A high-efficiency demolding device and method for a mold surface carbon film layer based on a variable volume cavity

Abstract

The application discloses a high-efficiency demolding equipment and method for a mold surface carbon film layer based on a variable volume cavity, relates to the technical field of precise mold surface treatment, and proposes a volume self-adaptive cavity design and a process parameter dynamic matching strategy, realizes closed-loop control of cavity volume change-process parameter self-adaption-optimal demolding effect through setting a variable volume cavity module and a built-in specific algorithm dynamic control unit, combining dynamic matching of radio frequency, gas flow, temperature and other parameters, and realizes efficient and uniform demolding of different specifications of molds, so that the limitation of the existing vacuum plasma carbon film layer removal method is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of precision mold surface treatment technology, specifically to a high-efficiency mold removal device and method based on a variable volume cavity for removing carbon film layers from the surface of a mold. Background Technology

[0002] Carbon films are formed by carbon atoms passing through sp... 3 and sp 2 Metastable structures formed by hybrid bonds possess a variety of excellent properties, including high hardness (up to 2300 HV), high elastic modulus, and low coefficient of friction (approximately 0.1 for steel). These properties make them widely used in tool coatings, molds, and precision mechanical components to improve wear resistance, lubrication, and service life. For example, in the production of optical lenses, the surface of the molding die is typically coated with a diamond-like carbon (DLC) film for protection. However, after a certain period of use, the carbon film will gradually deteriorate, requiring removal of the old film and recoating. Therefore, efficient removal of the carbon film is fundamental to the maintenance of important components such as molds.

[0003] In existing technologies, vacuum plasma reaction methods have been widely used for carbon film removal. For example, patent application CN107236926A discloses a vacuum plasma carbon film removal method. Specifically, in a low vacuum environment, charged plasma is generated by a strong oxidizing gas (such as oxygen) induced by a power source (medium frequency, pulse, or radio frequency power supply). This plasma reacts with the DLC film layer by layer, achieving damage-free film removal. This method has advantages such as no need for chemical reagents, defect-free substrate, and low cost, but it has the following limitations:

[0004] 1. Fixed cavity volume: The reaction space cannot be dynamically adjusted according to the mold size or batch size, resulting in excessive energy consumption when processing small molds and requiring batch processing of large molds, which leads to low efficiency.

[0005] 2. Static setting of process parameters: Parameters such as RF power supply frequency and gas flow rate need to be preset manually and cannot be optimized in real time according to changes in cavity volume, which can easily lead to uneven plasma distribution and fluctuations in film removal efficiency. Summary of the Invention

[0006] This invention discloses an efficient decoction device and method for removing carbon film from the surface of a mold based on a variable volume cavity. It proposes a strategy of adaptive volume cavity design and dynamic matching of process parameters to achieve efficient and uniform decoction of molds of different specifications, thereby overcoming the limitations of existing vacuum plasma carbon film removal methods.

[0007] The technical solution adopted in this invention is as follows:

[0008] A high-efficiency demolding device based on a carbon film layer on the surface of a mold with a variable volume cavity, comprising:

[0009] The variable volume cavity module consists of a cavity body and an openable cavity cover. The volume of the cavity body can be dynamically adjusted by replacing the modular cavity or the telescopic cavity wall to adapt to molds of different sizes or batches.

[0010] The frame is fixedly connected to the cavity body by flat bolts, and the bottom of the frame is provided with a set of movable wheels;

[0011] The vacuum system includes a vacuum pump, a vacuum gauge, and a KF vacuum interface. The KF vacuum interface is welded to the outer wall of the cavity body and is used to maintain the vacuum level inside the cavity ≤10Pa.

[0012] The gas supply system includes a strong oxidizing gas source, a mass flow meter, and a mosquito coil-shaped gas distributor. The bottom surface of the gas distributor has capillary holes for uniformly introducing the reaction gas.

[0013] The radio frequency (RF) power supply unit provides high-frequency current with an output frequency range of 10-18MHz. The current output terminal of the RF power supply is connected to a conductor located inside the cavity. Its power is dynamically adjusted according to the cavity volume. The adjustment relationship is as follows: when the cavity diameter increases by 50%, the power of the RF power supply is increased by 20-40%.

[0014] The control unit is electrically connected to the vacuum system, gas supply system, and radio frequency power supply unit. It is used to monitor the cavity volume, vacuum level, temperature, and plasma current in real time, and dynamically adjust the radio frequency power supply frequency, gas flow rate, reaction temperature, and time through a specific algorithm to match changes in cavity volume.

[0015] Furthermore, the variable volume cavity module has a volume range of 5~18L, the cavity body is pot-shaped, and the openable and closable cavity cover is connected to the cavity body through an adjustable hinge.

[0016] Furthermore, the cavity body has a bottom opening in the middle, and a metal tube is fixed inside the bottom opening. A fixed base is also provided inside the cavity body above the bottom opening. The fixed base is bolted to the bottom of the cavity. An insulating layer is provided on the fixed base. The insulating layer is connected to the fixed base by bolts at non-central positions. The conductor set in the cavity is a two-layer conductor disk. The conductor disk is fixed on the insulating layer. The upper layer of the conductor disk is a flat top plate for placing the mold. The lower layer of the conductor disk is a substrate. A conductor rod is fixed to the center of the substrate by conductor bolts. The conductor rod is sealed to the bottom of the cavity using a composite sealing method of plastic block interference fit, sealant and vacuum sealing clamp. The upper end of the conductor rod is covered with an insulating sleeve to prevent it from conducting with the cavity. The lower end of the conductor rod passes through the insulating layer, the fixed base, and the metal tube fixed in the bottom opening of the cavity in sequence, and is connected to the radio frequency power current output terminal of the radio frequency power supply unit.

[0017] Furthermore, the control unit is a PLC control system with a touch screen, which has a built-in volume-parameter matching algorithm and stores at least 10 sets of process parameter templates corresponding to different volumes of the algorithm. The volume-parameter matching algorithm is specifically as follows:

[0018] The RF power supply frequency f = 13 + 0.2 × (V - 10) (when V = 5L, f = 12MHz; when V = 18L, f = 14.6MHz, both within the effective output range of 10-18MHz).

[0019] Plasma current I = 0.6 + 0.04 × V;

[0020] Oxygen flow rate Q = 10×V (volume is positively correlated with gas flow rate, ensuring uniform plasma concentration in the cavity).

[0021] Reaction temperature T = 200 - 2×(V - 10) (The larger the volume, the lower the heat dissipation efficiency; appropriately reduce the temperature to avoid overheating of the mold substrate).

[0022] The effective reaction time for a single cycle is t = 25 + 0.5×(V - 10) (the larger the volume, the larger the mold size / batch size, and the longer the effective reaction time, the more thoroughly the carbon film layer is removed).

[0023] Duty cycle D = 50 + 1×(V - 10) (The larger the volume, the higher the duty cycle needs to be to maintain plasma stability).

[0024] In the above formulas, V is the cavity volume in L; f is the radio frequency power supply frequency in MHz; I is the plasma current in A; Q is the oxygen flow rate in sccm; T is the reaction temperature in °C; t is the effective reaction time in a single cycle in min; and D is the duty cycle in %.

[0025] A method for removing carbon film from the surface of a mold based on a variable volume cavity includes the following steps:

[0026] (1) Cavity volume adaptation: Select or adjust the volume of the variable volume cavity module according to the size and batch of the mold to be demolded;

[0027] (2) Vacuum environment construction: Place the mold to be demolded on the conductor plate in the cavity, close the cavity cover, and evacuate the cavity to a pressure ≤10Pa using the vacuum system;

[0028] (3) Dynamic parameter control: Input the cavity volume, and the control unit automatically adjusts or manually inputs process parameters based on the cavity volume. The volume-parameter matching algorithm is as follows:

[0029] The radio frequency power supply frequency f = 13 + 0.2×(V - 10);

[0030] Plasma current I = 0.6 + 0.04 × V;

[0031] Oxygen flow rate Q = 10 × V;

[0032] The reaction temperature T = 200 - 2×(V - 10);

[0033] The effective reaction time for a single cycle is t = 25 + 0.5 × (V - 10);

[0034] Duty cycle D = 50 + 1×(V - 10);

[0035] In the above formulas, V is the cavity volume in L; f is the radio frequency power supply frequency in MHz; I is the plasma current in A; Q is the oxygen flow rate in sccm; T is the reaction temperature in °C; t is the effective reaction time in a single cycle in min; and D is the duty cycle in %.

[0036] (4) Plasma reaction: A strong oxidizing reaction gas is introduced into the vacuum chamber and stabilized for a period of time. The radio frequency power supply is turned on to ionize the reaction gas into charged plasma, which is then used to bombard the carbon film layer on the surface of the mold in a directional manner. Through physical and chemical reactions, the carbon atoms are vaporized and discharged with the vacuum system.

[0037] (5) Real-time feedback adjustment: Monitor the plasma current and temperature inside the cavity, and fine-tune the gas flow rate and radio frequency power through a PID algorithm to ensure uniform film removal. The PID algorithm is as follows:

[0038] Plasma current deviation e I = I0 - I t ;

[0039] reaction temperature deviation e T = T0 - T t ;

[0040] Oxygen flow rate fine-tuning amount ΔQ = Kp1×e I + Ki1×∫e I dt + Kd1×(de I / dt), where Kp1=5, Ki1=0.2, Kd1=0.5;

[0041] RF power fine-tuning ΔP = Kp²×e T + Ki2×∫e T dt + Kd2×(de T / dt), where Kp2=3, Ki2=0.1, Kd2=0.3;

[0042] In the above formulas, I0 is the initially calculated plasma current, in amperes (A); I t To measure plasma current in real time, in A; T0 is the initially calculated reaction temperature, in °C; T t For real-time detection of reaction temperature, the unit is °C; Kp1, Ki1, and Kd1 are the proportional, integral, and differential coefficients for oxygen flow rate fine-tuning; Kp2, Ki2, and Kd2 are the proportional, integral, and differential coefficients for radio frequency power fine-tuning; ΔQ is the oxygen flow rate fine-tuning amount, in sccm; ΔP is the radio frequency power fine-tuning amount, in W.

[0043] (6) Cycle and termination: Stop the reaction every 30 minutes and observe the film removal effect. After a 5-10 minute break, repeat steps (3)-(5) until all or most of the carbon film layer is removed. Turn off the RF power supply, open the exhaust valve to release the gas in the cavity, and open the cavity cover to remove the mold.

[0044] Preferably, the strong oxidizing gas is oxygen.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0046] 1. Adaptive volume design enhances processing flexibility and mass production adaptability. This invention, by replacing cavity modules of different volumes (5~18L) or telescopic cavity walls, can adapt to molds with diameters of 50-500mm and batch requirements of 1-50 pieces per batch, avoiding the drawbacks of traditional fixed-volume equipment where "small molds consume high energy and large molds require batch processing." For example, when processing small molds with a diameter of 100mm, a 5L cavity is used, reducing energy consumption by 30%; when processing large molds with a diameter of 300mm, a 15L cavity is used, eliminating the need for disassembly and increasing efficiency by 50%. Furthermore, the cavity and frame are quickly fixed with bolts and equipped with movable wheels, allowing a single person to complete cavity replacement (≤10 minutes), meeting the flexible production needs of multiple mold specifications.

[0047] 2. Dynamic parameter control enables synergistic optimization of plasma uniformity and film removal efficiency. This invention uses a built-in dynamic control unit with a specific algorithm, combined with a PID algorithm to monitor plasma current and temperature, and finely adjust gas flow and radio frequency power in real time. This solves the problem of film residue or over-corrosion caused by traditional "open-loop control", increasing the film removal qualification rate from 85% to 99%.

[0048] 3. Optimized equipment structure ensures stability and automation. This invention features a mosquito coil-shaped gas distributor with capillary pores (0.5-1mm in diameter) on its bottom surface. This allows the strong oxidizing gas to form a spiral flow field within the cavity, increasing coverage to over 95% and avoiding the "edge effect" caused by traditional single-point air intake. The conductor rod uses a composite seal of "plastic block interference fit + sealant + vacuum sealing clamp," achieving a leakage rate ≤1×10⁻⁶. -5 Pa·m 3 / s; The cavity and RF power output are insulated from each other via a KF connector, with a breakdown voltage ≥2000V and improved operational stability for 3000 hours without failure; The PLC control system with touch screen has 10 built-in volume-parameter templates, supporting one-click recall and simplifying the operation process by 60%;

[0049] 4. Innovative process method, taking into account both film removal efficiency and surface quality. This invention stops the machine every 30 minutes to observe the film removal effect, combined with a "intermittent reaction" with a 5-10 minute pause, to avoid changes in substrate properties (such as a decrease in hardness) caused by continuous high temperature. The surface roughness Ra≤0.1μm, achieving a mirror-like effect. Attached Figure Description

[0050] Figure 1 A schematic diagram of the conductor at the bottom of the cavity body;

[0051] Figure 2 A schematic diagram of the sealing structure of the conductor rod;

[0052] The numbers in the diagram are as follows: 1. Top plate; 2. Substrate; 3. Insulating layer; 4. Fixed base; 5. Metal tube; 6. Conductor rod; 7. Sealing plastic block; 8. Vacuum tube connector; 9. Sealant; 10. Vacuum sealing clamp position. Detailed Implementation

[0053] The present invention will be described in detail below with reference to specific embodiments and examples, thereby making the advantages and various effects of the present invention more clearly apparent. Those skilled in the art should understand that these specific embodiments and examples are for illustrative purposes only and are not intended to limit the present invention.

[0054] Throughout this specification, unless otherwise specified, the terminology used herein should be understood to have the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any conflict, this specification shall prevail.

[0055] Unless otherwise specified, all raw materials, reagents, instruments and efficient membrane stripping equipment used in this invention can be purchased from the market or prepared by existing methods.

[0056] The demolding equipment structures used in the following embodiments include:

[0057] The variable volume cavity module consists of a cavity body and an openable cavity cover. The volume of the cavity body can be dynamically adjusted by replacing the modular cavity or the telescopic cavity wall. In this case, 10 volume cavity modules with a volume range of 5~18L (volumes of 5L, 6L, 7L, 8L, 9L, 10L, 12L, 14L, 16L, and 18L respectively) are set to adapt to molds of different sizes or batches. The cavity body is pot-shaped, and the openable cavity cover is connected to the cavity body by an adjustable hinge.

[0058] The frame is fixedly connected to the cavity body by flat bolts. The bottom of the frame is equipped with movable wheels to facilitate the replacement of the volume cavity module.

[0059] The vacuum system includes a vacuum pump, a vacuum gauge, and a KF vacuum interface. The KF vacuum interface is welded to the outer wall of the cavity body and is used to maintain the vacuum level inside the cavity ≤10Pa.

[0060] The gas supply system includes a strong oxidizing gas source, a mass flow meter, and a mosquito coil-shaped gas distributor. The bottom surface of the gas distributor has capillary holes for uniformly introducing the reaction gas.

[0061] The radio frequency (RF) power supply unit provides high-frequency current with an output frequency range of 10-18MHz. The current output terminal of the RF power supply is connected to a conductor located within the cavity. Its power is dynamically adjusted according to the cavity volume; the adjustment relationship is as follows: when the cavity diameter increases by 50%, the RF power supply power is increased by 20-40%. Figure 1 , Figure 2 The diagram shows the detailed connection between the conductor structure inside the cavity and the RF power supply. Specifically, the cavity body has a bottom opening in the middle, and a metal tube 5 is fixed inside the bottom opening. A fixed base 4 is located above the bottom opening inside the cavity body and is bolted to the bottom of the cavity. An insulating layer 3 is installed on the fixed base 4, and the insulating layer 3 is connected to the fixed base 4 via bolts at non-central positions. The conductor inside the cavity consists of two layers of conductor discs, fixed to the insulating layer 3. The upper layer of the conductor discs is a flat top plate 1 for placing the mold, and the lower layer is a substrate 2. A conductor rod 6 is fixed to the center of the substrate 2 via conductor bolts. The sealing between the conductor rod 6 and the bottom of the cavity is achieved using an interference fit of a sealing plastic block 7, sealant 9, and a vacuum sealing clamp (set in...). Figure 2The composite sealing method (position 10 of the vacuum sealing clamp) is used, in which the upper end of the conductor rod 6 is covered with an insulating sleeve to prevent it from communicating with the cavity, and the lower end of the conductor rod 6 passes through the insulating layer 3, the fixed base 4, and the metal tube 5 fixed in the opening at the bottom of the cavity in sequence, and is then connected to the radio frequency power supply current output terminal of the radio frequency power supply unit through the vacuum tube connector 8.

[0062] The control unit is electrically connected to the vacuum system, gas supply system, and radio frequency power supply unit. It is used to monitor the cavity volume, vacuum level, temperature, and plasma current in real time, and dynamically adjust the radio frequency power supply frequency, gas flow rate, reaction temperature, and time through a specific algorithm to match the changes in cavity volume. This case sets up 10 sets of process parameter templates and PID algorithms corresponding to different volumes (5L, 6L, 7L, 8L, 9L, 10L, 12L, 14L, 16L, 18L).

[0063] The present invention will be further illustrated below with specific experimental examples and comparative examples.

[0064] Example 1

[0065] I. Basic Experimental Conditions

[0066] Mold to be processed: Circular metal mold (material: 45 steel), with diamond-like carbon (DLC) film deposited on the surface, film thickness 5±0.5μm, and diameters of 100mm (small), 200mm (medium), and 300mm (large).

[0067] The conventional equipment used for comparison: fixed volume equipment (10L chamber, RF power frequency 13.56MHz, oxygen flow rate 100sccm, duty cycle 50%).

[0068] The experimental example uses the following equipment from this application: a variable volume chamber (5L / 10L / 16L) + a dynamic parameter control system (PLC control unit with 10 built-in volume-parameter matching algorithms + PID algorithm).

[0069] Evaluation indicators: film removal efficiency (μm / min), surface roughness Ra (μm), energy consumption (kWh / piece), and pass rate (%, with film residue rate ≤5% as pass).

[0070] II. Experimental Design

[0071] Experimental Example 1: Small mold (100mm in diameter) + 5L cavity

[0072] Cavity volume: 5L (suitable for small molds).

[0073] Dynamic parameter settings (calculated based on a cavity volume of 5L and the volume-parameter matching algorithm described above):

[0074] Radio frequency: f = 13 + 0.2 × (5 - 10) = 12 MHz;

[0075] Plasma current: I = 0.6 + 0.04 × 5 = 0.8 A;

[0076] Oxygen flow rate: Q = 10 × 5 = 50 sccm;

[0077] Duty cycle: D = 50 + 1 × (5 - 10) = 45%,

[0078] Reaction temperature: T = 200 - 2 × (5 - 10) = 210℃;

[0079] Reaction time: t = 25 + 0.5 × (5 - 10) = 22.5 min;

[0080] Processing procedure:

[0081] Evacuate the chamber to a pressure of 8 Pa, then introduce oxygen and stabilize for 7 minutes.

[0082] Turn on the RF power supply (initial power 180W), and fine-tune the PID algorithm in real time (current deviation (0.8A - real-time current) ≤ ±0.05A, ΔQ ≤ ±2sccm; temperature deviation (210℃ - real-time temperature) ≤ ±5℃, ΔP ≤ ±10W).

[0083] Stop the machine every 30 minutes for observation, and rest for 8 minutes; repeat for a total of 2 cycles (total processing time: 30min + 8min + 15min = 53min, effective reaction time: 22.5min + 15min = 37.5min).

[0084] Experimental results:

[0085] Film removal time: 37.5 min, efficiency: 0.13 μm / min;

[0086] Surface roughness Ra: 0.08 μm;

[0087] Energy consumption: 0.8 kWh / unit;

[0088] Pass rate: 100% (no residue in the film layer, no corrosion on the substrate).

[0089] Experimental Example 2: Medium-sized mold (200mm diameter) + 10L cavity

[0090] Cavity volume: 10L (suitable for medium-sized molds).

[0091] Dynamic parameter settings (calculated based on a cavity volume of 10L and the volume-parameter matching algorithm described above):

[0092] Radio frequency: f=13MHz;

[0093] Plasma current: I = 0.6 + 0.04 × 10 = 1.0 A;

[0094] Oxygen flow rate: Q = 100 sccm;

[0095] Duty cycle: D=50%;

[0096] Reaction temperature: T = 200℃;

[0097] Reaction time: t = 25 min;

[0098] Processing procedure:

[0099] Evacuate the chamber to a pressure of 6 Pa, then introduce oxygen and stabilize for 6 minutes.

[0100] Turn on the RF power supply (initial power 200W), and fine-tune the PID algorithm in real time (current deviation (1.0A - real-time current) ≤ ±0.05A, ΔQ ≤ ±3sccm; temperature deviation (200℃ - real-time temperature) ≤ ±5℃, ΔP ≤ ±8W).

[0101] Stop the machine every 30 minutes for observation, and rest for 5 minutes; repeat the cycle twice (total processing time: 30min + 5min + 15min = 50min, effective reaction time: 25min + 15min = 40min).

[0102] Experimental results:

[0103] Film removal time: 40 min, efficiency: 0.125 μm / min;

[0104] Surface roughness Ra: 0.09 μm;

[0105] Energy consumption: 1.2 kWh / unit;

[0106] Pass rate: 100%.

[0107] Experimental Example 3: Large mold (300mm in diameter) + 16L cavity

[0108] Cavity volume: 16L (suitable for large molds, no disassembly required).

[0109] Dynamic parameter settings (calculated based on a cavity volume of 16L and the volume-parameter matching algorithm described above):

[0110] Radio frequency: f = 13 + 0.2 × (16 - 10) = 14.2 MHz;

[0111] Plasma current: I = 0.6 + 0.04 × 16 = 1.24 A;

[0112] Oxygen flow rate: Q = 10 × 16 = 160 sccm;

[0113] Duty cycle: D = 50 + 1 × (16 - 10) = 56%,

[0114] Reaction temperature: T = 200 - 2 × (16 - 10) = 188℃;

[0115] Reaction time: t = 25 + 0.5 × (16 - 10) = 28 min;

[0116] Processing procedure:

[0117] Evacuate the chamber to a pressure of 7 Pa, then introduce oxygen and stabilize for 8 minutes.

[0118] Turn on the RF power supply (initial power 220W), and fine-tune the PID algorithm in real time (current deviation (1.24A - real-time current) ≤ ±0.08A, ΔQ ≤ ±4sccm; temperature deviation (188℃ - real-time temperature) ≤ ±5℃, ΔP ≤ ±12W);

[0119] Stop the machine every 30 minutes for observation, and rest for 10 minutes; repeat for a total of 2 cycles (total processing time: 30min + 10min + 15min = 55min, effective reaction time: 28min + 15min = 43min).

[0120] Experimental results:

[0121] Film removal time: 43 min, efficiency: 0.116 μm / min;

[0122] Surface roughness Ra: 0.10 μm;

[0123] Energy consumption: 1.8 kWh / unit;

[0124] Pass rate: 98% (3% residual rate at local corners, which meets the standard).

[0125] III. Proportional Design

[0126] Comparative Example 1: Traditional fixed-volume equipment for processing molds of different sizes

[0127] Experimental conditions: A 10L fixed chamber was used with fixed parameters (oxygen flow rate 100 sccm, frequency 13.56 MHz) to process small, medium and large molds respectively.

[0128] The experimental results are shown in Table 1.

[0129] Table 1 Results of traditional fixed-volume equipment processing molds of different sizes

[0130]

[0131] It is easy to see that the fixed volume device consumes a lot of energy when processing small molds (1.5kWh vs. 0.8kWh in Example 1), and is inefficient when processing large molds (0.04μm / min vs. 0.09μm / min in Example 3), and has poor surface quality (Ra>0.15μm).

[0132] Comparative Example 2: Variable volume but no dynamic parameter control (fixed parameters)

[0133] Experimental conditions: A 16L chamber was used to process a large mold (300mm in diameter), but the parameters were fixed at 100sccm oxygen flow rate and 13.56MHz frequency, meaning that the processing parameters were not increased proportionally to the volume.

[0134] Experimental results:

[0135] Delamination time: 90 min, efficiency: 0.06 μm / min (due to insufficient oxygen flow and low plasma concentration).

[0136] Surface roughness Ra: 0.18 μm (due to local film residue);

[0137] Pass rate: 60% (residual rate >10%).

[0138] It is evident that without dynamic parameter control, even with volume adaptation, the film removal effect cannot be guaranteed, which conversely verifies the necessity of "volume-parameter linkage".

[0139] Comparative Example 3: Dynamic parameter control + PID algorithm fine-tuning but fixed volume

[0140] Experimental conditions: A 300mm large mold was processed using a 10L fixed chamber (the mold size exceeded the chamber's compatibility range), and the dynamic parameters were set according to the 10L volume (oxygen flow rate 100sccm, frequency 13.56MHz).

[0141] Experimental results:

[0142] Demolding time: 85 min, efficiency: 0.06 μm / min (uneven plasma distribution between mold edge and center);

[0143] Surface roughness Ra: 0.22μm (edges over-etched, center residue);

[0144] Energy consumption: 2.5kWh / unit (energy consumption increased due to repeated parameter adjustments);

[0145] Pass rate: 50%.

[0146] It is evident that fixed volume cannot be adapted to large-size molds, and dynamic parameter control is insufficient to compensate for the uniformity problem caused by spatial mismatch.

[0147] Finally, it should be noted that the terms "comprising," "including," or any other variations are intended to cover a non-exclusive inclusion, such that a process, demolding method, article, or efficient demolding apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, demolding method, article, or efficient demolding apparatus. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make further changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0148] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A method for removing carbon film from the surface of a mold based on a variable volume cavity, characterized in that, Includes the following steps: (1) Cavity volume adaptation: Select or adjust the volume of the variable volume cavity module according to the size and batch of the mold to be demolded; (2) Vacuum environment construction: Place the mold to be demolded on the conductor plate in the cavity, close the cavity cover, and evacuate the cavity to a pressure ≤10Pa using the vacuum system; (3) Dynamic parameter control: Input the cavity volume, and the control unit automatically adjusts or manually inputs process parameters based on the cavity volume. The volume-parameter matching algorithm is as follows: The radio frequency power supply frequency f = 13 + 0.2×(V - 10); Plasma current I = 0.6 + 0.04 × V; Oxygen flow rate Q = 10 × V; The reaction temperature T = 200 - 2×(V - 10); The effective reaction time for a single cycle is t = 25 + 0.5 × (V - 10); Duty cycle D = 50 + 1×(V - 10); In the above formulas, V is the cavity volume in L; f is the radio frequency power supply frequency in MHz. I is the plasma current, in A; Q is the oxygen flow rate, in sccm; T is the reaction temperature, in °C; t is the effective reaction time in a single cycle, in min; D is the duty cycle, in %. (4) Plasma reaction: A strong oxidizing reaction gas is introduced into the vacuum chamber and stabilized for a period of time. The radio frequency power supply is turned on to ionize the reaction gas into charged plasma, which is then used to bombard the carbon film layer on the surface of the mold in a directional manner. Through physical and chemical reactions, the carbon atoms are vaporized and discharged with the vacuum system. (5) Real-time feedback adjustment: Monitor the plasma current and temperature inside the cavity, and fine-tune the gas flow rate and radio frequency power through a PID algorithm to ensure uniform film removal. The PID algorithm is as follows: Plasma current deviation e I = I0 - I t ; reaction temperature deviation e T = T0 - T t ; Oxygen flow rate fine-tuning amount ΔQ = Kp1×e I + Ki1×∫e I dt + Kd1×(de I / dt), where Kp1=5, Ki1=0.2, Kd1=0.5; RF power fine-tuning ΔP = Kp²×e T + Ki2×∫e T dt + Kd2×(de T / dt), where Kp2=3, Ki2=0.1, Kd2=0.3; In the above formulas, I0 is the initially calculated plasma current, in amperes (A); I t To measure plasma current in real time, in A; T0 is the initially calculated reaction temperature, in °C; T t For real-time detection of reaction temperature, the unit is °C; Kp1, Ki1, and Kd1 are the proportional, integral, and differential coefficients for oxygen flow rate fine-tuning; Kp2, Ki2, and Kd2 are the proportional, integral, and differential coefficients for radio frequency power fine-tuning; ΔQ is the oxygen flow rate fine-tuning amount, in sccm; ΔP is the radio frequency power fine-tuning amount, in W. (6) Cycle and termination: Stop the reaction every 30 minutes and observe the film removal effect. After a 5-10 minute break, repeat steps (3)-(5) until all or most of the carbon film layer is removed. Turn off the RF power supply, open the exhaust valve to release the gas in the cavity, and open the cavity cover to remove the mold.

2. The demolding method as described in claim 1, characterized in that, The strong oxidizing gas is oxygen.

3. A high-efficiency film removal device for the film removal method according to claim 1 or 2, characterized in that, include: The variable volume cavity module consists of a cavity body and an openable cavity cover. The volume of the cavity body can be dynamically adjusted by replacing the modular cavity or the telescopic cavity wall to adapt to molds of different sizes or batches. The frame is fixedly connected to the cavity body by flat bolts, and the bottom of the frame is provided with a set of movable wheels; The vacuum system includes a vacuum pump, a vacuum gauge, and a KF vacuum interface. The KF vacuum interface is welded to the outer wall of the cavity body and is used to maintain the vacuum level inside the cavity ≤10Pa. The gas supply system includes a strong oxidizing gas source, a mass flow meter, and a mosquito coil-shaped gas distributor. The bottom surface of the gas distributor has capillary holes for uniformly introducing the reaction gas. The radio frequency (RF) power supply unit provides high-frequency current with an output frequency range of 10-18MHz. The current output terminal of the RF power supply is connected to a conductor located inside the cavity. Its power is dynamically adjusted according to the cavity volume. The adjustment relationship is as follows: when the cavity diameter increases by 50%, the power of the RF power supply is increased by 20-40%. The control unit is electrically connected to the vacuum system, gas supply system, and radio frequency power supply unit. It is used to monitor the cavity volume, vacuum level, temperature, and plasma current in real time, and dynamically adjust the radio frequency power supply frequency, gas flow rate, reaction temperature, and time through a volume-parameter matching algorithm to match changes in cavity volume.

4. The high-efficiency film removal equipment as described in claim 3, characterized in that, The variable volume cavity module has a volume range of 5~18L. The cavity body is pot-shaped, and the openable cavity cover is connected to the cavity body via an adjustable hinge.

5. The high-efficiency film removal equipment as described in claim 3, characterized in that, The cavity body has a bottom opening in the middle, and a metal tube is fixed inside the bottom opening. A fixed base is also located inside the cavity body above the bottom opening. The fixed base is bolted to the bottom of the cavity. An insulating layer is provided on the fixed base, which is connected to the fixed base via bolts at non-central positions. The conductor inside the cavity consists of two layers of conductor discs, fixed to the insulating layer. The upper layer of the conductor discs is a flat top plate for placing the mold, and the lower layer is a substrate. A conductor rod is fixed to the center of the substrate via conductor bolts. The conductor rod is sealed to the bottom of the cavity using a composite sealing method of interference fit with a plastic block, sealant, and vacuum sealing clamp. An insulating sleeve is fitted over the upper end of the conductor rod to prevent it from conducting through the cavity. The lower end of the conductor rod passes through the insulating layer, the fixed base, and the metal tube fixed inside the bottom opening of the cavity before connecting to the RF power supply current output terminal of the RF power supply unit.

6. The high-efficiency film removal equipment as described in claim 3, characterized in that, The control unit is a PLC control system with a touch screen, which has a built-in volume-parameter matching algorithm and stores at least 10 sets of process parameter templates corresponding to different volumes of the algorithm. The volume-parameter matching algorithm is as follows: The radio frequency power supply frequency f = 13 + 0.2×(V - 10); Plasma current I = 0.6 + 0.04 × V; Oxygen flow rate Q = 10 × V; The reaction temperature T = 200 - 2×(V - 10); The effective reaction time for a single cycle is t = 25 + 0.5 × (V - 10); Duty cycle D = 50 + 1×(V - 10); In the above formulas, V is the cavity volume in L; f is the radio frequency power supply frequency in MHz. I is the plasma current, in A; Q is the oxygen flow rate, in sccm; T is the reaction temperature, in °C; t is the effective reaction time in a single cycle, in min; D is the duty cycle, in %.

Images