Sculpture Mold
By first making the fiberglass sculpture mold, the fiberglass products are produced to meet the needs of people in real production and life.
1. Fiberglass sculpture plaster mold
The advantages of plaster models are heat resistance, low price, small thermal conductivity, and good reproducibility. Generally used to make master molds. It is easy to manufacture and suitable for large products. But it is not durable, afraid of impact, and slow to dry. It is mostly used for single products and products with complex lines, such as reliefs, etc. The gypsum used is mostly hemihydrate gypsum or plaster of paris. Like the cement mold, bricks and wood can be used as the skeleton foundation, and then covered with a gypsum layer. In order to improve rigidity and prevent cracks, sufficient fillers can be added to gypsum, such as adding quartz, which can reduce shrinkage and cracks, and adding cement (gypsum:cement=7:3) to increase strength. It was also proposed to add an appropriate amount of latex to gypsum and dilute it with water to make a mold, which has good strength and does not powder.
The plaster mold can be used as the master mold of the low melting point alloy mold, and the alloy is cast in the hot state. When using a gypsum master mold to remake a plaster mold (sub-mold), the surface of the master mold should be coated with a separating agent, such as potassium soap solution, transformer oil, cooking oil, 20% stearic acid + 80% kerosene, or gasoline + vaseline, etc. The gypsum mold can be repaired with a pen dipped in gypsum powder. The plaster mold drying process is: (60-120) ℃/(4-5) L, lightly polish with metallographic sandpaper after natural cooling, and then bake (100-150) ℃/(8-10) L, ( 200～230)°C/(20～24)L.
2. Fiberglass sculpture rubber mold
Rubber molds are generally made of silicone rubber and polyurethane resin. They are used to make reliefs, round sculptures and various shapes with complex shapes. They are not used alone. They must be combined with plaster molds and other materials. Or a certain part that overlaps and cannot be directly demoulded, because it has a certain degree of softness, after the outer mold is demoulded, it can be pulled out at will, such as lions, dragons and other animals or Bodhisattvas and cartoon characters. Use this method when the batch size is small.
3. FRP sculpture paraffin film
Paraffin film is used for products with small quantity or complex line shape, which are not easy to release. For example, to manufacture an integral elbow, including a 90° elbow, two elbow Huffs can be used as the master mold. After the inner 90° cavity is filled with paraffin, after the Huff master mold is removed, the paraffin core is slightly After finishing, the outer wall is covered with glass fiber reinforced plastic, heated after solidification, so that the paraffin wax melts and flows out, and a whole glass fiber reinforced plastic product can be obtained.
In order to reduce shrinkage deformation and increase rigidity, about 5% stearic acid can be added to paraffin. It is easy to manufacture, easy to demould, and the paraffin can be used repeatedly. But the accuracy is not high. Another usage: when rolling the pipe by wet method, the steel pipe can be dipped into the paraffin wax melted at 70-80°C, lifted up and cooled, then dipped, and repeated until the required thickness is reached, and the surface can be slightly trimmed to coat FRP, in order to prevent the paraffin from cracking, a small amount of butter can be added to the wax. It can also be coated with a thin layer of cellophane on the outside of the wax as a mold core. After the glass fiber reinforced plastic is solidified, it can be demoulded by heating the steel pipe to melt the paraffin wax.
4. Concrete mold
Concrete molds are mostly used for products with regular lines and few repeated uses, such as spiral, wave, round, arched or three-dimensional trough products. Low cost and good rigidity, the foundation can be built with bricks, then covered with cement mortar, polished, puttyed, and then polished, polished, painted and other measures. This cement mold can be directly used to produce FRP products, and can also be used to remake the master mold of FRP molds. Cement molds dry slowly, and even under normal conditions, it takes more than a week for surface construction such as painting.
5. Fiberglass sculpture wood mold
Wooden formwork is mainly used for large-scale products with relatively straight lines. Wooden molds can be directly used as forming molds for FRP products, and can also be used as transition master molds for remaking FRP molds. The wood used to make molds includes red pine, ginkgo, fir, etc., which require a water content of 15%, and are not easy to shrink and deform, and have no knots. After the wooden mold is made, it can be coated with resin (surface putty) with a thickness of 0.2 to 0.3, and then polished four times with water sandpaper from coarse to fine, and polished with 800# or 1000# sandpaper for the last time, and then coated with polishing paste Polish with a polisher, then apply paraffin, and the wooden mold is ready. It is also possible to directly paint and cover the wooden mold to make the wooden mold.
6. Fiberglass sculpture metal mold
Metal molds, especially steel molds, are generally used for molded products with small sizes and large batches. For example, stainless steel plates with smooth surface when making FRP flat plates; angle steel and channel steel are used when making profiles. Because molded products not only need to be pressurized, but also heated. There are also large products for uncomplicated shapes. Although brass is a common metal, it is easily corroded by resin additives and will have an adverse effect on resin curing, so it should not be used unless the working surface has been plated with chrome or other metals. Manufacturing and processing of metal molds is difficult and costly. There is also a low melting point alloy mold whose composition is: Zn93%, Al4%, Cu3%, Mn0.5%, when the temperature is 50-80 °C, the alloy hardness (HB) is about 100. It has good fluidity and poor wear resistance, and is suitable for manufacturing plastic molding cavities with complex shapes and fine patterns, and the operating temperature is generally >80°C. Another low melting point metal is 58% bismuth, 42% tin, melting point 135°C. The advantage of the low melting point alloy mold is that the mold making cycle is short, the process is simple, and it can be used repeatedly.