When the average person considers plastic molding, the cold runner method often come to mind first. Just because something is more popular, doesn't always mean it's better. In many instances, the hot runner method yields better results. With the hot runner method, controlled heating devices are inserted into the mold to maintain the material's temperature at a level that allows for a molten-like flow. Maintaining the mold material's temperature at this level affords a number of benefits.
More Plastic Resin Options
The hot runner method offers more options when it comes to the plastic resins you can use. The cold runner method creates limitations with certain resins. Take glass-reinforced resin, for instance. When set at a temperature that is too cold, this material starts to decompose.
Even when mixed with other resins, the glass-reinforced resin will still sustain damage during the setting process, which will lower the quality of the finished product. With the hot runner method, this type of damage is avoided because you can specifically set the temperature to the optimal setting based on the type of resin being used.
Minimize Injection Pressure Drops
The fact that the plastic inside the mold remains hot during the hot runner method ensures that any pressure drops are minimal, if at all present. With the cold runner method, pressure drops are often more significant, which can alter the integrity of the final result of the mold.
This level of temperature control is especially important for those types of plastic resin that are sensitive to pressure drops. By maintaining a heat flow, you prevent a drop in the resin, which ultimately gives you greater control and a better finished product.
Shorter Cycle Time
For plastic molding, faster turnaround times are better for business because they make way for cost savings when it comes to labor and materials. A hot runner method offers a shorter cycle time than the cold runner method. In a cold state, it takes a greater effort to press resin into a mold.
When plastic resin is maintained at a higher temperature, it easily flows through the nozzle and into the mold. The faster the resin is input into the mold, the faster the setting period can begin. Additionally, hot runner molding comes along with less leftover scrap resin, which helps to minimize wasted material costs.
When it comes to plastic molding, there is no one-size-fits-all solution. Make sure you aren't overlooking the benefits the hot runner method can offer you. A professional like one from Qualicase Ltd can help you ensure you are making the right selection.