What Is Plastic Fabrication?

Also known as plastic molding. It is a general term for various processes for converting synthetic resins or plastics into plastic products. It is a large production sector in the plastics industry. Plastic processing generally includes compounding, forming, machining, joining, modifying, and assembling plastics. The last four steps are performed after the plastic has been formed into a product or a semi-product, which is also called secondary plastic processing.

Plastic processing

Plastic processing has developed with the development of synthetic resins. It and

The Chinese government has a series of promotion policies for the development plan of the plastics industry and will vigorously promote the steady and sustainable development of the entire industry

In order to deal with the impact of the international financial crisis, implement the government's general requirements for maintaining growth, expanding domestic demand, and restructuring the structure, ensure the stable development of the light industry, accelerate structural adjustment, and promote industrial upgrading. Plan among the three key industries.

As one of the pillar industries of the light industry, the total industrial output value, total assets, number of employees, and export value of the plastic products industry have accounted for more than 10% of the total of the light industry. Therefore, the adjustment and revitalization of the plastics processing industry is directly related to the revitalization and development of the entire light industry and occupies a pivotal position.

In the process of responding to the international financial crisis, the central and local governments have adopted a series of powerful measures to help enterprises solve their difficulties and overcome difficulties with them.

The main measures are as follows: First, support key enterprises to "go global" in various ways, and set up logistics centers and distribution centers in major sales markets. The second is to establish economic and trade cooperation zones and actively promote the construction of overseas industrial parks and economic and trade cooperation zones. The third is to continue to support the construction of specialized foreign trade markets, which are targeted at Southeast Asia, Central Asia,

Processing shrink marks

Plastic processing shrinkage is one of the most common problems in plastic processing. For plastic products with high surface quality requirements, shrinkage is even more difficult. Therefore, with the continuous improvement of plastic processing technology, it is imperative to minimize the problem of plastic processing shrinkage and improve product quality.

Shrinkage at thicker locations, such as ribs or protrusions, in plastic-processed injection-molded plastic parts is more severe than in adjacent locations, because thicker areas cool much more slowly than surrounding areas. Different cooling rates lead to the formation of depressions at the connection surfaces, which are familiar shrink marks. This defect severely limits the design and molding of plastic products, especially large thick-walled products such as beveled housings for televisions and display housings. In fact, shrinkage marks must be eliminated for products with strict requirements such as household appliances, while some products with low surface quality requirements, such as toys, are allowed to have shrinkage marks in plastic processing.

There may be one or more reasons for the formation of shrinkage marks in plastic processing, including processing methods, part geometry, choice of materials, and mold design. The geometry and material choice are usually determined by the raw material supplier and are not easy to change. However, there are many factors related to mold design that may affect the shrinkage of plastic processing. Cooling runner design, gate type, and gate size can have multiple effects. For example, small gates such as tube gates cool much faster than tapered gates. Premature cooling at the gate reduces the filling time in the cavity and increases the chance of shrinkage marks. For molding workers, adjusting the processing conditions is one way to solve the problem of plastic processing shrinkage. Filling pressure and time significantly affect shrinkage. After the part is filled, excess material continues to fill the cavity to compensate for material shrinkage. Too short the filling phase will lead to increased shrinkage and eventually more or larger shrink marks. This method of solving shrinkage in plastic processing itself may not reduce the shrinkage marks to a satisfactory level, but the molding workers can adjust the filling conditions to improve the shrinkage marks.

Plastic processing molding Plastic processing thermoplastics commonly used methods include extrusion, injection molding, calendering, blow molding and thermoforming, etc. Plastic processing thermoset plastics generally use compression molding, transfer molding.

The mechanical processing of plastic processing borrows plastic processing methods such as metal and wood to produce plastic products with very precise dimensions or small quantities. It can also be used as an auxiliary process for molding, such as sawing of extruded profiles. Because the properties of plastic are different from those of metal and wood, plastic has poor thermal conductivity, low thermal expansion coefficient and low modulus of elasticity. When the clamp or tool is pressurized too much, it is easy to cause deformation, and it is easy to melt when heated and stick to the tool on. Therefore, when machining plastics, the tools used and the corresponding cutting speed must be adapted to the characteristics of plastics. In addition, plastics can also be laser cut, punched and welded.

Plastic processing joining Plastic processing methods to join plastic parts are welding and bonding.

Surface modification of plastic processing Plastic processing hot stamping is to transfer the colored aluminum foil layer (or other pattern film layer) on the hot stamping film to the product under heat and pressure.

In plastic machinery processing, various plastic processing faults are often encountered. What kind of technical terms are used to express these faults more accurately in the plastic machinery industry? Let's analyze the technical terms of plastic processing faults one by one. .

1. Insufficient note: In plastic processing, the shape of the plastic part is incomplete and incomplete due to dissatisfaction with cavity filling.

2. Flash material flashing: During the plastic processing and molding process, it overflows into the gap between the mold clamping surface and leaves the remaining material on the plastic part.

3. Welding mark: a linear mark on the surface of the plastic part, which is formed by the injection and extrusion of several streams of material in the mold, and the fusion materials are not completely fused at the interface, and they cannot be welded together, resulting in fusion. Blotting affects the appearance quality and mechanical properties of plastic parts.

4, wave flow marks: due to the improper flow of molten material in the mold cavity, resulting in the surface of the plastic parts and the ring-shaped, spiral or cloud-like wave irregularities.

5, surface turbidity: refers to the surface of the plastic parts with void cracks and the resulting damage. The phenomenon that cracks occur outside or inside a plastic part due to prolonged or repeated application of stress lower than the mechanical properties of the plastic is called stress cracking; the plastic part suddenly bursts completely due to a constant load at a certain temperature under a certain temperature. This phenomenon is called stress cracking; cracks and ruptures that occur when certain thermoplastic parts are exposed to higher temperatures are called thermal stress cracking.

6. Fracturing: refers to the obvious cracks in one or more layers of reinforced material of laminated plastic that can be seen through the resin layer covered on the surface.

7. Wrinkle: A defect that causes cracking and obvious separation on the surface of the laminated plastic.

8. Wrinkle: During the plastic processing, the appearance of creases or wrinkles on the surface of the plastic part is defective.

9, cracking and whitening: the more obvious microcracks on the surface of plastic parts are called cracking, and frost-like microcracks similar to cracking are called whitening, and cracking and whitening are fine cracks without cracks. Environmental stress cracking occurs when plastic parts are exposed to certain chemical environments or under stress conditions.

10, silver silk pattern: the needle-like silver-white fine lines on the surface of the plastic parts along the direction of the flow.

11. Streaks: linear streak defects on the surface or inside of the plastic part.

12. Streaks: Mica flake-like dark spots on the surface of plastic parts due to poor dispersion or mixing of colorants and other reasons.

13, orange peel: the appearance of uneven appearance defects on the surface of plastic parts, such as orange peel.

14. Cell streak: refers to the cell layer in foam plastic that is very different from its inherent cell structure.

15. Black spots: During the plastic processing and molding process, the molten material is overheated and decomposed under high temperature and pressure conditions, resulting in black carbonized points on the surface of the plastic part.

16. White spots or bright spots: There are insufficiently plasticized particles in transparent or translucent plastic films, sheets or plastic parts, and white particles can be seen when transmitted by light. Such particles are called "fish eyes" ". If the material is opaque or colored, such particles are called white or bright spots.

17, pitting: regular or irregular small pits on the surface of the plastic parts, usually its depth and width are about the same.

18. Filler marks: obvious marks caused by the presence of fillers such as wood flour or asbestos in plastic parts.

19. Dark spots: dark colors appearing in the fabric-based laminate structure

People's Daily Online, Beijing, March 29 (Reporter Sun Boyang) Yesterday, ^{[1] The} Ministry of Industry and Information Technology announced the analysis of the economic operation of the plastics processing industry in 2012. According to the data released by the Ministry of Industry and Information Technology, from January to December, the total industrial output value of enterprises above designated size for plastic products has increased by 15.04% year-on-year, which is a slowdown compared to last year.

According to the data of the Ministry of Industry and Information Technology, in 2012, China's plastic product industry's output and total production and sales value increased steadily and showed a warming trend. According to statistics from the National Bureau of Statistics, compared with the previous year, the growth rate has dropped by 12.5 percentage points, and the growth rate has slowed down significantly. In the whole year, the sales output value increased by 14.95% year-on-year, and the production-sales ratio reached 98.17%, which was 0.13 percentage points higher than in 2011, and the production-sales ratio continued to maintain a high level. In terms of output, the output of plastic products in 2012 increased by 8.99% year-on-year. Among them, agricultural films increased by 7.74% year-on-year, foam plastics increased by 23.13% year-on-year; artificial leather and synthetic leather increased by 15.55% year-on-year, daily plastics increased by 14.43%, and other plastics increased by 7.26% year-on-year. Except for daily-use plastics, artificial leather, synthetic leather, and foam The year-on-year growth of plastics was higher than 10% compared to the previous year, and the growth of other product varieties was lower than 10% year-on-year. Among them, agricultural plastic films and other plastic products had the lowest growth rates, which were 6.75 and 21.33 percentage points lower than the same period of the previous year.

The Ministry of Industry and Information Technology said that in the second half of 2012, the foreign trade situation of the plastic products industry showed signs of recovery. According to the statistics of the General Administration of Customs, from January to December, the total value of imports and exports of plastic products in the country increased by 16.55% over the same period of the previous year. Among them, the export volume increased by 5.79% compared with the same period last year; the export value increased by 24.55% year-on-year. China's foreign trade export growth rate in 2012 (7.9%) was 16.65 percentage points, and export growth picked up. Exports accounted for approximately 23.91% of the country's total output of plastic products during the same period, indicating the importance of the export market in the entire industry. In 2012, the production of plastic products in China basically met the domestic market demand, which led to a continued decline in the growth rate of imports of plastic products. From January to December, the import volume of plastic products nationwide decreased by 3.46% compared with the same period of the previous year; the import value decreased by 0.46% year-on-year.