Characteristics of insert molding process

Overmolding and Insert Molding refers to the molding process of inserting a pre-prepared insert of a different material into the mold and then injecting resin, so that the molten material and the insert are bonded and solidified to form an integrated product. Out-sert molding refers to the process of inserting the injection molded part on a part of the metal plate surface. The above two molding processes are essentially the same. Its characteristics are as follows.

1. The combination of the easy molding and bendability of the resin and the rigidity, strength and heat resistance of the metal can be used to make a complex and delicate metal-plastic integrated product.
2. In particular, the combination of the insulation of the resin and the electrical conductivity of the metal can make the molded product meet the basic functions of electrical products.
3. The pre-molding combination of multiple inserts makes the post-processing of the product unit combination more rational.
4. The insert products are not limited to metal, but also include cloth, paper, wire, plastic, glass, wood, coils, electrical parts and many other types. 5. For rigid molded products and curved elastic molded products on rubber sealing pads, after being made into an integrated product through injection molding on the substrate, the complicated operation of arranging the sealing ring can be omitted, making the automation combination of the subsequent process easier. 6. Because it is a combination of molten material and metal inserts, the metal insert gap can be designed to be narrower than the press-in molding method. 7. Selecting appropriate resin and molding conditions, even for products that are easy to deform and break (such as glass, coils, electrical parts, etc.), they can be sealed and fixed by resin. 8. Selecting appropriate mold structure, the insert product can also be completely enclosed in the resin. 9. After the insert is molded, it can also be made into a product with a hollow groove after the core hole is removed. 10. The combination of vertical injection molding machine, robot, insert product arrangement device, etc., can realize automated production in most insert molding projects. Precautions for the design and selection of automatic insert molding systems 1. Metal insert molding is prone to uneven molding shrinkage, so the shape and dimensional accuracy of important parts should be tested in advance. 2. Metal inserts are prone to deformation and displacement during injection, so the mold structure and the design of the mold shape that is easy to maintain the metal insert should be fully considered. For products where the shape of the insert cannot be changed, prior testing is indispensable. 3. When the metal inserts are arranged separately and a conveyor is used, the contact between the metal inserts and the inserts and the vibrating balls will cause slight damage to the surface of the inserts, affecting the quality of the product. The permissible limit range of quality should be confirmed in advance. 4. The serration, warpage, material thickness difference, diameter difference, thickness difference caused by the metal insert due to stamping processing should be measured in advance. On this basis, the matching selection design of the automation device and the design of the mold structure are carried out. 5. Foreseeable matters that restrict the mold structure, such as the mold gate position method and the molding cycle, should be solved in advance as much as possible or have corresponding improvement measures. 6. It should be confirmed whether the metal insert needs to be preheated or dried. The purpose is to ensure product quality and molding stability. 7. The various detection devices installed in the mold are used to ensure the stability of molding action when the mold is affected by environmental conditions such as heat, force, and vibration. It should be confirmed whether they are used. 8. In order to prevent the accumulation of fine pieces of metal inserts and molded products in the mold cavity, an air blowing device can be assembled if necessary. 9. Due to the high investment price of system equipment, it is necessary to fully consider whether the production volume can be guaranteed after the equipment is put into operation before adoption. When using a dedicated machine, it is necessary to ensure that the product can be continuously produced without form updates for several years.

10. When using a general-purpose machine, it is necessary to confirm how many combinations of multi-variety and small-batch inserts can be produced. If large-scale production cannot be guaranteed as a whole, it is difficult to recover the fixed assets of each product. In this case, it is necessary to replace some devices to adapt to the requirements of variety updates within a certain range. 11. The factors that determine the insert molding rate, productivity and molding cost conditions include the accuracy of metal inserts, the shape of inserts, whether the mold is conducive to insert molding and the shape of molded products, and other factors and technical decisions. 12. The effective combination of injection machines, molds, and automation devices and how to make them function in a short time are the key to determining the automatic insert molding system.