Molded shaping
The principle of compression molding involves adding a specific quantity of molding material into a preheated mold, then heating and pressurizing to solidify and shape plastic products. The basic process includes placing a predetermined amount of pre-processed molding material into a preheated mold, applying high pressure to fill the mold cavity. Under specific pressure and temperature, the molding material gradually solidifies, and then the product is removed from the mold, followed by necessary auxiliary processing to obtain the final product.
2. Molding Process Flow
The molding process is mainly divided into two stages: preparation before pressing and the pressing stage.
3. Molding Equipment
(1)胶浸机
The main equipment for producing adhesive tape is the adhesive immersion machine, which consists of several parts including the fabric feeding frame, heat treatment furnace, adhesive immersion tank, drying chamber, and traction roller. Depending on the placement of the heat treatment furnace and drying chamber, they can be categorized into horizontal immersion machines and vertical immersion machines.
(2) Pre-impregnated Material Unit
The equipment used in this method includes cutting machines, kneading machines, and tearing machines. Common types of cutting machines are punch presses, abrasive disk cutters, three-roller cutters, and single-rotary knife roll cutters. The function of the kneading machine is to thoroughly mix the resin system with the fiber system uniformly. The mixing blades are generally in the Z-paddle structure. During the kneading process, the main parameters controlled are the kneading time and the viscosity of the resin system. Sometimes, a jacket with hot and cold water is installed in the mixing chamber to control the mixing temperature. The longer the mixing time, the greater the fiber strength loss. In some resin systems, excessive kneading time can even cause significant thermal effects. Short mixing times result in uneven mixing of resin and fiber. Improper control of resin viscosity affects the uniform wetting and penetration speed of the resin into the fibers and can also impact fiber strength.
The main function of the tearing machine is to fluff up the mass of material after compaction. The tearing machine consists primarily of an infeed roller and a pair of tearing rollers, which fluff up the incoming material mass through the reverse movement of the tearing rollers.
(3) Sheet Molding Compound (SMC) Molding Line
A complete SMC (Sheet Molding Compound) assembly typically consists of 7 main components: the frame, conveyor system, PE film supply unit, scraper, glass fiber cutter, dipping and compaction units, and winding device, along with 3 essential auxiliary systems: the glass fiber yarn rack, resin slurry preparation and feeding system, and static eliminator.
(4) Press Machine
Press machines are the main equipment for mold forming. Their function is to provide the pressure required for shaping and the demolding force needed to remove the product when the mold opens, and most are now hydraulic presses.
