Plastic Mould Drying

Impact of Uncontrolled Humidity

Uncontrolled humidity during injection moulding processes can lead to condensation on the mould surface. This condensation, caused by the temperature differential between the chilled mould and the surrounding air, results in the formation of water droplets on the mould surface. The presence of moisture adversely affects the quality, structure, and tensile strength of the final product. Additionally, prolonged cooling times due to condensation can increase cycle times, reducing overall productivity.

Consequences of High Humidity

The consequences of high humidity in injection moulding include mould sweating, low cycle times, and a high scrap rate. High humidity can also shorten the lifespan of moulds, reduce part or product quality, and lead to structural defects such as streaks and bubbles. Moreover, the tensile and impact strength of the final product may be compromised

Additional Effects

In addition to the direct impact on product quality and productivity, high humidity levels in injection moulding processes can increase maintenance requirements and operational costs. Mould sweating and prolonged cooling times may necessitate more frequent cleaning and maintenance of moulds, leading to downtime and increased expenses.

Causes of Uncontrolled Humidity

Uncontrolled humidity in injection moulding processes is primarily caused by the use of chilled water for cooling plastic melts. The temperature difference between the chilled mould and the surrounding air leads to condensation on the mould surface, creating moisture-related issues. This can occur especially in environments with high ambient humidity levels.

Recommendation

To mitigate the effects of uncontrolled humidity during injection moulding, it is recommended to maintain lower humidity levels in the surrounding air compared to the temperature of the chilled water supplied to the mould. This can help prevent condensation and its associated problems, ensuring consistent product quality and productivity.

Solution

Josem offers rotary Dehumidification System, specifically designed to prevent mould sweating by providing a dry air envelope. The Josem rotary Dehumidification System – E Series helps increase production efficiency by reducing cycle times. It is particularly suitable for critical applications, such as the manufacturing of PET preforms and various plastic caps, where maintaining optimal humidity levels is essential for quality and productivity.