Injection mold is an indispensable part of injection molding. We introduced the design principles of cavity quantity, gate position, hot runner, assembly drawing and material selection of injection mold. Today we will continue to introduce the design of exhaust system of plastic injection mold.

除了型腔中的原始空气外，型腔中的气体还包含由注射成型材料的加热或固化产生的低分子挥发性气体。有必要考虑这些气体的顺序放电。一般来说，对于结构复杂的模具，很难预先估计气锁的准确位置。因此，通常需要通过试模确定其位置，然后打开排气槽。排气槽通常在空腔Z填充的位置打开。

In addition to the original air in the cavity, the gas in the cavity also contains low molecular volatile gases produced by the heating or curing of injection molding materials. It is necessary to consider the sequential discharge of these gases. Generally speaking, for the mold with complex structure, it is difficult to estimate the accurate position of air lock in advance. Therefore, it is usually necessary to determine its position through die test, and then open the exhaust slot. The exhaust slot is usually opened where cavity Z is filled.

排气方式是利用模具零件配合间隙，打开排气槽排气。

The exhaust mode is to open the exhaust slot for exhaust by using the matching clearance of die parts.

注塑件成型需要排气，注塑件脱模需要排气。对于深腔壳体注射成型零件，注射成型后，腔中的气体被吹走，在脱模过程中，塑料零件的外观和型芯的外观之间形成真空，这是很难脱模的。如果强制脱模，注塑件很容易变形或损坏。因此，有必要引入空气，即在注塑件和芯之间引入空气，以便塑料注塑件能够顺利脱模。同时，在分型面上加工几个浅槽，以便于排气。

Exhaust is required for injection molding, and exhaust is required for injection mold demoulding. For deep cavity shell injection molding parts, after injection molding, the gas in the cavity is blown away. In the demoulding process, a vacuum is formed between the appearance of plastic parts and the appearance of core, which is difficult to demould. If forced demoulding, the injection molded parts are easy to deform or damage. Therefore, it is necessary to introduce air, that is, between the injection molded part and the core, so that the plastic injection molded part can be demoulded smoothly. At the same time, several shallow grooves are machined on the parting surface to facilitate exhaust.

1.腔体和芯的模板需要使用锥形定位块或精 密定位块，该指南安装在四个侧面或模具周围。

1. The template of cavity and core needs to use conical positioning block or precision positioning block, and the guide is installed on four sides or around the mold.

2.模架A板与复位杆的接触面需使用平垫或圆垫块，以免损坏A板。

2. Flat pad or round pad shall be used for the contact surface between the a plate of the mold base and the reset rod to avoid damaging the a plate.

3.导轨的穿孔部分应倾斜2度以上，以避免毛刺和毛刺，穿孔部分不得为薄叶片结构。

3. The perforated part of the guide rail shall be inclined more than 2 degrees to avoid burrs and burrs. The perforated part shall not be of thin blade structure.

4.为防止注塑制品产生凹痕，加强筋宽度应小于外观表面壁厚的50%（理想值<40%）。

4. In order to prevent dents on injection molded products, the width of stiffener shall be less than 50% of the wall thickness of the appearance surface (ideal value < 40%).

5.产品的壁厚应为平均值，且少应考虑突变，以避免出现凹痕。

5. The wall thickness of the product shall be the average value, and at least sudden change shall be considered to avoid dents.

6.如果注塑件是电镀件，则活动模具也需要抛光。抛光要求仅次于镜面抛光要求，以减少成型过程中冷材料的产生。

6. If the injection molded part is electroplated, the movable mold also needs polishing. Polishing requirements are second only to mirror polishing requirements to reduce the generation of cold materials in the forming process.

7.必须嵌入通风不良的型腔和型芯中的肋和凹槽，以避免不满意和烧焦痕迹。

7. Ribs and grooves in poorly ventilated cavities and cores must be embedded to avoid dissatisfaction and scorch marks.

8.镶件、镶件等应定位固定牢固，圆片应有防旋转措施。不允许在插入件下方垫铜和铁片。如果焊垫较高，则焊接部分应形成较大的表面接触并磨平。

8. Inserts, inserts, etc. shall be positioned and fixed firmly, and the disc shall be provided with anti rotation measures. It is not allowed to pad copper and iron under the insert. If the welding pad is high, the welded part shall form a large surface contact and be ground flat.