TPU put out the production process.
Author： CablePublication time：2018-08-13 14:48:14Hits：74【SML】
Regardless of which TPU is processed, the first (and important) thing is proper drying of the resin. The TPU used to be loaded is packed in a steam tight bag or...
（a）First, wood must be dried.
Regardless of which TPU is processed, the first (and important) thing is proper drying of the resin. The TPU used to be loaded is packed in a steam tight bag or sealed bag. It is recommended that this material be processed at room temperature. Because TPU is hygroscopic material, it is recommended to pre dry it. TPU timber should be pre dried before being released. The big wet can not exceed 0.05. If this limit is exceeded, even a small amount of it may result in damage to the quality of the model product being delivered or injected, such as the uneven surface, the sticking of the residue in the nozzle or the ejecting tool, etc. Pre drying should be done carefully, and moisture should be avoided after drying. In general, the drying time is 2~4 hours for the resin package that has just been opened. The actual drying time is related to the type, humidity and drying temperature of the resin.
All TPU lumber can be mixed by mixing strong color or color. Color matching can also be easily achieved by using -PU based color masterbatch. Usually, the percentage of color masterpieces is 2. Non-TPU-based masterbatches are usually incompatible, which may lead to color dispersion, surface heterogeneity, color variability and other problems.
The ejector barrel shall be divided into at least three temperature-controlled zones and a temperature controller for the converter and eye mold. Thermocouples and controllers for controlling these sections should be regularly checked. Most modern machines have many heating zones. For TPU, it is very important to set precise and consistent settings for all parameters. Voltage-controlled temperature controllers should be used because on/off controllers can cause temperature fluctuations greater than 5F. The fluctuation of temperature will cause the thermal refraction to be uneven, which will cause the size of the product to be deviated. Especially, slight fluctuations in temperature in the counting area, adapter, and eye mold can lead to discharges and quality. For TPU (Shore Hard A80, A90), the inlet temperature should be set at 165C, and the allowable temperature should be set at 185C. The temperature of nozzle / eye mould is low 5C, such as 180C. Too high temperature leads to heavy molecular weight, resulting in degradation of its mechanical properties.