SU539911A1 - The method of manufacturing products from thermoreactor - Google Patents

Description

one

The invention relates to the processing of plastics into products and can be used in the manufacture of products made from effluent bodies.

In the manufacture of plastic products, the well-known three main methods are used: compression (direct) pressing, injection molding, and injection molding. Under the conditions of these methods, the pressure on the press material in the molding cavity is set by the pressing body through the press material, which changes its properties during the molding process, the transition from the solid to the liquid and vice versa. Change the properties of the press state to liquid and back. Changes in the properties of the press material depends on many factors and therefore have not been studied. The molding pressure (the hydrostatic pressure of the molding cavity) remains uncertain, as it is determined by the force of the pressing member, uncertainly (due to the aforementioned reasons) of the transformed press mass. The uncertainty of the transformed force into the forming cavity is caused by the uncertainty of the process of changing the phase state of the press mass during pressing.

When implementing one of the known ci Oco6oB, the value of the required set molding pressure kgf / cm determined for thermoset plastics significantly exceeds the yield strength of the plastic-viscous press material, i.e. 10-30 kgf / cm 1. The effect of such a high pressure is molding provides (accumulates) a force impulse that overcomes the resistance at the entrance to the slots of the molding cavity and besides filling the molding cavity ensures the flow of the press mass

0 into the gaps of the forming cavity, i.e., it produces the formation of a mold on the product, the durability of the mold and leads to the need to spend additional effort to keep the mold in the closed

5 states.

The purpose of the invention is to form products without scrap.

According to the invention, the hydrostatic molding pressure is maintained at 2-5 kgf / cm above the yield point of the plasticized (liquid) press. Such a force during the plastic-viscous state of the press mass ensures that the molding mass is filled with the press mass and

5 does not accumulate a pulse of force capable of overcoming the input resistances of the slots of the forming cavity.

Example 1. A mold is selected for a product of complex configuration, in

0 which is above the gating gap installed

direct pressure regulator. The products are made of iress-material AG-4B GOST 10087-62 of three different parts and batches. The pressing is carried out at a mold temperature of 150-155 ° C and an injection speed of Uzap 42-45.

Under these conditions, the yield strength of the plasticized press material is 30 kgf / cm.

The remaining data is tabulated.

As can be seen from the table, the blank product is molded at a pressure that is 2-5 kgf / cm higher than the yield strength of the press mass.

The accuracy of the dimensions that intersect the plane of the connector for the products formed by the proposed method is much higher, and the other indicators are not worse.

 00 Hard control sign.

Claims (1)

1. A. Sokolov and I. F. Kanavets. Forming thermoreactoplasts, Plastics, 1963, No. 12, p. 15 (prototype).