Multi-Gating leverages 2 or more hot runner gates per part to improve part filling. The benefits include moving the gate closer to end-of-fill, reducing the overall flow length “L”. The light-weighting potential depends on the aspect ratio of the part, but multi-gating has demonstrated part weight reduction by up to 15%.
StackTeck’s ability to custom design and manufacture the hot runner makes it feasible to offer effective multi-gating for a variety of applications. Optimized gate location is critical to minimizing injection pressure and clamp tonnage to run the tool in an appropriate machine.
Multiple gates can help in many ways to improving and lightweighting injection molded components. Each project will have its own demands and priorities – this is where the simulation will put those gates in the proper positions to achieve those particular goals.
For multiple gate parts , melt flow analysis software is a powerful simulation tool to help determine the optimum gate locations providing the best balance of injection pressure, gas trap prevention, even part fill, packing, clamp tonnage and overall part quality. This illustration of a melt flow analysis shows a comparison between 4 scenarios.
- A typical single gate location for this rectangular container will generate approximately 11,000 psi just for filling the part. It will have an uneven packing condition since the plastic will not reach the end of fill around the perimeter at the same time.
- When we add a 2nd gate to the part and position them as shown in the top right graphic, you can see the results of a significant reduction in injection pressure – just over 31% – from the part with a single gate.
- Take a look at the sketch at the bottom left where we have 3 gates. This scenario didn’t really help to reduce injection pressure compared the 2 gate option but it may have other benefits for better fill characteristics. Analyzing the melt flow through a moving simulation will help determine if this is a useful 3 gate solution.
- In the final scenario, the 5 gate layout gives us another good reduction in injection pressure.
Other proven injection molding solutions from our toolbox for more sustainable, lighter-weight, plastics packaging:
- Ultra-Fast Injection
- Microcellular Molding
- TRIM – Thin Recess Injection Molding
- Injection Compression Molding
