plastic stool mould classification and common plastics […]
plastic stool mould classification and common plastics
First, the classification of plastic mold
1, based on injection molding materials, can be divided into:
A, thermoplastic injection mold;
B, thermosetting plastic injection mold;
C, elastomer plastic injection mold (such as rubber silicone mold);
D. Structural foam plastic injection mold;
The injection mold can be divided into two-plate molds and three-plate molds.
Second, the most commonly used one is thermoplastic injection mold
1. Thermoplastic characteristics:
Such plastics soften upon heating, and when the temperature rises to a certain extent, they are in a molten state, becoming a flowable viscous fluid, and a shaped product can be formed by means of a mold and a pressure, and the formed shape can be maintained after cooling. When heated again, it can be softened, melted, and reshaped. It has only physical changes during the heating and cooling process without chemical changes. Usually most of the commonly used plastics belong to this type, and the characteristics of plastic products determine whether to open the standard of injection molds.
2, Thermosetting plastic features:
These plastics soften when first heated, solidify after cooling and appear rigid. It does not soften when reheated, and it decomposes when the temperature rises to a certain level. This is because the plastic changes in the plastic injection process, the linear molecules become body-shaped molecules, and the resin transforms into a shape that neither softens nor dissolves, no longer changes, no longer has plasticity, and its texture is generally hard and brittle. Commonly used thermosetting plastics are PF, UF, MF, EP, UP, and the like.
3, According to the use of plastics
A, general plastic
This type of plastic is widely used, with a large output, accounting for about three-quarters of the total output of plastics. The price is low, and it is used to make small-sized daily necessities, such as TV casings, telephone casing molds, and home appliance molds. Commonly used plastics are ordinary ABS, PP, PE, PVC, PS, etc.
B, Engineering plastics:
General-purpose plastics are inexpensive, but their mechanical properties, temperature resistance and corrosion resistance are difficult to meet the needs of structural materials used in certain engineering and equipment. For this reason, engineering plastics have emerged as a result of high mechanical strength and rigidity. It can replace some steel or non-ferrous materials, and can manufacture mechanical parts with complicated structure or engineering stress parts. Many of them use more than the original materials. Commonly used engineering plastics are POM, PC, PA, PBT, etc.
C, Special plastics
This plastic has some unique functions and can be used in special occasions such as magnetic conductive plastics, medical plastics, pearlescent plastics, photosensitive plastics, etc.