In the field of blister, the product requirements are different, and the forming method used is also different. Of course, the effect is also different. In the blister process, light vacuum becomes. There are a variety of methods and expressions of the mold, such as: vacuum forming of concave molds, vacuum forming of convex molds, vacuum forming of concave and convex molds, vacuum blowing and vacuum forming of auxiliary convex molds.
1. Die vacuum forming
First, place the plastic sheet on top of the mold, fix it with the surroundings, and heat it to soften it; then pull it under the mold Vacuum makes the softened plate adhere tightly to the mold, when gradually cooled After that, blow in air from below the mold and take out the plastic part.
2. Vacuum forming of punch
First, will step up the plastic sheet is heated and softened under the heater. After heating, the softened sheet is cooled when it contacts the punch, and loses its thinning energy.
With continuous heating, the softened material continues to move downwards until it is completely in contact with the punch, and then the vacuum starts, and the edges and surroundings are thinned And forming.
3. The concave and convex molds are vacuumed and formed successively
First, fasten the plastic sheet to the concave mold and heat it, and remove the heater after softening; then blow compressed air into the convex mold upwards, while the concave mold is evacuated to bulge the plastic sheet.
The rear male mold is inserted downward into the bulging plastic plate and a vacuum is drawn from it. At the same time, compressed air is introduced into the female mold, so that the plastic plate is attached to the outer surface of the male mold to form.
4. Blowing and vacuum forming
First heat the plate, and then send compressed air into the closed box, The sheet is blown up, and then the punch is raised to form a closed state with the sheet, and finally vacuum is drawn from the vacuum hole on the punch, and the outside atmospheric pressure is used to shape it. Should be the forming method is to simultaneously thin all parts of the sheet in advance, so that the thickness of the plastic part in the final forming is roughly the same.
5. Vacuum forming of auxiliary punch
First heat the plastic plate fixed to the concave mold to a softened state, then remove the heater, and use the auxiliary punch to push the plastic plate down. The air in the concave mold is compressed to soften the plastic the plate is extended due to the thrust of the auxiliary punch and the closed air movement in the row, and then the concave mold is vacuumed and formed.
6. Compressed air forming method
After the plate is heated, it is tensioned on the mold, and compressed air (6-8kg/cm2) is passed in from the upper pressing plate to make the softened sheet close to the mold for cooling and shaping.