The runner system design has several wrong concepts
Even if the mold design of an injection machine can meet the performance requirements of the product at the lowest cost, it may become uneconomical due to unreasonable runner design.Before the establishment of the runner system, people could design various gate and runner through the CAD program. Once the runner system was completed, the reconstruction work was very limited.
In the past, people had several wrong concepts about reasonable runner design.System. For example, for the cold runner think the runner, the greater the molten material into the cavity, the faster this effectively means that quench cycle longer, injection and machine volume requires a larger size, so that produce more of the scrap, rework cost and the increase of pollution;The area of the projection becomes larger, which requires a greater modulus of convergence, etc.In order to get higher benefit, people have to invest a lot of manpower and material resources to reconstruct the mould, runner and cavity.It is much easier to design a reasonable die at the beginning with as many efficient methods as possible.
Hot runner molds have been in large-scale industrial production since the 1960s and have become more common in the past decade.The advantage of the hot runner system is that it eliminates the cold runner material and prevents the plastic from cooling during the process from the nozzle to the mold cavity, thus shortening the cycle.Other advantages include increased volume, reduced injection pressure, reduced raw material requirements and improved gate appearance.However, the heat channel is not suitable for some plastics and some types of products