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Rapid prototye - Common structural materials PP,PE

Oct 19,20

Rapid prototye - Common structural materials PP,PE 

一,PP, known as polypropylene in Chinese, is one of the most commonly used plastics, known as hundred-fold glue.
1.The advantage of PP
1)Easy to match colors
2)Strong impact resistance, good toughness, not easy to break.
3)Non-toxic, tasteless, low density.
4)Good heat resistance, can be used in boiling water for a long time.

2.The disadvantage of PP
1)Forming shrinkage rate, forming size is easy to be affected by temperature, pressure, cooling speed, there will be different degrees of warping, deformation, thick and thin bend is easy to produce convex, so it is not suitable for manufacturing high dimensional precision requirements or easy to deformation defects products.
2)Insufficient rigidity should not be used as mechanical components.In particular, the gap on the product is very sensitive to stress, so the design should avoid the existence of sharp Angle gap.
3)Poor weather resistance.In the sun vulnerable to ultraviolet radiation and accelerate the aging of plastic, so that the products become hard cracking, fading dyeing or migration.
4)The surface treatment effect is poor.


Density 0.90g/cm3 (able to float on water)
4.Surface treatment
Because the surface treatment effect is poor, it is not easy to fuse, so few surface treatment.If spray oil needs special treatment, PP water is usually added.
5.The connection method
The connection mode is divided into clasp, screw, hot melt, ultrasonic and so on.
6.Scope of application
Suitable for daily use, medical instruments, food bags, plastic bottles, hinges, etc.

二,PE, called polyethylene in Chinese, is one of the most commonly used plastics.

1.The classification of the PE
According to the manufacturing method, it can be divided into three types: low pressure high density (HDPE), medium pressure (MDPE) and high pressure low density (LDPE).HDPE has a hard texture, good wear resistance, corrosion resistance and electrical insulation.LDPE is the lightest, chemically stable, high frequency insulation, impact resistance and transparency.Among them commonly used is HDPE, LDPE.
2.The advantages of PE
1)Injection molding has good fluidity and easy color matching.
2)Excellent electrical insulation.
3)Good wear resistance.
4)It is impervious to water and has good resistance to chemicals. It hardly dissolves in any solvent at 60℃.
5)Good low temperature resistance, still has softness at -70℃.
6)Non-toxic, tasteless, low density.
  1. The disadvantage of PE
The quench resistance is poor, the mechanical strength is not high, the thermal deformation temperature is low.LDPE has better flexibility, elongation, impact resistance and light transmittance than HDPE, but less mechanical strength and heat resistance than HDPE.
4.The density of PE
1)LDPE density was 0.910 ~ 0.925 g/cm3
2)The MDPE density was 0.926 ~ 0.940 GCM
3)The HDPE density was 0.941 ~ 0.965 g/cm3

5.Surface treatment
Because the surface treatment effect is poor, it is not easy to fuse, so few surface treatment.
6.The connection method
The connection mode is buckle, screw, hot melt, ultrasonic, etc.
7.Scope of application
1)LDPE is used for cable wrapping, corrosion resistant pipes, etc.
2)HDPE is often used for blow molding into hollow products, films, hoses, plastic bottles, etc.Food bags and containers are usually made because they are non-toxic and tasteless.