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November 06, 2023
What are the designs for the exhaust system of plastic molds
Injection molding is an indispensable part of injection molding. We introduced the design principles of the injection mold cavity quantity, gate position, hot runner, assembly drawing, and material selection of the injection mold. Today we will continue to introduce the design of the exhaust system for plastic injection molds.
In addition to the original air in the cavity, the gas in the cavity also contains low molecular volatile gases generated by the heating or solidification of injection molding materials. It is necessary to consider the sequential discharge of these gases. Generally speaking, for molds with complex structures, it is difficult to estimate the exact position of the air lock in advance. Therefore, it is usually necessary to determine its position through mold testing and then open the exhaust slot. The exhaust slot is usually opened at the position where the cavity Z is filled.
The exhaust method is to use the clearance between mold parts and open the exhaust groove for exhaust.
Injection molded parts require exhaust, and demolding of injection molded parts requires exhaust. For deep cavity shell injection molded parts, after injection molding, the gas in the cavity is blown away, and during the demolding process, a vacuum is formed between the appearance of the plastic part and the appearance of the core, which is difficult to demould. If forced demolding is carried out, the injection molded parts are easily deformed or damaged. Therefore, it is necessary to introduce air between the injection molded part and the core, so that the plastic injection molded part can be smoothly demolded. At the same time, several shallow grooves are machined on the parting surface to facilitate exhaust.
1. The template for the cavity and core requires the use of conical positioning blocks or precision positioning blocks, which are installed on four sides or around the mold.
2. The contact surface between the mold base A plate and the reset rod needs to use flat or circular pads to avoid damaging the A plate.
3. The perforated part of the guide rail should be tilted at least 2 degrees to avoid burrs and burrs, and the perforated part should not be of a thin blade structure.
4. To prevent dents in injection molded products, the width of the reinforcing rib should be less than 50% of the appearance surface wall thickness (ideal value<40%).
5. The wall thickness of the product should be the average value, and at least sudden changes should be considered to avoid dents.
If the injection molded parts are electroplated, the movable mold also needs to be polished. Polishing requirements are second only to mirror polishing requirements to reduce the generation of cold materials during the forming process.
7. Ribs and grooves in poorly ventilated cavities and cores must be embedded to avoid dissatisfaction and burnt marks.
In addition to the original air in the cavity, the gas in the cavity also contains low molecular volatile gases generated by the heating or solidification of injection molding materials. It is necessary to consider the sequential discharge of these gases. Generally speaking, for molds with complex structures, it is difficult to estimate the exact position of the air lock in advance. Therefore, it is usually necessary to determine its position through mold testing and then open the exhaust slot. The exhaust slot is usually opened at the position where the cavity Z is filled.
The exhaust method is to use the clearance between mold parts and open the exhaust groove for exhaust.
Injection molded parts require exhaust, and demolding of injection molded parts requires exhaust. For deep cavity shell injection molded parts, after injection molding, the gas in the cavity is blown away, and during the demolding process, a vacuum is formed between the appearance of the plastic part and the appearance of the core, which is difficult to demould. If forced demolding is carried out, the injection molded parts are easily deformed or damaged. Therefore, it is necessary to introduce air between the injection molded part and the core, so that the plastic injection molded part can be smoothly demolded. At the same time, several shallow grooves are machined on the parting surface to facilitate exhaust.
1. The template for the cavity and core requires the use of conical positioning blocks or precision positioning blocks, which are installed on four sides or around the mold.
2. The contact surface between the mold base A plate and the reset rod needs to use flat or circular pads to avoid damaging the A plate.
3. The perforated part of the guide rail should be tilted at least 2 degrees to avoid burrs and burrs, and the perforated part should not be of a thin blade structure.
4. To prevent dents in injection molded products, the width of the reinforcing rib should be less than 50% of the appearance surface wall thickness (ideal value<40%).
5. The wall thickness of the product should be the average value, and at least sudden changes should be considered to avoid dents.
If the injection molded parts are electroplated, the movable mold also needs to be polished. Polishing requirements are second only to mirror polishing requirements to reduce the generation of cold materials during the forming process.
7. Ribs and grooves in poorly ventilated cavities and cores must be embedded to avoid dissatisfaction and burnt marks.
8. The inserts, inserts, etc. should be positioned and fixed firmly, and the circular discs should have anti rotation measures. It is not allowed to place copper and iron sheets under the insert. If the welding pad is high, the welded part should form a large surface contact and be ground flat.
Injection Mold Processing - TV Plastic shell mold, Electronic product mold,Electronic Digital Product Mold,Mobile Phone Peripheral Product Mold,Toy product molds, Household.
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Privacy statement: Your privacy is very important to Us. Our company promises not to disclose your personal information to any external company with out your explicit permission.