TPU Injection Molds
TPU, or thermoplastic polyurethane, stands out as a remarkable material renowned for its exceptional properties, making it a prime choice for a wide range of applications. Its exceptional elasticity, wear resistance, and aging resistance make it an ideal material for demanding applications such as shoe soles and mobile phone cases.
Key Characteristics of TPU Injection Molds
1.Superior Elasticity, Wear Resistance, and Aging Resistance: TPU boasts exceptional elasticity, wear resistance, and aging resistance, making it an ideal choice for applications that demand durability and resilience.
2.High Flowability: TPU exhibits high flowability, enabling it to fill complex mold cavities with precision, ensuring intricate designs are accurately replicated.
3.Ease of Processing: TPU is versatile and can be processed using various methods, including injection molding, extrusion, and blow molding, catering to diverse manufacturing needs.
Essential Considerations for TPU Injection Molds
1.Mold Steel Selection: Employ high-hardness mold steel, such as H13, H21, or 42CrMo, to withstand the pressures of TPU injection molding.
2.Vent Design: Strategically position vents in thick mold sections and add venting grooves along product thick walls and corners to facilitate air evacuation and prevent voids.
3.Sprue Design: Opt for needle-gate or submarine-gate designs, minimizing gate length and diameter to reduce material waste and optimize part quality.
4.Mold Temperature Control: Maintain mold temperature within the range of 20-60°C. The specific temperature should be determined based on the TPU material grade and properties.
Parting Considerations
1.Mold Cavity Surface: Achieve a mold cavity surface roughness of 0.5 - 0.6 µm to minimize parting force and reduce the need for parting agents. This roughness promotes smooth parting compared to coarser surfaces or coatings.
2.Draft Angle: Maintain a draft angle of at least 5° for molds, especially when using softer TPU grades. Intersecting draft angles further enhances part release from the mold walls.
3.Ejection System: For TPU molds, the ejection system should have a large surface area to prevent deformation of the finished part.
