Foam packaging of water and volatile matter from two aspects, one is left in the production process and before molding in the transport, the tube during the absorption; Second, foam the process of chemical reaction generated by the by-product. If the moisture and volatiles in the foam package will promote the mobility, easy to produce the material, the molding cycle increases, the shrinkage increases, the plastic parts are prone to bubble, foam the group loose, deformation warping, ripple and other defects. Foam packaging in the moisture content and volatile matter is too small will also cause the flow down, forming difficulties, but also not conducive to the ingot.
Foam packaging in a certain temperature and pressure conditions with mobility, fluid care in the straight tube flow in the form of laminar and turbulent two. foam Laminar flow is a layer of layers of adjacent thin liquid in the direction of the external force of the slip. The mass of the foam packaging fluid moves along many of the flow layers parallel to each other, and the same stream layer moves forward at the same speed, and the velocity of each stream is not necessarily equal, but there is no obvious interaction between the flow layers. Also known as "turbulence", the particle in addition to the movement of the fluid, the speed of the size of the point, the direction of the time with the strengthening of the flow line was chaotic state. The laminar flow and turbulence are determined by the critical Reynolds number (Re). In general, when the m is between 2100 and 4000, the laminar flow is more than 4000, and the turbidity is less than 4000. During the molding process, 10, the foam package dispersion Reynolds number will not be greater than 2100, so the flow is basically a laminar flow.
Foam packaging machine, also known as foam molding machine, is a machine, foam electricity, liquid integration of equipment, the overall structure of the more complex type of system are more, of which screw-type foam packaging machine should be the most extensive class of drugs The
According to the structure and function of the different, foam generally the foam packaging machine is divided into fuselage, plastic and sand ripper device, Taiwan mold mechanism (installed hydraulic system, lubrication system, cooling system, electrical and control systems, safety protection devices.
The preparation of plastic
Powder, pellets are the same in composition, but the degree of mixing, foam plasticizing and subdividing is different. The preparation is mainly divided into two stages, namely the preparation process of powder and the plasticizing process of powder. The preparation process of the powder material includes the preparation of the raw material and the mixing of the raw materials in two steps. Preparation of raw materials are mainly raw materials, pretreatment, weighing and transportation. The mixing of raw materials is only a simple mixture, foam the raw materials will be weighing according to the polymer, stabilizer, foam colorants, fillers, lubricants and other additives into the mixing device, so the powder preparation process can be expressed as follows: Resin + Auxiliaries A Pretreatment One Weighing One Conveying an Early Mixing Powder
The preparation of the pellets is made by using the prepared powder, foam after one step of plasticizing and granulating, the process is as follows: powder a plastic (or fly refining) a grain of a pellet
Plasticization or plasticization is the use of mechanical shear and friction heat to melt the polymer, shear mixing and get rid of volatile matter, foam and break the condensate cavity particles, foam so that mixing more uniform. Masticated and then crushed or chopped into pellets for preparation. Pellets are more conducive to foam packaging forming a consistent product.
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