Sandwich injection molding, as an advanced plastic molding technology, forms plastic products with special structure and properties by injecting plastic materials with different properties in the same mold. This technology not only improves the strength and stability of the products, but also reduces the material cost, which is widely used in many fields such as automotive, aviation, electronics, household and so on. This report manual aims to comprehensively explain the process content of sandwich injection molding, including basic principles, material selection, mold design, process parameters, actual cases and data, so that laymen can clearly understand the connotation and application value of sandwich injection molding.
1. Basic principles of sandwich injection molding
Sandwich injection molding, also known as sandwich injection molding, is a kind of co-injection technology, through the same mold were injected into the inner and outer layers of different properties of the plastic material, the formation of plastic products with a sandwich structure. This technique can realize the complementary advantages of the inner and outer materials and improve the overall performance of the product.
2. Material selection and matching
Outer layer material: Usually choose plastic materials with high strength, high wear resistance, high gloss and other characteristics, such as ABS, PC/ABS, PMMA, etc., to improve the appearance quality and durability of the product.
Inner layer materials: according to the specific needs of the product, choose plastic materials with specific properties, such as fiberglass filler, conductive materials, foam materials, etc., in order to improve the strength, stability, sound insulation and vibration damping performance.
Material matching principle: the inner and outer materials should have good adhesion and compatibility to avoid delamination or peeling phenomenon in the injection molding process. At the same time, the difference in shrinkage rate of the material should be considered to ensure the dimensional accuracy of the product.
3.Mold Design and Manufacturing
Mould structure: sandwich injection molds usually adopt single-cavity structure with two gates inside and outside, which are used for injecting inner and outer materials respectively. The mold design should ensure the uniform distribution and good combination of the inner and outer materials.
Gate design: The location, size and shape of the gate should be reasonably designed according to the fluidity of the inner and outer materials and the injection capacity of the injection molding machine to ensure the smooth injection of the material and the uniform filling of the product.
Cooling system: The mold should be designed with a reasonable cooling system to ensure that the product is cooled and cured quickly during the injection process to avoid deformation and shrinkage.
4. Process parameters and optimization
Injection temperature: According to the melting point and fluidity of the inner and outer materials, the injection temperature should be set reasonably to ensure the smooth injection and full melting of the materials.
Injection pressure: The injection pressure should be moderate to ensure the full filling of the material and avoid the damage of the mold and the deformation of the product.
Injection speed: The injection speed should be reasonably adjusted according to the fluidity of the inner and outer materials and the structure of the mold to ensure the uniform distribution of the material and the good quality of the product.
Holding time: The holding time should be long enough to ensure that the product does not shrink and deform during the cooling process.
5.Actual cases and data
Case 1: sandwich injection molding of automotive interior parts
An automobile manufacturing company adopts sandwich injection molding technology to produce automobile interior parts, the outer layer is made of high glossy ABS material, and the inner layer is made of glass fiber filler. Through the optimization of mold design and process parameters, a good combination of inner and outer materials and uniform filling of the product were achieved. After testing, the interior parts have excellent properties such as high strength, high abrasion resistance, high gloss, etc., and the cost is reduced by about 20% compared with the traditional injection molding process.
Case 2: electronic product shell sandwich injection molding
An electronics manufacturer uses sandwich injection molding technology to produce cell phone shells, the outer layer of PC / ABS material, the inner layer of conductive materials. Through precise control of the injection temperature, pressure and speed and other process parameters, to achieve a close bonding of the inner and outer materials and the uniform distribution of the product. After testing, the cell phone shell has excellent conductive properties and drop resistance, and good appearance quality, loved by consumers.
6. Advantages and applications of sandwich injection molding
Improve product performance: Through the complementary advantages of the inner and outer materials, the strength, stability, sound insulation and vibration damping of the product can be significantly improved.
Reduce cost: the inner layer material can be recycled or low-cost materials, reducing material costs; at the same time, because the sandwich injection molding technology can achieve efficient production, reducing production costs.
Broaden application fields: sandwich injection molding technology can be used in automotive, aviation, electronics, household and other fields to meet the special needs of different products.
Conclusion
As an advanced plastic molding technology, sandwich injection molding realizes the improvement of product performance and cost reduction through the complementary advantages of inner and outer materials and precise control of process parameters. This report manual comprehensively describes the process content of sandwich injection molding, including basic principles, material selection, mold design, process parameters, actual cases and data, etc., which provides laymen with clear knowledge and understanding. With the continuous progress of technology and the broadening of application fields, sandwich injection molding technology will have a broader development prospect.
