Mold filling simulation helps mold builders stay competitive. It does this by enhancing efficiencies and helping to better meet customer expectations - while also creating more business opportunities. Mold fill 3D simulation is a very helpful tool for injection molders and plastic part designers because it uses software to simulate the filling, packing and cooling of a molded plastic part virtually.
3D simulation improves the ability to predict melt-filling and air-venting behavior. Plastics flow behavior involves a combination of flow, pressure, cooling and heat. Any time alterations influence this complex combination (ie: part geometry, runner system, or cooling system) the molding behavior can change. The gates need to be placed at the most appropriate locations in order to allow enough melted plastic to fill and pack/hold into the cavity.
Simulation tools provide a series of features that enable mold designers to evaluate cold/hot runner scenarios, gate locations and runner types. Flow analysis predicts the required injection pressure and further estimates the required press size range.
Mold Fill Simulation for Determining Gate Locations
Flow distance will have an effect on the amount of pressure required to fill the mold, this in turn will affect the amount of clamp force required to hold your mold shut during the molding process. This means when the molding machine can’t handle the pressure or clamping requirements, it might be time to use more gates.
Sheering and packing are the two most important reasons for paying close attention to gate size. Simulation is the best way to strike the balance within several variables. This means evaluation through a series of pathways within the simulation software will eventually provide the best overall solution. Venting is always another concern, with flow front analysis, air traps can be predicted and displayed in a 3D model.
The Primary Benefits of Mold Fill Simulation
The ability to evaluate different cooling arrangements can deliver more accurate cycle time estimation. With mold fill simulation - you have the ability to evaluate different cooling arrangements by comparing accurate cycle time based on the whole system, efficiency of each cooling loop, adequate cooling channel size and plastic frozen percentage.
An optimized cooling system will facilitate improvement in mold temperature control which helps to maintain a minimum cycle time. Cooling analysis also helps maintain part shrinkage and warp. It is also possible to integrate with 3D cad/cam which boosts efficiency. This also helps the mold designer analyze his mold designs more efficiently in-house.
- A few clicks will enable the mold designer to a observe flow pattern - providing for a more precise mold building capability.
- The simulation shows areas of the part that will not completely fill with plastic making it possible to make a few alterations to the design to resolve the issue.
- The simulation also exposes areas where weld lines develop, part areas where two different flow fronts meet to weld the plastic together.
- Simulation can help determine if these areas are structurally sound or not.
- Simulation can facilitate proactive communication which can assure a successful tool-launch.
- Mold builders can be proactive because the simulation illustrates potential problems which can be addressed before production of the mold and part.
- Simulation can calculate the pressure inside the filling plastic which could point towards potential problems.
- Simulation also enables other evaluations such as material sheering, so that temperature and pressure can be determined. This helps to determine if a specific resin will work with a given part design.
All of these capabilities can be useful on existing problem injection molds. An analysis can point to fixes for injection molds that have issues such as uneven fill times between parts, trouble filling and heating or cooling issues. Although a completed mold is more expensive to change than one in the design stage, molding fill simulation may point to a solution that would otherwise require trial and error on the bench.
This is an advantage when working with Crescent Industries engineers who utilize 3D mold fill simulation software to evaluate gate locations, runner systems, venting, cooling systems, flow pattern, weld lines and material selection with a specific part/mold design. Contact Crescent Industries to partner with a quality injection molder.
*The content for this article was inspired by the article Add Value to Your Mold Designs by Jeff Kloberdanz, Engineering Manager for MOldex3D Northern America Inc. It was published by Moldmaking Technology on May 2014