Meaning
Deliberate modulation of the tool temperature during each shot optimizes the flow characteristics and finish of high precision plastic components. Unlike conventional methods that keep the tool at a constant temperature, variothermal injection moulding uses active heating and cooling to change the environment for the resin. This approach allows for the use of lower melt temperatures while still achieving a high quality surface.
It is particularly effective for resins with high filler content or low flow rates.
Flow Optimization
Optimization of the melt flow occurs because the hot tool surface reduces the viscosity of the polymer skin as it travels. In variothermal injection moulding, this allows the material to reach the ends of long or thin cavities without the need for excessive injection pressure. This reduces the risk of flashing and lowers the residual stress in the molded part.
Weld Integrity
Integrity of the bond between two flow fronts is improved when the tool temperature is held above the glass transition point during the fill. Because the resin stays molten for longer at the interface, the polymer chains can entangle more effectively across the weld line. This leads to a stronger part and the removal of the visible line that often weakens the structure.
For automotive or structural parts, this increased strength is a measurable improvement over standard production methods.
Process Economy
Economy in the production of complex parts comes from the ability to mould features that would normally require a second assembly step. By using this technique, a finished surface is produced directly from the tool.
