CS216740B1 - Equipment for shaping large-area moldings from plastic foils - Google Patents

Abstract

The device consists of a cooled mold of the desired shape, equipped with upper channels for distributing compressed air or vacuum, a frame, a suction device for placing the foil on a heated plate equipped with lower channels for supplying vacuum or compressed air, a carriage, a sliding device for moving the mold above the container for stacking the moldings, and a lifting device that clamps the foil by lifting the heating plate onto the frame.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for molding plastic sheet moldings, particularly for cooling tower plates.

Thermoforming foils are used to produce a variety of consumer and industrial products such as various packaging, linings, covers, inserts, containers, etc. Vacuum machines are used for forming, using an infrared heating film (IFC) and peripheral film holding to heat the film. high demands are placed on material. When forming foils in this way of heating, the foil is unevenly heated to the forming temperature due to the undesirable concentration of radiated energy both in the vicinity of individual bodies and in the center of the whole system. The drawback of IFG heating is the different sensitivity of the heated films to heat reception due to different radiation reflectivity, which results in poor quality of the film heating and a considerable amount of energy dissipating into the space, including long heating of the film. An unfavorable property of the foil is the different shrinkage in the longitudinal and transverse directions, which determines the orientation of the film blanks with respect to the produced shape. If this condition is not observed, the quality of moldings is considerably reduced, or production is not possible at all. Furthermore, in the case of the existing devices, great demands are placed on labor.

These drawbacks are overcome by the device according to the invention, which is based on a combination of contact heating, cooled mold and other elements, wherein the contact heating and cooled mold are provided with channels for supplying compressed air and vacuum. The starting thermoplastic foil is circumferentially pressed by the frame of the cooled mold of the desired shape onto the heated plate of the desired temperature, to which it achieves a good temperature transfer by vacuum and pressed by compressed air introduced into the mold space, thereby uniformly heating the foil to the molding temperature and changing the pressure air and vacuum, the film is formed into a cooled mold shape and thereby fixed. This device achieves perfect and fast heating of the foil over the whole surface, which enables the shaping of even very demanding moldings with high energy efficiency, increasing production and quality.

By clamping the film under vacuum during heating to the heating plate, unwanted effects of unequal shrinkage of the film are eliminated and the use of considerably lower temperatures reduces the risk of overheating and thus degradation of the film. This creates the conditions for automating the entire working cycle. The compactness of the machine enables the construction of machines with a high saving of human labor and elimination of bad working conditions in the previous production. Using a combination of vacuum and compressed air is achieved by processing blanks of smaller dimensions.

The attached drawing (Figs. 1 to 3) shows the device according to the invention in three basic phases of the duty cycle.

The device according to Fig. 1 comprises a cooled mold 1 with a frame 2 placed on the travel 3, moved by a sliding device 4 provided with suction cups 6, ejectors 6 and upper ducts J for the supply of vacuum of the compressed air cell. A heated plate 8 is provided below the mold 1, provided with lower channels 9 for the supply of vacuum or compressed air and a lifting device 10.

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Below the suction cups there is a container 11 of sheet cuttings 12. On the opposite side there is a container 14 of finished products 13.

The device according to the invention can be adapted for direct automatic insertion of shaped moldings into additional devices, such as shearing tools, packaging devices, etc. The device can be easily equipped with an additional device for shaping the moldings from foil wrapping, etc.

Claims (1)

SUBJECT OF THE INVENTION Apparatus for forming large-size moldings, in particular for cooling tower plates, characterized in that it consists of a cooled mold (1) of the desired shape, provided with upper ducts (7) for distributing compressed air or vacuum, a frame (2), a suction device ( 5) for placing the foil (12) on a heated plate (8) provided with lower channels (9) for supplying vacuum or compressed air, from the travel (3), a slide (4) serving to move the mold (1) over the container (14) for stacking the moldings and from a lifting device (10) which clamps the foil by lifting the heating plate (8) onto the frame (2). 1 drawing