stability under high-temperature conditions; this process forms the functional layer.

[0040] In step S5, the workpiece is removed after being cooled to 120-150°C in the reactor in a stepwise manner.

[0041] For workpieces weighing less than 100kg, remove them when the temperature drops below 150℃; for workpieces weighing more than 100kg, remove them when the temperature drops below 120℃.

[0042] Specifically, the pretreatment in step S1 can be used to treat the rust layer of metal, residual salt and oxide layer on the surface of heat-treated parts, oxide layer on the surface of rolled parts, oxide layer on the surface of forgings, oxide layer on the surface of welded parts, molding sand and oxide layer on the surface of castings, residual dirt and microburrs on the surface of machined parts, and the surface of old machine parts, etc., to remove the surface adhering layer and reveal the original color of the substrate. It can be used as a pretreatment step for various electroplating processes, brush plating processes, spraying processes and bonding processes to obtain an active surface and improve the adhesion between plating, coating and bonded parts.

[0043] More specifically, sandblasting equipment can be used for polishing. Polishing is a common surface treatment method that aims to improve the surface quality and smoothness of a workpiece through mechanical grinding and chemical reactions. Polishing is widely used in the surface treatment of materials such as metals, ceramics, and plastics, and can achieve effects such as deburring, scratch removal, oxide layer removal, and improved surface brightness.

[0044] Polishing equipment generally includes polishing machines, polishing discs, grinding heads, polishing cloths, polishing paste, polishing wax, and oilstones. After polishing, the workpiece should achieve a polishing grade of Ra0.2 at the working position.

[0045] Cleaning is the process of removing oil, rust, dust, and other contaminants from workpieces using chemical or (and) physical methods to ensure good coating adhesion and smooth production.

[0046] Cleaning standards: The workpiece surface is clean and free of oil. Blind holes and their interiors are cleaned from the outside to the inside with a high-pressure air gun, and there is no oil, water, or iron filings. There is no sealant or PTFE tape residue at the water pipe joints.

[0047] Specifically, in step S2, during the mounting process: Mounting standards: 1. Sufficient space is left between workpieces, and the workpieces are not obstructed.

[0048] 2. The working position is aligned with the target material.

[0049] 3. The load transfer frame should not jam or make any abnormal noises; the insulation between the workpiece bearing platform and the shielding cover, and the transfer frame slide should be above 1000 megohms.

[0050] 4. After the workpiece is mounted, the outermost part of the plated workpiece must not exceed the maximum diameter of the rotating frame.

[0051] Specifically, in step S3, during vacuum preheating: Vacuum chamber and heating time and temperature: For large workpieces (mold core, slider), the preheating temperature is 500℃ and the time is ≥4 hours; for small workpieces (inserts, ejector pins, pins), the preheating temperature is 500℃ and the preheating time is ≥3 hours; for large workpieces (inserts, ejector pins, pins) that have been used in production, the baking temperature is 500℃ and the time is ≥4 hours; for production preheating, the temperature is 500℃ and the preheating time is ≥3 hours.

[0052] Vacuum chamber vacuum degree: Baking: For large workpieces (inserts, ejector pins, pins) used in production, the baking temperature is 500℃ and the time is ≥4 hours, with a vacuum degree ≤5.0E-3. For large workpieces (mold cores, sliders) and small workpieces (inserts, ejector pins, pins), the preheating temperature of the workpiece is 500℃ and the preheating time is ≥4 hours, with a vacuum degree below 5.0E-3. After cooling down to 450℃, the vacuum degree is below 3.0E-3.

[0053] Specifically, in step S4, during ion etching: Etching conditions: 1. Fill with high-purity argon and high-purity hydrogen, vacuum 5.0-7 / 0E-2Pa. 2. Ionization power ranges from 1-3KW. The visual effect increases with increasing power. The etching process consists of three steps: First, 1kW (4 minutes) cleans surface dust. This low power level reduces the risk of arcing and short circuits, protecting the power supply and the product. Second, power is gradually increased from 1-3kW (30 minutes) to enhance the etching effect and reduce abnormal phenomena. Finally, a constant power etching process at 3kW (30 minutes) effectively removes impurities and oxidation from the product surface.

[0054] Etching effect: 1. Remove any slight oxidation, rust, or adhering impurities and dust from the product surface.

[0055] 2. Hydrogen ions in the ionized gas can effectively remove oxygen in the chamber, ensuring the purity of the film-forming environment.

[0056] Specifically, in step S5, the ion nitriding process proceeds as follows: 1. Vacuuming: Reduce the pressure inside the treatment chamber to below 5.0^-3 Pa.

[0057] 2. Ionization: The reaction gas is added to the ion source in the processing chamber, and ions are generated by adjusting the power and frequency of the ion source.

[0058] 3. Ion bombardment: A load is applied to the product through a bias power supply, causing the ion beam to bombard the material surface, resulting in displacement, breakage, and rearrangement of surface atoms.

[0059] 4. Ammonia infiltration: While bombarding with ions, reactive gases such as nitrogen are added to allow atoms on the material surface to combine with hydrogen atoms to form nitrides, with the thickness controlled at 5-10 μm.

[0060] Specifically, in the secondary ion etching step S6: The second ion etching is a crucial intermediate step in the integrated 3D printing mold coating process, bridging ion nitriding and PVD coating. Its core function is to precisely remove any residual reaction byproducts (such as loose nitride layers and unreacted reactive particle aggregation areas) that may remain on the surface after nitriding, thereby preventing these weak interface layers from negatively impacting the bonding strength of subsequent coatings. Compared to the first etching (1-3KW, 64 minutes), the second etching requires parameter optimization based on the surface condition of the nitrided layer. Typical adjustments include optimizing the gas ratio (such as increasing the proportion of inert gas to reduce over-etching) and shortening the etching time to 40-50 minutes, efficiently removing surface defects while avoiding damage to the already formed high-quality nitrided layer.

[0061] Specifically, in the coating deposition process of step S7: Film formation conditions: (Arc target current 60-120A, as the current increases, the particles and droplets become larger) 1. Auxiliary layer (underlay layer + transition layer): temperature 430-450℃, vacuum 4.0E0pa, bias voltage 40V, target current 80A.

[0062] 2. Functional layer: Temperature 430-450℃, Vacuum 2.0E0pa, Bias voltage 150V, Target current 80A. Film-forming effect: 1. Auxiliary layer (2000-2500HV): It is ion-bonded to the substrate surface, relatively soft and highly elastic, and can withstand the deformation of the substrate and release excess stress of the functional layer. The thickness is 3-5um.

[0063] 2. Functional layer (3000-3200HV): High hardness, high temperature resistance, low thermal conductivity, low affinity, chemical stability, thickness 4-6um.

[0064] Specifically, in step S8, the product is being cooled and removed from the oven: Due to the difference in thermal expansion coefficients between the mold substrate and the coating, rapid cooling can easily lead to thermal stress concentration at the interface, which in turn can cause the coating to crack or peel off. Therefore, precise control is required from four dimensions: cooling rate, final temperature, auxiliary cooling, and safe operation.

[0065] In terms of cooling rate control, natural cooling in a vacuum environment is adopted to avoid damage to coating adhesion caused by rapid cooling. Considering the process temperature of 430-450℃ during the PVD coating deposition stage, gradient cooling needs to be achieved through an in-furnace temperature control system. Typically, the initial stage (450-300℃) is controlled at a rate of 5-8℃ / min, and the rate is gradually reduced to 2-3℃ / min in the low-temperature stage (below 300℃) to match the shrinkage characteristics of the coating and the substrate.

[0066] The final temperature setting needs to be adjusted according to the weight of the workpiece: small molds (weight < 5 kg) need to be cooled to below 80℃ before being removed from the furnace, medium-sized workpieces (5-20 kg) should be controlled below 100℃, and large molds (> 20 kg) should be cooled to below 120℃. This threshold setting is based on the heat capacity theory to ensure that the temperature difference between the inside and outside of the workpiece is less than 50℃, thus avoiding the accumulation of residual stress.

[0067] For large workpieces, nitrogen is required for auxiliary cooling. Heat removal is accelerated through coordinated control of nitrogen flow rate (15-25 L / min) and pressure (0.1-0.15 MPa). However, strict adherence to safety operating procedures is essential. The furnace temperature must be corrected before charging to ensure the actual temperature is at least 5°C below the set threshold, preventing safety risks caused by the violent thermal expansion of nitrogen at high temperatures.

[0068] The above embodiments only illustrate one or more implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A one-piece coating for 3D printed molds, characterized in that, The coating consists of, from the inside out, an ion nitriding layer, a base coat, a transition layer, and a functional layer.

2. The integrated coating for a 3D printed mold according to claim 1, characterized in that, The base layer is a CrN material layer, the transition layer is an AlCrN material layer, and the functional layer is composed of a titanium silicide layer and an AlCrN layer stacked sequentially.

3. The integrated coating for a 3D printed mold according to claim 2, characterized in that, The thickness of the ion nitriding layer is 7-10 μm; the thickness of the underlayer is 2-3 μm; the thickness of the transition layer is 3-5 μm; and the thickness of the functional layer is 4-6 μm.

4. A process for preparing an integrated infiltration coating for a 3D printed mold, used to form the integrated infiltration coating as described in claim 1 on the surface of a workpiece, characterized in that, Includes the following steps: Step S1: Pretreatment, which removes the rust layer, oxide layer and microburrs attached to the workpiece surface through physical and chemical methods to obtain a clean surface with high activity, so as to improve the adhesion between the coating and the substrate. Step S2, Hanging: The workpiece processed in step S1 is hung on the load rack inside the reactor. Step S3: Vacuum preheating. The high-temperature vacuum environment removes volatiles from the workpiece and simultaneously homogenizes the temperature of the workpiece substrate to reduce the thermal shock effect during the coating deposition process, thereby improving the bonding strength between the coating and the workpiece substrate. Step S4, Ion etching, involves bombarding the workpiece surface with high-energy ions to remove the thin oxide layer of physically adsorbed impurities, while simultaneously activating surface atoms to enhance interface energy. Step S5, Ion nitriding: Nitrogen atoms are diffused into the surface of the workpiece by bombardment with high-energy nitrogen ions to form a dense ion nitriding layer. Step S6: Secondary ion etching, which uses high-energy ions to bombard the workpiece surface to remove any reaction byproducts that may remain on the workpiece surface after nitriding. Step S7: Coating deposition, using physical vapor deposition technology to sequentially construct a gradient composite structure consisting of an underlayer, a transition layer, and a functional layer; Step S8: Cooling down and removing from the furnace. The internal stress is controlled by step cooling to ensure the structural integrity of the integrated coating and the workpiece.

5. The process for preparing an integrated coating for a 3D printed mold according to claim 4, characterized in that, Step S4 includes the following steps in sequence: In the low-power cleaning stage, the surface of the workpiece is cleaned by bombarding the workpiece surface with constant low-power ions to remove surface dust. During the medium-power transition phase, the power is gradually increased to enhance the etching effect by bombarding the workpiece surface with ions. In the high-power strengthening stage, the surface of the workpiece is bombarded with constant high-power ions to remove surface impurities and oxide layers.

6. The process for preparing an integrated coating for a 3D printed mold according to claim 5, characterized in that, The etching conditions in step S4 are a vacuum environment with high-purity argon and high-purity hydrogen.

7. The process for preparing an integrated coating for a 3D printed mold according to claim 4, characterized in that, The total time for the secondary ion etching in step S6 is less than the total time for the ion etching in step S4.

8. The process for preparing an integrated coating for a 3D printed mold according to claim 4, characterized in that, In step S7 First, under the conditions of temperature 430-450℃, vacuum 4.0E0pa, bias voltage 40V, and target current 80A, by controlling the ion bombardment energy and diffusion rate, a transition interface with uniform thickness and low defect density is formed on the surface of the workpiece. This process forms the aforementioned underlayer. Furthermore, while maintaining a deposition temperature of 430-450℃, the coating hardness is smoothly transitioned from the underlayer level to the functional layer level by adjusting the target power or gas flow rate, and this process forms the transition layer. Finally, the bias voltage is increased to 150V to enhance the ion bombardment effect, thereby refining the grains and increasing the coating density. At the same time, titanium silicide is introduced to form a nanoscale dispersed strengthening phase, which significantly improves the coating's oxidation resistance and thermal stability under high-temperature conditions. The functional layer is formed during this process.

9. The process for preparing an integrated coating for a 3D printed mold according to claim 4, characterized in that, In step S5, the workpiece is removed after being cooled to 120-150°C in the reactor in a stepwise manner.

10. The process for preparing an integrated coating for a 3D printed mold according to claim 9, characterized in that, For workpieces weighing less than 100kg, remove them when the temperature drops below 150℃; for workpieces weighing more than 100kg, remove them when the temperature drops below 120℃.