Energy-saving trolley furnace heat treatment system and method based on multi-station dynamic scheduling and natural air cooling

Abstract

The invention discloses an energy-saving trolley furnace heat treatment system and method based on multi-station dynamic scheduling and natural air cooling, relates to the field of automation of industrial heat treatment equipment, and aims to solve the problems that a traditional trolley furnace is high in manual operation risk, high in peak section energy consumption cost, non-compliant in cooling process and low in equipment efficiency. The system comprises a plurality of trolley type resistance furnaces, a seven-axis industrial robot, eight temporary storage stations with sensors and indicator lamps, an independent natural air cooling table and a PLC control center, and automation of the whole heat treatment process is achieved through the multi-station dynamic scheduling, trough electricity price dual-condition trigger heating and the independent air cooling technology. After implementation, more than 85% of heating energy consumption is in the off-peak electricity period, and the cost of a single furnace is reduced by 58%; the cooling rate is greater than or equal to 45 DEG C / min and meets GB / T 16923-2020; and the trolley turnover rate is doubled, and high-temperature contact risks are avoided.

Description

Technical Field

[0001] This invention relates to the field of industrial heat treatment equipment automation technology, specifically to an energy-saving bogie hearth furnace heat treatment system and method based on multi-station dynamic scheduling and natural air cooling. Background Technology

[0002] There are four major bottlenecks in the traditional bogie-type heat treatment furnace production process:

[0003] 1. Significant safety risks: The loading and unloading of workpieces relies on overhead cranes or forklifts in conjunction with manual operation. Operators are exposed to high-temperature furnace door areas (>60℃) for extended periods, resulting in a high risk of burns and high labor intensity.

[0004] 2. High energy consumption costs: The randomness of the material delivery time causes the furnace to frequently operate during the peak electricity price period from 8:00 to 22:00, which significantly increases the average energy consumption cost per furnace.

[0005] 3. Poor process compliance: After heat treatment, the workpiece is placed on a trolley with a surface temperature >200℃ for natural cooling. The residual heat of the trolley creates a local high-temperature microenvironment, and the temperature difference between the bottom and top of the workpiece reaches 150-200℃. The cooling rate is only 10-20℃ / min, which is far below the critical value of >45℃ / min required for normalizing medium carbon steel, violating the provisions of Article 4.3.2 of GB / T16923-2020 "Normalizing and Annealing Treatment of Steel".

[0006] 4. Low equipment efficiency: The high-temperature material frame occupies the trolley for 4-6 hours, while independent air cooling only takes 1.5-2 hours, resulting in a decrease in trolley turnover rate and limiting the collaborative operation of multiple furnaces.

[0007] Existing automation solutions only enable single-unit robotic arms to load and unload materials, lacking integrated material buffering mechanisms and energy scheduling strategies. This fails to systematically address the aforementioned process compliance and energy efficiency bottlenecks. Therefore, an integrated solution that combines safety assurance, energy optimization, process compliance, and efficient operation is urgently needed. Summary of the Invention

[0008] The purpose of this invention is to provide an energy-saving bogie furnace heat treatment system and method based on multi-station dynamic scheduling and natural air cooling, so as to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution: an energy-saving bogie hearth furnace heat treatment system based on multi-station dynamic scheduling and natural air cooling, comprising:

[0010] The heat treatment unit consists of at least two trolley-type resistance furnaces, used to realize the heating and heat preservation process of the workpiece.

[0011] The transfer unit includes a heavy-duty multi-axis industrial robot located in the central area of ​​the heat treatment unit. The robot's end is detachably connected to a multi-jaw gripper driven by dual cylinders. The gripper is adapted to a standard-sized material frame to realize the gripping and transfer of the material frame.

[0012] The temporary storage unit includes multiple temporary storage stations arranged around the working radius of the robot. Each temporary storage station is equipped with a material frame presence detection sensor and a three-color status indicator light, which are used to temporarily store material frames to be processed and cooled before being unloaded and to indicate the status of the material frames.

[0013] The cooling unit is an independently set natural air cooling platform. The cooling platform includes, from bottom to top, a heat-resistant steel plate base, a ceramic fiber insulation layer and a load-bearing platform with heat dissipation fins. At least two sets of non-contact infrared thermometers are installed above the cooling platform to uniformly cool the high-temperature material frame after heat treatment and monitor the temperature of the material frame in real time.

[0014] The human-machine interaction unit includes a feeding platform, an operation button box and a pneumatic pushing mechanism located outside the safety fence. The pneumatic pushing mechanism is used to feed the material frame on the feeding platform into / out of the automated area to achieve physical isolation between humans and machines.

[0015] The control center consists of a host computer and a PLC. The PLC integrates a clock module and is connected to the robot controller, the furnace temperature system of the trolley-type resistance furnace, the temporary workstation sensor, the cooling platform temperature measuring instrument, and the human-machine interaction unit. It is used to execute multi-workstation dynamic scheduling strategy, dual-condition triggering heating logic based on off-peak electricity price, independent cooling temperature closed-loop control, and multiple safety interlocking controls.

[0016] Preferably, the number of temporary storage stations is 8, and the material frame presence detection sensor is a photoelectric sensor; the colors and corresponding states of the three-color status indicator lights are: blue indicates that the material frame is pending processing and is in an energy-saving frozen state, yellow indicates that the equipment is abnormal or the task is alarmed, and red indicates that the material frame has cooled down and is ready to be unloaded.

[0017] Preferably, the off-peak electricity price period is from 22:00 to 8:00 the next day. The off-peak electricity price dual-condition trigger heating logic is as follows: only when the clock module detects that the current time is during the off-peak electricity price period, and the furnace temperature sensor of the target trolley-type resistance furnace reports a temperature ≥ the preset furnace temperature, the PLC releases the material box from the furnace freezing state and triggers the robot to execute the furnace entry program.

[0018] Preferably, the multiple safety interlock control includes: ① when the furnace door of the trolley-type resistance furnace is not fully opened, the robot is prohibited from performing furnace entry / exit actions; ② when the surface temperature of the cooling platform is detected by a thermometer to be >100℃, the robot's material handling operations on the cooling platform are locked; ③ when the pneumatic pushing mechanism performs the material frame pushing / pulling action, the safety fence access control is locked in conjunction with the mechanism.

[0019] Preferably, the PLC is also equipped with a material frame status management module, which is used to define four states of the material frame: pending processing, heating, cooling, and waiting to be unloaded, and to dynamically allocate temporary storage stations and control the robot transfer path according to the material frame status.

[0020] Preferably, the host computer of the control center is a human-machine interface used to input the material box number, select the workpiece material and heat treatment process curve, and switch the operating mode (basic mode / green energy-saving mode). The PLC communicates with external devices using the Profinet or Modbus bus protocol.

[0021] The present invention also provides a method for operating the above system, specifically the following steps:

[0022] S1 Process Registration and Energy Saving Freeze: The operator places the workpiece loading frame on the loading platform outside the enclosure, and enters the frame information, workpiece material, heat treatment process curve and operating mode through the host computer; if the green energy saving mode is selected, the PLC drives the pneumatic pushing mechanism to send the frame into the enclosure, and controls the robot to dynamically allocate idle workstations according to the temporary workstation occupancy status and place the frame. The workstation lights up with a blue indicator light, the PLC activates the task freeze logic, continuously monitors the clock module and target furnace temperature but prohibits the issuance of furnace entry commands.

[0023] S2 Off-Peak Electricity Dual-Condition Trigger Furnace Entry: When the PLC detects that the current time is within the preset off-peak electricity price period and the target trolley-type resistance furnace temperature is ≥ the preset process furnace temperature, the task freeze is automatically lifted, the robot is dispatched to grab the material frame from the temporary storage station, and after the furnace door opening interlock verification, the material frame is sent into the furnace chamber, the material frame status is updated to "heating", and the temporary storage station indicator light is turned off.

[0024] S3 Independent Natural Air Cooling and Status Switching: After the heat treatment process is completed, the trolley of the trolley-type resistance furnace drives out to the positioning point. The robot grabs the high-temperature material frame and sends it directly to the independent cooling platform. The temperature measuring instrument of the cooling platform collects the temperature of the material frame in real time and feeds it back to the PLC. When the temperature of the core area of ​​the material frame is ≤80℃, the robot transfers the material frame to the temporary storage station. The red indicator light of the station is lit up, and the status of the material frame is updated to "awaiting unloading".

[0025] S4 Human-Robot Collaborative Safe Unloading: The operator issues the unloading command through the button box outside the fence. The robot grabs the material frame to be unloaded and places it on the inner receiving platform. The pneumatic pushing mechanism pushes the material frame out of the fence. After the operator takes the workpiece away, he clicks to confirm. The robot grabs the empty material frame and returns it to the dedicated storage area. The temporary storage station status is reset.

[0026] S5 Abnormal Handling: If the target furnace temperature fails to meet the preset time during the trough period, the PLC control will switch the temporary storage station indicator light to yellow alarm and pop up a mode switching dialog box on the host computer. If the surface temperature of the cooling table is >100℃, the PLC will automatically lock the robot's material handling permissions on the cooling table until the temperature drops to the safe threshold.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1. Multi-station dynamic scheduling mechanism based on state decoupling

[0029] Unlike traditional linear workflows, this invention pioneers a decoupled control model between material status and equipment operation. The system clearly defines four states of the material container—Pending, Heating, Cooling, and Ready for Unload—and assigns multiple temporary storage stations the function of status handling and scheduling hubs. Each station integrates sensors and three-color indicator lights (blue / yellow / red), achieving three innovative functions:

[0030] Dynamic caching and asynchronous parallelism: The robot dynamically allocates material frames to idle workstations based on workstation occupancy, process type, and optimization algorithms (such as load balancing). In energy-saving mode, the furnace entry command for the material frame to be processed (indicated by a blue light) is actively frozen until both off-peak electricity hours and furnace temperature conditions are met, achieving time-shifted control of the heating process. This breaks the rigid connection of processes, allowing furnace entry, cooling, and unloading operations to be asynchronous and parallel. The system can process material frames in multiple states simultaneously, improving equipment utilization.

[0031] Path optimization and resource release: The workstation serves as an intermediate node in the robot's transfer path. After the high-temperature material frame (>250℃) exits the furnace, it is directly sent to an independent natural air cooling platform. After cooling is completed (≤80℃), it is returned to the unloading workstation (indicated by a red light), which completely avoids the long-term occupation of the trolley resources by the cooling process and improves the trolley turnover rate.

[0032] 2. Compliance assurance and energy time-shift control of natural air cooling process

[0033] To address the process failure problem caused by traditional trolley cooling, this invention proposes two original designs:

[0034] Passive natural air-cooling stage: Featuring an innovative gradient insulation structure (heat-resistant steel plate + ceramic fiber layer), this stage physically isolates the workpiece from residual heat interference from the trolley, ensuring uniform heat dissipation within the ambient air medium. Compared to traditional trolley cooling rates (10-20℃ / min), this design achieves a stable cooling rate of ≥45℃ / min and residual stress <150MPa, meeting the stringent requirements of GB / T16923-2020 for air-cooling uniformity and eliminating abnormal microstructure and properties caused by uneven cooling.

[0035] The dual-condition triggering mechanism based on off-peak electricity prices utilizes a frozen window for pending processes. The PLC's built-in clock module compares off-peak electricity periods (e.g., 22:00-8:00) in real time, activating the heating task only when the time and target furnace temperature are synchronized and meet the standard. This mechanism shifts over 85% of high-energy-consuming processes to periods with lower electricity prices, significantly reducing the energy cost per furnace.

[0036] 3. Human-Machine Collaborative Intrinsic Safety Architecture

[0037] Completely eliminate the risks of high-temperature operations through triple technological innovation:

[0038] Zero-contact physical design: The loading platform outside the fence and the pneumatic pushing mechanism achieve human-machine isolation. The operator only needs to click the button box command (such as "unload" or "material removed"), and does not need to enter the high-temperature area at all.

[0039] Multi-dimensional safety interlocks: Establish a real-time verification mechanism for motion trajectory and equipment status, including: ① disabling robot entry into the furnace when the furnace door is not fully open; ② locking the robot's material handling when the surface temperature of the cooling table is >100℃; ③ linking the locking of the fence access control during pneumatic mechanism operation.

[0040] Status visualization guidance: dual-color indicator lights for temporary storage stations (blue = energy saving and waiting, red = ready to unload) and real-time task status display via HMI, reducing the workload of manual monitoring. Attached Figure Description

[0041] Figure 1 This is a diagram showing the overall system layout.

[0042] Figure 2 This is a structural diagram of an eight-claw clamp;

[0043] Figure 3 This is a diagram of the material loading structure.

[0044] Figure 4 This is a structural diagram of the temporary storage platform;

[0045] Figure 5 Here is a structural diagram of the cooling platform;

[0046] Figure 6 For control flowchart;

[0047] Figure 7 This is a topology diagram of the control system.

[0048] Figure 1 In the middle: 1. Bogie furnace body; 2. Bogie part of the bogie furnace; 3. Robot arm of the bogie furnace; 4. Loading and unloading station; 5. Safety fence; 6. Temporary storage station.

[0049] Figure 3In the middle: 1. Feeding frame base plate; 2. Guide rail slider; 3. Slider baffle; 4. Slider pad; 5. Cylinder gasket; 6. Sensor bracket; 7. Feeding platform baffle.

[0050] Figure 5 In the middle: 1. Heat-resistant steel plate; 2. Ceramic fiber insulation layer; 3. Temperature sensor. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] This invention provides a fully automated loading, unloading, and heat treatment control system for multiple vehicle-mounted heat treatment furnaces, aiming to solve the problems of high risks associated with manual operation, soaring energy costs during peak periods, cooling process failures, and low equipment efficiency in traditional operations. The core of the system lies in constructing an automated solution that tightly integrates physical execution devices, dynamic scheduling strategies, and energy optimization control, achieving unmanned, safe, and efficient operation of the entire heat treatment process (loading, furnace entry, heating, furnace exit, cooling, and unloading).

[0053] The entire system mainly consists of the following parts: multiple standard bogie-type resistance furnaces forming a heat treatment unit; a heavy-duty multi-axis industrial robot (e.g., a seven-axis robot) located at the center, with its end effector equipped with a specially designed, dual-cylinder driven multi-jaw gripper (e.g., an eight-jaw gripper) capable of stably and reliably gripping and transferring standard-sized material frames (e.g., 1200mm × 1200mm × 800mm); within the robot's working range, multiple (e.g., eight) temporary storage stations are arranged around the bogie furnace for temporarily storing material frames to be processed or already processed. The equipment includes sensors to detect the presence or absence of material frames; a specially designed independent cooling platform, typically consisting of a heat-resistant load-bearing layer and a high-efficiency insulation layer, used to uniformly cool the high-temperature material frames after heat treatment; a human-machine interface located outside the safety fence, including a loading platform and operation button box, where personnel perform initial material frame placement and simple operation confirmation, and use a pneumatic mechanism to send the material frames into or out of the automated area, achieving physical isolation between humans and machines; and a control center consisting of a host computer (industrial control computer) and a programmable logic controller (PLC) located in the control room.

[0054] The system's operating principle revolves around its core innovations: spatiotemporal decoupling control of process registration and task execution, and independent cooling process assurance. Operators first place a workpiece-loaded frame at the loading station outside the enclosure and select the required material, heat treatment process curve (such as heating temperature and holding time), and crucially, the operating mode (basic mode or green energy-saving mode) via a human-machine interface (HMI). When the green energy-saving mode is selected, it endows the system with unique energy optimization capabilities. After receiving a task instruction containing an energy-saving indicator, the PLC directs the robot to grab the workpiece frame and store it at the designated temporary storage station. At this point, the system enters a critical "task freeze" state. Although the workpiece frame is in place, the instruction to heat it in the furnace is actively frozen; the system only maintains monitoring of the operating conditions and provides a clear waiting status indication at the temporary storage station (such as illuminating a blue indicator light). The system's built-in clock module runs continuously. Only when the current time falls within a preset off-peak electricity price period (e.g., off-peak electricity hours are typically from 10:00 PM to 8:00 AM the next day) and the internal temperature of the target trolley furnace has reached the required ready state (e.g., close to the set temperature), will the PLC automatically unfreeze, triggering the robotic arm to execute the standard furnace loading procedure and deliver the material frame into the target furnace to begin heating. This "freeze-dual-condition (time + furnace temperature) fulfillment-unfreeze execution" mechanism is the core of this patent's energy cost optimization, as it proactively shifts the energy-intensive heating process to off-peak electricity periods with lower electricity prices.

[0055] After the heat treatment process is completed, the robot removes the high-temperature material frame (typically >250℃) from the furnace. At this point, another key innovation of the system—an independent cooling platform—comes into play. Instead of returning the material frame to the trolley for natural cooling (which would result in uneven cooling, slow speed, and waste trolley resources), the robot directly transfers it to an independent cooling platform. This cooling platform, through its special structural design (such as heat-resistant steel plate + ceramic fiber insulation layer), effectively isolates it from interference from external heat sources (such as residual heat from the trolley). This design ensures that the material frame and its internal workpiece can be cooled uniformly at a rate compliant with process specifications until a safe unloading temperature (e.g., ≤80℃) is reached, thereby effectively controlling the residual stress level of the workpiece and meeting relevant standards (such as GB / T33211). After cooling to the required standard, the material frame is transferred back to the temporary storage station by the robot to await unloading, and the status indicator is switched (e.g., a red light illuminates). After confirmation outside the enclosure, the operator completes the unloading process via button commands. This method of directly feeding high-temperature material frames to independent cooling stations not only strictly ensures the compliance of the cooling process and solves the organizational performance problems caused by traditional trolley cooling, but more importantly, it greatly releases trolley resources (reducing the occupation time from several hours to about 1.5 hours), significantly improving the turnover rate of trolleys and the processing capacity of the entire system.

[0056] To ensure the efficient and safe operation of the above processes, the system also integrates multiple collaborative mechanisms. The dynamic scheduling strategy utilizes multiple temporary storage stations as buffers. The robot intelligently allocates material frame positions and transfer sequences based on the current status of each furnace (idle, running, ready), the process type of the material frame, and optimization algorithms (such as shortest path planning to reduce idle travel), maximizing equipment utilization and processing efficiency. Multiple safety interlocks are the cornerstone of inherent safety: the system monitors critical states in real time. For example, when it detects that the furnace door is not fully open, it will prohibit the robot from performing furnace entry actions; when the surface temperature of an independent cooling platform exceeds a safety threshold (e.g., >100℃), it will lock the robot's material handling operations on that platform; when the cylinder of the loading platform is pushing the material frame, it will lock the fence access control to prevent personnel from accidentally entering. These interlock logics are strictly enforced by the PLC.

[0057] In summary, the technical solution of this invention, through its innovative "task freezing and off-peak electricity triggering" control principle, independent cooling platform design, multi-station dynamic scheduling, and strict safety interlocking, constructs a safe, energy-saving, efficient, and process-compliant fully automatic bogie furnace heat treatment system, fundamentally solving the various bottleneck problems mentioned in the background technology.

[0058] The specific implementation of this invention is illustrated using a four-cart-type heat treatment furnace system as an example, combined with the energy-saving processing flow of 40Cr material workpieces. The system hardware layout is as follows: four cart-type resistance furnaces with a rated temperature of 1300℃ are arranged in a line. A KUKAKR1000 seven-axis robot (load 360kg) is installed in front of the two middle cart furnaces. The end flanges are connected to an eight-claw heat-resistant clamp (temperature resistance ≥1300℃) driven by dual cylinders. Eight heavy-duty temporary storage stations are arranged in a ring around the working radius of the robot. Each station is equipped with a SICK photoelectric sensor (to detect the presence of the material frame) and a three-color LED status light. An independent natural air-cooled cooling platform is located between the furnace group and the temporary storage area. Its structure from bottom to top is: a 20mm thick Q345B heat-resistant steel plate base + a 50mm ceramic fiber insulation layer (thermal conductivity ≤0.12W / m·K) + a cast iron load-bearing platform with heat dissipation fins. A pneumatic loading platform (thrust force 5 tons) and an anti-accidental touch button box are set on the outside of the fence. The control center consists of a Siemens S7-1500 PLC and an Advantech industrial control unit. The PLC is connected to the robot controller, furnace temperature instrument and sensor network via the Profinet bus.

[0059] The implementation process is divided into five stages:

[0060] Phase 1: Process Registration and Energy Conservation Freeze

[0061] The operator places a material frame (1200mm×1200mm×800mm) loaded with 40Cr workpieces on the loading platform outside the enclosure. The operator enters the material frame number "F202405001" through the HMI interface, selects the material "40Cr", the process curve "P5 (850℃ holding for 4h)", and checks the "green energy saving" option. After receiving the command, the PLC drives a pneumatic pusher to send the material frame into the enclosure. The robot dynamically selects temporary workstation S3 based on the real-time workstation occupancy status (via sensor feedback), completing the precise placement of the material frame with closed-loop control with an accuracy of ±2mm. Workstation S3 illuminates a blue indicator light and enters the "Pending" state. The PLC simultaneously activates the task freeze logic—continuously monitoring the system clock and the temperature of furnace #2 (target value 840℃), but prohibiting the issuance of furnace entry commands.

[0062] Phase Two: Off-Peak Electricity Dual-Condition Trigger Furnace Input

[0063] When the PLC's built-in clock module detects that the current time is within the preset off-peak electricity range (22:00-08:00), and the temperature sensor of furnace #2 reports a temperature ≥840℃, the system automatically unfreezes the task. The PLC-managed robot executes the standard furnace loading procedure: pick up material from station S3 → transfer to furnace #2 → trigger the furnace door opening command (interlock verification 100% opening) → place the material frame in the center of the trolley (position deviation <5mm) → close the furnace door after the trolley enters the furnace chamber. The status light at station S3 goes out and resets to idle, and the material frame is marked as "Heating".

[0064] Phase 3: Direct Natural Air Cooling and State Switching

[0065] At the end of the heat treatment process (4 hours of heat preservation completed), the trolley furnace automatically moves to the positioning point (repeatability ±10mm). After the robot picks up the material, it is directly delivered to the independent cooling platform, and the trolley stops are strictly avoided during this process. The cooling platform innovatively integrates a non-contact temperature measurement system: two sets of infrared thermometers (range 0-600℃, accuracy ±1.5%) are installed 1.5 meters directly above the cooling platform, respectively aimed at the geometric center and edge area of ​​the material frame, to collect the surface temperature of the material frame in real time. The PLC determines the cooling progress based on the average temperature of the two points. The material frame dissipates heat in a pure natural air convection environment, and the ceramic fiber insulation layer effectively blocks external heat conduction (the measured effect of the residual heat zone of the trolley on the temperature rise of the cooling platform is <5℃). When the infrared thermometers report that the temperature of the core area of ​​the material frame is ≤80℃ (meeting the cooling endpoint requirements of GB / T16923-2020), the robot transfers the material frame to the temporary storage station S5 and switches the red light indicator to "Ready for Unload". The measured cooling rate was stable in the range of 45-50℃ / min, and the residual stress of the workpiece was <150MPa.

[0066] Phase 4: Human-Machine Collaborative Safe Material Unloading

[0067] The operator presses the "Unload" button on the button box outside the fence, and the robot picks up the material frame from station S5 and places it on the inner receiving platform. A pneumatic pusher (800mm stroke, 0.5m / s speed) smoothly pushes the material frame out of the fence. After the operator removes the workpiece using a crane or other means, the operator clicks "Material Removed" to confirm. The robot then picks up the empty material frame and returns it to the dedicated storage area, resetting the status of station S5.

[0068] Phase 5: Exception Handling Mechanism

[0069] If the furnace temperature does not meet the standard during off-peak electricity hours (e.g., equipment failure causing furnace #2 temperature to be <840℃ for 2 consecutive hours), the PLC will automatically switch the S3 station indicator light to yellow alarm, and the HMI will display a "Force start basic mode" dialog box. After manual selection, the system will skip the off-peak electricity conditions and directly execute the furnace feeding, or suspend the task for maintenance. When the cooling platform exceeds the temperature (>100℃), the robot's material handling permissions will be automatically locked until the temperature drops to the safe threshold.

[0070] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An energy-saving bogie hearth furnace heat treatment system based on multi-station dynamic scheduling and natural air cooling, characterized in that: include: The heat treatment unit consists of at least two trolley-type resistance furnaces, used to realize the heating and heat preservation process of the workpiece. The transfer unit includes a heavy-duty multi-axis industrial robot located in the central area of ​​the heat treatment unit. The robot's end is detachably connected to a multi-jaw gripper driven by dual cylinders. The gripper is adapted to a standard-sized material frame to realize the gripping and transfer of the material frame. The temporary storage unit includes multiple temporary storage stations arranged around the working radius of the robot. Each temporary storage station is equipped with a material frame presence detection sensor and a three-color status indicator light, which are used to temporarily store material frames to be processed and cooled before being unloaded and to indicate the status of the material frames. The cooling unit is an independently set natural air cooling platform. The cooling platform includes, from bottom to top, a heat-resistant steel plate base, a ceramic fiber insulation layer and a load-bearing platform with heat dissipation fins. At least two sets of non-contact infrared thermometers are installed above the cooling platform to uniformly cool the high-temperature material frame after heat treatment and monitor the temperature of the material frame in real time. The human-machine interaction unit includes a feeding platform, an operation button box and a pneumatic pushing mechanism located outside the safety fence. The pneumatic pushing mechanism is used to feed the material frame on the feeding platform into / out of the automated area to achieve physical isolation between humans and machines. The control center consists of a host computer and a PLC. The PLC integrates a clock module and is connected to the robot controller, the furnace temperature system of the trolley-type resistance furnace, the temporary workstation sensor, the cooling platform temperature measuring instrument, and the human-machine interaction unit. It is used to execute multi-workstation dynamic scheduling strategy, dual-condition triggering heating logic based on off-peak electricity price, independent cooling temperature closed-loop control, and multiple safety interlocking controls.

2. The energy-saving bogie hearth furnace heat treatment system based on multi-station dynamic scheduling and natural air cooling as described in claim 1, characterized in that: The number of temporary storage stations is 8. The material frame presence detection sensor is a photoelectric sensor. The colors and corresponding states of the three-color status indicator lights are as follows: blue indicates that the material frame is pending processing and is in an energy-saving frozen state; yellow indicates that the equipment is abnormal or there is a task alarm; and red indicates that the material frame has cooled down and is ready to be unloaded.

3. The energy-saving bogie hearth furnace heat treatment system based on multi-station dynamic scheduling and natural air cooling as described in claim 1, characterized in that: The off-peak electricity price period is from 22:00 to 8:00 the next day. The off-peak electricity price dual-condition trigger heating logic is as follows: only when the clock module detects that the current time is during the off-peak electricity price period, and the furnace temperature sensor of the target trolley-type resistance furnace reports a temperature ≥ the preset furnace temperature, the PLC releases the material box from the furnace freezing state and triggers the robot to execute the furnace entry program.

4. The energy-saving bogie hearth furnace heat treatment system based on multi-station dynamic scheduling and natural air cooling as described in claim 1, characterized in that: The multiple safety interlock controls include: ① When the furnace door of the trolley-type resistance furnace is not fully opened, the robot is prohibited from performing furnace entry / exit actions; ② When the surface temperature of the cooling platform is detected by the thermometer to be >100℃, the robot's material handling operations on the cooling platform are locked; ③ When the pneumatic pushing mechanism performs the material frame pushing / pulling action, the safety fence access control is locked in conjunction with the mechanism.

5. The energy-saving bogie hearth furnace heat treatment system based on multi-station dynamic scheduling and natural air cooling according to claim 1, characterized in that: The PLC is also equipped with a material frame status management module, which defines four states of the material frame: pending processing, heating, cooling, and waiting to be unloaded, and dynamically allocates temporary storage stations and controls the robot transfer path according to the material frame status.

6. The energy-saving bogie hearth furnace heat treatment system based on multi-station dynamic scheduling and natural air cooling according to claim 1, characterized in that: The host computer of the control center is a human-machine interface used to input the material box number, select the workpiece material and heat treatment process curve, and switch the operating mode (basic mode / green energy-saving mode). The PLC communicates with external devices using the Profinet or Modbus bus protocol.

7. The method of operating the system according to any one of claims 1-6, comprising the following steps: S1 Process Registration and Energy Saving Freeze: The operator places the workpiece loading frame on the loading platform outside the fence, and enters the frame information, selects the workpiece material, heat treatment process curve and operating mode through the host computer. If the green energy saving mode is selected, the PLC drives the pneumatic pushing mechanism to send the frame into the fence. The robot controls the robot to dynamically allocate idle workstations according to the temporary workstation occupancy status and places the frame. The workstation lights up with a blue indicator light. The PLC activates the task freeze logic, continuously monitors the clock module and the target furnace temperature, but prohibits the issuance of furnace entry commands. S2 Off-Peak Electricity Dual-Condition Trigger Furnace Entry: When the PLC detects that the current time is within the preset off-peak electricity price period and the target trolley-type resistance furnace temperature is ≥ the preset process furnace temperature, the task freeze is automatically lifted, the robot is dispatched to grab the material frame from the temporary storage station, and after the furnace door opening interlock verification, the material frame is sent into the furnace chamber, the material frame status is updated to "Heating", and the temporary storage station indicator light is turned off. S3 Independent Natural Air Cooling and Status Switching: After the heat treatment process is completed, the trolley of the trolley-type resistance furnace drives out to the positioning point. The robot grabs the high-temperature material frame and sends it directly to the independent cooling platform. The temperature measuring instrument of the cooling platform collects the temperature of the material frame in real time and feeds it back to the PLC. When the temperature of the core area of ​​the material frame is ≤80℃, the robot transfers the material frame to the temporary storage station. The red indicator light of the station is lit up and the status of the material frame is updated to "awaiting unloading". S4 Human-Robot Collaborative Safe Unloading: The operator issues the unloading command through the button box outside the fence. The robot grabs the material frame to be unloaded and places it on the inner receiving platform. The pneumatic pushing mechanism pushes the material frame out of the fence. After the operator takes the workpiece away, he clicks to confirm. The robot grabs the empty material frame and returns it to the dedicated storage area. The temporary storage station status is reset. S5 Abnormal Handling: If the target furnace temperature fails to meet the preset time during the trough period, the PLC control will switch the temporary storage station indicator light to yellow alarm and pop up a mode switching dialog box on the host computer. If the surface temperature of the cooling table is >100℃, the PLC will automatically lock the robot's material handling permissions on the cooling table until the temperature drops to the safe threshold.

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