Injection molding process for ABS housings

Abstract

The application discloses an injection molding process for ABS shell, comprising the following steps: S1, preliminary detection and treatment of raw materials: first, select part of the raw materials for moisture detection, the water content of ABS raw materials is about 0.2%-0.8%, and the drying oven should be dried at 80-85 DEG C for 2-4 hours before production, or the dried hopper is dried at 90 DEG C for 1-2 hours, to ensure the dryness of ABS raw materials. The application detects the moisture of ABS raw materials in the early stage, ensures the dryness of ABS raw materials, greatly improves the injection molding effect of subsequent ABS products, avoids the increase of the scrap rate of ABS products caused by too much water contained in ABS raw materials, improves the yield of ABS products, reduces the production cost, and improves the demolding agent, so that the demolding frequency is increased, and good demolding effect is ensured, and problems such as difficult demolding and demolding damage of subsequent ABS products do not occur, the mold is easy to demold after use, the labor intensity is improved, the product brightness is high, and the yield of demolding is ensured.

Description

Technical Field

[0001] This invention relates to the technical field of ABS shell production, and more specifically, to an injection molding process for ABS shells. Background Technology

[0002] ABS plastic combines the properties of its three components: A makes it resistant to chemical corrosion and heat, and provides a certain degree of surface hardness; B gives it high elasticity and toughness; and S gives it the processing and molding characteristics of thermoplastics and improves its electrical properties. ABS plastic has been widely used in manufacturing industries such as machinery, electrical, textile, automotive, aircraft, and shipbuilding, as well as in the chemical industry. ABS plastic is mostly produced using injection molding. Different molds are designed for different shapes, and corresponding injection molding processes are used for production. Mass production is possible, and production costs are low.

[0003] However, current injection molding equipment does not perform pre-treatment or targeted treatment of ABS raw materials in the early stage of injection molding, and ABS raw materials are highly susceptible to interference from external environmental factors. When the moisture content of ABS raw materials is too high, defects such as bubbles, spray marks, and silver streaks on the surface will occur in the products. Therefore, the moisture content of plastic is an important factor affecting the processing technology, product appearance, and product characteristics. In addition, current injection molding equipment has problems such as difficulty in demolding and high demolding workload. To address these issues, we propose an injection molding process for ABS shells. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of current injection molding equipment not conducting pre-injection testing and treatment of ABS raw materials, as well as the difficulties in demolding and the high workload of demolding.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an injection molding process for ABS housings, comprising the following steps: S1. Preliminary testing and processing of raw materials: First, select a portion of the raw materials for moisture testing. The moisture content of ABS raw materials is approximately 0.2%-0.8%. Before production, the raw materials should be dried in a drying oven at 80-85℃ for 2-4 hours, or dried in a drying hopper at 90℃ for 1-2 hours to ensure the dryness of the ABS raw materials. S2. Selection of injection molding machine and mold: The standard injection molding machine that can be used should be determined according to the clamping force of 4700-6200t; The mold temperature should be set to 60-65℃, the channel diameter to be 6-8mm, the inlet width to be about 3mm, the thickness to be the same as the ABS shell, the inlet length to be less than 1mm, and the vent width to be 4-6mm and the thickness to be 0.025-0.05mm. S3. Apply release agent: Then, apply release agent evenly to the mold so that the ABS shell can be quickly peeled off the mold to achieve demolding. S4. Raw material feeding and melting: Set the heating temperature of the injection molding machine to 220℃-260℃ to heat and melt the ABS raw material; S5, Injection: The raw material after S4 is quickly injected into the mold cavity for molding, maintaining a back pressure of 5 bar; S6. Cooling and Demolding: After the product is injection molded, the mold is cooled to accelerate the product molding and demolding process. S7. Post-processing of products: Conduct appearance inspection on the products and clean up any release agents or other substances generated during processing.

[0006] Preferably, in step S1, for high-temperature resistant ABS raw materials containing PC components, the drying temperature is appropriately increased to 100°C.

[0007] Preferably, in S2, the extruder screw of the injection molding machine has a length-to-diameter ratio of 20:1, a compression ratio of more than 2, and an injection pressure of 1500 bar.

[0008] Preferably, the coating step of the release agent in S3 is as follows: Step 1: Soak a non-woven or pure cotton cloth with release agent, but do not drip it onto the coated surface. Observe that the release agent to be wiped has spread on 1 / 4 of the mold surface, and then wipe it vigorously. Step 2: Soak a non-woven or pure cotton cloth with the residue-free release agent and evenly coat the mold surface. If there is no dust, there is no need to wipe it. Step 3: Repeat steps 1 and 2, paying attention to applying and wiping the release agent on the smaller vertical surfaces of the mold; Step 4: After 30 minutes, use masking tape to test the surface of the mold, especially small vertical surfaces or corners; Step 5: Test different angles with masking tape. If the adhesion is greater than in other places, apply more release agent.

[0009] Preferably, if the cloth used to apply the release agent is found to be discolored or contaminated, it should be replaced with a clean cloth, and new masking tape should be used each time to test the effect.

[0010] Preferred ingredients include the following components by weight: (1) 30-40 parts water (2) 10-20 parts of turpentine (3) 8-10 parts salad oil (4) 3-5 parts gasoline (5) 20-30 parts of phenolic resin (6) Stearic acid 2-8 parts (7) 3-6 parts lanolin (8) 6-8 parts silicone grease (9) 5-7 parts surfactant (10) 8-10 parts of potassium hydroxide (11) 10-12 parts xanthan gum.

[0011] The technical effects and advantages of this invention are as follows: This invention involves detecting the moisture content of ABS raw materials in the early stages and drying them in a drying oven at 80-85℃ for 2-4 hours or in a drying hopper at 90℃ for 1-2 hours before production. This ensures the dryness of the ABS raw materials, thereby greatly improving the injection molding effect of subsequent ABS products, avoiding excessive moisture in the ABS raw materials that would lead to a higher scrap rate, improving the yield of ABS products, and reducing production costs.

[0012] The present invention further describes the application of a release agent to the mold. This release agent is composed of water, turpentine, salad oil, gasoline, phenolic resin, stearic acid, lanolin, silicone grease, surfactant, potassium hydroxide, xanthan gum, and other components. This extends the service life of the release agent, increases the number of demolding cycles, and ensures a good demolding effect. It prevents problems such as difficulty in demolding and demolding damage that may occur with ABS products later on. After use, the mold is easy to demold, reducing labor intensity, resulting in high product gloss and ensuring a high yield rate of demolded products. Attached Figure Description

[0013] Figure 1 This is a schematic diagram showing a dent in the product of the present invention; Figure 2 This is a schematic diagram showing the silver wires on the surface of the product of the present invention. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. Example 1

[0015] An injection molding process for ABS housings includes the following steps: S1. Preliminary testing and processing of raw materials: First, select a portion of the raw materials for moisture testing. The moisture content of ABS raw materials is approximately 0.2%-0.8%. Before production, the raw materials should be dried in a drying oven at 80-85℃ for 2-4 hours, or dried in a drying hopper at 90℃ for 1-2 hours to ensure the dryness of the ABS raw materials. S2. Selection of injection molding machine and mold: The standard injection molding machine that can be used should be determined according to the clamping force of 4700-6200t; The mold temperature should be set to 60-65℃, the channel diameter to be 6-8mm, the inlet width to be about 3mm, the thickness to be the same as the ABS shell, the inlet length to be less than 1mm, and the vent width to be 4-6mm and the thickness to be 0.025-0.05mm. S3. Apply release agent: Then, apply release agent evenly to the mold so that the ABS shell can be quickly peeled off the mold to achieve demolding. S4. Raw material feeding and melting: Set the heating temperature of the injection molding machine to 220℃-260℃ to heat and melt the ABS raw material; S5, Injection: The raw material after S4 is quickly injected into the mold cavity for molding, maintaining a back pressure of 5 bar; S6. Cooling and Demolding: After the product is injection molded, the mold is cooled to accelerate the product molding and demolding process. S7. Post-processing of products: Conduct appearance inspection on the products and clean up any release agents or other substances generated during processing.

[0016] Preferably, in step S1, for high-temperature resistant ABS raw materials containing PC components, the drying temperature is appropriately increased to 100°C.

[0017] Preferably, in S2, the extruder screw of the injection molding machine has a length-to-diameter ratio of 20:1, a compression ratio of more than 2, and an injection pressure of 1500 bar.

[0018] Preferably, the coating step of the release agent in S3 is as follows: Step 1: Soak a non-woven or pure cotton cloth with release agent, but do not drip it onto the coated surface. Observe that the release agent to be wiped has spread on 1 / 4 of the mold surface, and then wipe it vigorously. Step 2: Soak a non-woven or pure cotton cloth with the residue-free release agent and evenly coat the mold surface. If there is no dust, there is no need to wipe it. Step 3: Repeat steps 1 and 2, paying attention to applying and wiping the release agent on the smaller vertical surfaces of the mold; Step 4: After 30 minutes, use masking tape to test the surface of the mold, especially small vertical surfaces or corners; Step 5: Test different angles with masking tape. If the adhesion is greater than in other places, apply more release agent.

[0019] Preferably, if the cloth used to apply the release agent is found to be discolored or contaminated, it should be replaced with a clean cloth, and new masking tape should be used each time to test the effect.

[0020] Preferably, the release agent in S3 comprises the following components in parts by mass: (1) 30 parts water (2) 10 parts of turpentine (3) 8 parts salad oil (4) 3 parts gasoline (5) 20 parts of phenolic resin (6) 2 parts stearic acid (7) 3 parts lanolin (8) 6 parts silicone grease (9) 5 parts surfactant (10) 8 parts of potassium hydroxide (11) 10 parts xanthan gum. Example 2

[0021] The difference from Example 1 is as follows: The release agent in S3 is composed of the following components in parts by mass: (1) 35 parts water (2) 15 parts of turpentine (3) 9 parts salad oil (4) 4 parts gasoline (5) 25 parts of phenolic resin (6) 6 parts stearic acid (7) 5 parts lanolin (8) 7 parts silicone grease (9) 6 parts surfactant (10) 9 parts of potassium hydroxide (11) 11 parts xanthan gum. Example 3

[0022] The difference from Example 1 is as follows: The release agent in S3 is composed of the following components in parts by mass: (1) 40 parts water (2) 20 parts of turpentine (3) 10 parts salad oil (4) 5 parts gasoline (5) 30 parts of phenolic resin (6) 8 parts stearic acid (7) 6 parts lanolin (8) 8 parts silicone grease (9) 7 parts surfactant (10) 10 parts of potassium hydroxide (11) 12 parts xanthan gum.

[0023] The appearance of commercially available ABS shells was compared with that of the ABS shells prepared in Examples 1, 2 and 3 of this invention.

[0024] The testing method is as follows: ABS shells produced by ordinary injection molding processes on the market, as well as ABS shells prepared in Examples 1, 2, and 3 of this invention, are selected for use. Then, the corresponding ABS shells are sent to an appearance inspection device for appearance inspection, and defects and dents on the surface of the ABS shells (as shown below) are examined. Figure 1 ), cracks, surface silver streaks (as follows) Figure 2 The system detects bubbles and also selects the same number of manufactured products for testing to obtain the scrap rate.

[0025] As can be seen from the above, the ABS shell prepared by the present invention, due to the testing and treatment of the ABS raw materials in the early stage to ensure the dryness of the ABS raw materials, greatly improves the injection molding effect of the subsequent ABS products, reduces the scrap rate of ABS products, increases the yield of ABS products, and reduces production costs.

[0026] The number of demolding cycles of commercially available demolding agents and the demolding agents prepared in Examples 1, 2 and 3 of this invention were tested.

[0027] The testing method is as follows: molds coated with common release agents on the market and molds coated with the release agents prepared in Examples 1, 2 and 3 of this invention are selected for production demolding. The number of demoldings is recorded in real time for easy subsequent query. After each demolding, the appearance of the product is inspected to check for any damage.

[0028]

[0029] As shown in the table above, the release agent of this invention is composed of water, turpentine, salad oil, gasoline, phenolic resin, stearic acid, lanolin, silicone grease, surfactant, potassium hydroxide, xanthan gum, and other components. This extends the service life of the release agent, increases the number of demolding cycles, and ensures a good demolding effect. It avoids problems such as difficulty in demolding and demolding damage that may occur with ABS products later on. After use, it makes mold demolding easier, improves labor intensity, increases product gloss, and ensures a high yield rate of demolded products.

[0030] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An injection molding process for ABS housings, characterized in that: Includes the following steps: S1. Preliminary testing and processing of raw materials: First, select a portion of the raw materials for moisture testing. The moisture content of ABS raw materials is 0.2%-0.8%. Before production, the raw materials should be dried in a drying oven at 80-85℃ for 2-4 hours, or dried in a drying hopper at 90℃ for 1-2 hours to ensure the dryness of the ABS raw materials. S2. Selection of injection molding machine and mold: The standard injection molding machine that can be used should be determined according to the clamping force of 4700-6200t; The mold temperature should be set to 60-65℃, the channel diameter to be 6-8mm, the inlet width to be 3mm, the thickness to be the same as the ABS shell, the inlet length to be less than 1mm, and the vent width to be 4-6mm and the thickness to be 0.025-0.05mm. S3. Apply release agent: Then, apply release agent evenly to the mold so that the ABS shell can be quickly peeled off the mold to achieve demolding. S4. Raw material feeding and melting: Set the heating temperature of the injection molding machine to 220℃-260℃ to heat and melt the ABS raw material; S5, Injection: The raw material after S4 is quickly injected into the mold cavity for molding, maintaining a back pressure of 5 bar; S6. Cooling and Demolding: After the product is injection molded, the mold is cooled to accelerate the product molding and demolding process. S7. Post-processing of products: Conduct appearance inspection on the products and clean the release agent generated during processing. The release agent in S3 is composed of the following components in parts by mass: (1) 30-40 parts water (2) 10-20 parts of turpentine (3) 8-10 parts salad oil (4) 3-5 parts gasoline (5) 20-30 parts of phenolic resin (6) Stearic acid 2-8 parts (7) 3-6 parts lanolin (8) 6-8 parts silicone grease (9) 5-7 parts surfactant (10) 8-10 parts of potassium hydroxide (11) 10-12 parts xanthan gum.

2. The injection molding process for an ABS housing according to claim 1, characterized in that: In step S1, for high-temperature resistant ABS raw materials containing PC components, the drying temperature is appropriately increased to 100°C.

3. The injection molding process for an ABS housing according to claim 1, characterized in that: The injection molding machine in S2 has an extruder screw length-to-diameter ratio of 20:1, a compression ratio exceeding 2, and an injection pressure of 1500 bar.

4. The injection molding process for an ABS housing according to claim 1, characterized in that: The application step of the release agent in S3 is as follows: Step 1: Soak a non-woven or pure cotton cloth with release agent, but do not drip it onto the coated surface. Observe that the release agent to be wiped has spread on 1 / 4 of the mold surface, and then wipe it vigorously. Step 2: Soak a non-woven or pure cotton cloth with the residue-free release agent and evenly coat the mold surface. If there is no dust, there is no need to wipe it. Step 3: Repeat steps 1 and 2, paying attention to applying and wiping the release agent on the smaller vertical surfaces of the mold; Step 4: After 30 minutes, use masking tape to test the vertical surfaces or corners of the mold surface; Step 5: Test different angles with masking tape. If the adhesion is greater than in other places, apply more release agent.

5. The injection molding process for an ABS housing according to claim 4, characterized in that: If the cloth used to apply the release agent is found to be discolored or stained, it should be replaced with a clean cloth, and new masking tape should be used each time to test the effect.

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