Advertising in MoldMaking Technology offers
Issue link: https://mmt.epubxp.com/i/401488
Software 28 MoldMaking Technology November 2014 Make Mold Cooling Easy and Effective By Dan Branch W hen it comes to injection molds, the importance of an efficient cooling system cannot be overem- phasized. A reduction of just one or two seconds in cooling time can lead to as much as a 10- to 20-percent increase in the production rate. That alone could directly affect the profitability of the job. However, saving time is not the only benefit of a cooling system. Controlled cooling of the entire plastic part is vital to the preservation of its dimensional stability and mechanical properties. Properly cooled parts are less likely to warp, get stressed or be brittle. It is easy to see why a well-designed cooling system is a key component of a well-designed injec- tion mold, leading to the profitable production of high-qual- ity parts. Here are some tips to help you design an effective mold cooling system, while reducing design time and effort: Decide on the most critical components to cool. In most tools with inserted cavities, the cavity blocks and slides are the only components in the tool that require cooling lines. While the surrounding plates will get hot, adding cooling into them will not contribute much towards the ultimate goal of removing heat from the plastic part. In molds with individual cavity blocks, the cooling design typically can be viewed as a circuit. It will have an inlet and an outlet, and will trace a path through the block. The circuit should be close enough to the part to effectively remove the heat, but not so close as to risk drilling holes into any of the mold features. Make smart material choices. Items like core pins and lifters are often too small to get any effective cooling inside them. If you are concerned about removing heat from small inserts, you may want to use material with a high rate of thermal conductivity for these components. Aluminum and bronze alloys have much higher thermal transfer rates than steel and can be very useful for pulling the heat out of the plastic and towards the cooling circuits. Strategies for designing an effective cooling system with less time and effort. VIDEO Access video at end of article. Images courtesy of Cimatron Technologies. Simulating plastic fll with molding analysis will show the expected temperature of the plastic part throughout the molding process. Create an effective water circuit. Creating a water circuit with a thorough path around the part is the most important consideration for cooling effectiveness. Bending the circuit around the part contributes to a turbulent water flow, which helps to pull the most heat from the steel. At the same time, be careful not to make the circuit too long and complex, which would cause the water temperature to rise to the point that it diminishes the cooling effect. Generally speaking, you want to keep the water temperature no higher than 2-3°C above the entry-point temperature. Speed up design using catalog parts. Once the circuit is designed, get the plugs and other water components in place. Using standard components from 3D catalogs can save you as much as 80 percent in design time. All you need to do is pick the part and drop it into your design. Adjust your strategy when dealing with large parts. A dif- ferent type of strategy often is applied to cooling very large parts or typical automotive tools where left- and right-hand parts are both required. With large core plates that measure LEARN MORE Visit our archived webinars for one on "Mold Cooling Design Made Easy." short.moldmakingtechnology.com/easycool