3D printing device and printing method based on pressure sensing intelligent temperature control

Abstract

The application discloses a kind of 3D printing equipment and printing method based on pressure sensing intelligent temperature control, belong to food 3D printing technical field.The 3D printing equipment includes 3D printing module, texture detection module, control module, texture detection module is used to monitor printing material mechanical parameter in real time, control module receives and handles the data signal sent by texture detection module, compares with texture standard parameter, and sends temperature control instruction to 3D printing module, and the intelligent temperature control system of 3D printing module carries out efficient temperature control to printing material, to change material mechanical property.The application adjusts temperature according to real-time texture detection data, realizes intelligent temperature control to printing process, and improves printing precision by adjusting material texture parameter.The application is suitable for food low-temperature 3D printing, can meet the printing demand of different food raw materials, improves the flexibility and applicability of production process, meets the demand of market to individualization, customization food.

Description

Technical Field

[0001] This invention relates to the field of food 3D printing technology, specifically to a 3D printing device and printing method based on pressure sensing intelligent temperature control. Background Technology

[0002] 3D printing is a solid free-form additive manufacturing technology with broad application prospects. It utilizes digital models to construct complex solid geometries layer by layer. In the food processing field, 3D printing technology has proven to have significant advantages, including manufacturing highly complex food shapes, enabling personalized food customization, precisely controlling the proportion of nutrients, simplifying supply chain management, reducing waste in the production process, and expanding the range of ingredients. These advantages not only improve the production efficiency and quality of food processing but also bring new development opportunities and challenges to the food industry.

[0003] The textural quality of food materials is closely related to the precision of 3D printing, and this correlation significantly impacts the quality and performance of the printed product. In 3D printing technology, the material, as one of the components, directly participates in the printing process, and its textural quality directly affects the molding effect and final quality of the printed product. For example, the elasticity and viscosity of the material are crucial for the precision of 3D printing. High-quality materials should have appropriate elasticity and viscosity to ensure accurate extrusion and uniform deposition on the printed layer during the printing process. If the material has poor flowability or excessive viscosity, it may lead to blockages or overflows during printing, affecting printing precision and speed.

[0004] Food materials are typically liquids containing specific components. When heated, these materials become more fluid because heating increases the movement of molecules, putting them into a fluid state. In this state, the material's texture parameters, such as hardness and elasticity, usually decrease, and the molecular arrangement becomes more loose, resulting in a softer and more fluid material overall. During cooling, the molecular movement slows down, and the material gradually solidifies. In this process, the material becomes semi-solid, and the molecules rearrange to form a solid structure. During this process, the material's texture parameters, such as hardness and elasticity, usually increase. The solid structure makes the material harder and more elastic, which is beneficial for the printed product's support properties. Therefore, high-precision 3D printing can be achieved by controlling the material's state through temperature.

[0005] Patent document CN109820224A discloses a method and printer for microwave 3D printing of food. It utilizes a microwave heating probe embedded in the inner wall of a material cylinder to release microwaves, combined with the size settings of a non-absorbing material, to achieve instant curing of the extruded material. However, the equipment is cumbersome to operate, requiring calculation of the distance between the microwave heating probe and the extruder head based on the dielectric properties of the material, and requiring the heating probe to be replaced when printing different materials. Under this heating method, the microwave electric field is difficult to effectively heat the extruder head, resulting in poor heating performance. Furthermore, microwave heating is difficult to precisely control the temperature, which may lead to uneven temperature during the heating process, affecting the quality and performance of the printed product.

[0006] Patent document CN117545109A discloses an intelligent heating device and its control method for 3D printed food products. A halogen light source generator provides an infrared light source, which radiates the light onto the printing layer via optical fiber, ensuring accurate irradiation of the printed product requiring heating. However, the safety of the radiation and its impact on food components are not considered; it only provides high-temperature heating and does not address low-temperature cooling, making it unsuitable for printing some low-temperature foods (such as ice cream, yogurt, and chilled cakes).

[0007] Patent document CN117204591A discloses a food 3D printing composite nozzle device with thermosetting and cooling functions, which uses simultaneous printing and freezing or drying to enhance the stability of the food structure during the printing process, allowing the front layer of the food to adhere better to the next layer and preventing deformation and collapse caused by the food's own weight. However, using liquid nitrogen and hot air drying not only causes the loss of the food's texture and flavor, but also makes it impossible to precisely control the temperature settings.

[0008] Therefore, there is an urgent need for a precise, intelligent, and automated temperature control device to directionally regulate the texture and quality of food materials, thereby achieving high-precision printing of food materials and improving the molding quality of printed products. Summary of the Invention

[0009] The purpose of this invention is to provide a 3D printing device and printing method that can achieve intelligent control, so as to solve the problems of insufficient mechanical strength of liquid slurry after extrusion in the current food 3D printing process, inability to achieve three-dimensional printing of complex shapes, and easy occurrence of flow and collapse.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] This invention provides a 3D printing device based on pressure sensing and intelligent temperature control, comprising a 3D printing module, a texture detection module, and a control module. The 3D printing module includes a material extrusion unit and a printing platform. The material extrusion unit includes a temperature-controlled material cylinder and an extrusion device for extruding the material, the extrusion device including an extrusion probe in contact with the material. A cooling device is provided on the printing platform. The texture detection module includes a mechanical sensor for measuring the force on the extrusion probe. The control module receives and processes data signals sent by the texture detection module, compares them with standard texture parameters, and then sends temperature control commands to the 3D printing module.

[0012] The temperature-controlled material cylinder is equipped with an intelligent temperature control system, which can accurately control the temperature of the printing material inside the cylinder.

[0013] This invention achieves high-precision 3D printing by precisely controlling the temperature of the printing material to meet the printing accuracy requirements, and by setting a cooling device on the printing platform to improve the support performance of the printed product through cooling.

[0014] In this invention, the extrusion device moves downward under the drive of a stepper motor, extruding the printing material inside the extrusion cylinder from the printing nozzle at the other end. By installing a mechanical sensor on the extrusion device to monitor the mechanical parameters of the printing material in real time, the device reflects the material's textural properties under the current temperature conditions. For example, when the material has high hardness, its resistance to external forces is enhanced, resulting in a relatively high pressure value measured by the sensor; conversely, when the material has high viscosity, its deformation rate under external forces is slower, resulting in a lower pressure value achieved under the same external force.

[0015] This invention intelligently adjusts the temperature based on real-time data to alter the textural properties of the printing material, achieving the required printing precision. Specifically, the control module receives data signals from a mechanical sensor, converts the signals, calculates the material's textural parameters based on the resulting force-time curve, and compares them with built-in standard textural parameters. If the parameters are higher than the standard range, a heating command is sent to the intelligent temperature control system of the material extrusion unit to initiate the heating process; if the parameters are lower than the standard range, a cooling command is sent to the material extrusion unit to initiate the cooling process. This continues until the detected textural parameters are within the standard range.

[0016] This invention achieves precise control of the 3D printing process by setting up a texture detection module and combining it with an intelligent temperature control system, ensuring that the printing environment is always maintained within the ideal temperature range required by the material, thereby improving printing efficiency and product quality.

[0017] As a preferred embodiment of the present invention, a rigid extrusion probe is provided in the part of the extrusion device that contacts the printing material, so as to accurately feed back the pressure value of the material when it is being squeezed while the printing material is being squeezed.

[0018] Preferably, the extrusion probe is a rigid structure in the shape of a cylinder or a cone.

[0019] A mechanical sensor is connected to the extrusion probe to detect the pressure value of the extrusion probe when extruding the printing material, and transmits the signal to the control module. The control module processes the signal and analyzes the textural parameters of the printing material. Taking gel-type food printing material as an example, the textural parameters include: hardness, viscosity, elasticity, cohesiveness, resilience, chewiness, and adhesiveness.

[0020] Preferably, the mechanical sensor is a piezoelectric pressure sensor or a strain gauge pressure sensor.

[0021] Preferably, the texture detection module further includes a method for measuring the speed and distance of the extrusion probe's downward pressure. By comprehensively evaluating the downward pressure speed, distance, and triggering force, the accuracy of the detection results is improved. For example, the detection results of speed and distance can reflect the resistance or pressure experienced by the material during its movement, thereby indirectly reflecting its hardness characteristics. The viscosity of the material affects its flowability and damping effect during movement. The elastic properties of the material affect its response to external forces in a certain way and to a certain extent.

[0022] In a preferred embodiment of the present invention, temperature control of the material cylinder is achieved by using a circulating medium for heat conduction. Specifically, the material extrusion unit further includes a temperature control device for accommodating the material cylinder. The temperature control device includes a hollow jacket structure adapted to the material cylinder, the jacket being filled with a circulating medium and connected to a constant temperature circulation controller via a pipeline.

[0023] The sandwich structure is connected to the thermostatic circulation controller via piping, and the heat transfer medium circulates between the sandwich structure and the thermostatic circulation controller. The sandwich structure fits tightly against the material cylinder, ensuring uniform heat conduction and enabling rapid heating and cooling of the printed material inside the cylinder. The sandwich structure can be made of a metal material with good thermal conductivity.

[0024] Preferably, the material cylinder and the temperature control device are detachable and can be assembled separately.

[0025] Preferably, the constant temperature circulation controller includes a medium circulation system, a temperature sensor, a temperature control element, and a communication interface.

[0026] The circulating medium can be, but is not limited to, water, ethylene glycol, and silicone oil. The medium circulation system drives the medium's circulation flow. A temperature sensor monitors the temperature of the circulating medium in real time. The temperature control components include a heating system and a cooling system, with a temperature adjustment range of 0–150°C. A communication interface connects to the control module, used to receive commands from the control module and control the temperature control components.

[0027] In a preferred embodiment of the present invention, a temperature sensor is installed on the printing platform to monitor the temperature of the printing platform in real time and transmit temperature parameters to the control module. The control module is electrically connected to a cooling device on the printing platform and controls its on / off state. When the temperature of the printing platform exceeds a set temperature, the control module activates the cooling device until the set temperature is reached.

[0028] Preferably, the cooling device is a semiconductor cooling device, whose components include: semiconductor cooling element, heat sink, and fan.

[0029] The semiconductor cooling element is composed of N-type and P-type semiconductor materials. The cooling end of the semiconductor cooling element is attached to the printing platform to provide low temperature conditions for the printing platform. The heating end of the semiconductor cooling element is equipped with a heat sink, and a fan is installed at the corresponding heat sink.

[0030] The cooling temperature range is 25 to -40℃.

[0031] Preferably, an insulation layer is provided on the outer periphery of the printing platform.

[0032] In a preferred embodiment of the present invention, the control module is integrated into computer program control software.

[0033] The control module includes a model building program, a printing program, a data processing program, and a temperature control program;

[0034] The model building program includes 3D scanning and imaging software and 3D model slicing program; it achieves procedural modeling by scanning the target object, draws it into a printable model in the software, and sets the printing path with the help of the 3D model slicing program.

[0035] The printing program controls the printing parameters of the 3D printing module, including printing speed, infill rate, and nozzle size; it mainly adjusts the material hopper's movement speed, printing time, printed product density, and extrusion line width during the printing process.

[0036] The data processing program is used to process and calculate the texture parameters by the pressure speed, distance, trigger force and other detection data collected by the texture detection module. After comparing with the texture standard parameters, it generates a temperature control command. The data processing program has a built-in data conversion algorithm and a texture standard parameter reference table.

[0037] The data processing includes:

[0038] Data acquisition: The software first extracts key data points from the force-time curve, such as maximum force, breaking force, and elastic modulus. These data reflect the mechanical properties of the sample during the test.

[0039] Data conversion: The software converts these key data points into textural properties parameters, such as hardness, elasticity, and viscosity, based on preset conversion algorithms and models. The conversion algorithm can be based on a mechanical model, taking into account factors such as sample deformation and stress distribution.

[0040] The temperature control program is used to receive temperature control commands sent by the data processing program and control the heating or cooling of the material cylinder, as well as to control the opening or closing of the refrigeration unit.

[0041] In this invention, the 3D printing equipment achieves three-dimensional printing by setting up X, Y, and Z axis guide rails to realize the three-dimensional movement of the 3D printing module. Alternatively, the printing platform can be integrated with a certain axis in three-dimensional space to achieve dynamic printing.

[0042] In a preferred embodiment of the present invention, the 3D printing equipment includes a printer base and a fixed bracket erected on the base. A Y-axis guide rail is provided on the fixed bracket, and an X-axis guide rail is installed on the slider of the Y-axis guide rail. The 3D printing module is fixed on the slider of the X-axis guide rail, enabling the 3D printing module to move in the X and Y axis directions. A Z-axis guide rail is provided on the printer base, and the printing platform is installed on the slider of the Z-axis guide rail, enabling it to move along the Z-axis direction.

[0043] The present invention also provides a method for low-temperature 3D printing of food using the above-mentioned 3D printing equipment, the method comprising the following steps:

[0044] (1) Confirm that the texture parameters of the printed material meet the requirements of precision printing, and input them into the control module program as standard parameters;

[0045] (2) Load the printing material into the material cylinder, assemble the 3D printing module, start the equipment, the extrusion device drives the extrusion probe to touch the material, the texture detection module performs mechanical property detection and transmits it to the control module; the control module processes the collected data and compares it with the standard parameters. If it is higher than the standard parameter range, the heating program of the material cylinder is started, otherwise the cooling program is started, and the texture parameters are detected again until they are within the standard range; the printing platform starts the cooling program to the set temperature and maintains it;

[0046] (3) Start 3D printing according to the preset program. The printing material in the material cylinder is extruded and deposited on the printing platform, and printed layer by layer. During the printing process, the texture parameters of the printing material are kept within the standard range.

[0047] Preferably, in step (2), the temperature is increased or decreased to the set temperature at a rate of 0.5-20℃ / min, and the temperature is maintained for 5-30 minutes before the texture parameters are detected again.

[0048] Preferably, in step (3), when the texture parameter is detected to be outside the standard range of ±5N during the printing process, the heating or cooling program is started.

[0049] The beneficial effects of this invention are as follows:

[0050] (1) The 3D printing equipment provided by the present invention monitors the flowability of the printing material in real time through a pressure sensor and adjusts the temperature through an intelligent temperature control system, so that the printing material has smooth flowability and mechanical properties in a suitable temperature environment, thereby improving printing accuracy and product quality.

[0051] (2) The present invention provides a cooling device on the printing platform, which cools and solidifies the printing material when it is deposited on the printing platform, thereby improving the printing accuracy.

[0052] (3) In the printing process, the present invention uses a mechanical sensor to monitor the mechanical parameters of the printing material in real time, and the intelligent temperature control system dynamically adjusts the temperature of the print head and the printing platform, realizing functions such as temperature preheating and constant temperature maintenance, making the printing process more stable and efficient, reducing the impact of temperature fluctuations on the product during the printing process, and improving the printing success rate.

[0053] (4) This invention is applicable to low-temperature 3D printing of food and can be widely used in the manufacture of various foods, such as ice cream. Through the adjustment of the intelligent temperature control system, the printing requirements of different food raw materials can be met, improving the flexibility and applicability of the production process, which is conducive to meeting the market demand for personalized and customized foods. Attached Figure Description

[0054] Figure 1 This is a three-dimensional view of the 3D printing equipment of the present invention.

[0055] Figure 2 This is the main perspective view of the 3D printing equipment of the present invention.

[0056] Figure 3 This is a schematic diagram of the semiconductor cooling system of the low-temperature printing platform of the present invention.

[0057] Figure 4 This is a perspective view of the mechanical sensor of the present invention.

[0058] Figure 5 These are printing accuracy diagrams of different types of starch hydrogels.

[0059] Figure 6 This is a graph showing the changes in printing accuracy and elasticity of cassava starch gel at different temperatures.

[0060] Among them, 1-material extrusion unit, 11-material cylinder, 12-jacketed structure, 13-constant temperature circulation controller, 14-temperature sensor, 15-printing nozzle, 16-extrusion probe, 2-printing platform, 21-semiconductor cooling element, 22-heat sink, 23-fan, 24-temperature control element, 25-insulation layer, 3-mechanical sensor, 31-diaphragm, 32-piezoelectric element, 33-signal lead, 34-insulator, 35-housing, 4-printer base, 5-fixed bracket, 6-Z-axis guide rail, 7-Y-axis guide rail, 8-X-axis guide rail. Detailed Implementation

[0061] Considering the temperature-sensitive nature of materials during food 3D printing, especially those food ingredients that require specific temperatures to achieve ideal solidification or gelatinization, this invention proposes a pressure-sensing intelligent temperature control 3D printing device and its low-temperature food printing method. This device utilizes a high-precision pressure sensor to monitor the mechanical parameters of the printing material and, combined with an intelligent temperature control system, automatically adjusts the operating status of the heating or cooling devices to ensure the printing environment is always maintained within the ideal temperature range required by the food material.

[0062] Taking starch gel as an example, starch gels of different varieties and sources exhibit textural differences, resulting in significant variations in the elasticity of printing materials even when prepared with the same formulation. During the printing process, heating reduces the elasticity of the starch, allowing for smooth extrusion; cooling increases its elasticity, providing support properties. Therefore, by using a mechanical sensor to detect the elasticity value of the printing material before 3D printing and adjusting the appropriate temperature based on the measured value until the standard elasticity range for high-precision printing is achieved, accurate 3D printing of starch gel can be realized.

[0063] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0064] Example 1: A 3D printing device based on pressure sensing and intelligent temperature control

[0065] This embodiment provides a 3D printing device based on pressure sensing and intelligent temperature control. The 3D printing device includes a 3D printing module, a texture detection module, and a control module. The texture detection module monitors the mechanical properties of the printing material in real time. The control module processes and analyzes the collected data and controls the intelligent control system in the 3D printing module to perform efficient temperature control on the printing material and change the mechanical properties of the material to meet the requirements of precision printing.

[0066] Specifically, such as Figure 1-2 As shown, the 3D printing module realizes 3D printing, including a material extrusion unit 1 and a printing platform 2. The material extrusion unit 1 includes a material cylinder 11 for loading printing material, a temperature control device for containing the material cylinder 11, and an extrusion device for extruding the material.

[0067] In this embodiment, the temperature of the material cylinder is controlled by circulating medium heat conduction. Specifically, the temperature control device includes a hollow sandwich structure 12 adapted to the material cylinder 11, the sandwich is filled with circulating medium, and is connected to a constant temperature circulation controller 13 through a pipeline.

[0068] The constant-temperature circulation controller 13 includes a medium circulation system, a temperature sensor 14, a temperature control element, and a communication interface. The circulation medium can be, but is not limited to, water, ethylene glycol, or silicone oil. The medium circulation system drives the medium circulation flow. The jacket structure 12 is connected to the constant-temperature circulation controller 13 via piping, and the heat-conducting medium circulates between the jacket and the controller. The temperature sensor 14 is used to monitor the temperature of the circulation medium in real time. The temperature control element includes a heating system and a cooling system, with a temperature adjustment range of 0–150°C. The communication interface connects to the control module and is used to receive commands from the control module and control the temperature control element.

[0069] Temperature control elements heat or cool the circulating medium. After the temperature sensor detects that the target temperature has been reached, the medium circulation system transfers the circulating medium to the jacket structure through pipelines to achieve the temperature transfer function of the material cylinder.

[0070] The sandwich structure 12 between the material cylinder 11 and the temperature control device is detachable. The sandwich structure 12 fits tightly against the material cylinder 11, ensuring uniform heat conduction and allowing for rapid heating and cooling of the printed material inside the cylinder. The sandwich structure 12 can be made of a metal material with good thermal conductivity.

[0071] The extrusion device is connected above the material cylinder 11 and provides extrusion pressure to force the printing material inside the material cylinder 11 to be extruded from the print nozzle 15 onto the print platform 2. Specifically, the extrusion device moves downward under the drive of a stepper motor, squeezing the printing material inside the material cylinder 11.

[0072] The printing platform 2 is used to receive the printed products. In this embodiment, a semiconductor cooling device is provided on the printing platform, the components of which include: a semiconductor cooling element 21, a heat sink 22, and a fan 23. The semiconductor cooling element 21 is composed of N-type and P-type semiconductor materials, and its structure is as follows: Figure 3As shown, the cooling end of the semiconductor cooling element 21 is attached to the printing platform 2 to provide low temperature conditions for the printing platform. The heating end of the semiconductor cooling element 21 is provided with a heat sink 22, and a fan 23 is provided at the corresponding heat sink 22. The heating end of the semiconductor cooling element 21 dissipates heat through the heat sink 22 and the fan 23.

[0073] The semiconductor cooling element 21 cools and transmits heat to reduce the temperature of the printing platform 2, thereby cooling and solidifying the printed material.

[0074] A temperature sensor 24 is installed on the printing platform 2. The temperature sensor 24 monitors the temperature of the printing platform in real time and transmits the temperature parameters to the control module. The control module is electrically connected to the cooling device on the printing platform 2 and controls its on / off state. When the temperature of the printing platform 2 exceeds the set temperature, the control module activates the cooling device until the set temperature is reached. The cooling temperature range is 25 to -40℃.

[0075] An insulation layer 25 is provided on the outer periphery of the printing platform 2 to maintain the low temperature environment of the printing platform 2.

[0076] The texture detection module is used to detect the texture parameters of the printed material, and its components include a mechanical sensor 3. To accurately measure the mechanical parameters, this embodiment includes a rigid extrusion probe 16, which is cylindrical or conical, installed at the point where the extrusion device contacts the printed material. The mechanical sensor 3 is connected to the extrusion probe 16, detects the pressure value of the extrusion probe 16 when extruding the printed material, and transmits the signal to the control module.

[0077] like Figure 4 As shown, the mechanical sensor 3 is a piezoelectric pressure sensor, whose components include: a diaphragm 31, a piezoelectric element 32, a signal lead 33, an insulator 34, and a housing 35. Its working principle is as follows: when subjected to pressure, the diaphragm 31 undergoes physical deformation. This change in shape leads to a redistribution of charges within the piezoelectric element 32, generating voltage and current. The direct piezoelectric effect allows these charges to accumulate on two opposing surfaces of the material, generating a measurable voltage signal. The generated voltage signal is very weak and needs to be amplified and converted by the signal lead 33 for further processing and reading. The amplified signal is typically converted into a digital signal for easier processing and analysis. The insulator 34 and housing 35 serve as protective measures to prevent interference from environmental pressure and charges during the testing process.

[0078] In this embodiment, the control module is integrated into computer program control software, including a model building program, a printing program, a data processing program, and a temperature control program;

[0079] The model building program includes 3D scanning and imaging software and 3D model slicing program; it achieves procedural modeling by scanning the target object, draws it into a printable model in the software, and sets the printing path with the help of the 3D model slicing program.

[0080] The printing program controls the printing parameters of the 3D printing module, including printing speed, infill rate, and nozzle size; it mainly adjusts the material hopper movement speed, printing time, printed product density, and extrusion line width during the printing process.

[0081] The data processing program is used to process and calculate the texture parameters from the pressure speed, distance, trigger force and other detection data collected by the texture detection module. After comparing the parameters with the texture standard parameters, a temperature control command is generated. The data processing program has a built-in data conversion algorithm and a texture standard parameter reference table.

[0082] The temperature control program includes a material cylinder temperature control program and a printing platform temperature control program. The material cylinder temperature control program receives temperature control commands sent by the data processing program and controls the heating or cooling of the material cylinder. The printing platform temperature control program controls the opening or closing of the refrigeration unit.

[0083] This embodiment uses a texture detection module to monitor the mechanical parameters of the printed material in real time, reflecting the material's textural properties under current temperature conditions. Based on this real-time data, the temperature is intelligently adjusted. Specifically, the control module receives data signals from the mechanical sensor, converts the signals, calculates the material's textural parameters based on the resulting force-time curve, and compares them with built-in standard textural parameters. If the parameters are higher than the standard range, a heating command is sent to the intelligent temperature control system of the material extrusion unit to initiate the heating process; if the parameters are lower than the standard range, a cooling command is sent to the material extrusion unit to initiate the cooling process. This continues until the detected textural parameters are within the standard range.

[0084] In this embodiment, the 3D printing equipment also includes a printer base 4 and a fixed bracket 5 erected on the base. The printer base 4 is provided with a Z-axis guide rail 6, and the printing platform 2 is fixedly installed on the slider of the Z-axis guide rail, allowing it to move along the Z-axis direction. The fixed bracket 5 is provided with a Y-axis guide rail 7, and an X-axis guide rail 8 is installed on the slider of the Y-axis guide rail 7. The 3D printing module is fixed in the slider of the X-axis guide rail 8, enabling the 3D printing module to move in the X and Y axis directions. Three-dimensional printing is achieved through precise control of the position on the X, Y, and Z axes.

[0085] Example 2: A method for low-temperature 3D printing of food based on pressure sensing and intelligent temperature control

[0086] This embodiment utilizes the 3D printing equipment provided in Embodiment 1 to perform low-temperature 3D printing of food. The process is as follows:

[0087] Open the computer program control software and import the printing information. At the same time, input the texture standard parameters (determine the range of texture parameters required for high-precision printing of food materials, and set them as standard parameters).

[0088] Inject an appropriate amount of food material to be printed into the material cylinder 11 and place it into the control device interlayer structure. Adjust the relative positions of the printing platform 2, X-axis guide rail 8, Y-axis guide rail 7, and Z-axis guide rail 6, and begin the texture detection of the material.

[0089] At a certain temperature (0–100°C), the extrusion device drives the extrusion probe 16 to contact the material for texture testing. The control module processes the collected mechanical data to obtain texture parameters and compares them with standard parameters.

[0090] After comparison, if the parameters exceed the standard range, the constant temperature circulation controller 13 will initiate the heating program, heating at a rate of 0.5–20℃ / min to the set temperature. The circulating medium is transferred to the sandwich structure through pipelines to achieve temperature transfer to the material cylinder. After maintaining the temperature for 5–30 minutes, the texture parameters will be checked again until they are within the standard range. If the parameters are below the standard range, the cooling program will initiate, cooling at a rate of 0.5–20℃ / min, and maintaining the temperature for 5–30 minutes before checking the texture parameters again until they are within the standard range. Once the parameters meet the standard range, 3D printing will begin according to the preset program.

[0091] Printing platform 2 initiates a cooling program, reducing the temperature to 25 to -40°C at a rate of 0.5 to 20°C / min, thereby providing support for the printed product through low temperature.

[0092] After the test begins, the material in the material cylinder 11 is gradually extruded under the pressure generated by the extrusion probe 16 of the extrusion device and deposited on the low-temperature printing platform 2. The Z-axis guide rail 6 and X-axis guide rail 8 complete two-dimensional movement under the guidance of the printing information, so that the extruded filament forms the target two-dimensional pattern. After one layer of printing is completed, the Y-axis guide rail 7 drives the sandwich material cylinder to a certain height, repeating the above movement steps to complete the next layer of printing.

[0093] During the printing process, the extrusion probe 16 detects the material's mechanical parameters in real time and transmits them to the control module for real-time processing and analysis via the mechanical data transmission line. If the temperature reaches ±5N outside the standard range threshold, the constant temperature circulation controller 13 is immediately activated to perform the corresponding heating and cooling programs until the printing program ends.

[0094] Example 3: Printing accuracy and texture testing of different types of starch gels

[0095] 1. Preparation of starch gel

[0096] A certain amount of starch was weighed and added to deionized water to prepare a 13% (w / v, on a dry basis) suspension. The starch suspension was heated at 80°C for 17 minutes with continuous magnetic stirring. After the gel cooled to room temperature, it was loaded into the barrel of the 3D printing equipment of Example 1 for printing.

[0097] Starch types: cassava starch (CAS: 9005-25-8), wheat starch (CAS: 68412-29-3), corn starch (CAS: 9005-25-8), sweet potato starch (CAS: 9005-25-8), potato starch (CAS: 9005-25-8), buckwheat starch (CAS: 9005-25-8).

[0098] 2. Texture testing

[0099] 50g of gel was placed in a container, and a 35mm cylindrical probe was selected. The test program was set to two-stage compression testing (TPA). The test parameters were set as follows: velocity before test 1.50mm / s; velocity after test 1.50mm / s; compression distance 1.5mm; time 10.00s; trigger point force 0.4g. Based on the obtained force-time curve, the textural properties of the starch gel were output using TexturePro CT software.

[0100] 3. Results Analysis

[0101] The results are as follows Figure 5 As shown, different types of starch gels exhibit significant differences in printing precision, ranked in the following order: corn starch > wheat starch > buckwheat starch > tapioca starch > potato starch > sweet potato starch. This indicates that different starch gels require different printing environments to produce high-precision printed products.

[0102] As shown in Table 1, different types of starch gels exhibit significant differences in textural properties, with a significant positive correlation between hardness and printing precision. The printing precision of corn starch, wheat starch, and buckwheat starch all exceeded 90%, therefore, the standard range for hardness can be set between 115-130g.

[0103] Table 1. Lymphoid properties of different types of starch gels

[0104]

[0105] Example 4: Changes in printing accuracy of cassava starch gel at different printing temperatures

[0106] The cassava starch gel from Example 3 was placed at different printing temperatures (5℃, 10℃, 15℃, 20℃, 25℃, 30℃) for 20 minutes to determine the printing accuracy and hardness value of the cassava gel.

[0107] The results are as follows Figure 6 As shown, the hardness of cassava gel increases significantly with decreasing temperature, and the corresponding printing accuracy also gradually increases. This indicates that adjusting the printing temperature according to texture parameters can effectively improve the printing accuracy of starch gel.

Claims

1. A method for low-temperature 3D printing of food using a pressure-sensing intelligent temperature control 3D printing device, characterized in that, The pressure-sensing intelligent temperature control 3D printing equipment includes: The 3D printing module includes a material extrusion unit and a printing platform. The material extrusion unit includes a temperature-controlled material cylinder, a temperature control device for containing the material cylinder, and an extrusion device for extruding the material. The temperature control device includes a hollow sandwich structure adapted to the material cylinder, the sandwich being filled with a circulating medium and connected to a constant temperature circulation controller via a pipeline. The extrusion device includes an extrusion probe that contacts the material, and the extrusion probe is a rigid cylindrical or conical structure. The printing platform is equipped with a cooling device, which includes a semiconductor cooling element, a heat sink, and a fan. The cooling end of the semiconductor cooling element is attached to the printing platform, the heating end is equipped with a heat sink, and a fan is positioned corresponding to the heat sink. An insulation layer is provided along the outer periphery of the printing platform. A temperature sensor is installed on the printing platform to monitor the temperature of the printing platform in real time and transmit temperature parameters to the control module. The texture detection module includes a mechanical sensor for measuring the force applied to the extrusion probe. The mechanical sensor is connected to the extrusion probe, detects the pressure value of the extrusion probe when extruding the printed material, and transmits the signal to the control module. The mechanical sensor is a piezoelectric pressure sensor or a strain gauge pressure sensor. The texture detection module also includes a sensor for measuring the speed and distance of the extrusion probe pressing down. The control module includes: Model building programs, including 3D scanning and imaging software and 3D model slicing programs; The printing program controls the printing parameters of the 3D printing module, including printing speed, infill rate, and nozzle size. The data processing program includes a built-in data conversion algorithm and a reference table for standard texture parameters. It processes and calculates texture parameters from the test data collected by the texture testing module, compares these parameters with standard texture parameters, and generates temperature control commands. Data processing includes data acquisition and data conversion. Data acquisition involves extracting key data points from the force-time curve, including maximum force, breaking force, and elastic modulus. Data conversion uses a preset conversion algorithm and model to convert these key data points into texture performance parameters, including hardness, elasticity, and viscosity. The temperature control program is used to receive temperature control commands sent by the data processing program and control the heating or cooling of the material cylinder, as well as to control the opening or closing of the refrigeration unit. The method for low-temperature 3D printing of food includes the following steps: (1) Confirm that the texture parameters of the printed material meet the requirements of precision printing, and input them into the control module program as standard parameters; (2) Load the printing material into the material cylinder, assemble the 3D printing module, start the equipment, the extrusion device drives the extrusion probe to touch the material, the texture detection module performs mechanical property detection and transmits it to the control module; the control module processes the collected data and compares it with the standard parameters. If it is higher than the standard parameter range, the heating program of the material cylinder is started, otherwise the cooling program is started. The temperature is increased or decreased at a rate of 0.5-20℃ / min to the set temperature, and the texture parameters are detected again after 5-30 minutes until they are within the standard range; the printing platform starts the cooling program to the set temperature and maintains it. (3) Start 3D printing according to the preset program. The printing material in the material cylinder is extruded and deposited on the printing platform, and printed layer by layer. During the printing process, keep the texture parameters of the printing material within the standard range. When the texture parameters are detected to be outside the standard range of ±5 N, start the heating or cooling program. The printing material is starch gel.

2. The method as described in claim 1, characterized in that, The material cylinder and temperature control device are detachable and can be assembled separately.

3. The method as described in claim 1, characterized in that, The constant temperature circulation controller includes a medium circulation system, a temperature sensor, a temperature control element, and a communication interface.

4. The method as described in claim 1, characterized in that, The refrigeration temperature range of the refrigeration device is 25~-40℃.

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