Molding Technology of Composite Materials-SMC Moulding.
Sep 06, 2019
The abbreviation of SMC (Sheet Molding Compound (sheet molded plastic) is to cut and cut the sheet according to the requirements of product size, shape, thickness, weight, etc., and then stack the cut material into the heated metal mold cavity. The process of curing and molding in a predetermined way of pressing.
Key words in the above introduction:
Sheet: the sheet used in the traditional SMC process is composed of short-cut fiber, resin and filler. Now HRC has the molding process of CF-SMC, which is obtained by hybrid processing of continuous carbon fiber and short-cut fiber.
CF-SMC molding process is to prepare composite parts with complex shape and high dimensional precision by different forms of hybrid processing of continuous carbon fiber and short-cut fiber. Here, the continuous fiber as a reinforcement makes up for the mechanical deficiency of the short-cut fiber, achieves the purpose of local reinforcement, and is far superior to the traditional SMC preparation technology in mechanical properties. It is suitable for the production of semi-structured automobile parts with large batch, high repeatability and complex structure.
Cutting: the above sheets will be preserved in rolls, design dimensions according to product requirements, set cutting bed parameters, and cut to obtain sheets that can continue to be processed.
Superposition: according to the product design requirements, a number of cut sheets are stacked to obtain the curing molding of the molding material to meet the thickness requirements: the stacked sheet is put into the mold, and the temperature, pressure and time are controlled. To make it solidify, we string the above keywords together to get the basic technological process, such as the following figure: there are many advantages of SMC molding process. For example, it has the advantages of simple operation, easy automation, short beat (3-5min), smooth surface and complex structure, and so on. In addition, the SMC molding process is used to obtain the products. Its performance is also excellent: excellent electrical insulation, mechanical properties, thermal stability, chemical corrosion resistance. SMC process is not a new composite molding process, it has appeared in the 1960s, after more than half a century of development, constantly updated and optimized. Now it is widely used in automobile industry, construction industry, communication engineering, electronics, electrical and other industries. Among them, in the automobile industry, developed countries have long had a large number of application cases. With the rapid development of the new energy vehicle industry in recent years, the demand for lightweight vehicles is becoming more and more obvious. Local automobile manufacturers are also carrying out the application of large quantities of SMC molded products. Includes: internal and external accessories, such as front and rear bumpers, body skirt, spoiler, etc., body panels and body structures, such as body inner panel structure and door structure, side circumference, machine cover inner plate, It is worth mentioning that the materials and production processes used in the production of SMC promote each other, and the overall development trend is low density, low mold pressure, etc., such as the inner plate of the tail door and other parts with special performance requirements, such as engine cover, battery shell, etc., it is worth mentioning that the materials and production processes used in the production of Tailgate promote each other. Among them, low molding pressure refers to the pressure needed in the curing process, and low density refers to the properties of materials. The direct result of low-density SMC is to continue to reduce weight without sacrificing mechanical properties and surface quality.
Let's take a look at the actual application of the product case:
HRC's CF-SMC products on display at 2019 JEC World.
(the series was shortlisted for the JEC Innovation Award in 2019 and last week won the "Top Ten innovative Technologies" Award in the 2019 Gold Editor Award.)