According to customer's requirement, the mold was designed into 4 cavities mold. It was cooled by cold water. The part was foldable box. The concave shape of the cover was designed in the cavity side of the mold. In that case, the cover was easy to stick in the cavity side when opening the mold. The part should be damaged and deformed.
To solve the problem, we designed a ejecting system in the cavity side of the mold. The ejecting system was actuated by two hydraulic cylinder. In this way, the cavity side was too thick. And the sprue was very long. It was bad for injecting. The cycle time of production increased. And more plastic material was wasted. The cost was increased a lot. So we suggest customer to add a hot runner system in the mold.
The tip gate of the hot nozzle was directly on the part. So no plastic material was wasted on the cold runner and the cycle time was short. It was about 38 seconds. The link connected cover and frame, which's thickness was very critic. If it too thick, it was hard and very difficult to fold it. If it was too thin, it was difficult to fill full when injecting. And it was easy to break during in use. Also its lifetime was short. It can't meet the requirement of the part.