Views: 0 Author: Site Editor Publish Time: 2020-05-23 Origin: Site
During the melt-filling phase of the injection molding process, the air at the melt front can be trapped and caught inside the mold cavity. This trapped air in cavity is compressed that increases the pressure and the temperature at the front of flowing polymer. This highly compressed air can ris in temperature similar to superheated steam and can cause defects such as burn marks, dulled or
poor surface finish, weak weld lines that cause the workpiece to fail in service prematurely such as strength, short shots or incompletely filled parts, variations in workpiece dimensions
This compressed air needs a location to escape out off cavity. The design of passes or vent slor is to allow this highly compressed air to evacuate the cavity. The air at melt front must be slowed to leave the cavity in the time required for the plastic melt to fill out the cavity during shot. This time usually just is in a few seconds, so the size and location must be considered carefully shows the ventilation design. The length of the vent slot is generally 1.0-2.0 mm, height 0.02-0.05 mm and the height of the vent duct05-10 mm. Consequently, vent slots are designed narrow and the height of the vent slot should be selected so as to prevent the plastic melt from flowing in Tab. 5.2 provides same recommendations for design in injection mold.
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Tuofang company is specialized in designing and manufacturing Plastic Injection.
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