Spray-free materials, like most materials, absorb water vapor in the air. Drying must be done before forming. Otherwise, it may lead to silk and sparkle on the surface of the product and affect the surface gloss of the product.

It is usually required that the moisture content of non-spraying material be controlled below 0.05 after drying. For example, for non-spraying materials of ABS substrates, the drying temperature is usually 70-85 C, and the drying time is 3-4 hours.

Excessive temperature can easily lead to material performance degradation; too low temperature, insufficient drying time, too high moisture content of resin, easy to produce gas marks on the surface of products.

2. Injection Temperature-Medium and Low Temperature Injection Molding

Due to the addition of metal pigments in the spray-free resin, it is easy to cause discoloration of metal pigments under the high shear of screw. Therefore, the setting principle of forming temperature for spray-free materials is to use medium and low temperature injection moulding as far as possible to prevent material degradation on the premise of ensuring full plasticization of materials.

For example, the processing temperature of the non-spraying material based on ABS is 210 - 230 C. When the temperature is too high, the material will degrade and the surface of the product will produce gas marks.

3. Injection Molding Speed-Medium Speed Step Control

When using spray-free materials for injection molding, the selection of injection speed mainly considers the appearance of the product, the exhaust of the mould and the resistance of resin flow in the cavity of the injection molding machine.

Faster injection speed will generally lengthen the melt process, suitable for filling thin-walled products, and form a better surface finish and surface effect. However, too fast injection speed can easily make the melt suffer strong shear, resulting in the destruction of the shape and particle size of pearlescent toner and reducing the special color effect of products. In addition, spray marks and bad exhaust are easy to appear near the gate.

Therefore, on the premise of guaranteeing the surface effect and quality of the product, it is suggested to select the middle-speed stepped speed control to ensure smooth filling and appearance of the product.