Water purifier injection parts

Material:PE-HD

What is injection molding?
Injection moulding is a manufacturing process for producing parts by injecting molten material into a mould, or mold. Injection moulding can be performed with a host of materials mainly including metals (for which the process is called die-casting), glasses, elastomers, confections, and most commonly thermoplastic and thermosetting polymers. Material for the part is fed into a heated barrel, mixed (using a helical screw), and injected into a mould cavity, where it cools and hardens to the configuration of the cavity. Injection moulding is widely used for manufacturing a variety of parts, from the smallest components to entire body panels of cars. Advances in 3D printing technology, using photopolymers that do not melt during the injection moulding of some lower-temperature thermoplastics, can be used for some simple injection moulds.
What is the application range of high-density polyethylene (PE-HD) injection molded parts?

Refrigerator containers, storage containers, household kitchen utensils, sealed lids, etc.

What are the conditions for high-density polyethylene (PE-HD) injection molded parts?

Melting temperature: 220~260℃. For materials with larger molecules, it is recommended that the melting temperature range is between 200 and 250°C.
Mold temperature: 50~95℃. Plastic parts with a wall thickness of 6mm or less should use a higher mold temperature, and plastic parts with a wall thickness of 6mm or more should use a lower mold temperature. The cooling temperature of the plastic parts should be uniform to reduce the difference in shrinkage. For the optimal processing cycle time, the diameter of the cooling channel should not be less than 8mm, and the distance from the mold surface should be within 1.3d (where “d” is the diameter of the cooling channel).
Injection pressure: 700~1050bar.
Injection speed: High-speed injection is recommended.
Runner and gate: The diameter of the runner is between 4 and 7.5mm, and the length of the runner should be as short as possible. Various types of gates can be used, and the gate length should not exceed 0.75mm. Especially suitable for the use of hot runner molds.

What are the chemical and physical properties of high-density polyethylene (PE-HD)?
The high crystallinity of PE-HD results in its high density, tensile strength, high temperature distortion temperature, viscosity and chemical stability. PE-HD has stronger resistance to penetration than PE-LD. The impact strength of PE-HD is low. The characteristics of PH-HD are mainly controlled by density and molecular weight distribution. The molecular weight distribution of PE-HD suitable for injection molds is very narrow. For the density of 0.91~0.925g/cm3, we call it the first type of PE-HD; for the density of 0.926~0.94g/cm3, we call it the second type of PE-HD; for the density of 0.94~0.965g/cm3 , Called the third type PE-HD. The material has very good flow characteristics, with an MFR between 0.1 and 28. The higher the molecular weight, the worse the flow characteristics of PH-LD, but it has better impact strength. PE-LD is a semi-crystalline material with a high shrinkage rate after molding, ranging from 1.5% to 4%. PE-HD is prone to environmental stress cracking. It is possible to reduce internal stress by using materials with very low flow characteristics, thereby reducing cracking. PE-HD is easy to dissolve in hydrocarbon solvents when the temperature is higher than 60℃, but its solubility resistance is better than PE-LD.