Environment-friendly and energy-saving injection molding system and process

Abstract

The present application relates to an environment-friendly and energy-saving injection molding system and process, comprising an injection molding host, a mold unit, a feed drying unit, a waste heat recovery unit, an environmental compliance control unit, an intelligent control unit, and a traceability unit. When the environmental compliance control unit detects changes in material code, supplier code, batch number, and expiration of environmental file expiration date, it automatically triggers environmental compliance review. After the review is passed, the injection molding host is allowed to enter the production state. If the review is not passed, the intelligent control unit sends a signal to the injection molding host to prohibit the machine from starting, closes the feed valve of the feed drying unit, locks the machine, or prohibits the feed. The present application embeds environmental review into the production process, implements "no production without review", has a mandatory closed loop for environmental compliance, embeds environmental confirmation of material replacement / supplier replacement into the production process, and does not produce without confirmation. The file is automatically retained.

Description

Technical Field

[0001] This invention relates to the field of injection molding technology, and in particular to an environmentally friendly and energy-saving injection molding system and process. Background Technology

[0002] The following problems are commonly found in existing injection molding production lines during the production process: 1. A large amount of waste heat is generated during the heating of the barrel and the cooling of the mold, which is usually directly discharged, resulting in low energy utilization. 2. When materials are substituted or suppliers are changed, environmental compliance confirmation relies on manual management, which can easily lead to problems such as missing documents and the wrong production of materials that exceed standards; 3. Insufficient temperature control accuracy leads to product size fluctuations, warping, shrinkage, and increased defect rates; 4. Incomplete traceability information during material and mold changes makes batch management difficult and fails to meet customer audit and regulatory requirements.

[0003] Existing technologies typically optimize only a single aspect of energy saving, temperature control, or management, lacking a system solution that integrates environmental compliance, waste heat utilization, intelligent control, and traceability management.

[0004] Therefore, it is necessary to propose a new injection molding system and process to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide an injection molding system and process that features environmental compliance management, waste heat recycling, and intelligent temperature control.

[0006] To achieve the above objectives, the present invention provides the following technical solution.

[0007] An environmentally friendly and energy-saving injection molding system, the system comprising: Injection molding machines are used to plasticize, inject, hold pressure and mold plastic raw materials; The mold unit is installed on the injection molding machine and is used for product molding. The mold unit is equipped with a cooling circuit and a temperature detection component. The feeding and drying unit is used for raw material conveying, preheating, and drying. The waste heat recovery unit connects the mold unit and the material supply and drying unit, and is used to recover waste heat in the mold cooling circuit and transport it to the material supply and drying unit. The environmental compliance management unit is used to audit the environmental compliance of materials and suppliers used in production and to control the start and stop of production. The intelligent control unit is electrically connected to the injection molding machine, mold unit, material feeding and drying unit, waste heat recovery unit and environmental compliance management unit respectively, and is used to collect operating parameters and perform linkage control. Traceability units are used to record material batches, supplier information, environmental confirmation documents, and production process parameters, and to create archives. Wherein: When the environmental compliance control unit detects changes in material code, supplier code, batch number, or the expiration date of environmental protection documents, it automatically triggers an environmental compliance audit. If the audit is passed, the injection molding host is allowed to enter the production state. If the audit is not passed, the intelligent control unit sends a prohibition signal to the injection molding host and closes the feed valve of the material drying unit, locking the machine or prohibiting material supply. The approval signal from the environmental compliance control unit serves as a condition for starting the injection molding machine and simultaneously triggers the start-up of the material feeding drying unit and the waste heat recovery unit.

[0008] Preferably, the waste heat recovery unit includes a heat exchanger, a circulating pump, an insulated pipeline, and an electric regulating valve. The heat source side of the heat exchanger is connected to the cooling circuit of the mold unit, and the heat exchange side is connected to the preheating channel of the material feeding and drying unit.

[0009] Preferably, the feeding and drying unit includes a vacuum feeding device, a storage tank and a drying tank. The drying tank is equipped with a waste heat preheating chamber for preheating the raw materials to 60-80°C before drying.

[0010] Preferably, the environmental compliance management unit includes a material database, an environmental standard database, a document upload module, and an approval process module. The environmental standard database includes at least one or more of RoHS, REACH, halogen-free standards, or customer-specified environmental standards.

[0011] Preferably, the environmental compliance management unit verifies one or more of the following documents: environmental compliance declaration, third-party testing report, ingredient list, and environmental commitment letter.

[0012] Preferably, the intelligent control unit includes a PLC controller, a human-machine interface (HMI), and a data acquisition module, used to collect parameters such as barrel temperature, mold temperature, drying temperature, injection pressure, and flow rate, and to perform closed-loop regulation to control key temperature fluctuations within ±1℃.

[0013] Preferably, the traceability unit is used to generate traceability reports that include production batch, material code, supplier information, environmental audit records, test reports and process parameters.

[0014] An environmentally friendly and energy-saving injection molding process as described in any one of claims 1-7, characterized in that it includes the following steps: S1. Create a production task and enter material codes and supplier information; S2. The environmental compliance control unit automatically verifies the environmental specifications of materials, supplier qualifications, and environmental documents. If the verification fails, the system will prevent the process from proceeding to step S3 and generate an error message. If the verification passes, the process will proceed to step S3. S3. After the verification is passed, start the waste heat recovery unit to transfer the mold cooling waste heat to the material feeding and drying unit to preheat and dry the raw materials. S4. The intelligent control unit controls the injection molding machine to perform plasticizing, injection, pressure holding and cooling molding, and adjusts the process parameters in real time. It automatically corrects the pressure holding parameters according to the weight deviation of continuous products. S5. The traceability unit records production process data and automatically archives it; S6. When there are changes to materials or suppliers, repeat step S2 and continue production after approval.

[0015] Preferably, in step S3, the waste heat utilization rate of the waste heat recovery unit is not less than 82%.

[0016] Preferably, in step S4, the intelligent control unit adaptively optimizes and adjusts the holding time, cooling time, and injection speed based on mold temperature, product weight fluctuations, or molding cycle changes.

[0017] Compared with the prior art, the present invention has the following advantages: 1. Reliable environmental compliance: Environmental audits are embedded in the production process to achieve "no production without audit," meeting RoHS, REACH, and customer factory audit requirements. It has a mandatory closed-loop environmental compliance mechanism, embedding environmental confirmation of material substitution / supplier replacement into the production process. No production without confirmation, and documents are automatically saved. 2. Significant energy-saving effect: waste heat recovery from the mold is used for raw material preheating, which can reduce drying energy consumption by 3, resulting in a comprehensive power saving of 30%–45%.

[0018] 3. Stable quality: Intelligent temperature control ensures stable molding temperature, reducing dimensional fluctuations and defect rates. Temperature fluctuation is ≤±1℃, improving dimensional accuracy and consistency.

[0019] 4. Highly efficient management: production data and environmental protection documents are automatically archived, making traceability convenient. Batch, supplier, environmental protection documents, and test reports can be accessed with one click. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall system structure of the present invention.

[0021] Figure 2 This is a process flow diagram of the present invention.

[0022] Figure 3 This is a flowchart illustrating the environmental compliance management process of this invention.

[0023] Figure 4 This is a comparison table of energy-saving data for the present invention. Detailed Implementation

[0024] 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.

[0025] An environmentally friendly and energy-saving injection molding system includes an injection molding machine, a mold unit, a material feeding and drying unit, a waste heat recovery unit, an environmental compliance management and control unit, and an intelligent control unit. The environmental compliance management and control unit is configured to: perform mandatory verification of environmental specifications for material substitution and supplier replacement; if the verification is not passed, material feeding and production are prohibited. The waste heat recovery unit introduces the waste heat from mold cooling into the material feeding and drying unit to achieve preheating and energy saving.

[0026] The environmental compliance management unit includes a material warehouse, an environmental standard warehouse, a document upload module, and an approval workflow module, and automatically retains environmental confirmation documents for at least the product lifecycle plus one year.

[0027] The intelligent control unit achieves temperature fluctuations of ≤±1℃ and forms a traceability chain for batches, suppliers, environmental documents, and test reports.

[0028] Material / supplier environmental compliance pre-confirmation, waste heat preheating and drying, intelligent stable temperature injection molding, online testing and full-chain traceability; when materials are substituted or suppliers are replaced, environmental compliance confirmation is re-triggered, and production can only proceed after passing the confirmation. Pre-confirmation includes environmental compliance declaration, third-party testing report, ingredient list, supplier environmental commitment, and compliance with RoHS, REACH and customer environmental specifications.

[0029] For this invention, when there are changes in materials, batches, parameters, or production lines / materials, the system will automatically trigger a secondary environmental compliance review, locking production access. Mass production can only proceed after the review is passed. The environmental review triggering rules are as follows: 1. Material code determination: If the material code of the current production task is not the same as the material code of the previous production task, an environmental audit will be automatically triggered; 2. Batch number determination: Changes in production batch numbers for the same material across different production batches trigger environmental ledger review and audit. 3. Material type determination: switching between ordinary / modified materials, PCR recycled materials, flame retardant materials, and food-grade / medical-grade materials, subject to mandatory environmental audits; 4. Change of raw material supplier: Changing the upstream raw material supplier for the same material triggers environmental traceability audit; 5. Abnormal shutdown and restart: If a single shutdown exceeds 30 minutes or production is restarted across shifts, an automatic pop-up window will appear to confirm and approve environmental compliance.

[0030] For the system of this invention, the automatic closed-loop correction rule for product weight deviation uses the injection molding continuous mold weight data as the judgment basis. The system collects the weighing data of each mold in real time, and automatically fine-tunes the process in stages to avoid material shortage, shrinkage, and overflow, as detailed below: 1. Minor Deviation Correction For products with a weight less than 1% of the target weight after three consecutive molding cycles: increase holding pressure by 5% and synchronous holding time by 0.2 seconds. If the weight of the product in three consecutive molds is greater than the target weight + 1%, the holding pressure is reduced by 5%, and the synchronous holding time is reduced by 0.2s.

[0031] 2. Moderate Deviation Warning Continuous weight deviation of 5 molds ±2%: Automatic process fine-tuning upper limit, while pop-up operator warning and record of abnormality log; 3. Severe abnormal machine lock If the weight deviation of 8 consecutive molds is ±3%, mass production will be automatically paused and the process parameters will be locked. Manual confirmation of the raw material, barrel temperature, and screw status is required before unlocking.

[0032] 4. Modify the constraints All automatic corrections have upper and lower limit thresholds. Holding pressure, injection speed, and temperature must not exceed the equipment's rated parameters to prevent equipment overload and malfunctions.

[0033] Standard parameter range for temperature control PID algorithm (applicable to injection molding cylinders / molds) It is compatible with commonly used materials such as PC, ABS, PC / ABS, modified nylon, and general-purpose plastics, providing a standardized range for industry applications. Scale factor P: 1.2-2.0 Integral coefficient I: 0.1-0.5 Differential coefficient D: 0.05-0.2 Specifically, for high-flowability modified materials and thin-walled products: P should be low, 1.2-1.5, to reduce temperature fluctuations; for fiber-reinforced modified materials and thick-walled structural parts: P should be high, 1.6-2.0, to improve temperature control response speed; for barrel temperature control: D should be small (0.05-0.1); for mold oil temperature control: D should be moderate (0.1-0.2).

[0034] In practical applications, the following limitations apply to the cooling water temperature: Common materials (ABS, PP, general plastics): Cooling water temperature 25℃-35℃; Engineering plastics (PC, PC / ABS, nylon): Cooling water temperature 28℃-38℃; High-precision appearance parts and anti-shrinkage parts: strictly control the temperature difference ≤ ±2℃, and the inlet / outlet water temperature difference ≤ 5℃; Strict restrictions: The minimum temperature of the cooling water shall not be lower than 20°C (to prevent condensation in the mold and whitening of the product), and the maximum temperature shall not exceed 40°C (to prevent insufficient cooling, deformation and warping).

[0035] The preheating and constant temperature requirements for the drying cylinder are as follows: Standardized management based on material classification to prevent moisture content in raw materials from causing silver streaks, bubbles, and poor strength. 1. ABS / PS: Preheat to 60℃-70℃ and dry at a constant temperature for 2-3 hours; 2. PC / PC+ABS: Preheat to 100℃-120℃ and dry at a constant temperature for 3-4 hours; 3. Modified nylon (PA6 / PA66): Preheat to 85℃-95℃ and dry at a constant temperature for 4-6 hours; 4. Flame-retardant modified material: Drying time is extended by 1 hour by 5°C compared to the conventional temperature of the same substrate; 5. Preheating rules: Material feeding is prohibited during the heating stage of the drying cylinder. Material can only be fed after the set temperature has been reached and maintained for 30 minutes.

[0036] Once in use, the following process will run: S1. Create a production task and enter material codes and supplier information; S2. The environmental compliance control unit automatically verifies the environmental specifications of materials, supplier qualifications, and environmental documents. If the verification fails, the system will prevent the process from proceeding to step S3 and generate an error message. If the verification passes, the process will proceed to step S3. S3. After the verification is passed, start the waste heat recovery unit to transfer the mold cooling waste heat to the material feeding and drying unit to preheat and dry the raw materials. S4. The intelligent control unit controls the injection molding machine to perform plasticizing, injection, pressure holding and cooling molding, and adjusts the process parameters in real time. It automatically corrects the pressure holding parameters according to the weight deviation of continuous products. S5. The traceability unit records production process data and automatically archives it; S6. When there are changes to materials or suppliers, repeat step S2 and continue production after approval.

[0037] Production using this system and process achieves better energy efficiency compared to ordinary injection molding machines. Actual measured data using the same injection molding machine (without this system and its components) under the same product and production capacity conditions are as follows: Figure 4 As shown, this invention reduces frequent start-ups and shutdowns of heating / cooling through precise PID temperature control, intelligent load reduction during equipment standby, on-demand adjustment of cooling water via frequency conversion, and automatic cut-off of auxiliary heating during material change shutdown.

[0038] Furthermore, the overall operation process of this invention is as follows: task issuance → material scanning and binding → automatic triggering of environmental compliance verification → raw material drying and preheating compliance confirmation → mold cooling water parameter self-check → PID temperature control automatic tuning → mass production start-up → real-time acquisition of mold weight / temperature / pressure data → intelligent correction of weight deviation → real-time closed-loop adjustment of process parameters → abnormal warning / machine lock-up → production end data archiving + automatic generation of environmental protection ledger.

[0039] In this embodiment, the production of a PC+ABS modified material shell is taken as an example; 1. Material change triggers environmental audit In this embodiment, the previous task was ABS raw material. When switching to PC / ABS modified material, the material codes are inconsistent, the system automatically locks the production line and pops up an environmental audit form. After the quality inspection confirms that the material SGS report, PCR content, and hazardous waste management are compliant, the audit is passed and production is unlocked.

[0040] 2. Hands-on practice of automatic weight correction During mass production, the weight of three molds was continuously collected: the target single weight was 120g, and the actual weights of the three molds were 118.5g, 118.2g, and 118.6g, with deviations of more than 1%. The system automatically executed the following: pressure holding pressure +5% and pressure holding time +0.2s. The subsequent mold weights returned to the qualified range of 119.5~120.3g, without the need for manual machine adjustment.

[0041] 3. Temperature control is linked with drying and cooling water. Before production, the drying cylinder is preheated to 115℃ and kept at a constant temperature for 3 hours to complete dehumidification; the cooling water is set to a constant temperature of 32℃, and the PID parameters are set to P=1.6, I=0.25, and D=0.1. The temperature fluctuation of the barrel is controlled within ±1℃ to prevent product cracking and silver streaks.

[0042] 4. Energy-saving implementation performance The equipment dynamically adjusts the heating power according to the production capacity, automatically reduces the insulation power of the barrel when there is no product forming gap, and uses frequency conversion to reduce the speed of cooling water. With an 8-hour production shift, it directly saves about 65 kWh of electricity compared to the old mode, resulting in long-term stable cost reduction.

[0043] 5. Abnormal closed-loop management If continuous issues such as excessive mold weight, abnormal temperature control, or excessive cooling water temperature occur, the system will issue a real-time pop-up alert, simultaneously save the process anomaly record, and link it to the product traceability code to facilitate quality review and traceability for environmental protection and system audits.

[0044] The above is a detailed description of the present invention in conjunction with specific embodiments, and it should not be construed that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, any equivalent substitutions or obvious modifications made without departing from the concept of the present invention, and which have the same performance or use, should be considered to fall within the patent protection scope defined by the submitted claims.

Claims

1. An environmentally friendly and energy-saving injection molding system, characterized in that: The system includes: Injection molding machines are used to plasticize, inject, hold pressure and mold plastic raw materials; The mold unit is installed on the injection molding machine and is used for product molding. The mold unit is equipped with a cooling circuit and a temperature detection component. The feeding and drying unit is used for raw material conveying, preheating, and drying. The waste heat recovery unit connects the mold unit and the material supply and drying unit, and is used to recover waste heat in the mold cooling circuit and transport it to the material supply and drying unit. The environmental compliance management unit is used to audit the environmental compliance of materials and suppliers used in production and to control the start and stop of production. The intelligent control unit is electrically connected to the injection molding machine, mold unit, material feeding and drying unit, waste heat recovery unit and environmental compliance management unit respectively, and is used to collect operating parameters and perform linkage control. Traceability units are used to record material batches, supplier information, environmental confirmation documents, and production process parameters, and to create archives. Wherein: When the environmental compliance control unit detects changes in material code, supplier code, batch number, or the expiration date of environmental protection documents, it automatically triggers an environmental compliance audit. If the audit is passed, the injection molding host is allowed to enter the production state. If the audit is not passed, the intelligent control unit sends a prohibition signal to the injection molding host and closes the feed valve of the material drying unit, locking the machine or prohibiting material supply. The approval signal from the environmental compliance control unit serves as a condition for starting the injection molding machine and simultaneously triggers the start-up of the material feeding drying unit and the waste heat recovery unit.

2. The environmentally friendly and energy-saving injection molding system according to claim 1, characterized in that: The waste heat recovery unit includes a heat exchanger, a circulating pump, insulated pipelines, and an electric regulating valve. The heat source side of the heat exchanger is connected to the cooling circuit of the mold unit, and the heat exchange side is connected to the preheating channel of the material feeding and drying unit.

3. The environmentally friendly and energy-saving injection molding system according to claim 1, characterized in that: The feeding and drying unit includes a vacuum feeding device, a storage tank and a drying tank. The drying tank is equipped with a waste heat preheating chamber, which is used to preheat the raw materials to 60-80°C before drying.

4. The environmentally friendly and energy-saving injection molding system according to claim 1, characterized in that: The environmental compliance management unit includes a material database, an environmental standard database, a document upload module, and an approval process module. The environmental standard database includes at least one or more of RoHS, REACH, halogen-free standards, or customer-specified environmental standards.

5. The environmentally friendly and energy-saving injection molding system according to claim 1, characterized in that: The environmental compliance management unit verifies one or more of the following documents: environmental compliance declaration, third-party testing report, ingredient list, and environmental commitment letter.

6. The environmentally friendly and energy-saving injection molding system according to claim 1, characterized in that: The intelligent control unit includes a PLC controller, a human-machine interface (HMI), and a data acquisition module, which is used to collect parameters such as barrel temperature, mold temperature, drying temperature, injection pressure, and flow rate, and perform closed-loop regulation to keep key temperature fluctuations within ±1℃.

7. The environmentally friendly and energy-saving injection molding system according to claim 1, characterized in that: The traceability unit is used to generate traceability reports that include production batches, material codes, supplier information, environmental audit records, test reports, and process parameters.

8. An environmentally friendly and energy-saving injection molding process as described in any one of claims 1-7, characterized in that: Includes the following steps: S1. Create a production task and enter material codes and supplier information; S2. The environmental compliance control unit automatically verifies the environmental specifications of materials, supplier qualifications, and environmental documents. If the verification fails, the system will prevent the process from proceeding to step S3 and generate an error message. If the verification passes, the process will proceed to step S3. S3. After the verification is passed, start the waste heat recovery unit to transfer the mold cooling waste heat to the material feeding and drying unit to preheat and dry the raw materials. S4. The intelligent control unit controls the injection molding machine to perform plasticizing, injection, pressure holding and cooling molding, and adjusts the process parameters in real time. It automatically corrects the pressure holding parameters according to the weight deviation of continuous products. S5. The traceability unit records production process data and automatically archives it; S6. When there are changes to materials or suppliers, repeat step S2 and continue production after approval.

9. The environmentally friendly and energy-saving injection molding process according to claim 8, characterized in that: In step S3, the waste heat utilization rate of the waste heat recovery unit shall not be less than 82%.

10. The environmentally friendly and energy-saving injection molding process according to claim 8 or 9, characterized in that: In step S4, the intelligent control unit adaptively optimizes and adjusts the holding time, cooling time, and injection speed based on mold temperature, product weight fluctuations, or molding cycle changes.

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