Standard Parts of Commonly Used Molds
Molds are an integral part of the manufacturing of a wide variety of products and parts. While the design and production of molds is highly specialized and complex, it is necessary to understand the basic components used in the construction of molds. In this article, we will look at the standard parts of commonly used molds.
Hot Runner: A hot runner is an essential part of all thermoplastic injection molds. It is responsible for the delivery of molten plastic into the desired shape of the part. It is comprised of a hot runner block, several runners and their associated nozzles. The block itself is composed of several separate sections where the nozzles can be connected. The material to be injected flows through these paths of plastic towards the perfect part shape.
Runner System: The runner system is a method of delivering the plastic material from the hot runner block to the cavities in the mold. It consists of plastic runners, gates, and other necessary components. The runners, which are usually made from plastic, are connected to the hot runner block and the mold respectively. They are designed in such a way so as to regulate the amount and flow of plastic into the mold.
Cavity and Core: The cavity, also known as the die cavity, is the shaped area of the mold where the desired shape of the plastic parts is formed. The core is part of the mold, which concentrates on the internal features of the plastic parts. The cavity and the core are usually divided into several sections, which are then connected through a runner system.
Sprue Bushing: The sprue bushing is a cylindrical part, which is bolted onto the face of the aluminum plate on the injection mold. It acts as a junction between the injection system of the plastic machine and the cutting cavity of the die. The sprue bushing is essential for the injection of plastic material into the die cavity. In addition, it also prevents plastic from leaking out of the cutting cavity.
Stripper Plate: It is a flat plate that is placed on the highest part of the mold. Its main purpose is to assist with the quick and safe ejection of the finished parts. The ejector pins are placed around the perimeter of the stripper plate and are used to push the part out of the cutting cavity once it has been cooled down.
Ejector Pins: Ejector pins are the devices used to push the finished parts out of the cutting cavity once the molding process has been completed. They usually come in different shapes and sizes, depending on the size and shape of the parts that are being manufactured.
Mold Base: The mold base is the frame of the injection mold. It provides support for the several components like the hot runner, the cutting cavity, and the stripper plate. It is usually made from steel, aluminum, or other strong metals.
These are the standard parts of commonly used molds. While there are endless variations based on the type of mold being produced and the complexity of the parts being manufactured, understanding the basics of each of these components allows inventory managers and shop floor personnel to readily address issues related to molds and their components. With the proper maintenance, these components can last for many years and produce consistent parts with minimal downtime.
