Characteristics and design of FRP pultrusion mold
which is similar to the shape and size of the molding cavity according to the configuration of the profile section, and then enter the fiberglass drawing Extrusion die, so as to ensure the uniform yarn content of the product cross section.
Frp Pultrusion Mold:
The ratio of the cross-sectional area of the forming die to the cross-sectional area of the product shall be generally greater than or equal to 10, so as to ensure that the die has sufficient strength and rigidity, and the heat distribution is uniform and stable after heating.
The length of the pultrusion die is determined by the speed of the drawing process and the curing speed of the resin gel, so as to ensure the degree of demoulding and curing when the product is pulled out. Generally, the surface of die steel is chrome plated, and the surface of die cavity is required to be clean and wear-resistant, so as to reduce the friction resistance during pultrusion and improve the service life of glass die.
The key points of FRP pultrusion die design are as follows:
The design of FRP pultrusion die directly affects the traction force used in pultrusion process. If the traction resistance is too large, it is easy to cause mechanical accidents.
For example, a section of mold cavity is roughened, resulting in the surface is not smooth enough, and the traction resistance increases, resulting in the skid between the track and wheel of the tractor, the resin retention time in the mold is too long and early curing, and the tractor can not be pulled.
It is necessary to shut down the machine for mold removal and even repair the mold. It brings great inconvenience to continuous production.
According to the structural form, the forming mould can be divided into integral forming mould and combined forming mould. The integral die is made of integral steel, which is generally applicable to bars and pipes.
The combined forming mould is composed of upper and lower moulds.
This type of mould is easy to process and can produce all kinds of profiles, but there are traces of parting line on the surface of products.
Core mold is used for hollow products.
One end of the core mold is fixed, the other end is cantilevered into the space formed by the upper and lower mold, and together with the upper and lower mold, the cross-section shape required by the product is formed.
In order to reduce the resistance of the core mould during demoulding, the tail of the core mould is processed into a taper of 1 / 300 ~ 1 / 200, and the larger core mould should be considered to adopt the heating device of the core mould.
5t caterpillar pultrusion machinery