Jan 17, 2019
To display the chronological history of the filling behavior of an injection molded part, the dosage volume is extended in the injection molding machine from shot to shot until the cavity is completely filled.
The different filling percentages explain, which area is filled at which time and give hints on the process and possible optimization.
All shots with different filling percentage collectively are called filling study.
In injection molding simulation the filling study is an inherent part of the displayed results.
Injection Molding Process: The filling study of a toy car shows the filling behavior in detail.
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This glossary of plastic industry is provided by PLEXPERT Canada Inc.
Aug 14, 2019
The total amount of a medium transported through a cross section in a given time is called flow rate.
In mathematical formula, the letter Q can be found as representative of the flow rate.
The filling in injection molding is generally controlled by flow rate from the start of the injection phase until the switch over point is reached.
In this phase the machine keeps the flow rate on the set value.
Therefore dependent on the cavity volume the given flow rate results in a pressure profile.
Usually the screw moves forward until the given switch over point is reached. The movement can be done with different speeds (profile).
At the switch over point, the machine switches to pressure control until the end of packing phase.
This means that a given pressure is kept before the tip of the screw.
Based on that a flow rate is determined.
The flow rate it not only important regarding injection, but also for the coolant.
It decisively decides on the height of the Reynolds number and therefore on laminar or turbulent flow.
The possible flow rate depends on the respective cooling device and needs to be checked based on the pump curve.
Injection molding process: The
flow rate Q is the amount of a medium, which flows in a given time through a cross section.
Related topics:
This glossary of plastic industry is provided by PLEXPERT Canada Inc.
Jan 25, 2019
No further melt can enter the cavity of the injection mold after the smallest diameter of the cold runner freezes off.
This duration is called freeze time and represents the theoretically maximum packing time.
While increasing the packing time stepwise it is possible to find out the freeze time by taking the weight of the parts. As soon as the weight stays the same, the cold runner is frozen.
In the simulation the freeze temperature in this area or the flow rate help additionally.
Apr 8, 2019
In two shot molding, the first component is commonly robust and gives the shape of the geometry.
Therefore, it is also called the hard component.
Its rigidity leads to the main influence for the warpage.
Typically, its materials are PP, PS or PC+ABS.
Aug 22, 2019
The primary molding process mainly used in the plastic industry is injection molding.
With the help of the injection molding machine and the influence of heat, the plastic material is brought to a viscous state.
Subsequently, the melt is injected under pressure into the cavity in the mold.
The shape and surface structure is determined by the geometry of the cavity.
Cooling or cross-linking reaction (for elastomers) solidifies the part and it can be ejected after opening the two mold halves.
The injection molding process is particularly suitable for large quantities.
This is due to the fact of high mold costs which need to be payed proportionally by the produced parts.
Injection molded parts can be used directly after ejection.
