A post-processing system for PBF printed plastic parts and a processing method thereof

Abstract

The application discloses a post-processing system for PBF printed plastic parts and a processing technology thereof. The post-processing system comprises a solvent storage bottle, a part processing assembly and a solvent recovery assembly. The solvent storage bottle stores solvent inside. The part processing assembly is used for fairing treatment of PBF printed plastic parts. The solvent recovery assembly is used for recovering the vaporized solvent in the part processing assembly and storing the recovered solvent in liquid form. The output end of the solvent storage bottle is connected with the input end of a solvent cabin of the part processing assembly through a peristaltic pump. The part processing assembly and the solvent recovery assembly are connected through a recovery valve. The application utilizes the principle that the solvent is rapidly vaporized under pressure difference, uniformly reaches any surface position of the workpiece and is condensed and liquefied again, so that the surface defects of the workpiece are gradually dissolved and leveled under the action of the solvent, and then the solvent vapor is recovered and the residual solvent on the surface of the workpiece is removed. The application can effectively improve the common surface roughness problem of 3D printed plastic parts and improve the appearance quality of the parts.

Description

Technical Field

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

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

[0003] There are two methods for polishing 3D printed plastic parts: physical and chemical. The first involves sandblasting the surface with non-metallic microbeads of appropriate particle size. However, physical sandblasting can easily damage the part's fine structure. Furthermore, whether treating hard plastics or elastomers, the polishing level is low, and the surface cannot be smooth. The second method involves chemical post-treatment of the part's surface using organic solvents for plastics, either through immersion or steam fumigation. The immersion process is difficult to control during mass production and often results in defective products due to structural variations in different parts and a lack of specialized equipment. The cumbersome procedures and complex working environment lead to exposure to organic chemicals, causing significant environmental and personnel pollution. Fumigation, on the other hand, produces a more uniform surface finish. Currently, commercially available equipment for smoothing 3D printed plastic parts is available. The part is placed in a sealed chamber, then heated steam containing an organic solvent is introduced to the part, causing the solvent to slowly condense and deposit on the surface. The solvent then slightly dissolves the surface, filling any surface irregularities or imperfections, achieving a smooth, polished finish. The equipment and process operation process has less pollution and is easier to control.

[0004] Specialized fumigation and smoothing 3D printing post-processing equipment primarily comes from foreign companies. However, these processes are often limited by the paths through which solvent vapor and droplets are introduced, making it difficult to achieve uniform surface treatment due to structural variations. Complex and delicate structures are even difficult for the solvent to reach, resulting in uneven surface treatment or deformation of the final part.

[0005] With the expansion and advancement of the 3D printing consumer product market, achieving the diverse and complex mass production of 3D-printed parts has placed higher demands and standards on equipment and processes. While printer equipment companies both domestically and internationally continue to advance and develop, the research and development of post-processing equipment and related processes has remained relatively stagnant, dominated by foreign technology. Even with relevant patents and information reported for domestic equipment, a lack of in-depth research into the correlation between processing and part performance has led to issues such as unsatisfactory processing results requiring multiple treatments, poor process-material compatibility, and high levels of residual solvents requiring secondary drying.

[0006] Therefore, there is much room for improvement in the working principles, operating systems 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] 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 parts processing assembly, and a solvent recovery assembly;

[0009] The solvent storage bottle stores a solvent;

[0010] The part processing assembly is used to smooth the 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 includes a reaction chamber, wherein a hanger for hanging PBF-printed plastic parts is provided inside the reaction chamber.

[0014] One side of the reaction chamber is connected to a first vacuum pump, and the reaction chamber adjusts the air pressure in the reaction chamber through 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 includes a recovery cabin, an air bag is provided inside the recovery cabin, and an air inlet valve and an air exhaust valve for controlling the air pressure of the air bag are provided 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, 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 1000 g, and the number of the PBF-printed plastic parts is 1 to 50.

[0022] A post-processing system for PBF-printed plastic parts includes the following steps:

[0023] Step A: Mount the PBF-printed plastic parts on a removable rack and place them in the reaction chamber. Once the PBF-printed plastic parts are no longer shaking or touching each other, seal the reaction chamber and secure the end caps.

[0024] Step B: Based on the material, weight, number of plastic parts to be printed by PBF in the reaction chamber, as well as the processing target, the solvent type, solvent dosage, vacuum pressure, holding time, drying temperature and time, and circulating air temperature are set. After the settings are completed, the solvent in the solvent storage bottle is transported to the solvent chamber via a peristaltic pump for use.

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

[0026] Step D: Open the pressure valve between the reaction chamber and the solvent chamber. The solvent chamber instantly reaches a vacuum state, causing the solvent in the solvent chamber to boil violently and vaporize. The solvent vapor fills the reaction chamber, forming a uniform steam atmosphere in the reaction chamber. 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: Turn on the heater to heat the reaction chamber to dry the parts inside the reaction chamber, turn on the second vacuum pump to pump the pressure in the recovery chamber and the airbag to below 0.1 kPa. At this time, the airbag is in a state where the exhaust valve is open and the intake valve is closed;

[0029] Step G: Turn off the second vacuum pump and open the recovery valve. The solvent vapor in the reaction chamber quickly enters the recovery chamber under the action of the pressure difference, while the liquid solvent on the surface of the part evaporates faster.

[0030] Step H: Close the recovery valve and the airbag exhaust valve, open the airbag inlet valve and the condensation valve, and the inflated airbag in the recovery chamber is rapidly compressed, and the pressure in the chamber increases to normal pressure. At this time, the high-concentration solvent vapor is pushed into the condenser and condensed into droplets that are 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 chamber 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 targets include surface smoothing 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 leverages the high-speed, uniform diffusion of gas molecules during vacuum inflation. It rapidly connects a solvent chamber at atmospheric pressure to a reaction chamber under vacuum. The solvent in the chamber then boils violently due to the rapid drop in pressure, and is introduced into the reaction chamber as vapor through a pressure-injection valve. The solvent vapor then reaches all surface locations of all parts at the speed of sound, unaffected by external obstructions. It then rapidly liquefies and adheres to the part surface, forming a liquid layer. Surface defects gradually dissolve and level under the action of the solvent, increasing the pressure in the reaction chamber. Once the pressure in the chamber exceeds the saturated vapor pressure of the solvent, the remaining liquid solvent ceases to evaporate, thus avoiding overtreatment and material softening and collapse caused by excessive solvent exposure. After a predetermined period of time, the part surface is smoothed, and the drying and solvent recovery stages then begin. This process ensures controllable part treatment results, minimizes deformation, and produces a uniform, smooth surface with no residual solvent or unpleasant 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 device after treatment, and the solvent solution in the recovery chamber can be recycled and reused, which is safe and environmentally friendly.

[0039] This method studies the microstructure and properties of various plastic printed parts before and after post-processing. Combining comprehensive data analysis with processing practices, it selects key and readily available properties as input parameters. Algorithms for material type, weight, density, and other properties are incorporated. During processing, the solvent dosage and related process parameters are tailored to the actual part conditions. This allows for precise control of the treatment effect, minimizing solvent waste and ensuring efficient processing.

[0040] The device comprises two compartments: a solvent evaporation chamber and a solvent storage chamber. Before each treatment, the required amount of solvent is calculated and then delivered quantitatively from the storage chamber to the evaporation chamber via a peristaltic pump for product processing. This eliminates the need for manual solvent addition for each treatment, significantly reducing solvent volatilization and human inhalation.

[0041] The present invention utilizes a pressurized condensation method. After processing is complete, the gas is transferred from the reaction chamber to a recovery chamber. The airbag is then inflated to compress the effective space within the recovery chamber, thereby pressurizing the gas within the chamber before passing through a condenser. At this point, the solvent concentration far exceeds the critical point of saturated vapor pressure under these conditions, enabling solvent liquefaction, separation, and recycling.

[0042] The present invention adopts an upper door design, combined with a pull-type 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 diagram of an embodiment of the present invention;

[0044] Figure 2 Schematic diagram of the system structure of an embodiment of the present invention;

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

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

[0047] Figure 5 These are SEM images of the surface of the PEBAX part before and after smoothing treatment according to an embodiment of the present invention;

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

[0049] Figure 7 This is an SEM image of a PA12 part subjected to 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. Hanger; 203. First vacuum pump; 204. Heating element; 205. Charging valve; 206. Solvent chamber; 3. Solvent recovery assembly; 301. Recovery chamber; 302. Air bag; 303. 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 solutions and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with embodiments.

[0052] Examples 1 to 4 are surface smoothing treatments performed on different materials, Example 5 is 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, five groups of PA12 parts that have been sandblasted and passed the standard tensile test (GB / T528-200), flexural test (GB T9341-2008), and impact test (GB / T 18743.1-2022) 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 contact with each other, the reaction chamber 201 is sealed and the end cover is locked.

[0055] On 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;

[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, and the solvent chamber 206 instantly reaches a vacuum state. The hexafluoroisopropanol boils briefly and then vaporizes instantly, forming a steam atmosphere that surrounds the PA12 part. The pressure-charging valve 205 is closed, and the solvent vapor condenses into an equal amount of liquid layer on the surface of the part. At this time, the pressure is maintained and waited. The surface of the PA12 part 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. The second vacuum pump 308 is turned on to reduce the pressure in 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 exhaust 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 rapidly enters the recovery chamber 301 under the action of the pressure difference, and the liquid solvent on the surface of the parts is accelerated to evaporate.

[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 and 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, and 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 , 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 the 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 depth 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 example compares the processed data of printed plastic parts after processing in Examples 1 to 4 with the data before 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 table above, parts treated with the two methods described in this invention exhibit significant improvements in physical and mechanical properties such as tensile strength, elongation at break, room-temperature flexural modulus, and surface roughness. Compared to the surface smoothing method, the deep enhancement treatment further improves both tensile strength and elongation at break, while further reducing the room-temperature flexural modulus and significantly improving the part's flexibility. This effectively addresses the common surface roughness and poor print quality issues of 3D-printed plastic parts, while simultaneously improving their appearance quality and physical and mechanical properties, ultimately achieving superior aesthetics and reliability.

[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 all perspectives. In addition, it should be understood that although this specification is described in terms of implementation methods, it does not contain only one technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should read the specification as a whole. The technical solutions in the embodiments can also be appropriately combined to form other implementation methods 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 assembly (2) is used to perform smoothing on PBF-printed plastic parts; the part processing assembly (2) comprises a reaction chamber (201), one side of the reaction chamber (201) is connected to a first vacuum pump (203), and the reaction chamber (201) adjusts the air pressure in the reaction chamber (201) through the first vacuum pump (203), and the air pressure is 0.1 to 20 kPa; 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); 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 solvent recovery component (3) comprises a recovery cabin (301), an air bag (302) is provided inside the recovery cabin (301), and an air inlet valve (303) and an air extraction valve (304) for controlling the air pressure of the air bag (302) are provided outside the recovery cabin (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); 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); The output end of the solvent storage bottle (1) is connected to the input end of the solvent chamber (206) of the part processing assembly (2) via a peristaltic pump (4), and the part processing assembly (2) is connected to the solvent recovery assembly (3) via a recovery valve (5).

2. A post-processing system for PBF-printed plastic parts according to claim 1, characterized in that: A hanger (202) for hanging PBF-printed plastic parts is provided inside the reaction chamber (201).

3. The 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), and the heating element (204) comprises a heater, and the heater is used to heat the reaction chamber (201).

4. The post-processing system for PBF-printed plastic parts according to claim 3, characterized in that: The solvent is one or a mixture of hexafluoroisopropanol, methanol, isopropanol, xylene, p-xylene, acetone, chloroform, and dichloromethane.

5. The post-processing system for PBF-printed plastic parts according to claim 4, 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.

6. A processing process for a post-processing system for PBF-printed plastic parts according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step A: Mount the PBF-printed plastic parts on a detachable hanger (202) and place them in the reaction chamber (201). After the PBF-printed plastic parts are no longer shaking or in contact with each other, seal the reaction chamber (201) and tighten the end cap. 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, 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) for use through the peristaltic pump (4); Step C: using a first vacuum pump (203) to evacuate the reaction chamber (201) to a vacuum state; Step D: Open the pressure-charging valve (205) between the reaction chamber (201) and the solvent chamber (206), and the solvent chamber (206) instantly reaches a vacuum state. The solvent in the solvent chamber (206) boils violently, and the solvent vaporizes. The solvent vapor fills the reaction chamber (201), forming a uniform steam atmosphere in the reaction chamber (201). At the same time, the steam atmosphere wraps the parts on the rack (202); Step E: Close the pressure valve (205), 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; 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 this time, the air bag (302) is in a state where the exhaust valve (304) is open and the air inlet valve (303) is closed; Step G: Turn off the second vacuum pump (308), open the recovery valve (5), and the solvent vapor in the reaction chamber (201) quickly enters the recovery chamber (301) under the action of the pressure difference, while the liquid solvent on the surface of the part evaporates faster; Step H: Close the recovery valve (5) and the airbag exhaust valve (304), open the airbag inlet valve (303) and the condensation valve (305), and the inflated airbag (302) in the recovery chamber (301) is rapidly compressed, and the pressure in the chamber increases to normal pressure. At this 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.

7. The post-processing system for PBF-printed plastic parts according to claim 6, characterized in that: in, The holding time in step B is 5 to 20 minutes.

8. The post-processing system for PBF-printed plastic parts according to claim 6, characterized in that: in, The processing targets in step B include surface smoothing 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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