High-density polyethylene (HDPE),a thermoplastic polymer in pellet form, is an ideal injection molding material. Due to its low cost, chemical resistance, high tensile strength, impact resistance, and low moisture absorption, HDPE can facilitate manufacturing in the process of injection molding.HDPE injection molding refers to the process that meltedHDPE is injected to a mold at high pressure and temperature for the creation of HDPE products. With its own expertise and team, Echofast is able to provide customers with custom HDPE injection molding services in a cost-effective way.
| Drying | Not normally necessary if stored properly. |
|---|---|
| Melt Temperature |
180 - 280 C (356 - 536 F); for high molecular weigh grades, the
suggested melt temperature range is 200 - 250 C (392 - 482 F) |
| Mold Temperature |
20 - 95 C (68 - 194 F) (higher temperatures for wall thickness of
up to 6 mm; lower temperature for wall thicknesses greater than 6 mm.) The cooling rate should be uniform to minimize shrinkage variations. For optimum cycle times, the cooling channel diameters should be at least 8 mm and must be within a distance of 1.3 d from the mold surface (where "d" is the diameter of the cooling channel). |
| Material Injection Pressure | 70 - 105 MPa |
| Injection Speed |
High injection velocity is recommended; profile injection velocity
can be used to reduce warpage in the case of components with a large surface area. |
| Density ASTM D792 | Tensile Strength ASTM D638 |
Elongation at Break ASTM D638 |
Hardness (Shore D) ASTM D2240 |
Heat Deflection ASTM D648 |
|
|---|---|---|---|---|---|
| Unipol DMDA 8007 | 0.967 g/cm³ | 31.0 MPa | 350% | 61 | 83.9 C |
| Marlex 9006 HID | 0.953 g/cm³ | 28.0 MPa | 950% | 62 | n/a* |
| Dow DMDA 8907 | 0.952 g/cm³ | 27.0 MPa | 1,100% | 59 | 73.0 C |
Designed to provide excellent processability for molders,HDPE is an excellent choice among various injection molding materials for its following advantages.
Weather-Resistance
HDPE boasts high resistance to moisture ingress. It also can be an ideal material for outdoor applications with the addition of UV stabilizers, which can make itself resistant to UV(ultraviolet) radiation.
Lightweight
Compared to metals and even some plastics, HDPE is lightweight for its density of around 960kg/m³. Besides,it’s known for high strength-to-density ratio. In another word, thin -walled products like bottles or chemical tanks but still maintain high levels of strength and rigidity can be produced with HDPE in use.
FDA and Medical Grade Available
Since that HDPE is highly inert and stable,it can meet FDA (Food and Drug Administration) and medical-grade standards,ensuring that it is safe for use in food, beverage, pharmaceutical and medical applications.
Cost -effective
HDPE is also a relatively low-cost material compared to other plastics,which is recyclable and can decrease raw material and waste. Meanwhile, the lifespan of HDPE products is usually longer and less frequent replacement is required.
Some disadvantages as listed below:
Consumer Product Applications:
Industrial Applications Of HDPE Injection Molding:
