Dosing liquid materials like colorants is most common in injection molding and extrusion. The innovative, high-quality gravimetric dosing system for liquid material proves that efficient use of liquid colorants secures a stable production process. This results in high savings on expensive liquid colorants and a high-quality end product.
Liquid dosing, particularly the use of liquid colorants, can lower the costs of materials through lower letdown ratios. This occurs because less colorant is needed to achieve the same color compared to pelletized or powdered options. The reason for this is because less liquid colorant is needed to get the same color because the liquid colorant will spread more easily during the melt state compared to the pellets or powder.
Today, many processors use liquid colorants in tinted clear resins and translucent parts; and opaque parts with letdown ratios of less than 2%.
There are several components connected with liquid color dosing equipment, including a delivery vessel for the liquid color, a pickup lance or wand, and a color pump.
The pumps often use a compressed air controlled diaphragm to move the liquid colorant. This type of pump is installed directly onto the delivery for neatness. It also eliminates the need to tap the vessel when beginning the coloring process. The pump is pre-installed onto the drum by the liquid colorant supplier, significantly improving cleanliness.
The process also includes metering control, including at-the-throat units that fit below the standard material supply hopper and work in conjunction with the molding cycles of the processing machine.
For throat metering, a throat adaptor can be utilized. In this instance, a nozzle to inject the liquid colorant into the resin is installed below the material supply hopper on the machine.
Dosing masterbatch material can be done with gravimetric, volumetric and optometric dosing systems.
With the increasing demand for liquid silicone rubber (LSR) molding, dosing systems can ensure efficient operation. Some systems make sure ones uses 99 percent of the LSR components in the drums.
On many shop floors, the use of liquid colorant is seeing a bit of a resurgence. This can be attributed to closed-drum pump systems, which now make it an attractive option. It eliminates the mess.
Sealed drums also are returnable, and there is never an open drum sitting next to a machine.
Dispersion also is strong with liquid color and other additives.