Features of car parts mould:
There are many types of plastics, which can be divided into thermosetting plastics and thermoplastics according to their different thermal properties. Thermosetting plastics refer to plastics that can only be molded once after being cured once and are no longer softened by heat. Such plastics have good heat resistance and are not easily deformed under pressure, but have poor mechanical properties. Thermoplastics refer to plastics that soften when heated, harden when cooled, soften when heated, harden when cooled, and can be re-manufactured by repeated heating. This type of plastic is easy to process and form and has good mechanical properties, but it has a relatively poor heat resistance and is easy to deform. Thermoplastics are large in number, accounting for about 80% of all plastics.
Vacuum forming of car parts mould:
The heated and softened sheet is stretched by blowing bubbles, and then placed on the plastic mold, forming a seal between the sheet and the mold, and vacuuming through the vacuum holes on the mold to form a negative pressure, and the sheet is attached to the surface of the mold. This is the forming process of car parts mould vacuum forming.
①Bubble blowing: The compressed air is blown out through the vacuum chamber, and the heated plate is stretched evenly like a blowing balloon. The height of the blowing bubble is generally 2/3 of the height of the mold.
②Auxiliary forming Some products have complex shapes, so it is necessary to configure an auxiliary pressing frame to perform the plate.
③Vacuum degree Usually, the vacuum degree is controlled above 0.1MPa. To pump out the air in the mold in a short time, a vacuum tank with a larger volume should be equipped.
④ The diameter of vacuum holes is generally 0.5-1.2mm. The size and number of vacuum holes are related to the thickness of the plate. When the plate thickness is below 1.5mm, the diameter is 0.5-0.8mm, and the diameter is 1.2mm when the plate thickness is above 3mm. If the aperture is too large, there will be traces of vacuum holes after blistering, which will affect the appearance. The greater the number of vacuum holes, the easier the molding.
⑤ The vacuuming time depends on the size of the part and the thickness of the plate. When the thickness of the plate is 1.5mm, the control time is 10s. When the thickness of the plate is not less than 3mm, the time is about 25s. The time is long and the material is well-shaped. During production, vacuuming can be carried out at the same time as cooling.
⑥ The mold temperature is controlled by the mold temperature control machine. For parts with a small width and depth, such as a refrigerator door, the mold temperature can be controlled at 40-50 °C; for parts with large width and depth, such as the inner box of a refrigerator, the temperature is 80-90 °C. Especially for square parts, if the four corners are wrinkled, it means that the material cools too fast after contacting the mold, and the mold temperature needs to be increased, but the maximum temperature should not exceed 95 °C.