Features of Insert Molding Technology

Insert molding refers to the molding method in which the mold is filled with pre-prepared inserts of different materials and then injected with resin, and the molten materials are joined with the inserts and cured to make integrated products.

Injection molding on the substrate refers to the method of injection molding parts embedded on the local surface of the metal sheet.

These two molding methods are essentially the same. Their characteristics are as follows.

1. The combination of the ease of molding and bending of resin and the rigidity, strength, and heat resistance of metal can make complex and delicate metal-plastic integrated products.

In particular, the combination of the insulating properties of resin and the electrical properties of metal enables the molded products to meet the basic functions of electrical products.

3. The prior molding combination of multiple inserts makes the post-engineering of the product unit combination more rational.

4. Insert products that are not limited to metal, but also include cloth, paper, wire, plastic, glass, wood, wire coils, electrical parts, etc.

5. For rigid molded products and flexible molded products on rubber gaskets, the complex work of arranging the sealing coils can be eliminated by injection molding on the substrate to make integrated products, making it easier to automate the post-process assembly.

6. Since the molten material is joined to the metal insert, the gap between the metal insert can be designed to be narrower than that of the press-in molding method, and the composite product can be molded with higher reliability.

7. Select the appropriate resin and molding conditions, even for products that are easily deformed and broken (such as glass, coils, electrical parts, etc.), the resin can be sealed and fixed.

8. Select the appropriate mold structure, the insert can also be completely sealed into the resin.

9. After the insert is formed, it can also be made into products with hollow grooves after core removal.

10. The combination of the vertical injection molding machine, robot and insert molding device can realize automatic production.

 

Automatic insert molding system design considerations

1. Metal insert molding is prone to uneven molding shrinkage, so the limit test of shape and dimensional accuracy of important parts should be done beforehand.

2. The metal insert is easily deformed and displaced during the injection process, so the mold composition and the design of the mold shape that can easily keep the metal insert should be fully considered. For products whose insert shape cannot be changed, prior testing is indispensable.

3. In the case where the metal inserts are arranged separately and a conveyor is used, the contact between the metal inserts and between the inserts and the vibrating ball may cause slight damage to the surface of the inserts and affect the product quality. The quality tolerance range should be confirmed in advance.

4. The jaggedness, warpage, material thickness difference, diameter difference, and thickness difference caused by the gilding process of the metal insert should be measured in advance. On this basis, the design of the supporting design of the automation device and the design of the mold structure should be carried out.

5. Predictable matters such as mold gate position, molding cycle, and other constraints on mold structure should be solved or improved in advance as much as possible.

6. It should be confirmed whether the metal insert needs to be preheated or dried. The purpose is to ensure the quality of the product and the stability of the molding.

7. Various testing devices are installed in the mold to ensure the stability of molding action under the influence of heat, force, vibration, and other environmental conditions, and it should be confirmed whether they are used.

8. To avoid the accumulation of metal inserts and fine pieces of molded products in the mold cavity, air-blowing devices can be installed if necessary.

9. Due to the high investment cost of the system equipment, it is necessary to consider whether the production capacity can be ensured after the operation of the equipment before adoption. In the case of using a dedicated machine, it is necessary to ensure that the product can be produced continuously for several years without any form of renewal.

10. When using a general-purpose machine, it is necessary to confirm how many combinations of multi-species and low-volume inserts can be produced. If it is not possible to guarantee mass production as a whole, it is difficult to recover the fixed assets of each product. In this case, it is necessary to replace a part of the machine to meet the requirement of variety renewal within a certain range.

11. There are various factors and technical decisions that determine the molding rate, productivity, and cost of the insert, such as the accuracy of the metal insert, the shape of the insert, whether the mold is conducive to insert molding, and the shape of the molded product.

12. The effective combination of injection machine, mold, and automation device and how to function in a short time is the key to the automatic insert molding system. It is recommended to consult with a manufacturer who has considerable experience and track record to select one.