A 3D printing device

Abstract

The utility model belongs to 3D printing technical field, specifically disclose a kind of 3D printing equipment, including box and door body, the door body closes the box, the printing unit for printing elastic material is installed in the box, further include low temperature temperature control unit, the low temperature temperature control unit includes compressor, condenser, throttling component, evaporator, low pressure pipe and high pressure pipe;The evaporator is installed in the box, the compressor and the condenser are installed in the box outside side;The outlet of the evaporator is connected with the suction port of the compressor by the low pressure pipe;The exhaust port of the compressor is connected with the inlet of the condenser by the high pressure pipe, and the inlet of the evaporator and the outlet of the condenser are communicated by the throttling component.The utility model can make the part that has printed be in low temperature state, improve the moving speed of printing nozzle, to improve printing speed.

Description

Technical Field

[0001] This utility model relates to the field of 3D printing technology, specifically to a 3D printing device. Background Technology

[0002] 3D printing is a technology that manufactures three-dimensional objects by adding materials layer by layer. It integrates cutting-edge technologies from many fields. Among them, FDM 3D printing technology is a rapid prototyping process belonging to the material extrusion category, characterized by low energy consumption, low cost, and high forming accuracy. FDM is an abbreviation for "Fused Deposition Modeling," also known as FFF, or "Fused Filament Fabrication." In FDM printing technology, objects are constructed by selectively depositing molten material layer by layer along a predetermined path.

[0003] Typically, in FDM 3D printing technology, when printing elastic materials, the printing nozzle moves and deposits the next layer on top of the previous layer as the molten material is selectively deposited layer by layer. The already printed part creates resistance to the movement of the printing nozzle. Since elastic materials are flexible, the printed product is also flexible. As the height of the printed part increases, the reaction force of this resistance will cause the printed part to wobble more and more significantly, resulting in increasingly significant misalignment between layers. Ultimately, this leads to a low yield rate of printed products, or even printing failure and product scrap.

[0004] During the printing process described above, the faster the print head moves, the greater the resistance, which increases the risk of printing failure. Therefore, when printing elastic materials using FDM 3D printing technology, the printing speed is very slow and the printing efficiency is extremely low. Currently, it usually takes 90-104 hours to print a pair of size 42-43 elastic shoes using this technology. Utility Model Content

[0005] This invention provides a 3D printing device that aims to keep the printed part at a low temperature, thereby increasing the moving speed of the printing nozzle and thus increasing the printing speed.

[0006] This utility model is achieved through the following technical solution: a 3D printing device, including a box and a door, the door enclosing the box, a printing unit for printing elastic materials installed inside the box, and a low-temperature control unit, the low-temperature control unit including a compressor, a condenser, a throttling component, an evaporator, a low-pressure pipe and a high-pressure pipe; the evaporator is installed inside the box, and the compressor and the condenser are installed outside the box; The outlet of the evaporator is connected to the suction port of the compressor via the low-pressure pipe; the discharge port of the compressor is connected to the inlet of the condenser via the high-pressure pipe; and the inlet of the evaporator and the outlet of the condenser are connected via the throttling component.

[0007] Compared with existing technologies, this solution has the following advantages and beneficial effects: During the printing of elastic materials, in a closed chamber, the low-temperature control unit, through the coordinated work of components such as the compressor, condenser, and evaporator, stably maintains the internal temperature below the glass transition temperature (Tg) of the printing material. This keeps the printed areas at a low temperature, increasing the nozzle's movement speed and thus improving printing speed. The printed areas freeze rapidly due to the low temperature environment—the movement of amorphous chain segments is restricted, and the crystallization rate in the semi-crystalline region accelerates, transforming the material from a viscoelastic state to a rigid solid state, with deformation controllable at the micrometer level. This low-deformation characteristic allows the nozzle to move at 10-15 times the speed of traditional FDM technology (without slowing down while waiting for material to solidify), significantly shortening the printing cycle (e.g., the time to print a pair of elastic material footwear parts can be reduced from 90-104 hours to 7-11 hours), making mass 3D printing of elastic materials possible.

[0008] Elastic materials are prone to deformation at room temperature due to creep, their own weight, or nozzle disturbance, leading to problems such as interlayer misalignment and line distortion. In this solution, the low-temperature environment significantly improves the rigidity of the printed area and enhances its anti-interference ability: even with slight impacts from the high-speed movement of the nozzle or airflow disturbances, the structural dimensions remain stable. Simultaneously, the low temperature only freezes the deeper layers of the printed area. When the newly extruded molten material comes into contact with the low-temperature substrate, the contact surface briefly heats up due to localized heat conduction, ensuring effective entanglement of interlayer molecular chains. This avoids structural collapse without sacrificing interlayer bonding strength, solving the pain point of "difficulty in balancing speed and accuracy" in printing elastic materials.

[0009] Low temperatures can suppress chemical reactions such as oxidation and hydrolysis in elastic materials during the printing process, reducing material performance degradation (e.g., yellowing, decreased mechanical strength). For semi-crystalline elastic materials, low temperatures can regulate their crystallinity distribution, resulting in more uniform mechanical properties (e.g., tensile strength, elastic modulus) in the printed parts. Furthermore, the rigid printed structure provides stable support for subsequent layers, enabling the direct molding of complex shapes such as suspended structures and mesh-like cutouts without the need for additional support structures, reducing post-processing steps and minimizing material waste.

[0010] The low-temperature control unit achieves efficient use of the internal space of the cabinet through a reasonable layout (evaporator built-in, compressor and condenser external), avoiding the refrigeration components from occupying the printing work area; the piping design of low-pressure pipe, high-pressure pipe and throttling device ensures efficient refrigerant circulation.

[0011] Furthermore, the condenser is provided with a condenser tube and multiple heat sinks, the multiple heat sinks are fixed inside the condenser, the condenser tube is coiled in a serpentine shape inside the condenser, the multiple heat sinks are distributed at intervals and connected to the condenser tube, and a fan is provided inside the condenser.

[0012] Beneficial effects: In this design, the condenser tubes feature a serpentine coil design, extending the flow path of the high-temperature, high-pressure gaseous refrigerant within the condenser and increasing the contact time between the refrigerant and the heat sinks. Simultaneously, multiple spaced heat sinks are tightly connected to the condenser tubes, rapidly dissipating the heat transferred by the tubes to a larger surface area. This structure allows the refrigerant to efficiently release heat during flow, ensuring its complete condensation from a gaseous state to a liquid state. This provides a stable supply of high-pressure liquid refrigerant for the subsequent pressure-reducing and throttling components, preventing a decrease in refrigeration efficiency due to insufficient condensation (such as abnormally high compressor discharge pressure and reduced cooling capacity).

[0013] The serpentine coiled condenser tubes achieve a long pipeline layout within the limited internal space of the condenser. Combined with spaced heat sinks, heat dissipation requirements can be met without increasing the overall size of the condenser. This compact design is particularly suitable for integrated 3D printing equipment scenarios—the condenser can be installed on the outside of the housing (such as the back, sides, or bottom of the housing), without occupying internal space in the printing chamber, while reducing the overall footprint of the equipment, thus balancing cooling performance with the need for miniaturization.

[0014] This design incorporates a fan inside the condenser to dissipate heat and improve the condenser's heat dissipation efficiency.

[0015] Furthermore, the evaporator includes an evaporation tube, which is coiled in a serpentine shape inside the evaporator, and the evaporator is laid on one or more sides of the inner layer of the housing.

[0016] Beneficial effects: The evaporator tube has a serpentine coil design, which extends the flow path of the low-temperature and low-pressure refrigerant within the limited space inside the evaporator, and increases the heat exchange time between the refrigerant and the air inside the printing chamber (box).

[0017] Furthermore, the throttling component is a capillary tube or an expansion valve.

[0018] Beneficial effects: Whether it's the fixed throttling of the capillary tube or the dynamic throttling of the expansion valve, the throttling components in this solution can effectively separate the high-pressure side (condenser, compressor discharge end) and the low-pressure side (evaporator, compressor suction end) of the refrigeration system, preventing system turbulence (such as compressor overload, refrigerant backflow) caused by direct pressure exchange between the two sides. This pressure isolation reduces load fluctuations in core components such as the compressor and condenser, lowers the risk of mechanical wear and fatigue aging, and extends the overall service life of the equipment.

[0019] Furthermore, both the housing and the door include an inner layer, a sandwich layer, and an outer layer. The inner and outer layers are both metal or plastic shells, and the sandwich layer is an insulation layer.

[0020] Beneficial effects: The insulation layer in the interlayer (such as polyurethane foam, vacuum insulation board or glass wool) forms a thermal resistance barrier through materials with low thermal conductivity, which can effectively prevent heat from the external environment (such as room temperature and heat dissipation from equipment operation) from being transferred to the low-temperature area inside the box, while reducing the loss of cold air from inside the box to the outside.

[0021] Furthermore, a sealing strip is provided on the edge contour of the inner side of the door that contacts the box body.

[0022] Beneficial effects: The sealing strip, through its own deformation, tightly fills the gap between the door and the cabinet, forming a complete sealed barrier. This effectively prevents ambient air (containing heat and moisture) from seeping into the cabinet, while also preventing the leakage of cold air from inside. This design, combined with the cabinet's three-layer insulation structure, reduces heat exchange at the gap between the cabinet and the door by more than 90%, avoiding temperature fluctuations inside the chamber caused by air convection. This ensures that the printing area is in a uniform low-temperature environment, guaranteeing the stability of the frozen state of the elastic material segments.

[0023] Furthermore, the door is provided with an observation window, which is a transparent observation window.

[0024] Beneficial Effects: The transparent observation window allows operators to directly observe the 3D printing progress of the elastic material inside the chamber (such as interlayer bonding status and nozzle filament output stability), equipment operation (such as the printing platform movement trajectory and whether the evaporator is frosted), and low-temperature environment status (such as whether there is abnormal fogging and whether the material deforms due to temperature fluctuations) without opening the door. This real-time visual monitoring can promptly detect printing defects (such as stringing, warping, and blockage), avoid sudden temperature rises inside the chamber due to frequent door openings, thereby reducing the risk of material scrap and preventing a decrease in printing accuracy caused by changes in material viscosity due to temperature fluctuations. Without the observation window, operators need to frequently open the door to check the printing status. Each opening causes ambient air (containing heat and moisture) to rush into the chamber, disrupting the low-temperature environment, increasing the energy consumption of the cooling system, and potentially causing the printed layers to soften and deform due to temperature increases. The transparent observation window avoids this problem through "non-contact observation," ensuring the continuous and efficient operation of the cooling system, reducing energy consumption, and guaranteeing the dimensional stability of the printed parts.

[0025] Furthermore, a temperature controller is installed on the housing, the temperature controller including a temperature sensor and a temperature controller body, the temperature sensor being installed inside the housing and the temperature controller body being installed outside the housing; a relay is connected to the power supply of the compressor, and both the temperature sensor and the relay are electrically connected to the temperature controller body.

[0026] Beneficial effects: The temperature sensor monitors the chamber temperature in real time and transmits the data to the temperature controller. When the chamber temperature rises to a set threshold due to heat release during printing (such as nozzle heating or material melting), the temperature controller automatically connects the compressor power supply via a relay, initiating the refrigeration cycle. When the temperature drops below the target value, the relay disconnects the compressor power supply, stopping refrigeration. This closed-loop control logic of "monitoring-judgment-execution" stabilizes the chamber temperature within the error range, precisely matching the glass transition temperature requirements of elastic materials. This avoids repeated switching between frozen and relaxed states of the material chain due to temperature fluctuations, thus ensuring the rigidity and dimensional accuracy of the printed parts.

[0027] Furthermore, it also includes a defrosting unit for defrosting the evaporator, wherein the defrosting unit is a direct-cooling defrosting module or an air-cooling defrosting module, the direct-cooling defrosting module includes heating wires disposed near the evaporator; the air-cooling defrosting module includes a fan installed on one side of the evaporator.

[0028] Beneficial effects: The defrosting unit in this solution solves the problem of reduced cooling efficiency caused by evaporator frosting, providing a key guarantee for the continuous and efficient operation of elastic material 3D printing equipment.

[0029] Furthermore, it also includes a drying and dehumidification unit, which is a rotary dehumidifier.

[0030] Beneficial effects: The rotary dehumidifier continuously adsorbs moisture from the air inside the printing chamber using a honeycomb-shaped moisture-absorbing wheel (containing materials such as activated silica gel and molecular sieves), maintaining a low humidity level inside the chamber and keeping the humidity stably below 50% RH. In low-temperature printing environments, reducing the moisture content in the air fundamentally reduces the risk of frost / condensation on the evaporator, heat sink fins, and printed surfaces. Attached Figure Description

[0031] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of an embodiment of a 3D printing device according to the present invention; Figure 2 This is a schematic diagram of another embodiment of the 3D printing equipment of this utility model; Figure 3 This is a schematic diagram of a 3D printing device according to the present invention, showing a fan installed inside the condenser.

[0032] The attached diagram shows the markings and corresponding component names: 1. Cabinet; 2. Door; 201. Sealing strip; 3. Door handle; 4. Compressor; 5. Condenser; 501. Heat sink; 502. Condenser tube; 6. Evaporator; 601. Evaporator tube; 602. Heat sink fins; 7. Printing nozzle; 8. Printing model; 9. Printing platform; 10. Low-pressure pipe; 11. High-pressure pipe; 12. Throttling component; 13. Material supply system; 14. Fan. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0034] As one embodiment of this application, such as Figure 1 As shown, this embodiment provides a 3D printing device, including a housing 1 and a door. The door closes the housing 1, and in this embodiment, a door handle 3 is connected to the outside of the door.

[0035] The housing 1 contains a printing unit for printing elastic materials. The printing unit adopts the existing 3D printing technology principle. The components inside the printing unit (such as motors, belts, bearings, lubricating oil, grease; cables; limit sensors, pressure sensors, etc.) are all made of low-temperature resistant materials.

[0036] The 3D printing equipment in this embodiment also includes a low-temperature temperature control unit, which includes a compressor 4, a condenser 5, a throttling component 12, an evaporator 6, a low-pressure pipe 10, and a high-pressure pipe 11. The evaporator 6 is installed inside the housing 1 by screws or welding, while the compressor 4 and the condenser 5 are installed outside the housing 1. In this embodiment, an inwardly recessed space is provided at the lower right corner of the housing 1 for installing the compressor 4, thus fixing the compressor 4 to the housing 1 and facilitating overall movement. In this embodiment, the condenser 5 is located at the back, sides, or bottom of the housing 1. When the condenser 5 is installed at the bottom of the housing 1, the inwardly recessed space at the lower right corner of the housing 1 can be enlarged, and the condenser 5 can also be installed in this space, which makes the entire equipment occupy less space and has a more aesthetically pleasing appearance.

[0037] The outlet of the evaporator 6 is connected to the suction port of the compressor 4 through the low-pressure pipe 10; the discharge port of the compressor 4 is connected to the inlet of the condenser 5 through the high-pressure pipe 11; and the inlet of the evaporator 6 and the outlet of the condenser 5 are connected through the throttling device 12.

[0038] Compressor 4 compresses the low-temperature, low-pressure refrigerant gas into a high-temperature, high-pressure gas, driving the refrigeration cycle.

[0039] High-pressure pipe 11 and low-pressure pipe 10 are the "blood vessels" connecting the core components, responsible for transporting refrigerant on the high-pressure and low-pressure sides respectively. High-pressure pipe 11 is the pipeline for transporting high-pressure refrigerant (usually a copper pipe with strong pressure resistance), connecting the exhaust port of compressor 4 to the inlet of condenser 5. Compressor 4 compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant through mechanical work, and discharges it into high-pressure pipe 11 through the exhaust port of compressor 4. The high-temperature, high-pressure gaseous refrigerant is transported to the inlet of condenser 5 through high-pressure pipe 11 and enters condenser 5. At this time, condenser 5 dissipates the heat in the refrigerant into the outside air through air convection or fan 14 cooling, and the refrigerant gradually condenses into a high-pressure liquid due to heat release.

[0040] The low-pressure pipe 10 is a conduit for transporting low-pressure refrigerant (its pressure resistance requirement is lower than that of the high-pressure pipe 11, but it must be resistant to low temperatures). It connects the outlet of the evaporator 6 to the suction port of the compressor 4. The low-temperature, low-pressure gas-liquid mixture of refrigerant, after being throttled and depressurized by the throttling device 12, enters the evaporator 6. Inside the evaporator 6, it absorbs heat from the casing 1 (achieving cooling) and completely evaporates into a low-temperature, low-pressure gaseous refrigerant. This gaseous refrigerant enters the low-pressure pipe 10 through the outlet of the evaporator 6. The low-temperature, low-pressure gaseous refrigerant is then transported through the low-pressure pipe 10 to the suction port of the compressor 4, where it is drawn in again and compressed, entering the next refrigeration cycle.

[0041] In one embodiment, the printing unit is an existing 3D printing device, which includes a printing nozzle 7 (hot end), a material supply system 13 (cold end), a printing platform 9, a motion control system, and an extrusion drive mechanism.

[0042] Solid filamentous elastic material (such as PU / PEBA) is extruded from the cold end by gears and fed into the hot end. After being melted by the heating block, it is extruded from the nozzle. At the same time, the motion system (such as XYZ three-axis linkage) controls the printing nozzle 7 to move according to the G-code path generated by the slicing software, depositing the molten material layer by layer on the printing platform 9. After each layer is completed, the platform moves down by one layer thickness (usually 0.1–0.3 mm), and the process is repeated until the printed model 8 (three-dimensional solid) is formed.

[0043] The printing unit can also be a UV-curable resin extrusion printing system, including a printhead 7, a curing lamp, a material supply system 13, a printing platform 9, a motion control system, and an extrusion drive mechanism (such as a metering pump). The UV-curable resin can be single-component, two-component, or multi-component. Liquid UV-curable resin material is fed into the printhead 7 by the drive mechanism (such as a metering pump) and extruded from the nozzle. Simultaneously, the motion system (such as XYZ three-axis linkage) controls the printhead 7 to move along the G-code path generated by the slicing software. The curing lamp irradiates the extruded resin material to cure it. The material is deposited layer by layer on the printing platform 9. After each layer is completed, the platform moves down by one layer thickness (typically 0.1–0.3 mm), and this process is repeated until a three-dimensional solid is formed. After the UV-curable resin extrusion printing is completed, if its physical and mechanical properties do not meet the requirements, post-curing (such as thermal curing, moisture curing, or UV curing) can be performed to improve its physical and mechanical properties.

[0044] In one embodiment, a condenser 5 is provided with a condenser tube 502 and multiple heat sinks 501. The heat sinks 501 are fixed inside the condenser 5, and the condenser tube 502 is coiled in a serpentine shape inside the condenser 5. This increases the contact area between the condenser tube 502 and the heat sinks 501, thereby increasing heat dissipation. In this embodiment, the multiple heat sinks 501 are spaced apart and connected to the condenser tube 502. In this embodiment, the heat sinks 501 are typically thin metal sheets (such as aluminum or copper sheets), which are fixed to the serpentine condenser tube 502 by welding, expansion, or snap-fitting to ensure tight contact (reducing thermal resistance). This connection allows the heat of the high-temperature refrigerant inside the condenser tube 502 to be efficiently transferred to the heat sinks 501.

[0045] In one embodiment, such as Figure 3 As shown, the condenser 5 is provided with a condenser tube 502 and multiple heat sinks 501. The multiple heat sinks 501 are fixed inside the condenser 5. The condenser tube 502 is coiled in a serpentine shape inside the condenser 5. In this embodiment, a fan 14 is provided inside the condenser 5. The condenser 5 is cooled by the fan 14, which can quickly release heat into the air and reduce the heat exchange time.

[0046] In one embodiment, such as Figure 1 As shown, in this embodiment, the evaporator 6 includes an evaporator tube 601, which is coiled in a serpentine shape inside the evaporator 6. The evaporator 6 is laid on one or more surfaces of the inner layer of the housing 1. In this embodiment, the serpentine design of the evaporator tube 601 extends the flow path of the low-temperature, low-pressure refrigerant within the limited space inside the evaporator 6, increasing the heat exchange time between the refrigerant and the air inside the printing chamber (housing 1).

[0047] In one embodiment, such as Figure 2As shown, the evaporator 6 also includes multiple heat dissipation fins 602 and a bracket. The multiple heat dissipation fins 602 are connected to the evaporation tube 601 at intervals. The heat dissipation fins 602 and the evaporation tube 601 are fixed to form an evaporation assembly by welding, expansion or snap-fit. The evaporation assembly is fixed on the bracket, and the bracket is fixed inside the housing 1.

[0048] Multiple heat dissipation fins 602, which are spaced apart and connected to the evaporation tube 601, greatly expand the heat exchange area, enabling the heat inside the chamber 1 to be quickly transferred to the refrigerant inside the evaporation tube 601 through the heat dissipation fins 602. The efficiency of the liquid refrigerant absorbing heat and vaporizing inside the evaporation tube 601 is significantly improved, which can reduce the temperature of the printing chamber 1 to the target value in a short time, providing an immediate low-temperature field for the low-temperature curing of elastic materials.

[0049] In one embodiment, the throttling component 12 is a capillary tube or an expansion valve, which throttles and reduces pressure to control the flow rate of the liquid refrigerant. The capillary tube is a long, thin copper or stainless steel tube with a uniform inner diameter, containing no moving parts and having an extremely simple structure. It is typically coiled into a spiral shape, with both ends directly connected to the condenser 5 (high-pressure side) and the evaporator 6 (low-pressure side). Throttling is achieved by utilizing the resistance effect of the fluid flowing in the long, thin tube. The expansion valve is an adjustable throttling component 12 that can dynamically adjust the flow rate according to the refrigerant state at the outlet of the evaporator 6.

[0050] In one embodiment, both the housing 1 and the door 2 include an inner layer, a sandwich layer, and an outer layer. The inner and outer layers are both metal or plastic shells, and the sandwich layer is an insulation layer. Specifically, the sandwich layer is a polyurethane foam insulation layer that isolates the exchange of heat between the inside and outside.

[0051] In one embodiment, a sealing strip 201 is provided on the edge contour where the door 2 contacts the housing 1. The sealing strip 201 is made of magnetic rubber sealing ring. The sealing strip 201 can ensure the airtightness of the contact between the housing 1 and the door 2, thereby preventing cold air from leaking out and hot air from entering.

[0052] In one embodiment, an observation window is provided on the door 2, and the observation window is a transparent observation window, so that the internal situation of the box 1 can be easily observed through the observation window without opening the door 2.

[0053] In one embodiment, the housing 1 is equipped with a light, which automatically turns on when the door is opened and automatically turns off when the door is closed through a combination of a mechanical triggering device and a circuit switching switch.

[0054] Specifically: A door control microswitch (or contact switch) is installed at the connection between door 2 and housing 1, consisting of a "trigger rod," "internal contacts," and a "spring." Door 2 is hinged to housing 1.

[0055] When the door is opened: the door body 2 rotates around the hinge, releasing the pressure on the trigger rod, the spring inside the switch springs up, closing the contacts, completing the circuit, and powering on the light. When the door closes: the door body 2 presses the trigger rod, pushing the internal mechanical structure to disconnect the contacts, cut off the circuit, and turn off the lighting.

[0056] In one embodiment, a thermostat (not shown in the figure) is installed on the housing 1. The thermostat includes a temperature sensor and a thermostat body. The temperature sensor is installed inside the housing 1, and the thermostat body is installed outside the housing 1. A relay is connected to the power supply of the compressor 4. Both the temperature sensor and the relay are electrically connected to the thermostat body.

[0057] Temperature sensors are installed inside enclosure 1 to monitor the temperature inside the enclosure in real time (commonly thermistors, thermocouples, etc., with accuracy varying depending on requirements); The main body of the temperature controller includes a setting panel (where the user inputs the target temperature), a comparison circuit (which compares the measured temperature with the set temperature), and a control module (which outputs commands). Compressor 4, as the power source of the refrigeration system, directly affects the temperature inside the cabinet when it operates (cooling occurs during operation, and temperature rises when stopped). The temperature sensor transmits a high-temperature signal to the thermostat, which determines that cooling is needed and outputs a start signal (such as a relay closing), energizing compressor 4. At this time, the refrigeration system is working (the refrigerant circulates and absorbs heat), and the temperature inside cabinet 1 gradually decreases.

[0058] The temperature sensor transmits a signal indicating that cooling is not required. The thermostat then outputs a stop signal (relay disconnects), and compressor 4 is powered off and stops operating. The temperature inside chamber 1 slowly rises due to external heat leakage and other factors until the restart conditions are triggered again, forming a cycle. This process is automated through "temperature difference triggering," requiring no manual intervention and maintaining the internal temperature within the set range.

[0059] In this embodiment, the compressor 4 is automatically started and stopped to maintain the set temperature, and the temperature inside the printer housing 1 is controlled from -90°C to 15°C.

[0060] In one embodiment, the temperature inside the printer housing 1 is controlled at -60°C to 0°C. In another embodiment, the more preferred temperature inside the printer housing 1 is controlled at -40°C to -10°C.

[0061] In one embodiment, a 3D printing device further includes a defrosting unit for defrosting the evaporator 6, wherein the defrosting unit is a direct-cooling defrosting module or an air-cooling defrosting module. In this embodiment, a controller is installed on the housing 1, and the direct-cooling defrosting module or the air-cooling defrosting module is electrically connected to the controller. The controller has an operating interface and integrates functions such as temperature setting, mode switching, printing, leveling, and light switching.

[0062] The direct-cooling defrosting module includes a heating wire located near the evaporator 6, as well as defrosting sensors (such as temperature sensors and frost thickness sensors) and a timing module. It periodically melts the frost. The principle is as follows: the frost on the surface of the evaporator 6 is melted by active heating. The heating wire is directly attached to or wrapped around the surface of the coil of the evaporator 6 (such as in the gap of the serpentine tubes of the evaporator 6), or fixed on the support below or around the evaporator 6 to ensure that heat can be efficiently transferred to the frosted area of ​​the evaporator 6. The heating wire is connected to the controller on the housing 1 through wires and is controlled by the defrosting sensor or the timing module, forming an interlock with the compressor 4 (the compressor 4 stops working during defrosting to avoid conflict between heating and cooling). The air-cooled defrosting module includes a fan installed on one side of the evaporator 6 to force cold air circulation and prevent frost formation. The fan is usually fixed to one side or directly in front of the evaporator 6 (such as the air inlet or outlet of the evaporator 6), forming an airflow path of "evaporator 6 - fan": after the air is cooled by the evaporator 6, it is forced by the fan to blow into various areas inside the cabinet, and then flows back to the evaporator 6 from the return air vent, forming a closed loop. The fan and the evaporator 6 are not mechanically rigidly connected, but an airflow connection is formed through the air duct structure (such as air guide plate, fan cover) on the cabinet 1 to ensure that all airflow passes through the evaporator 6; the fan motor is connected to the controller through wires and works in conjunction with the compressor 4 and the defrosting heating wire (if any) (the fan and compressor 4 run synchronously during cooling, and the fan can be paused during defrosting).

[0063] In one embodiment, a 3D printing apparatus further includes a drying and dehumidification unit to prevent frost formation inside the printing chamber 1. The drying and dehumidification unit controls the humidity inside the chamber 1 to be less than 50% RH; in this embodiment, the drying and dehumidification unit is a rotary dehumidifier.

[0064] Rotary dehumidifiers are a current technology. Their core structure includes a honeycomb-shaped moisture-absorbing rotor (made of ceramic fiber carrier composite active silica gel or molecular sieves and other moisture-absorbing materials), a processing fan, a regeneration fan, a regeneration heater (electrically or steam-heated), a sealing partition (dividing the rotor into a processing zone and a regeneration zone), and a control system. Their working principle is based on physical adsorption and thermal regeneration cycles: when humid air enters the processing zone (approximately 270° of the rotor's fan-shaped area), moisture is adsorbed by the moisture-absorbing material, and dry air is output. Simultaneously, the rotor rotates at 8-18 rpm, and the saturated portion enters the regeneration zone (approximately 90° of the fan-shaped area), where it is swept back by high-temperature regeneration air at 100-140°C, desorbing moisture and expelling the damp air. This restores the rotor's moisture-absorbing capacity, achieving continuous dehumidification and maintaining a low humidity level inside the printer housing 1. The drying system can control humidity to less than 50% RH.

[0065] In another embodiment, the dehumidification unit is a dehumidification bag containing an adsorbent material, such as a desiccant. The dehumidification bag is placed inside the housing 1 and mainly absorbs the moisture in the housing 1 through the adsorbent material inside the dehumidification bag to achieve the purpose of dehumidification and drying.

[0066] In the printing process of elastic materials, this invention utilizes a closed printing system. The temperature inside the printer housing 1 is lower than the glass transition temperature of the material, and the printed areas are in a low-temperature state. The chain segment movement in the amorphous or semi-crystalline structure of the material is frozen, resulting in rigidity and low deformation. This significantly increases the speed of the print head 7. Furthermore, the drying system controls humidity to below 50% RH, preventing frost buildup inside the printing chamber. This allows for printing speeds far exceeding traditional FDM 3D printing, reaching 10-15 times the speed of traditional 3D printing. For example, the printing time for elastic shoes can be reduced from 90-104 hours to 7-11 hours, greatly improving production efficiency, reducing time costs, and making mass production of elastic materials possible.

[0067] It should be noted that the above description of the disclosed embodiments enables those skilled in the art to implement or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A 3D printing device, comprising a housing and a door, the door enclosing the housing, and a printing unit for printing elastic materials installed inside the housing, characterized in that, It also includes a low-temperature control unit, which comprises a compressor, a condenser, a throttling device, an evaporator, a low-pressure pipe, and a high-pressure pipe; the evaporator is installed inside the housing, while the compressor and the condenser are installed outside the housing. The outlet of the evaporator is connected to the suction port of the compressor via the low-pressure pipe; the discharge port of the compressor is connected to the inlet of the condenser via the high-pressure pipe; and the inlet of the evaporator and the outlet of the condenser are connected via the throttling component.

2. The 3D printing equipment according to claim 1, characterized in that, The condenser is equipped with a condenser tube and multiple heat sinks. The multiple heat sinks are fixed inside the condenser. The condenser tube is coiled in a serpentine shape inside the condenser. The multiple heat sinks are spaced apart and connected to the condenser tube. A fan is provided inside the condenser.

3. The 3D printing equipment according to claim 1, characterized in that, The evaporator includes an evaporation tube, which is coiled in a serpentine shape inside the evaporator and is laid on one or more sides of the inner layer of the housing.

4. The 3D printing equipment according to claim 1, characterized in that, The throttling component is a capillary tube or an expansion valve.

5. A 3D printing device according to claim 1, characterized in that, Both the housing and the door include an inner layer, a sandwich layer, and an outer layer. The inner and outer layers are metal or plastic shells, and the sandwich layer is an insulation layer.

6. The 3D printing equipment according to claim 1, characterized in that, A sealing strip is provided on the edge contour where the door contacts the box.

7. A 3D printing device according to claim 1, characterized in that, The door is provided with an observation window, which is a transparent observation window.

8. A 3D printing device according to any one of claims 1-7, characterized in that, A temperature controller is installed on the housing. The temperature controller includes a temperature sensor and a main body. The temperature sensor is installed inside the housing, and the main body is installed outside the housing. A relay is connected to the power supply of the compressor. Both the temperature sensor and the relay are electrically connected to the main body of the temperature controller.

9. A 3D printing device according to any one of claims 1-7, characterized in that, It also includes a defrosting unit for defrosting the evaporator, wherein the defrosting unit is a direct-cooling defrosting module or an air-cooling defrosting module, wherein the direct-cooling defrosting module includes heating wires disposed near the evaporator; and the air-cooling defrosting module includes a fan installed on one side of the evaporator.

10. A 3D printing device according to any one of claims 1-7, characterized in that, It also includes a drying and dehumidification unit, which is a rotary dehumidifier or a dehumidification bag.

Images