3. How to control the product deformation (3rd. Mould design:runner system) As we know, if you want to control the product deformation, mould design is very important, there are three systems you need to be considered. These are runner system, cooling system and ejector system. First letâ€™s talk about the runner system. When you get a product, maybe you will ask which type of gate I should choose, hot runner or cold runner. First you should know more about the product information. Like the product quality, quantity, or whether this product need change the color frequently or some other requirements. Sometimes it was designated by our clients or whether the quotation contains the hot runner, if not. We should be able to determine them by ourselves, below are the things to be considered 1. Volume of production, how many parts do you plan to run per year or for the lifetime of the mold. One hundred thousand or one million? sprue and runner will not discharged due to hot runner method, so choice a hot runner can save plastic material especially for mass production. 2. For some large parts, dimension are exceed 600mmX600mm, also the parts shape or the structure are completed, the first choice is the hot runner, because this situation, cold runner may cause short shot happened, or the injection circle time was very long, or itâ€™s very hard to control the part dimension. 3. If the product should often change the color (some product should have many kinds of color, and the color should be changed frequently), at this time, hot runner wonâ€™t be a good choice, because when you switch to another color, it will be more difficult to clean it up than the cold runner, this is just based on my previous experience. Maybe someone knows how to clean it quickly. You can tell me. TKS And there are some advantages and disadvantages about the hot runner. 1. Shorten the mold cycle time, 2. Saving plastic material(no runners and gate) 3. Improve product quality 4. precise control the plastic melt temperature DISADVANTAGES 1. High price 2. The mould structure become more complicate 3. Maintenance is more complicated and easy to have problems with when improper operation. 4. . More difficult when change the product color.