Post-treatment system of PBF printing plastic part and treatment process thereof

Abstract

The invention discloses a post-treatment system and process for PBF printing plastic parts, and the post-treatment system comprises a solvent storage bottle, a part treatment assembly and a solvent recovery assembly; a solvent is stored in the solvent storage bottle; the part processing assembly is used for carrying out fairing treatment on the PBF printing plastic part; the solvent recovery assembly is used for recovering the vaporized solvent in the part treatment assembly and re-liquefying and storing the vaporized solvent; the output end of the solvent storage bottle is connected with the input end of a solvent cabin of the part treatment assembly through a peristaltic pump, and the part treatment assembly is connected with the solvent recovery assembly through a recovery valve. According to the principle that the solvent is rapidly vaporized under the pressure difference, then uniformly reaches any surface position of the workpiece and is condensed and liquefied again, the surface defects of the workpiece are gradually dissolved and leveled under the action of the solvent, then the solvent steam is liquefied and recovered again, and the residual solvent on the surface of the workpiece is removed. The common surface roughness problem of the 3D printing plastic part can be effectively improved, and the appearance quality of the part is improved.

Description

Technical Field

[0001] The invention relates to a post-processing system for PBF-printed plastic parts and a processing process thereof. Background Art

[0002] Compared with other 3D printing technologies, powder bed fusion (PBF) technology has shown an increasingly significant competitive advantage and important position in the growing field of 3D printed consumer products due to its higher degree of freedom in complex structure design and the recycling characteristics of powder raw materials during processing. For example, in the fields of high-end customized eyeglass frames, medical stents, customized robot parts, rehabilitation aids, automotive parts, and civilian wearable consumer products. However, due to its unique processing method, after the PBF-formed 3D printed plastic parts are processed, their appearance will inevitably have processing defects such as high roughness, plastic powder residue, and printing layer lines, which are unacceptable for consumer products with high appearance requirements. Therefore, the surface of the printed parts needs to be polished.

[0003] There are two ways to polish 3D plastic printed parts: physical and chemical. One is to sandblast the surface of the printed parts by selecting non-metallic microbeads of appropriate particle size, but the physical sandblasting method can easily damage the fine structure of the parts. At the same time, whether it is hard plastic or elastomer, the degree of polishing is low, and the surface of the parts cannot reach a smooth level; the second is to use chemical methods, using organic good solvents for plastics, and post-process the surface of the parts by dipping or steam fumigation. Among them, the dipping process is difficult to control during mass production, and often leads to the production of defective products due to structural differences in different positions of parts and the lack of special equipment. The cumbersome operating procedures and complex working environment lead to exposure to organic chemicals, which pollutes the environment and personnel. The fumigation process is more uniform for post-processing the surface of parts. At present, there are equipment for smoothing 3D printed plastic parts on the market. The principle is to place the parts in a closed chamber, and then pass the hot steam of organic solvents to wrap the parts, so that the solvent slowly condenses and deposits on the surface of the parts. Through the slight dissolution of the surface of the parts by the solvent, the uneven or defective positions on the surface are filled, so as to achieve the effect of smoothing and polishing the parts. The equipment and process operation process have less pollution and are easier to control.

[0004] Special fumigation and smoothing 3D printing post-processing equipment mainly comes from foreign companies. However, most of its processes are limited by the path of solvent vapor and droplet introduction, making it difficult to obtain uniform treatment on the surface of parts due to structural differences. It is even difficult for solvents to reach the location of complex and fine structures, which leads to uneven surface treatment of the final parts or deformation of the parts.

[0005] With the expansion and progress of the 3D printing consumer product market, how to achieve the diversity and complexity of mass production of 3D printing parts has put forward higher requirements and standards for equipment and processes. Domestic and foreign printer equipment companies continue to progress and develop, but the research and development and progress of post-processing equipment and related processes have been relatively stagnant and monopolized by foreign technology. Even though domestic equipment has relevant patents and information reports, there is still a lack of in-depth research on the correlation between processing technology and part performance, resulting in unsatisfactory processing results requiring multiple processing, poor matching between process and material, and high solvent residues requiring secondary drying.

[0006] Therefore, there is much room for improvement in the working principle, operating system and process parameters of post-processing equipment in terms of economy, scientificity and efficiency. Summary of the invention

[0007] The object of the present invention is to provide a post-processing system and a processing process for PBF-printed plastic parts to solve the problems raised in the above-mentioned background technology.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: a post-processing system for PBF-printed plastic parts, comprising a solvent storage bottle, a part processing component, and a solvent recovery component;

[0009] The solvent storage bottle stores a solvent inside;

[0010] The part processing assembly is used to perform smoothing on PBF printed plastic parts;

[0011] The solvent recovery component is used to recover the vaporized solvent in the parts processing component and re-liquefy and store it;

[0012] The output end of the solvent storage bottle is connected to the input end of the solvent compartment of the parts processing assembly through a peristaltic pump, and the parts processing assembly is connected to the solvent recovery assembly through a recovery valve.

[0013] Preferably, the part processing assembly comprises a reaction chamber, wherein a hanger for hanging PBF-printed plastic parts is provided inside the reaction chamber.

[0014] A first vacuum pump is connected to one side of the reaction chamber, and the air pressure in the reaction chamber is adjusted by the first vacuum pump;

[0015] The input end of the reaction chamber is connected to the output end of the solvent chamber through a pressure charging valve, and the input end of the solvent chamber is connected to the input end of the peristaltic pump.

[0016] Preferably, a heating element is provided at the reaction chamber, and the heating element comprises a heater, and the heater is used to heat the reaction chamber.

[0017] Preferably, the solvent recovery component comprises a recovery cabin, an air bag is arranged inside the recovery cabin, and an air inlet valve and an air exhaust valve for controlling the air pressure of the air bag are arranged outside the recovery cabin;

[0018] The output end of the recovery cabin is connected to a condenser pipe through a condenser valve, and the output end of the condenser pipe is connected to a recovery bottle.

[0019] Preferably, a second vacuum pump is provided at the recovery cabin, and the air pressure in the recovery cabin is adjusted by the second vacuum pump.

[0020] Preferably, the solvent is one or a mixture of hexafluoroisopropanol, methanol, isopropanol, xylene, p-xylene, acetone, chloroform, and dichloromethane.

[0021] Preferably, the PBF-printed plastic parts include PA12, PA11, PP, TPU, PEBAX, TPA plastic parts printed by PBF, and the plastic parts include solid and / or lattice parts; the weight of the PBF-printed plastic parts does not exceed 1000g, and the number of the PBF-printed plastic parts is 1 to 50.

[0022] A processing process of a post-processing system for PBF printing plastic parts, comprising the following steps:

[0023] Step A: Install the PBF-printed plastic parts on a detachable rack and place them in the reaction chamber. After the PBF-printed plastic parts are no longer shaking or touching each other, seal the reaction chamber and lock the end cap.

[0024] Step B: according to the material, weight, number and processing target of the PBF-printed plastic parts in the reaction chamber, set the solvent type, solvent dosage, vacuum pressure, holding time, drying temperature and time, and circulating air temperature. After the setting is completed, the solvent in the solvent storage bottle is transported to the solvent chamber by the peristaltic pump for standby use;

[0025] Step C, using a first vacuum pump to evacuate the reaction chamber to a vacuum state;

[0026] Step D, opening the pressure-charging valve between the reaction chamber and the solvent chamber, the solvent chamber instantly reaches a vacuum state, the solvent in the solvent chamber boils violently, the solvent vaporizes, the solvent vapor fills the reaction chamber, and a uniform steam atmosphere is formed in the reaction chamber, and at the same time, the steam atmosphere wraps the parts on the rack;

[0027] Step E, close the pressure valve, and the solvent vapor condenses into an equal amount of liquid layer on the surface of the part, and then maintain the pressure and wait;

[0028] Step F, turning on the heater to heat the reaction chamber to dry the parts inside the reaction chamber, turning on the second vacuum pump to pump the pressure inside the recovery chamber and the airbag to below 0.1 KPa, at which time the airbag is in a state where the exhaust valve is open and the intake valve is closed;

[0029] Step G, closing the second vacuum pump and opening the recovery valve, the solvent vapor in the reaction chamber rapidly enters the recovery chamber under the action of the pressure difference, and the liquid solvent on the surface of the parts evaporates faster;

[0030] Step H, closing the recovery valve and the air bag exhaust valve, opening the air bag air inlet valve and the condensation valve, the inflated air bag in the recovery cabin is rapidly compressed, and the pressure in the cavity increases to a normal pressure state. At this time, the high-concentration solvent vapor is pushed into the condenser tube and condensed into droplets to be collected in the recovery bottle;

[0031] Step I: close the condensation valve and the airbag inlet valve, open the airbag exhaust valve and the second vacuum pump, and pump the recovery cabin and airbag pressure to below 0.1Kpa to enter the next recovery cycle;

[0032] Step J: After the recovery cycle is completed, the reaction chamber is ventilated to the atmosphere, the end cover is opened, and the parts are taken out.

[0033] Preferably, the pressure of the vacuum state is 0.1 to 20 kPa, and the pressure holding time is 5 to 20 minutes.

[0034] Preferably, the processing target includes surface smoothing processing and depth enhancement processing;

[0035] The air temperature of the recycling cycle is 30 to 80 degrees Celsius, the number of recycling cycles is 0 to 20 times, and the recycling cycle time is 5 minutes;

[0036] The drying temperature is 30 to 80 degrees Celsius, and the drying time is 10 to 120 minutes.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] This method uses the principle of high-speed and uniform diffusion of gas molecules during vacuum inflation to quickly connect the solvent chamber under normal pressure with the reaction chamber under vacuum. At this time, the solvent in the solvent chamber boils violently due to the rapid drop in pressure, and is introduced into the reaction chamber through the pressure-charging valve in the form of steam. At this time, the solvent vapor will reach any surface position of all parts at the speed of sound evenly, and will not be affected by the shape of the shape. Then the solvent vapor will quickly liquefy and adhere to the surface of the parts to form a liquid layer. At this time, the surface defects of the parts are gradually dissolved and leveled under the action of the solvent, and the pressure in the reaction chamber also increases. When the pressure in the cavity exceeds the saturated vapor pressure value of the solvent, the remaining liquid solvent will no longer evaporate, which also avoids the problem of over-treatment and material softening and collapse caused by excessive contact of the surface of the parts with too much solvent. After maintaining the preset time, the surface of the parts is smoothed, and then enters the drying and solvent recovery stage. The process principle of this equipment has controllable processing effect on the parts, is not easy to deform, and the surface of the treated parts is uniform and smooth, without solvent residue or unfriendly odor. This method can be used to process commonly used 3D printing plastics PA12, PA11, TPA, Pebax, TPU, and PP; no solvent residue is left inside the equipment after treatment, and the solvent solution in the recovery chamber can be recycled and reused, which has good safety and environmental protection.

[0039] This invention studies the microstructure and performance of different plastic printed parts before and after post-processing, comprehensively analyzes data and combines processing practice, selects individual key and easily accessible characteristics as import parameters, introduces relevant algorithms for material type, weight, density and other characteristics, and during processing, matches the amount of solvent and related process parameters according to the actual situation of the parts to achieve precise control of the processing effect, reduce solvent waste and achieve efficient processing.

[0040] The equipment of the present invention has two compartments, a solvent evaporation compartment and a solvent storage compartment. Before each treatment, after calculating the amount, the solvent in the storage compartment is quantitatively delivered to the evaporation compartment via a peristaltic pump, and then the product is treated. This avoids the need to manually add solvents for each treatment, greatly reducing the volatilization of solvents and human inhalation.

[0041] The present invention adopts the method of pressurized condensation. After the treatment is completed, the gas is transferred from the reaction chamber to the recovery chamber. Then, the effective space in the recovery chamber is compressed by inflating the airbag, thereby pressurizing the gas in the chamber, and finally passing through the condenser. At this time, the solvent concentration far exceeds the critical point of the saturated vapor pressure under this condition, and the solvent can be liquefied, separated, and recycled.

[0042] The present invention adopts an upper-opening door design, and is matched with a pull-up steel hanger for parts of different sizes, which makes it more convenient to place and take out parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic diagram of a system flow of an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of the structure of a system device according to an embodiment of the present invention;

[0045] Figure 3 The SEM images of the PA12 parts before and after the surface smoothing treatment in the embodiment of the present invention;

[0046] Figure 4 The SEM images of the PA11 parts before and after the surface smoothing treatment in the embodiment of the present invention;

[0047] Figure 5 The SEM images of the surface of the PEBAX parts before and after smoothing treatment in the embodiment of the present invention;

[0048] Figure 6 The SEM images of the TPA parts before and after the surface smoothing treatment in the embodiment of the present invention are shown;

[0049] Figure 7 This is a SEM image of the PA12 part subjected to the depth enhancement treatment according to an embodiment of the present invention.

[0050] In the figure: 1. solvent storage bottle; 2. parts processing assembly; 201. reaction chamber; 202. rack; 203. first vacuum pump; 204. heating element; 205. charging valve; 206. solvent chamber; 3. solvent recovery assembly; 301. recovery chamber; 302. air bag; 303. air inlet valve; 304. exhaust valve; 305. condensation valve; 306. condensation tube; 307. recovery bottle; 308. second vacuum pump; 4. peristaltic pump; 5. recovery valve. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with embodiments.

[0052] Examples 1 to 4 are surface smoothing treatments for different materials, Example 5 is a deep treatment of the material in Example 1, and Example 6 is a control example.

[0053] Example 1

[0054] like Figure 1-3 As shown, 5 groups of PA12 parts subjected to standard tensile test (GB / T528-200), flexural test (GB T9341-2008) and impact test (GB / T 18743.1-2022) after printing and sandblasting are weighed and mounted on the rack 202 and placed in the reaction chamber 201. After the PBF-printed plastic parts have no obvious shaking and no mutual contact, the reaction chamber 201 is sealed and the end cover is locked;

[0055] In the equipment interface, select the material type PA12, the solid type, the part weight as 38.6g, the number as 15, and the processing target as surface smoothing.

[0056] The solvent type is hexafluoroisopropanol, the solvent dosage is 15 ml, the vacuum pressure is 10 kPa, the pressure holding time is 2 min, the drying temperature is 60 ° C, the time is 30 min, the circulating air temperature is 55 ° C, and the number of cycles is 2 times;

[0057] After the setting is completed, the solvent in the solvent storage bottle 1 is transported to the solvent chamber 206 by the peristaltic pump 4 for standby use;

[0058] After the reaction chamber 201 is evacuated to 10 kPa using the first vacuum pump 203; the pressure-charging valve 205 between the reaction chamber 201 and the solvent chamber 206 is opened, the solvent chamber 206 instantly reaches a vacuum state, the hexafluoroisopropanol boils briefly and then vaporizes instantly, forming a steam atmosphere including surrounding the PA12 parts, the pressure-charging valve 205 is closed, the solvent vapor condenses into an equal amount of liquid layer on the surface of the parts, and the pressure is maintained and waited, the surface of the PA12 parts is slightly dissolved by the hexafluoroisopropanol, and gradually leveled to achieve a smooth effect;

[0059] The heater is turned on to heat the reaction chamber 201 to dry the parts inside the reaction chamber 201, and the second vacuum pump 308 is turned on to reduce the pressure inside the recovery chamber 301 and the air bag 302 to below 0.1 Kpa. At this time, the air bag 302 is in a state where the air extraction valve 304 is open and the air inlet valve 303 is closed; the second vacuum pump 308 is turned off, and the recovery valve 5 is opened. The solvent vapor in the reaction chamber 201 quickly enters the recovery chamber 301 under the action of the pressure difference, and the liquid solvent on the surface of the parts evaporates faster.

[0060] Close the recovery valve 5 and the air bag 302 exhaust valve 304, open the air bag air inlet valve 303 and the condensation valve 305, the inflated air bag 302 in the recovery cabin 301 is rapidly compressed, and the pressure in the cavity increases to normal pressure. At this time, the high-concentration solvent vapor is pushed into the condenser 306, and condensed into droplets collected in the recovery bottle 307; close the condensation valve 305 and the air bag air inlet valve 303, open the air bag 302 exhaust valve 304 and the second vacuum pump 308, and pump the pressure of the recovery cabin 301 and the air bag 302 to below 0.1Kpa to enter the next recovery cycle; after the recovery cycle is repeated twice, after the cycle is completed, the reaction cabin 201 is ventilated to the atmosphere, the end cover is opened, and the parts are taken out.

[0061] Observe the surface, weigh, and perform physical and mechanical property tests according to standards.

[0062] Example 2

[0063] like Figure 1-2As shown in FIG. 4 , the difference between this embodiment and embodiment 1 is that the material type of this embodiment is PA11, the solid type, the weight of the part is 39.6 g, and the processing target is surface smoothing.

[0064] The corresponding process parameters are: solvent type is hexafluoroisopropanol, dosage is 21 ml, vacuum pressure is 8 kPa, holding time is 4 min, drying temperature is 60 ° C, time is 30 min, circulating air temperature is 55 ° C, and the number of cycles is 2 times.

[0065] Example 3

[0066] like Figure 1-2 As shown in Figure 5, the difference between this embodiment and embodiment 1 is that the material type of this embodiment is PEBAX, the solid type, the weight of the parts is 39.6 g, the number is 15, and the processing target is surface smoothing.

[0067] The corresponding process parameters are: solvent type is hexafluoroisopropanol:chloroform (3:1) mixed solvent, dosage is 18 ml, vacuum pressure is 15 kPa, holding time is 2 min, drying temperature is 60°C, time is 30 min, circulating air temperature is 55°C, and number of cycles is 4 times.

[0068] Example 4

[0069] like Figure 1-2 As shown in Figure 6, the difference between this embodiment and embodiment 1 is that the material type of this embodiment is TPA, the lattice part type, the weight of the part is 210g, the number is 2, and the processing target is surface smoothing.

[0070] The corresponding process parameters are: solvent type hexafluoroisopropanol and methanol (5:1) mixed solvent, dosage 18 ml, vacuum pressure 15 kPa, holding time 2 min, drying temperature 60 ° C, time 30 min, circulating air temperature 55 ° C and 4 cycles.

[0071] Example 5

[0072] like Figure 1-2 As shown in 7, the difference between this embodiment and embodiment 1 is that the material type of this embodiment is PA12, the solid type, the weight of the parts is 38.6g, the number is 15, and the processing target is set to deep enhancement processing.

[0073] The corresponding process parameters are: solvent type is hexafluoroisopropanol, dosage is 20 ml, vacuum pressure is 5 kPa, holding time is 5 min, drying temperature is 60 ° C, time is 30 min, circulating air temperature is 55 ° C, and the number of cycles is 2 times.

[0074] Example 6

[0075] This embodiment compares the processed data of the printed plastic parts after the processing of Embodiments 1 to 4 with the data before the processing, as shown in Table 1;

[0076] The data after processing in Example 5 are compared with the data after processing in Example 1, as shown in Table 2:

[0077] Table 1 Comparison of physical and mechanical properties of different materials with surface smoothing

[0078]

[0079] Table 2 Comparison of physical and mechanical properties of PA12 surface smoothing treatment and deep enhancement treatment

[0080]

[0081]

[0082] As can be seen from the above table, the parts treated by the two methods described in the present invention have significantly improved physical and mechanical properties such as tensile strength, elongation at break, flexural modulus at room temperature, and surface roughness. Compared with the surface smoothing treatment method, the parts after deep enhancement treatment have further improved tensile strength and elongation at break, while the flexural modulus at room temperature further decreases, and the flexibility of the parts is significantly improved. It can effectively solve the common problems of rough surface and poor printing quality of 3D printed plastic parts, while improving their appearance quality and physical and mechanical properties, and finally achieve good aesthetics and reliability of parts.

[0083] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view. In addition, it should be understood that although this specification is described in accordance with the implementation mode, it does not include only one technical solution. This narrative mode of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in the embodiments can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A post-processing system for PBF-printed plastic parts, characterized by: It includes a solvent storage bottle (1), a parts processing assembly (2), and a solvent recovery assembly (3); The solvent storage bottle (1) stores a solvent therein; The part processing component (2) is used to perform smoothing on the PBF printed plastic parts; The solvent recovery component (3) is used to recover the vaporized solvent in the parts processing component (2) and re-liquefy and store it; The output end of the solvent storage bottle (1) is connected to the input end of the solvent chamber (206) of the part processing component (2) via a peristaltic pump (4), and the part processing component (2) is connected to the solvent recovery component (3) via a recovery valve (5).

2. A post-processing system for PBF-printed plastic parts according to claim 1, characterized in that: The part processing assembly (2) comprises a reaction chamber (201), wherein a hanger (202) for hanging PBF-printed plastic parts is arranged inside the reaction chamber (201). A first vacuum pump (203) is connected to one side of the reaction chamber (201), and the reaction chamber (201) adjusts the air pressure in the reaction chamber (201) through the first vacuum pump (203); The input end of the reaction chamber (201) is connected to the output end of the solvent chamber (206) via a pressure charging valve (205), and the input end of the solvent chamber (206) is connected to the input end of the peristaltic pump (4).

3. A post-processing system for PBF-printed plastic parts according to claim 2, characterized in that: A heating element (204) is provided at the reaction chamber (201), wherein the heating element (204) comprises a heater, and the heater is used to heat the reaction chamber (201).

4. A post-processing system for PBF-printed plastic parts according to claim 3, characterized in that: The solvent recovery component (3) comprises a recovery chamber (301), an air bag (302) is arranged inside the recovery chamber, and an air inlet valve (303) and an air extraction valve (304) for controlling the air pressure of the air bag (302) are arranged outside the recovery chamber (301); The output end of the recovery chamber (301) is connected to a condenser pipe (306) via a condenser valve (305), and the output end of the condenser pipe (306) is connected to a recovery bottle (307).

5. A post-processing system for PBF-printed plastic parts according to claim 4, characterized in that: The recovery cabin (301) is provided with a second vacuum pump (308), and the recovery cabin (301) adjusts the air pressure in the recovery cabin (301) through the second vacuum pump (308).

6. A post-processing system for PBF-printed plastic parts according to claim 5, characterized in that: The solvent is one or a mixture of hexafluoroisopropanol, methanol, isopropanol, xylene, p-xylene, acetone, chloroform and dichloromethane.

7. A post-processing system for PBF-printed plastic parts according to claim 6, characterized in that: The PBF-printed plastic parts include PA12, PA11, PP, TPU, PEBAX, and TPA plastic parts printed by PBF, and the plastic parts include solid and / or lattice parts; the weight of the PBF-printed plastic parts does not exceed 1000g, and the number of the PBF-printed plastic parts is 1 to 50.

8. A processing process of a post-processing system for PBF-printed plastic parts according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step A, installing the PBF-printed plastic parts on a detachable hanger (202) and placing them in the reaction chamber (201), and after the PBF-printed plastic parts have no obvious shaking and no mutual contact, sealing the reaction chamber (201) and locking the end cover; Step B, according to the material, weight, number and processing target of the PBF-printed plastic parts in the reaction chamber (201), the solvent type, solvent dosage, vacuum pressure, pressure holding time, drying temperature and time, and circulating air temperature are set. After the setting is completed, the solvent in the solvent storage bottle (1) is transported to the solvent chamber (206) through the peristaltic pump (4) for standby use; Step C: using a first vacuum pump (203) to evacuate the reaction chamber (201) to a vacuum state; Step D, opening the pressure-charging valve (205) between the reaction chamber (201) and the solvent chamber (206), causing the solvent chamber (206) to instantly reach a vacuum state, causing the solvent in the solvent chamber (206) to boil violently, vaporize, and fill the reaction chamber (201) with solvent vapor, thereby forming a uniform steam atmosphere in the reaction chamber (201), and at the same time, the steam atmosphere wraps the parts on the rack (202); Step E, closing the pressure-charging valve (205), allowing the solvent vapor to condense into an equal amount of liquid layer on the surface of the part, and then maintaining the pressure and waiting; Step F, turning on the heater to heat the reaction chamber (201) to dry the parts inside the reaction chamber (201), turning on the second vacuum pump (308), and pumping the pressure inside the recovery chamber (301) and the air bag (302) to below 0.1 KPa, at which time the air bag (302) is in a state where the air extraction valve (304) is open and the air intake valve (303) is closed; Step G, closing the second vacuum pump (308), opening the recovery valve (5), and allowing the solvent vapor in the reaction chamber (201) to quickly enter the recovery chamber (301) under the action of the pressure difference, while accelerating the evaporation of the liquid solvent on the surface of the part; Step H, closing the recovery valve (5) and the airbag exhaust valve (304), opening the airbag air inlet valve (303) and the condensation valve (305), and rapidly compressing the inflated airbag (302) in the recovery chamber (301), increasing the pressure in the chamber to a normal pressure state, at which time the high-concentration solvent vapor is pushed into the condenser (306), and condensed into droplets that are collected in the recovery bottle (307); Step I: close the condensation valve (305) and the airbag air inlet valve (303), open the airbag exhaust valve (304) and the second vacuum pump (308), and pump the pressure of the recovery cabin (301) and the airbag (302) to below 0.1 KPa, and enter the next recovery cycle; Step J: After the recovery cycle is completed, the reaction chamber (201) is ventilated to the atmosphere, the end cover is opened, and the parts are taken out.

9. The processing technology of the post-processing system for PBF-printed plastic parts according to claim 8, characterized in that: in, The pressure of the vacuum state in step B is 0.1 to 20 kPa, and the pressure holding time is 5 to 20 minutes.

10. The processing technology of the post-processing system for PBF printing plastic parts according to claim 8, characterized in that: in, The processing targets in step B include surface smoothing processing and depth enhancement processing; The air temperature of the recycling cycle is 30 to 80 degrees Celsius, the number of recycling cycles is 0 to 20 times, and the recycling cycle time is 5 minutes; The drying temperature is 30 to 80 degrees Celsius, and the drying time is 10 to 120 minutes.

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