Delayed profiling extrusion device

Abstract

The embodiment of the invention discloses a delayed profiling extrusion device. According to one specific embodiment, the delay profiling extrusion device comprises a driver, a profiling extrusion pin, a controller, a displacement detector and a limiting device. An output rod is arranged on the driver; the profiling extrusion pin is connected with the upper end of the output rod; the shape of the extrusion end face of the profiling extrusion pin is matched with the outline of the thick-wall area of the product. The limiting device is arranged below the output rod; the controller is in communication connection with the driver and the displacement detector; the controller is configured to execute the steps that according to the three-dimensional model of the thick-wall area of the product, the shrinkage cavity volume is determined; according to the shrinkage cavity volume, the target moving distance of the profiling extrusion pin is determined; before a product is die-cast, a driver is controlled to drive a profiling extrusion pin to move downwards by a target moving distance; and the driver is controlled to drive the profiling extrusion pin to move upwards by the target moving distance. According to the embodiment, when the aluminum alloy liquid is not solidified, the profiling extrusion pin is used for extruding the aluminum alloy liquid to supplement the shrinkage cavity, the production process is simplified, and the production efficiency is improved.

Description

Technical Field

[0001] The embodiments disclosed herein relate to the field of metal processing technology, and more specifically to a time-delayed contour extrusion apparatus. Background Technology

[0002] Shrinkage cavities caused by shrinkage during solidification of molten aluminum alloy in thick-walled areas of the product have always been a challenge in the industry. Currently, risers are often used to reduce shrinkage cavities.

[0003] However, when using the above methods to reduce shrinkage cavities, the following technical problems often arise:

[0004] The riser volume is usually designed to be 1.5 to 2 times the volume of the thick-walled area of ​​the casting. This will cause the remaining molten aluminum alloy in the riser to solidify into a block on the casting product, which will require additional machining processes to remove it, resulting in low production efficiency.

[0005] The information disclosed in this background section is only intended to enhance the understanding of the background of the present disclosure concept, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The summary portion of this disclosure is intended to provide a brief overview of the concepts, which will be described in detail in the detailed description portion. This summary portion is not intended to identify key or essential features of the claimed technical solutions, nor is it intended to limit the scope of the claimed technical solutions.

[0007] Some embodiments of this disclosure propose a delayed contour extrusion apparatus to solve one or more of the technical problems mentioned in the background section above.

[0008] Some embodiments of this disclosure provide a delayed contour extrusion device, which includes a driver, a contour extrusion pin, a controller, a displacement detector, and a limiting device. The driver has an output rod; the contour extrusion pin is connected to the upper end of the output rod; the extrusion end face shape of the contour extrusion pin matches the contour of the thick-walled region of the product; the limiting device is disposed at the lower end of the output rod; the controller is communicatively connected to the driver and the displacement detector; the controller is configured to perform the following steps: determining the shrinkage volume based on a three-dimensional model of the thick-walled region of the product; determining the target moving distance of the contour extrusion pin based on the shrinkage volume; controlling the driver to drive the contour extrusion pin downwards by the target moving distance before die-casting the product; and controlling the driver to drive the contour extrusion pin upwards by the target moving distance in response to a preset time for injecting molten aluminum into the mold cavity.

[0009] Optionally, the upper end of the output rod is provided with a male thread; the lower end of the contouring extrusion pin is provided with a connecting cavity; and the connecting cavity is provided with a female thread that matches the male thread at the upper end of the output rod.

[0010] Optionally, the lower end of the output rod is provided with a sliding groove, and the outer surface of the lower end of the output rod is provided with a frosted layer; the sliding groove radially penetrates the output rod; the limiting device includes a first clamping block, a second clamping block, a screw, and a fastening nut; the width of the sliding groove is greater than or equal to the outer diameter of the screw; the first clamping block and the second clamping block are symmetrically arranged on both sides of the output rod; the screw sequentially penetrates the first clamping block, the output rod, and the second clamping block, and the fastening nuts are installed at both ends of the screw; the side of the first clamping block and the second clamping block that contacts the output rod is provided with an anti-slip layer.

[0011] Optionally, the lower end of the output rod is provided with scale lines, and the scale lines are distributed along the axial direction of the output rod.

[0012] Optionally, the anti-slip layer includes a rubber pad, and the contact surface of the rubber pad is provided with anti-slip texture; the thickness of the rubber pad is less than or equal to 3 mm.

[0013] Optionally, the displacement detector is a laser displacement detector; the laser displacement detector includes a laser emitting end and a reflective target plate; the reflective target plate is fixed on the lower surface of the limiting device; the laser emitting end is fixed on the top surface of the driver, and the laser emitting end is located below the limiting device.

[0014] Optionally, the aforementioned driver is fixed to the frame of the die-casting machine by bolts.

[0015] Optionally, the aforementioned conforming extrusion pin is made of high-speed steel.

[0016] Optionally, the aforementioned delayed contouring extrusion device further includes a pressure sensor; the pressure sensor is installed at the connection between the contouring extrusion pin and the output rod, and is used to detect the pressure on the contouring extrusion pin in the axial direction; the pressure sensor is communicatively connected to the controller; the controller is further configured to perform the following steps: in response to the contouring extrusion pin starting to extrude, controlling the pressure sensor to detect the pressure on the contouring extrusion pin in the axial direction at a preset frequency to obtain axial pressure information; in response to the axial pressure information being greater than a preset pressure threshold, reading the displacement detected by the displacement sensor to obtain displacement information; controlling the contouring extrusion pin to retract a preset distance, wherein the preset distance is less than the displacement information; in response to the completion of the contouring extrusion pin retracting the preset distance, controlling the alarm device to issue an alarm.

[0017] Some embodiments of this disclosure provide a delayed contour extrusion device that can improve the production efficiency of die casting processes. Specifically, the reason for the low production efficiency of most die casting processes is that currently, risers are often used to reduce shrinkage cavities caused by shrinkage during the solidification of molten aluminum alloy. However, the riser volume is usually designed to be 1.5 to 2 times the volume of the thick-walled area of ​​the casting. This causes the remaining molten aluminum alloy in the riser to solidify into a block on the casting product, requiring subsequent machining processes to remove it, thus resulting in low production efficiency. Based on this, some embodiments of this disclosure provide a delayed contour extrusion device, which includes a driver, a contour extrusion pin, a controller, a displacement detector, and a limiting device. The driver has an output rod; the contour extrusion pin is connected to the upper end of the output rod; the extrusion end face shape of the contour extrusion pin matches the contour of the thick-walled region of the product; the limiting device is located at the lower end of the output rod; the controller is communicatively connected to the driver and the displacement detector; the controller is configured to perform the following: determining the shrinkage cavity volume based on a three-dimensional model of the thick-walled region of the product; determining the target moving distance of the contour extrusion pin based on the shrinkage cavity volume; controlling the driver to drive the contour extrusion pin downwards by the target moving distance before die casting the product; and controlling the driver to drive the contour extrusion pin upwards by the target moving distance in response to a preset time for injecting molten aluminum alloy into the mold cavity. By reserving space for molten aluminum alloy to replenish the shrinkage cavity before die casting, and replenishing the shrinkage cavity through extrusion by the contour extrusion pin before the molten aluminum alloy solidifies. This eliminates the need for removing excess metal from castings, thus improving production efficiency. Attached Figure Description

[0018] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and elements are not necessarily drawn to scale.

[0019] Figure 1 This is a schematic diagram of the structure of a delayed contour extrusion device according to some embodiments of the present disclosure;

[0020] Figure 2 This is a cross-sectional view of a time-delayed contour extrusion apparatus according to some embodiments of the present disclosure;

[0021] Figure 3 This is a schematic diagram of the structure of a limiting device according to some embodiments of the present disclosure. Detailed Implementation

[0022] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0023] It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other.

[0024] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are used only to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0025] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0026] This disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] Figure 1 This is a schematic diagram of the structure of a time-delayed contour extrusion device according to some embodiments of the present disclosure. Figure 1 It includes a model cavity 1, an output rod 2, a driver 3, and a contour extrusion pin 4.

[0028] Figure 2 This is a cross-sectional view of a time-delayed contour extrusion apparatus according to some embodiments of the present disclosure. Figure 2 It includes a model cavity 1, an output rod 2, a driver 3, and a contour extrusion pin 4.

[0029] Figure 3 This is a schematic diagram of the structure of a limiting device according to some embodiments of the present disclosure. Figure 3 It includes output rod 2, first clamping block 5, sliding groove 6, fastening nut 7, and screw 8.

[0030] In some embodiments, the aforementioned delayed contouring extrusion device may include a driver 3, a contouring extrusion pin 4, a controller, a displacement detector, and a limiting device. The driver 3 may be a hydraulic cylinder or a servo motor. The contouring extrusion pin 4 may be a metal block used to extrude molten aluminum alloy within the mold cavity 1. The shape of the extrusion end face of the contouring extrusion pin 4 may match the contour of the thick-walled region of the product. The extrusion end face may be the end face on the contouring extrusion pin 4 that directly contacts the molten aluminum alloy. Because shrinkage cavities generally occur in the thick-walled region of the product, the contouring extrusion pin 4 is primarily used to extrude the thick-walled region of the product. Matching the shape of the extrusion end face to the contour of the thick-walled region of the product can protect the surface of the product and reduce the probability of surface deformation caused by the extrusion of the contouring extrusion pin 4. A metal bellows may be fitted at the root of the contouring extrusion pin 4, near the cavity entrance. The upper end of the metal bellows may be interference-fitted with the extrusion pin, and the lower end may be fixed to the mold cavity wall via a flange. A metal bellows is used to seal the gap between the conformal extrusion pin 4 and the mold, preventing molten aluminum alloy inside the mold cavity 1 from leaking out through the gap between the conformal extrusion pin 4 and the mold. The bellows can be made of stainless steel. The axial elastic deformation of the bellows, combined with the up-and-down movement of the conformal extrusion pin 4, and the tight fit of the metal walls, blocks the seepage path of the molten aluminum alloy. Additionally, the sides of the bellows can be coated with a ceramic coating, with a thickness of 5–10 μm, to reduce the coefficient of friction during the movement of the conformal extrusion pin 4. The controller can be an industrial computer, without specific limitations. The displacement detector can be a laser displacement detector, capable of detecting the displacement of the conformal extrusion pin 4.

[0031] In some embodiments, the driver 3 may be provided with an output rod 2. The output rod 2 may be a cylindrical metal rod used to transmit the driving force output by the driver 3 to the conforming extrusion pin 4. The conforming extrusion pin 4 may be welded or threaded to the upper end of the output rod 2. The limiting device may be provided at the lower end of the output rod 2. The limiting device may be a radially protruding protrusion block pre-installed on the metal rod. The limiting device and the output rod 2 may be an integral or separate structure, which is not specifically limited here. The limiting device can limit the displacement of the conforming extrusion pin 4, further protecting the surface of the thick-walled area of ​​the product. For example, if the conforming extrusion pin 4 has reached the target position, but due to signal transmission delay or other reasons, the conforming extrusion pin 4 continues to extrude the product, the limiting device will lock onto the bottom surface of the mold, preventing the output rod 2 from continuing to drive the conforming extrusion pin 4 to extrude the product. The controller may be communicatively connected to the driver 3 and the displacement detector using wires.

[0032] In some embodiments, the controller described above can be configured to perform:

[0033] The first step is to determine the shrinkage cavity volume based on the 3D model of the thick-walled region of the product. This 3D model can be created by the operator using CAD software and imported into the controller. In practice, the controller can import the 3D model of the thick-walled region into CAE analysis software to simulate solidification shrinkage during die casting and determine the shrinkage cavity volume. The CAE analysis software can be Moldflow or ProCAST; no specific limitation is made here.

[0034] The second step is to determine the target moving distance of the conformal extrusion pin based on the volume of the reduced cavity. This target moving distance must meet the following requirement: after moving the conformal extrusion pin to the target distance, it must extrude a space equal to the volume of the reduced cavity. In practice, the controller can obtain the target moving distance by dividing the volume of the reduced cavity by the cross-sectional area of ​​the conformal extrusion pin. The reason for using the cross-sectional area of ​​the conformal extrusion pin instead of its extrusion end face area is that the extrusion end face may be curved. When the extrusion end face of the conformal extrusion pin is curved, the volume of the geometric body formed by moving the bottom surface upwards by the target moving distance is still equal to the cross-sectional area of ​​the conformal extrusion pin multiplied by the target moving distance.

[0035] The third step involves controlling the driver to move the contouring extrusion pin downwards a target distance before the die-cast product is installed. In practice, the controller can send a start signal (e.g., a floating-point value "1") to the driver, causing it to move the contouring extrusion pin downwards. Then, the signal from the displacement detector is read at a preset frequency to monitor the downward movement of the contouring extrusion pin in real time. When the downward movement of the contouring extrusion pin reaches the target distance, a stop signal (e.g., a floating-point value "0") is sent to the driver.

[0036] The fourth step involves controlling the actuator to move the contour extrusion pin upwards a target distance in response to a preset time for injecting molten aluminum into the mold cavity. This preset time can be set by the operator. In practice, the controller can read a timer to determine if the molten aluminum injection time (e.g., 1 minute) has been reached. Upon detecting that the preset time has been reached, a start signal (e.g., a floating-point value "2") is sent to the actuator, causing it to move the contour extrusion pin upwards. The signal from the displacement detector is then read at a preset frequency to monitor the upward distance of the contour extrusion pin in real time. When the upward distance of the contour extrusion pin reaches the target distance, a stop signal (e.g., a floating-point value "0") is sent to the actuator.

[0037] Optionally, the upper end of the output rod 2 may be provided with a male thread. The lower end of the contouring extrusion pin 4 may be provided with a connecting cavity. The connecting cavity may be a circular chamber formed on the bottom surface of the contouring extrusion pin 4. The connecting cavity may be provided with a female thread that matches the male thread at the upper end of the output rod 2. The contouring extrusion pin 4 can be connected to the output rod 2 by threaded engagement between the connecting cavity and the output rod 2.

[0038] Optionally, such as Figure 3 As shown, the lower end of the output rod 2 may be provided with a sliding groove 6, and the outer surface of the lower end of the output rod 2 may be provided with a frosted layer. The sliding groove 6 may radially penetrate the output rod 2. The sliding groove 6 may be a slot extending axially at the lower end of the output rod 2. The limiting device may include a first clamping block 5, a second clamping block, a screw 8, and a fastening nut 7. The first clamping block 5 and the second clamping block may have the same shape. Both the first clamping block 5 and the second clamping block may be a rectangular stainless steel block. One side of the rectangular block may fit against the outer contour of the output rod 2. The width of the sliding groove 6 may be greater than or equal to the outer diameter of the screw 8, so that the screw 8 can pass through the sliding groove 6. The screw 8 may be a metal rod with a male thread pre-set on the side. It should be noted that the thread is not shown in the figure. The fastening nut 7 may be a nut with a fastening function. The fastening nut 7 may be matched with the screw 8. The first clamping block 5 and the second clamping block can be symmetrically arranged on both sides of the output rod 2. The screw 8 can pass through the first clamping block 5, the output rod 2, and the second clamping block in sequence, and fastening nuts 7 can be installed at both ends of the screw 8. When the fastening nuts 7 are tightened, the first clamping block 5 and the second clamping block will be fastened to both sides of the output rod 2. When the fastening nuts 7 are loosened, the first clamping block 5, the second clamping block, and the screw 8 can slide along the sliding groove 6, and the position of the first clamping block 5 and the second clamping block clamped on the output rod can be flexibly adjusted. By setting the limiting device to an adjustable structure, the position of the limiting device can be flexibly adjusted for the orifice volume of different products (corresponding to different target movement distances), improving the applicability of the extrusion device to different products. The side of the first clamping block 5 and the second clamping block that contacts the output rod 2 can be provided with an anti-slip layer. The anti-slip layer can be a soft rubber pad (such as a silicone pad), and the soft rubber pad is fixed to the first clamping block 5 and the second clamping block by adhesive bonding.

[0039] Optionally, the lower end of the output rod 2 may be provided with scale lines, and these scale lines may be distributed along the axial direction of the output rod 2. The scale lines may be laser-printed onto the output rod 2. The scale line corresponding to the bottom surface of the contouring extrusion pin 4 on the output rod 2 may be preset as the zero scale line. The scale line aligned with the upper surface of the first clamping block 5 indicates the distance between the limiting device and the bottom surface of the contouring extrusion pin 4. When the delayed contouring extrusion device is applied to different molds, the installation position of the limiting device may change; the scale lines allow for quick adjustment of the installation position of the limiting device.

[0040] Optionally, the anti-slip layer may include a rubber pad, and the contact surface of the rubber pad may be provided with anti-slip texture. The contact surface may be the surface where the rubber pad contacts the output rod 2. The anti-slip texture may include a grid-like protrusion. By cooperating with the frosted layer on the surface of the output rod 2, the connection stability between the limiting device and the output rod 2 can be improved. The thickness of the rubber pad may be less than or equal to 3mm. Because the rubber pad is a soft material, if the thickness is greater than 3mm, it may affect the positional accuracy of the first clamping block 5 and the second clamping block. For example, if the thickness of the rubber pad is 1cm, after adjusting the first clamping block 5 and the second clamping block to the preset position, as the fastening nut 7 is continuously tightened, the rubber pad may deform under pressure, which may cause the first clamping block 5 and the second clamping block to shift axially.

[0041] Optionally, the displacement detector can be a laser displacement detector. The laser displacement detector can include a laser emitter and a reflective target. The laser emitter can be a cuboid structure with an engineering plastic or aluminum alloy shell. The laser emitter can emit laser light and receive reflected laser light, and calculate the distance between the laser emitter and the reflective target using the round-trip time of the laser. The reflective target can be a rectangular piece made of stainless steel with a polished surface. The reflective target can be fixed to the lower surface of the limiting device. The laser emitter can be fixed to the top surface of the driver 3, and the laser emitter is located below the limiting device. Since the contouring extrusion pin 4 and the limiting device are both fixed to the output rod 2, when the contouring extrusion pin 4 moves, the limiting device will also move synchronously with the reflective target. This allows for the detection of the real-time movement distance of the contouring extrusion pin 4.

[0042] Optionally, the aforementioned driver 3 can be bolted to the frame of the die-casting machine. Bolting allows the driver 3 to output power stably, thereby improving the accuracy of the movement of the contour extrusion pin 4.

[0043] Optionally, the aforementioned contouring extrusion pin 4 can be made of high-speed steel. This is because high-speed steel, in addition to its high hardness and high wear resistance, also has high heat resistance, making it suitable for the working conditions of the aforementioned contouring extrusion pin 4.

[0044] Optionally, the aforementioned delayed contouring extrusion device may further include a pressure sensor. The pressure sensor may be a piezoelectric pressure sensor. The pressure sensor may be installed at the connection between the contouring extrusion pin and the output rod, and is capable of detecting the axial pressure on the contouring extrusion pin. The pressure sensor may be communicatively connected to the controller. The controller may also be configured to perform the following steps:

[0045] The first step involves controlling a pressure sensor to detect the axial pressure on the forming extrusion pin at a preset frequency in response to the extrusion pin's initiation of extrusion. This axial pressure information can be the pressure value experienced by the forming extrusion pin in the axial direction. In practice, the controller can detect the axial pressure on the forming extrusion pin at a preset frequency when the extrusion pin begins to compress, thus obtaining the axial pressure information. For example, the controller can detect the axial pressure on the forming extrusion pin at a frequency of 10 times per second.

[0046] The second step involves reading the displacement detected by the displacement sensor in response to the axial pressure exceeding a preset pressure threshold, thus obtaining displacement information. The preset pressure threshold can be the axial pressure value experienced by the conforming extrusion pin in a stationary state after the mold cavity is filled with molten aluminum alloy. The displacement information can be the distance traveled by the conforming extrusion pin in the extrusion direction. In practice, the controller can read the displacement detected by the displacement sensor when the axial pressure exceeds the preset pressure threshold to obtain displacement information. It should be noted that when the axial pressure value experienced by the conforming extrusion pin exceeds the preset pressure threshold, possible scenarios include misalignment of the mold or the base with the driver, causing the extrusion direction of the conforming extrusion pin to deviate from the preset direction, resulting in the conforming extrusion pin being stuck in the mold. Continuing to advance may damage the mold or the conforming extrusion pin, or even cause molten aluminum alloy to leak out. To prevent deformation of the conforming extrusion pin or mold due to prolonged extrusion, the conforming extrusion pin needs to be retracted.

[0047] The third step is to control the retraction of the contouring extrusion pin by a preset distance. This preset distance is less than the displacement information mentioned above. This is to prevent the contouring extrusion pin from retracting excessively and becoming stuck again. The preset distance can be obtained by multiplying the distance value represented by the displacement information by a positive number less than 1. For example, assuming that when the contouring extrusion pin has traveled 20mm, the controller detects that the axial pressure information is greater than a preset pressure threshold, the preset distance can be determined as 20 × 20% = 4mm. In practice, the controller can control the driver to retract in the opposite direction of the extrusion direction, causing the contouring extrusion pin to retract, and the displacement sensor can detect in real time whether the retraction displacement of the contouring extrusion pin has reached the preset distance.

[0048] Fourth, in response to the completion of the pre-set retraction distance of the contouring extrusion pin, the alarm device is activated to issue a warning. This alarm device may include a warning light and a buzzer. In practice, the controller can activate the alarm device and simultaneously issue both a light and an audible warning after the contouring extrusion pin has retracted the pre-set distance.

[0049] Furthermore, during the extrusion process of the conforming extrusion pin, the pin undergoes thermal expansion upon contact with molten aluminum alloy at 600–700°C, with the expansion increasing with temperature. This thermal expansion reduces the clearance between the extrusion pin and the mold cavity, and may even create localized interference, increasing the frictional resistance between the pin and the mold wall. If the driver power remains constant, it cannot compensate for this additional resistance caused by thermal deformation, potentially leading to fluctuating speeds of the extrusion pin that cause impact disturbances to the molten aluminum alloy within the mold cavity. This, in turn, results in poor product quality after the aluminum alloy solidifies.

[0050] Optionally, the controller described above can be further configured to perform:

[0051] The first step involves acquiring real-time data from the flow sensor at the mold cavity inlet, based on the obtained aluminum alloy molten material grade and mold cavity volume, to determine the actual injection rate of the molten aluminum alloy. The aluminum alloy grade can be a specific type of aluminum alloy (e.g., A356, ADC12), as different grades have different solidification shrinkage rates and fluidities. The flow sensor can be an electromagnetic flowmeter installed at the mold cavity inlet to monitor the inflow of the molten aluminum alloy in real time. In practice, the aluminum alloy grade and mold cavity volume can be input into the controller by the operator. The controller can then control the flow sensor to collect the injection rate of the molten aluminum alloy at a preset frequency to obtain the actual injection rate.

[0052] The second step is to determine the injection time based on the actual injection rate. This injection time is the time required for the molten aluminum alloy to completely fill the mold cavity, calculated from the cavity volume and the actual injection rate. In practice, the controller can determine the injection time by dividing the cavity volume by the actual injection rate.

[0053] The third step is to determine the preset time based on the injection time. This preset time represents the length of time from the start of injecting molten aluminum alloy into the cavity to the point where the conforming extrusion pin is triggered to press upwards. In practice, the controller can match the grade of the molten aluminum alloy with a preset grade-extrusion time mapping table, determining the appropriate extrusion time for the current grade of molten aluminum alloy from the table. The extrusion time can be the length of time from the point when the molten aluminum alloy has completely filled the cavity to the point where the conforming extrusion pin is triggered to press upwards. The extrusion time is then added to the injection time, and the sum is determined as the preset time.

[0054] Fourth, in response to the timer reaching the preset time, an upward squeezing drive signal is sent to the driver's control circuit. In practice, the controller can control the timer to start counting from the beginning of injection, and send an upward squeezing drive signal (such as a floating-point value "2") to the driver after the preset time is reached.

[0055] The fifth step is to implement closed-loop control of the axial displacement of the output rod. During the die-casting process, the conformal extrusion pin deforms due to heat, altering the extrusion resistance. Closed-loop control allows for real-time adjustment of the driving force to reduce speed fluctuations. In practice, the above controller can implement closed-loop control of the output rod's axial displacement through the following steps:

[0056] Step one: Drive the contouring extrusion pin upwards at a speed of 0.5–1 mm / s. Excessive speed of the contouring extrusion pin may cause localized disturbances, thus affecting product quality. Therefore, using a speed range of 0.5–1 mm / s effectively reduces the disturbance caused by the contouring extrusion pin to the molten aluminum alloy. The specific speed can be preset by the operator within the 0.5–1 mm / s range based on the grade of the molten aluminum alloy. In practice, the driver (such as a servo motor) can drive the output rod through a reducer. The aforementioned controller can change the pulse frequency sent to the driver to control the speed at which the driver drives the contouring extrusion pin.

[0057] Step two: Control the displacement detector to collect the displacement of the conforming extrusion pin at a preset frequency to obtain displacement information. This displacement information can be the magnitude of the displacement of the conforming extrusion pin. For example, the controller can control the displacement detector to emit laser light at a frequency above 100Hz to obtain displacement information.

[0058] Step 3: Adjust the output power of the driver based on the displacement information. The controller can input the target displacement and displacement information into a PID algorithm to adjust the driver's power. The target displacement represents the theoretical displacement that the contouring pin should travel at a preset speed at a given moment. This target displacement can be obtained by multiplying the preset contouring pin's moving speed by the actual movement time. For example, if the preset speed is 0.6 mm / s and the actual movement time is 5 seconds, then the target displacement is 3 mm.

[0059] Step six: In response to the contouring extrusion pin reaching the target moving distance, the controller stops the contouring extrusion pin. In practice, the controller can compare the displacement of the contouring extrusion pin detected by the displacement detector with the target moving distance in real time. When the displacement of the contouring extrusion pin equals the target moving distance, the controller stops driving the contouring extrusion pin.

[0060] The first to sixth steps described above are an inventive point of this disclosure, solving the technical problem that "the conformal extrusion pin easily causes impact disturbance to the product." The specific factors causing the conformal extrusion pin to easily cause impact disturbance to the product are as follows: Currently, the driver commonly uses a fixed power to drive the conformal extrusion pin. When the conformal extrusion pin expands due to heat, causing changes in lateral pressure, the extrusion speed fluctuates, creating impact disturbance to the molten aluminum alloy. Solving these factors can reduce the impact disturbance caused by the conformal extrusion pin on the product, thereby improving product quality. To achieve this effect, this disclosure also provides a closed-loop feedback method for adjusting the driver's output power. By adjusting the driver's output power in real time using a PID algorithm, the speed fluctuation of the conformal extrusion pin can be reduced. This reduces the impact disturbance caused by the conformal extrusion pin on the product, thereby improving product quality.

[0061] Optionally, the above-mentioned conforming extrusion pin can be made by the following steps:

[0062] The first step is to forge the base material to obtain a forged workpiece. The base material can be high-speed steel. In practice, the base material can be heated to 850–1200℃ to austenitize it, and then forged using a mechanical press, undergoing upsetting, drawing, and other plastic deformation processes according to the preset dimensions of the extruded pin. The forged workpiece is then air-cooled to room temperature to obtain the forged workpiece.

[0063] The second step is to perform spheroidizing annealing on the forged workpiece to obtain the annealed workpiece. In practice, the forged workpiece can be placed in a box annealing furnace, heated to 750–800℃, and held for 3–4 hours to allow the carbides to fully dissolve and distribute evenly. It is then cooled slowly at a rate of 5–10℃ / h to below 600℃, and finally air-cooled to obtain the annealed workpiece. Spheroidizing annealing transforms the carbides in the workpiece into uniformly distributed spherical particles, reducing material hardness, improving machinability, and preventing excessive tool wear or decreased machining accuracy during subsequent milling due to excessive material hardness.

[0064] The third step involves milling the extrusion end face contour onto the annealed workpiece to obtain a primary contoured workpiece. This primary contoured workpiece can be an annealed workpiece that has undergone rough milling; that is, the extrusion end face on the primary contoured workpiece is not fully formed but has a preset machining allowance. For example, a machining allowance of 1-2 mm can be left. In practice, a preset 3D model of the contoured extrusion pin can be imported into CAD software to generate the contour data of the extrusion end face. This contour data is then imported into a CNC milling machine to perform rough milling on the extrusion end face of the annealed workpiece, resulting in a primary contoured workpiece. Rough milling allows for rapid removal of excess material, improving milling efficiency.

[0065] The fourth step involves scanning the extruded end face of the primary contoured workpiece to obtain correction information. This correction information can be information recording the deviation between the extruded end face of the primary contoured workpiece and the target extruded end face. In practice, a 3D laser scanner can be used to scan the milled extruded end face to obtain 3D point cloud data of the end face. The point cloud data is imported into reverse engineering software and compared with the target 3D model to calculate the deviation between the actual contour and the theoretical contour, such as the dimensional error values ​​of each point in the 3D point cloud data and the target model. The calculated deviation value is then used as the correction information. It should be noted that scanning the extruded end face of the primary contoured workpiece can detect the errors generated during the rough milling process in the third step, further improving the accuracy of subsequent correction steps. For example, if the actual machining allowance at a certain point on the primary contoured workpiece obtained in the third step is 1.5mm and the preset machining allowance is 1.3mm, directly performing finish milling on the workpiece with the deviation may result in the finished workpiece protruding by 0.2mm at that point.

[0066] The fifth step is to correct the primary contour workpiece based on the correction information to obtain the secondary contour workpiece. In practice, the correction information can be imported into a CNC milling machine to perform finish milling on the primary contour workpiece, removing the reserved machining allowance to obtain the secondary contour workpiece.

[0067] The sixth step involves strengthening the secondary contoured workpiece to obtain a strengthened workpiece. In practice, the secondary contoured workpiece can be heated to 1200–1250℃ in a vacuum quenching furnace, then held for 1–2 hours to fully dissolve the carbides. It is then cooled to room temperature to obtain a martensitic structure. This is followed by three tempering treatments, each time heated to 550–580℃ and held for 1–2 hours, to obtain the strengthened workpiece. Quenching and tempering can give the workpiece high hardness, high wear resistance, and good red hardness, meeting the requirements of contoured extrusion pins used in high-temperature environments.

[0068] The seventh step involves nitriding the strengthened workpiece to obtain a nitrided workpiece. In practice, the strengthened workpiece can be placed in a nitriding furnace, with ammonia gas introduced as the nitriding medium, and held at 500–560℃ for 10–20 hours. During this time, the ammonia gas decomposes to produce active nitrogen atoms that diffuse into the workpiece surface, forming a nitrided layer. The nitrided layer can improve the wear resistance, corrosion resistance, and anti-galling properties of the workpiece surface, reducing surface wear or adhesion caused by direct contact with the high-temperature molten aluminum alloy during extrusion, and extending the service life of the profile extrusion pin.

[0069] Step 8 involves roughening the surface of the nitrided layer on the nitrided workpiece to obtain a roughened nitrided workpiece. In practice, white corundum sand with a particle size of 80–120 mesh can be used to sandblast the surface of the nitrided layer on the nitrided workpiece to achieve the purpose of roughening the nitrided layer and obtaining a roughened nitrided workpiece. The sandblasting pressure can be controlled at 0.2–0.4 MPa, and the treatment time is 10–30 seconds. This step increases the surface roughness of the nitrided layer through roughening treatment, thereby improving the adhesion between the subsequent composite coating and the substrate.

[0070] Step nine involves preparing a composite coating on the surface of the nitrided layer of the roughened nitrided workpiece to obtain the conformal extrusion pin. In practice, physical vapor deposition can be used to prepare the composite coating on the surface of the nitrided layer of the roughened nitrided workpiece to obtain the conformal extrusion pin. For example, Ti-Al alloy or Cr-Al alloy can be selected as the target material. At 150–300℃, the coating material is deposited on the surface of the roughened nitrided workpiece by ion bombardment, and the coating thickness can be controlled between 3–10 μm. The composite coating can further improve the surface wear resistance, high-temperature oxidation resistance, and anti-adhesion properties of the conformal extrusion pin.

[0071] The first to ninth steps described above are an inventive point of this disclosure, solving the technical problem of "short service life of the contour extrusion pin". The specific factors leading to the short service life of the contour extrusion pin are as follows: As a component that is in long-term contact with molten aluminum alloy, the molten aluminum alloy easily undergoes metallurgical bonding with the steel substrate at high temperatures, forming Fe-Al intermetallic compounds. After extrusion, these Fe-Al intermetallic compounds adhere to the extrusion end face, altering its contour. To maintain a fixed contour, this portion of metal needs to be ground and cleaned after each extrusion. During the cleaning process, wear may occur on the extrusion end face, further shortening the service life of the contour extrusion pin. Solving these factors can extend the service life of the contour extrusion pin. To achieve this effect, this disclosure also provides a processing solution for the contour extrusion pin. On one hand, a high-temperature resistant composite coating is added to the outer surface of the contour extrusion pin, preventing direct contact between the molten aluminum alloy and the substrate material of the contour extrusion pin, reducing the possibility of forming Fe-Al intermetallic compounds. On the other hand, nitriding treatment is applied to the surface of the contour extrusion pin to improve its wear resistance. This extends the service life of the conformal extrusion pin.

[0072] Some embodiments of this disclosure provide a delayed contour extrusion device that can improve the production efficiency of die casting processes. Specifically, the reason for the low production efficiency of most die casting processes is that currently, risers are often used to reduce shrinkage cavities caused by shrinkage during the solidification of molten aluminum alloy. However, the riser volume is usually designed to be 1.5 to 2 times the volume of the thick-walled area of ​​the casting. This causes the remaining molten aluminum alloy in the riser to solidify into a block on the casting product, requiring subsequent machining processes to remove it, thus resulting in low production efficiency. Based on this, some embodiments of this disclosure provide a delayed contour extrusion device, which includes a driver, a contour extrusion pin, a controller, a displacement detector, and a limiting device. The driver has an output rod; the contour extrusion pin is connected to the upper end of the output rod; the extrusion end face shape of the contour extrusion pin matches the contour of the thick-walled region of the product; the limiting device is located at the lower end of the output rod; the controller is communicatively connected to the driver and the displacement detector; the controller is configured to perform the following: determining the shrinkage cavity volume based on a three-dimensional model of the thick-walled region of the product; determining the target moving distance of the contour extrusion pin based on the shrinkage cavity volume; controlling the driver to drive the contour extrusion pin downwards by the target moving distance before die casting the product; and controlling the driver to drive the contour extrusion pin upwards by the target moving distance in response to a preset time for injecting molten aluminum alloy into the mold cavity. By reserving space for molten aluminum alloy to replenish the shrinkage cavity before die casting, and replenishing the shrinkage cavity through extrusion by the contour extrusion pin before the molten aluminum alloy solidifies. This eliminates the need for removing excess metal from castings, thus improving production efficiency.

[0073] The above description is merely a selection of preferred embodiments of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in the embodiments of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in the embodiments of this disclosure.

Claims

1. A time-delayed contour extrusion device, characterized in that, The delayed contouring extrusion device includes a driver, a contouring extrusion pin, a controller, a displacement detector, and a limiting device, wherein... The driver is equipped with an output lever; The contouring extrusion pin is connected to the upper end of the output rod; The shape of the extrusion end face of the conforming extrusion pin matches the contour of the thick-walled area of ​​the product. The limiting device is located at the lower end of the output rod; The controller is communicatively connected to the driver and the displacement detector; The controller is configured to perform the following steps: The volume of shrinkage cavity is determined based on the three-dimensional model of the thick-walled area of ​​the product; The target moving distance of the conformal extrusion pin is determined based on the volume of the reduced cavity. Before the die-cast product, the driver is controlled to drive the contour extrusion pin downwards by the target moving distance; In response to a preset time for injecting aluminum alloy liquid into the mold cavity, the driver is controlled to drive the contour extrusion pin upward by the target moving distance.

2. The delayed contour extrusion device according to claim 1, characterized in that, The upper end of the output rod is provided with a male thread; The lower end of the conformal extrusion pin is provided with a connecting cavity; The connecting cavity is provided with a female thread that matches the male thread at the upper end of the output rod.

3. The delayed contour extrusion device according to claim 1, characterized in that, The lower end of the output rod is provided with a sliding groove, and the outer surface of the lower end of the output rod is provided with a frosted layer. The sliding groove extends radially through the output rod; The limiting device includes a first clamping block, a second clamping block, a screw, and a fastening nut; The width of the sliding groove is greater than or equal to the outer diameter of the screw; The first clamping block and the second clamping block are symmetrically arranged on both sides of the output rod; The screw passes through the first clamping block, the output rod, and the second clamping block in sequence, and the fastening nuts are installed at both ends of the screw; The first clamping block and the second clamping block have an anti-slip layer on the side that contacts the output rod.

4. The delayed contour extrusion device according to claim 3, characterized in that, The lower end of the output rod is provided with scale lines, and the scale lines are distributed along the axial direction of the output rod.

5. The delayed contour extrusion device according to claim 3, characterized in that, The anti-slip layer includes a rubber pad, and the contact surface of the rubber pad is provided with anti-slip texture; The thickness of the rubber pad is less than or equal to 3 mm.

6. The delayed contour extrusion device according to claim 1, characterized in that, The displacement detector is a laser displacement detector; The laser displacement detector includes a laser emitting end and a reflective target plate; The reflective target plate is fixed to the lower surface of the limiting device; The laser emitting end is fixed to the top surface of the driver, and the laser emitting end is located below the limiting device.

7. The delayed contour extrusion device according to claim 1, characterized in that, The driver is bolted to the frame of the die-casting machine.

8. The delayed contour extrusion device according to claim 1, characterized in that, The conforming extrusion pin is made of high-speed steel.

9. The delayed contour extrusion device according to claim 1, characterized in that, The time-delayed contour extrusion device also includes a pressure sensor; The pressure sensor is installed at the connection between the conforming extrusion pin and the output rod to detect the axial pressure on the conforming extrusion pin. The pressure sensor is communicatively connected to the controller; The controller is also configured to perform the following steps: In response to the start of extrusion by the conforming extrusion pin, the pressure sensor is controlled to detect the pressure on the conforming extrusion pin in the axial direction at a preset frequency to obtain axial pressure information; In response to the axial pressure information being greater than a preset pressure threshold, the displacement detected by the displacement sensor is read to obtain displacement information; The contouring extrusion pin is controlled to retract a preset distance, wherein the preset distance is less than the displacement information; In response to the completion of the preset retraction distance of the contour extrusion pin, the control alarm device issues an alarm.

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