SU1821384A1 - Device for molding products from polymeric materials - Google Patents

Description

The invention relates to rotational molding devices for vulcanizing rubber and plastic products.

The aim of the invention is to improve the quality of manufactured products.

FIG. 1 shows a general view of the device; in fig. 2 is a general view of the locking device; FIG. 3 - Centering grooves of the mold.

The device (figure 1) contains a rotary table 1, a loading device including a casting device 2 and a manipulator 3 for feeding a mold 4 into the working cavity of a locking device 5, an unloading device including a pusher 6 and a separator-cleaner 7 of molds, and an annular heat chamber 8 with sectional heating. Loading and unloading devices are rigidly attached to the body of the heat chamber. On the body of the heat chamber, the stops 9 of the pre-compression mechanism and the stops 10 for unloading, located at the outlet from the heat chamber, are also rigidly fixed.

The locking device (Fig. 2) consists of upper Ϊ1 and lower 12 plates, guide columns 13, main power elements 14 with thermomechanical shape memory (TMPF) in the form of rods, return springs 15, intermediate plate 16 with vertical and horizontal slots. In the horizontal socket there is a latch 17, the position of which is determined by a fixing force element 18 made of material with TMPF and a counter-spring 19. In the vertical socket there is a pusher 20 with a hole 21 for the latch 17. The pusher is made in the form of a rod with a flange 22 with sections of different diameters. A section of a larger diameter 23 is located in a vertical slot of an intermediate plate 16 and is made with a radial hole 21 to interact with a retainer 17. A section 24 of a smaller diameter is located in and above the intermediate plate 16 and is connected to a flange 22. The latter is mounted on additional guides 25 fixed in intermediate plate 16. Between the flange 22 and the intermediate 5 plate 16 on additional guides there are additional load-bearing elements 26 in the form of springs made of TMPF material. In the upper plate 11 there is a multi-threaded screw 27 with levers 28 for interaction with stops 9 of the pre-compression mechanism. The lower traverse 12 and the intermediate plate 16 have centering grooves 29 for precise installation of the easy-to-use mold 4.

The device works as follows. At the loading position in the space between the bottom plate 12 and the intermediate plate 16, the manipulator 3 places a mold 20 equipped with a casting device 20 with a molded material. The turntable 1 rotates at a constant angular velocity, the value of which is selected based on the technological conditions of molding (vulcanization). As the movement progresses, the lever 28 of the multi-threaded clamping screw 27 interacts with the stops 9 and creates a preliminary compression. providing molding pressure up to 3 MPa and deformation of the main load-bearing elements 14 to 3%. Further, the locking device 5 enters the zone of the heat chamber 8, where the temperature of the medium (for vulcanization 140-150 ° C) does not exceed the temperature of the phase transition of additional power elements 2 6 and the fixing power element 18. Under the influence of this temperature, these power elements undergo reverse martensitic transformation and begin to act on the intermediate 40 plate 16. and performs pressing of the processed material, while filling the mold strands, compacting the processed material, decreasing porosity, eliminating possible folds. The vulcanization process begins if raw rubber is used as the molded material. The intermediate plate moves by the value ε. As the gap is selected, the hole 21 is aligned with the retainer 17 under the action of the retaining force element 18, and it enters the hole 21 of the pusher 20. Entering the zone of the heat chamber with a higher temperature (150-160 ° C), equal to the technological temperature of the molded (vulcanized) material , the main power elements 14 at the final stage of the reverse martensitic transformation, due to the generation of reactive stresses, carry out additional pressing to a given molding pressure of 8-10 MPa, which makes it possible to obtain articles with an optimal density.

After leaving the specified zone of the heat chamber in the main, additional and fixing power elements, as it cools, a direct martensitic transformation occurs and, under the action of return springs, the load is removed from the formed material as follows.

Under the action of the return spring 19, the latch comes out of the hole 21, and the intermediate plate 16, under the action of the return springs 15, rises upward by an amount ε. When leaving the last low-30 temperature zone of the heat chamber 2, the levers 28 of the multi-threaded screw 27 interact with the stops 10. and the load is completely removed. Having reached the unloading position, the pusher 6 pushes out. n press-form 4 into the area of action of the separator cleaner 7, carrying out the opening of the mold, extraction of the finished product, cleaning the mold and lubrication, followed by its supply to the loading position. ·

The device makes it possible to significantly reduce the percentage of rejects due to three-stage loading of the material being formed, as well as more efficient use of technological heat energy both to maintain the conditions for the molding process (vulcanization) and to create the required pressing force due to the shape memory effect of the force elements.

Claims (2)

Claim 1. A device for molding products from polymeric materials, containing a table that is rotatable in the horizontal plane, on which molds with locking devices are placed, each of which has upper and lower plates mounted on guide columns, return springs and a pre-compression mechanism, and mounted above a rotary table an annular heat chamber with sectional heating, which is distinguished by the fact that, in order to improve the quality of manufactured products, each locking device is equipped with basic power elements in the form of rods parallel to the guide columns made of a material with a thermomechanical shape memory located Between the upper and lower plates, an intermediate plate with vertical and horizontal nests, located in the horizontal nest with a retainer with a fixing force element made of a material with thermomechanical shape memory and a counter-spring and mounted with the possibility of axial movement by a pusher made in the form of a the flange of the rod with sections of different diameters, and the section of the larger diameter is made with a radial hole for interaction with the retainer and is placed in a vertical socket, and the section of the smaller diameter is located in the intermediate plate and above it and is connected to the flange, which is mounted with the possibility of axial movement on the intermediate plate by means of additional guides with additional load-bearing elements in the form of springs made of thermomechanical material. 2. The device according to claim 1, which is characterized by the fact that the pre-compression mechanism is made in the form of stops mounted on a rotary table and a multi-threaded screw with levers fixed in the upper plate to interact with the stops, and centering grooves for the mold are made in the lower and intermediate plates.