Preheater for injection molding

Abstract

The utility model relates to injection molding auxiliary equipment field especially, it relates to a preheating machine for injection molding. Including preheating machine, connection box, feed pipe, discharge pipe, mounting frame, pivot, support, compressor, air heater, air extraction pipe, filter assembly and connecting pipe etc. structure. Adopt the utility model can avoid local overheating or preheating deficiency, ensure that raw material temperature deviation controls in reasonable range, reduces plastic parts bubble, shrinkage mark quality problem, promotes product qualified rate.

Description

Technical Field

[0001] This utility model relates to the field of injection molding auxiliary equipment, and in particular to a preheating machine for injection molding. Background Technology

[0002] In the injection molding industry, the preheating treatment of plastic raw materials is a key pre-process that affects the quality of molded parts and production efficiency. As injection molded products develop towards higher precision, thinner walls, and functionalization, higher requirements are placed on the uniformity of raw material preheating, dehumidification effect, and adaptability.

[0003] Existing preheaters rely solely on single-chamber heating or heating elements that are attached to the chamber wall, which can easily lead to localized overheating or insufficient preheating. Utility Model Content

[0004] The present invention aims to provide a preheating machine for injection molding to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A preheating machine for injection molding includes a preheating machine connected to a connecting box, a feed pipe and a discharge pipe, and a mounting frame. The mounting frame is rotatably connected to a rotating shaft, and the other end of the rotating shaft is rotatably connected to a bracket. The bracket is connected to the preheating machine. The connecting box is connected to a compressor and an air heater. An air extraction pipe is connected to the input end of the compressor, and a filter assembly is detachably connected to the air extraction pipe, which extends out of the connecting box. A connecting pipe is shared by the output end of the compressor and the input end of the air heater. A transmission pipe is connected to the output end of the air heater, and a rotary joint is connected to the transmission pipe. The rotating end of the rotary joint is connected to the rotating shaft, and a stirring rod is connected to the rotating shaft. Both the rotating shaft and the stirring rod are hollow and interconnected. A one-way vent valve is connected to the stirring rod, and a controller is connected to the preheating machine.

[0007] Preferably, the preheater is connected to a heater, the preheater has a storage slot, the output end and input end of the heater are connected to a heating pipe, and the heating pipe is connected to the side wall of the storage slot.

[0008] Preferably, the heating tube is arranged in a serpentine pattern.

[0009] Preferably, the mounting frame is connected to a stepper motor, the output end of the stepper motor is connected to a helical gear one, the rotating shaft is connected to a helical gear two, and the helical gear one and the helical gear two mesh with each other.

[0010] Preferably, the stirring rod is connected to a scraper, and the scraper abuts against the inner wall of the preheater.

[0011] Preferably, the feed pipe passes through the connecting box, the feed pipe is threadedly connected to a top cover, and the discharge pipe is connected to a valve.

[0012] Preferably, the preheater is connected to a transparent observation window.

[0013] Preferably, the preheater is connected to an exhaust valve and a pressure gauge, with the exhaust valve passing through a connecting box.

[0014] The beneficial effects of this technical solution compared to existing technologies are as follows:

[0015] (1) This solution, by setting up a compressor, air heater, hollow rotating shaft and stirring rod, and one-way ventilation valve, forms a synergistic structure for hot air delivery and stirring diffusion, effectively solving the problem of poor uniformity of raw material preheating in existing preheaters. The compressor draws air purified by the filter assembly, heats it by the air heater, and then enters the hollow rotating shaft and stirring rod through the transmission pipe and rotary joint. It is then blown evenly onto the raw material by the one-way ventilation valve. At the same time, the stirring rod rotates with the rotating shaft, breaking up the raw material and ensuring full contact with the hot air, avoiding local overheating or insufficient preheating, ensuring that the temperature deviation of the raw material is controlled within a reasonable range, reducing quality problems such as bubbles and shrinkage marks in plastic parts, and improving the product qualification rate.

[0016] (2) By setting up a heating machine, a serpentine heating tube, and a receiving trough, the preheating efficiency and temperature stability are significantly improved. The serpentine heating tube fits against the side wall of the receiving trough, increasing the contact area with the inside of the preheating machine. The heating machine circulates heat through the heating tube, and together with hot air, it provides dual heating for the raw materials. Compared with the existing single heating method, it can quickly increase the temperature inside the preheating machine, and the serpentine structure makes the temperature distribution more uniform, avoiding excessive local temperature differences. At the same time, the heating power can be flexibly adjusted according to the characteristics of the raw materials, adapting to different types of plastics such as hygroscopic and heat-sensitive ones, thus broadening the applicability of the equipment.

[0017] (3) By setting up a stepper motor, helical gear one, and helical gear two, the rotation speed of the shaft can be precisely controlled, optimizing the mixing and hot air diffusion effects of raw materials. The stepper motor drives the shaft to rotate through the meshing transmission of helical gears. The motor speed can be adjusted by the controller according to the shape of the raw materials and the preheating requirements. For powder raw materials that are prone to agglomeration, the speed can be increased to enhance the mixing and dispersing effect; for granular raw materials, the speed can be reduced to avoid excessive friction that could cause damage to the raw materials. This further improves the uniformity of raw material preheating, and the transmission structure is stable, reducing the probability of equipment failure.

[0018] (4) By setting up a scraper, when the stirring rod rotates, the scraper slides synchronously along the inner wall of the preheater to scrape off the sticky raw materials adhering to the wall in real time, preventing the raw materials from accumulating and clumping; at the same time, it avoids the long-term high-temperature carbonization of accumulated raw materials, which pollutes the subsequent raw materials, reduces the number of shutdowns for cleaning, improves production efficiency, and saves maintenance manpower and time costs.

[0019] (5) By setting a controller, the controller can receive the feed speed signal of the injection molding machine and synchronously adjust the hot air supply, stirring speed and discharge pipe valve opening of the preheater: when the feed speed of the injection molding machine increases, the hot air temperature and stirring speed are automatically increased to increase the raw material output rate. When the injection molding machine is stopped for maintenance, the heating and hot air system is shut down in time to prevent the raw material from being overheated and energy wasted. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this utility model;

[0021] Figure 2 This is a front sectional view of the present invention;

[0022] Figure 3 for Figure 2 Enlarged view of point A;

[0023] Reference numerals: 1. Connecting box; 2. Preheater; 3. Controller; 4. Transparent observation window; 5. Pressure gauge; 6. Filter assembly; 7. Exhaust pipe; 8. Inlet pipe; 9. Top cover; 10. Heater; 11. Heating tube; 12. Storage tank; 13. Discharge pipe; 14. Valve; 15. Support; 16. Stirring rod; 17. Rotary shaft; 18. One-way vent valve; 19. Scraper; 20. Mounting frame; 21. Compressor; 22. Connecting pipe; 23. Air heater; 24. Transmission pipe; 25. Stepper motor; 26. Helical gear one; 27. Helical gear two; 28. Rotary joint; 29. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments:

[0025] like Figure 1-3The preheating machine for injection molding shown includes a preheating machine 2. A connecting box 1 is connected to the top of the preheating machine 2. A feed pipe 9 and a discharge pipe 14 are connected to the top and bottom of the preheating machine 2, respectively. A mounting frame 21 is connected to the top of the inner wall of the preheating machine 2. A rotating shaft 18 is rotatably connected to the mounting frame 21. A bracket 16 is rotatably connected to the other end of the rotating shaft 18. The bracket 16 is connected to the bottom of the inner wall of the preheating machine 2. A compressor 22 and an air heater 24 are connected to the inner wall of the connecting box 1. The compressor 22 is used to draw and compress air to provide airflow power for the system. The air heater 24 is used to heat the compressed air delivered by the compressor 22 to a preset temperature to form dry hot air. An air extraction pipe 7 is connected to the input end of the compressor 22. A filter assembly 6 is detachably connected to the air extraction pipe 7. The filter assembly 6 includes a filter frame and a filter screen. The filter frame is connected to the air extraction pipe 7 by multiple bolts, which facilitates later disassembly, replacement, or cleaning of the filter screen. The filter screen can effectively filter dust and impurities in the air, ensuring that the air entering the compressor 22 is clean and preventing impurities from entering the preheating machine 2 with the hot air and contaminating the raw materials. One end of the extraction pipe 7, away from the compressor 22, extends out of the connecting box 1. A connecting pipe 23 connects the output end of the compressor 22 and the input end of the air heater 24. The air drawn and pressurized by the compressor 22 is delivered to the air heater 24 via the connecting pipe 23, where it is heated to a preset temperature to form hot air that meets the preheating requirements. A transmission pipe 25 is connected to the output end of the air heater 24, and a rotary joint 29 is connected to the other end of the transmission pipe 25. The rotating end of the rotary joint 29 is connected to the rotating shaft 18. The rotary joint 29 is used to establish a sealed fluid transmission channel between the stationary pipe and the rotating shaft 18, ensuring that hot air can continuously enter the rotating hollow shaft 18. The shaft 18 is connected to multiple stirring rods 17. Both the shaft 18 and the stirring rods 17 are hollow and interconnected. Each stirring rod 17 is connected to several one-way vent valves 19. The one-way vent valves 19 only allow airflow to blow out from the inside of the stirring rod 17, effectively preventing the raw material powder from being sucked back into the stirring rod 17 under negative pressure and causing blockage. The outer wall of the preheater 2 is connected to the controller 3. The compressor 22, air heater 24, heater 11, stepper motor 26 and other electrical components are all electrically connected to the controller 3.

[0026] like Figure 2As shown, a heater 11 is connected to the outer wall of the preheater 2. The heater 11 is a circulating thermal oil heater used to provide a heat source for the heating tube 12. The preheater 2 has a receiving tank 13. The output and input ends of the heater 11 are connected to the heating tube 12. The heating tube 12 is connected to the side wall of the receiving tank 13. Thermal oil flows inside the heating tube 12 to provide auxiliary heating and insulation for the preheater 2 chamber. A stable temperature is maintained through circulating heating. The heating tube 12 is arranged in a serpentine pattern to maximize the contact area with the main body of the preheater 2, so that heat can be evenly transferred to the interior of the preheater 2, avoiding local overheating or underheating. A stepper motor 26 is connected to the inner wall of the mounting frame 21. A helical gear 27 is connected to the output end of the stepper motor 26, and a helical gear 28 is connected to the rotating shaft 18. The helical gear 27 and the helical gear 28 mesh with each other. The helical gear teeth are distributed in a spiral shape, not straight teeth. The tooth shape is compatible and the module is consistent. Both gears are made of wear-resistant metal to ensure that they are not easily worn during transmission. Compared with straight teeth, the helical gear design has the characteristics of smoother transmission, lower noise, and higher load-bearing capacity. When the stepper motor 26 is working, it drives the rotating shaft 18 to rotate through the helical gear meshing, which in turn drives the stirring rod 17 to rotate synchronously, realizing the stirring and dispersing of the raw materials, so that the raw materials are fully in contact with the hot air and improving the preheating uniformity. Moreover, the stepper motor 26 can adjust the speed through the controller 3 to adapt to different raw materials. Each stirring rod 17 is connected to a scraper 20. The scraper 20 abuts against the inner wall of the preheater 2. When the stirring rod 17 rotates with the rotating shaft 18, the scraper 20 slides synchronously along the inner wall of the preheater 2, which can scrape off the sticky raw materials adhering to the wall surface in real time, preventing the raw materials from accumulating and clumping on the cavity wall; at the same time, it avoids the accumulated raw materials from carbonizing in a high-temperature environment for a long time, contaminating the raw materials that are subsequently introduced, reducing the number of shutdowns for cleaning, and reducing maintenance costs.

[0027] like Figure 1 As shown, the feed pipe 9 passes through the connecting box 1 and is threadedly connected to a top cover 10. When not in use, the top cover 10 can be tightened to prevent dust and impurities from falling in. When feeding is needed, the top cover 10 can be unscrewed to add raw materials. The discharge pipe 14 is connected to a valve 15, which controls the material discharge rate. The discharge pipe 14 can also directly connect to downstream equipment such as injection molding machines, achieving seamless conveying of preheated raw materials and reducing heat loss and material waste in intermediate transfer stages. The preheater 2 is connected to a transparent observation window 4, allowing real-time monitoring of the preheating status of the internal raw materials for timely adjustment of operating parameters. The preheater 2 is connected to an exhaust valve 8 and a pressure gauge 5. The exhaust valve 8 passes through the connecting box 1 and can promptly discharge excess hot air. The pressure gauge 5 monitors the internal pressure of the preheater 2 in real time. When the pressure rises abnormally, operators can promptly detect and address the issue through the pressure gauge reading, preventing equipment damage due to overpressure and improving operational safety.

[0028] The specific implementation process is as follows:

[0029] In use, open the top cover 10 of the feed pipe 9, add the plastic raw material to be preheated into the preheater 2, and tighten the top cover 10 after adding. Set the preheating temperature, stepper motor speed 26 and pressure threshold through the controller 3. Then the controller 3 starts the compressor 22 and the air heater 24. The compressor 22 draws in outside air through the air extraction pipe 7. The air is purified by the filter component 6 and then enters the compressor 22. The pressurized air is sent to the air heater 24 through the connecting pipe 23 and heated to the preset temperature to form dry hot air. The hot air enters the hollow rotating shaft 18 through the transmission pipe 25 and the rotary joint 29, and then is distributed to each hollow stirring rod 17. Controller 3 starts the heater 11 and stepper motor 26. The heater 11 drives the heat transfer oil to circulate in the serpentine heating tube 12 to assist in heating and heat preservation of the preheater 2 chamber. Stepper motor 26 drives the rotating shaft 18 and stirring rod 17 to rotate through the meshing of helical gear 1 27 and helical gear 2 28. When the stirring rod 17 rotates, it disperses the raw materials. At the same time, hot air is blown evenly onto the raw materials through the one-way vent valve 19, achieving triple uniform preheating of hot air penetration, stirring and dispersing, and tube wall heat preservation. Scraper 20 simultaneously scrapes off the raw materials adhering to the chamber wall. The operator can check the status of the raw materials through the transparent observation window 4. The pressure gauge 5 monitors the pressure in the chamber in real time. If the pressure is too high or moisture accumulates, excess hot air and moisture can be discharged through the exhaust valve 8. Controller 3 automatically adjusts the power of air heater 24, heater 11 and stepper motor 26 according to temperature feedback to maintain stable preheating parameters. Once the raw material is preheated to the required level, open valve 15 on discharge pipe 14. The preheated raw material is then transported to the downstream injection molding machine via discharge pipe 14. The discharge rate can be adjusted via valve 15 to ensure it matches the feeding rhythm of the injection molding machine. After the raw material is discharged, close all components. The removable filter component 6 can be cleaned or replaced to complete one preheating process.

[0030] The above descriptions are merely embodiments of this utility model. Commonly known technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of this utility model. These modifications and improvements should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A preheating machine for injection molding, characterized in that: The system includes a preheater (2), which is connected to a connecting box (1). The preheater (2) is connected to an inlet pipe (9) and a discharge pipe (14). The preheater (2) is connected to a mounting frame (21), which is rotatably connected to a rotating shaft (18). The other end of the rotating shaft (18) is rotatably connected to a bracket (16), which is connected to the preheater (2). The connecting box (1) is connected to a compressor (22) and an air heater (24). The compressor (22) has an input end connected to an extraction pipe (7), which is detachably connected to a filter assembly (6). The exhaust pipe (7) extends out of the connecting box (1). The output end of the compressor (22) and the input end of the air heater (24) are connected to a connecting pipe (23). The output end of the air heater (24) is connected to a transmission pipe (25). The transmission pipe (25) is connected to a rotary joint (29). The rotating end of the rotary joint (29) is connected to a rotating shaft (18). The rotating shaft (18) is connected to a stirring rod (17). The rotating shaft (18) and the stirring rod (17) are both hollow and interconnected. The stirring rod (17) is connected to a one-way ventilation valve (19). The preheater (2) is connected to a controller (3).

2. A preheater for injection molding as claimed in claim 1, characterized in that: The preheater (2) is connected to the heater (11). The preheater (2) has a storage slot (13). The output end and input end of the heater (11) are connected to a heating pipe (12). The heating pipe (12) is connected to the side wall of the storage slot (13).

3. A preheater for injection molding as claimed in claim 2, characterized in that: The heating tube (12) is arranged in a serpentine pattern.

4. A preheater for injection molding as recited in claim 1, wherein: The mounting frame (21) is connected to a stepper motor (26), the output end of the stepper motor (26) is connected to a helical gear one (27), the rotating shaft (18) is connected to a helical gear two (28), and the helical gear one (27) and the helical gear two (28) mesh with each other.

5. A preheater for injection molding as recited in claim 1, wherein: The stirring rod (17) is connected to a scraper (20), which abuts against the inner wall of the preheater (2).

6. A preheater for injection molding as recited in claim 1, wherein: The feed pipe (9) passes through the connecting box (1), the feed pipe (9) is threadedly connected to the top cover (10), and the discharge pipe (14) is connected to the valve (15).

7. A preheater for injection molding as recited in claim 1 wherein: The preheater (2) is connected to a transparent observation window (4).

8. A preheater for injection molding as defined in claim 1, wherein: The preheater (2) is connected to an exhaust valve (8) and a pressure gauge (5), and the exhaust valve (8) passes through the connecting box (1).

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