Method for improving heating oven performance of hard PVC-U pipes

Abstract

The invention discloses a method for improving the heating oven performance of hard PVC-U pipes. According to the method, annular reinforcing ribs are arranged at a sprue of an injection mold of the hard PVC-U pipes, the height of the reinforcing ribs is smaller than or equal to 5mm, and the outer diameter of the reinforcing ribs is greater than the outer diameter of the sprue but not greater than 1.1 times of the outer diameter of the sprue. According to the method, the mold structure is improved; the reinforcing ribs have the beneficial effects that stress concentration at the sprue can be reduced, the product strength can be improved, cold materials can be effectively prevented from entering products, poor flow marks can be eliminated, flow resistance can be reduced, injection force can be easily transmitted to far parts of formed products, and the welding strength can be improved; and through the improvement, the disqualification problem of heating oven tests of the hard large-diameter PVC-U injection molding pipes (phi greater than or equal to 160) is effectively solved, and the qualification rate of the heating oven tests of the large-diameter PVC-U pipes is greatly increased.

Description

technical field [0001] The invention relates to the field of injection molding production of pipe fittings, and more specifically relates to a method for improving the performance of a heat oven for rigid PVC-U pipe fittings. Background technique [0002] With the widespread application of PVC-U upper and lower water supply and drainage pipes for construction, the demand for matching PVC-U pipe fittings is also increasing, and has been developed rapidly. The corresponding national standards not only classify pipe fittings, but also Corresponding regulations are made in terms of appearance and physical and mechanical properties. Due to the complex shape and variety of PVC-U large-diameter pipe fittings, it was mainly welded and formed by hand at first. In recent years, with the development and growth of my country's injection molding industry, large-diameter pipe fittings have realized direct injection molding products. In view of the characteristics of large weight and long...

AI Technical Summary

Problems solved by technology

When the structure is used to form PVC-U large-diameter pipe fittings by the injection molding machine, there will often be poor appearance defects such as white injection marks and butterfly spots, as well as physical and mechanical defects such as stress concentration in the gate and unsatisfactory bonding strength of the weld seam.

Images