616.368.2684 chris@bluebilles.com

One gate verses two gates

  • The Problem
    • “I am not sure how many gate locations I will need to properly fill the part and I am also not sure where to put them.”  
    • Gate location is critical in the injection molding process, gates are the points on the part where the plastics leaves the runner system and enters the cavity.  This location is critical to the way the part fills and how the plastic molecules are oriented during the injection phase.  This location will determine how the part looks and performs after the molding process is complete.  As the plastic molecules orient during flow this determines how much the plastic part will deform or warp during cooling.
    • The size of the gate is also of the utmost importance.  Too small of a gate and the part will not properly fill out as the plastic flow front will freeze, too large and the cycle time will increase dramatically and loss of profit will occur since the gate will not seal in a reasonable amount of time.
    • Depending of the distance the plastic will need to flow and how thick the part is, multiple gate locations may be necessary to properly fill the part.  Some parts will require one properly placed location, while others may require two or more.
    • The graphic below shows how important gate location is, this scenario shows how improper gate location unbalances the fill in the cavity.  This imbalance will lead to warping.

Imbalanced filling simulation

  • The Solution
    • SOLIDWORKS Plastics filling simulation.
    • Simulation can accurately predict where the gate location should be on the part and how many locations will be needed.  As the material flows through the cavity it is also very important that the cavity fills evenly so that the flow fronts reach each ends of the cavity at the same time.
  • How The Solution Helps
    • If a mold is created with the gate in the wrong location, it is expensive (15-20%) of the mold cost to correct it.  Once the steel is cut, it becomes difficult to change these locations in the mold.  If you are using a hot runner system, this typically means a new manifold design which can increase to 50% of the mold cost or more.
    • Running simulation give you confidence not only in part design but also mold design to ensure you can predict these issues and counteract them BEFORE the steel is cut.

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BlueBill Engineering Services