Injection Mold Fill Simulation

Injection Mold filling simulation can be a critically helpful tool for the injection molder as well as the plastic part designer.  The process involves software that virtually simulates the filling, packing and cooling of any Injection molded parts.  It also allows the mold/part designer to make essential decisions about the design before the mold is manufactured. This is a big advantage, as it is the point when design changes will be significantly less expensive.

Injection Moulding

Gate Location and Part Filling Simulation Advantages  

Gate locations and part filling are the foremost concerns when it comes time to consider part and mold design. The simulation is used to provide an accurate visual representation of how the molten plastic will fill the mold.

You can determine which areas might fail to fill with plastic, where any weld lines may develop – along with the ability to determine if those welds will hold properly when the time comes. The software makes it possible to assess the structural soundness of the design. This also helps the designer determine where the gates should be located. 

Resin Determinations are Also Enhanced by Mold Filling Simulation

Assessments can be made concerning a specific resin as well.  The software will calculate the pressure inside the filling plastic – this ability makes it so you can determine any other potential problems. There are other evaluations that can be made as well. Discover when the material is sheering, or what temperatures and pressures need to be.

This and other data is not only helpful for designing the part, but can also be used to decide if a specific material will work with any given part design.. 

The heating and cooling of the mold can be simulated through the entire molding cycle. It can be simulated over many cycles, and will help to determine the size and location of any necessary cooling lines. 

Because the cooling lines will affect how or if the part warps – this also allows for the potential warpage of the part to be viewed, analyzed, and adjusted for.  Any areas of the mold where the temperature is not as controllable – will always be visible through the simulation as well.    

The Advantages of Mold Filling Analysis

Injection Mold filling simulation is also incredibly helpful when using molds that produce multiple parts.  The analysis shows whether or not the parts fill at the same time, it shows any required adjustments needed to improve the parts and gives you the ability to assess the potential runners and gates to be made – all within the simulation.

Any air that might be trapped during part filling can be discovered. This makes it so that proper venting can be used in the tool.  Any areas of the part that might have sink marks can also be identified in order to be addressed as well.

3D Mold Fill Simulation with Crescent Industries

These capabilities are obviously immensely useful on existing molds. Simulation analysis can also point to fixes for molds that have issues such as:

  • Uneven fill times between parts 
  • Troubles with filling 
  • Any developing heating or cooling issues  

Mold filling simulation will point to solutions that would otherwise require trial and error on the bench. Once the gate locations are established, you need to size them properly. Shearing and packing are the two most important reasons for paying close attention to gate sizing. The shear rate determines which adjacent layers flow against each other, and at what force or velocity they will flow.

Every grade of plastic resin has a shear-rate limit. This is the limit where the molecular chains are stretched too far. Once this happens – the materials begin to degrade. This causes appearance problems like gate-blush or a decrease in mechanical properties.

Balanced shear rates flowing through the gate are proportional to the flow rate of your material. They are also inversely proportional to its orifice size. Control shear rates by controlling flow rates or gate sizes. Flow rates are most commonly controlled by the injection moulding speed of the machine.

Simulation is the best way to strike the balance within several variables. This means evaluation through pathways within the simulation software, which eventually provides the best overaeching solution. 

At Crescent Industries – engineers utilize 3D mold filling software to allow the mold and part designers to make these gate location decisions before the mold is manufactured.    

Our engineers know precisely where and when utilizing 3D mold flow simulation software will deliver the most advantages.  To obtain even more information on Crescent Industries design and development services please