Plastic pressure is one of the four basic plastic variables. Its accurate control is vital to a repeatable molding process.
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Of course we’re all familiar with the high pressures utilized during the molding cycle. High pressure is used to keep the mold halves closed during injection and high pressure is used to inject plastic into the cavities. In this FREE Webinar we’ll examine the principles of plastic pressure.
Pressure is required to make any liquid flow and pressure drop occurs along the flow path. In injection molding, high pressures are required because plastic is quite viscous, (resistant to flow), and gate sizes are small, so they’ll freeze quickly. Of course, all the plastic required to form the parts must flow through these small gates.
The accurate measurement of plastic pressure during the molding cycle gives us a lot of information. However, measuring plastic pressure in the cavity can be costly and is not commonly done. However all machines measure injection pressure during the molding cycle and this can be nearly as useful.
Plastic pressure and flow rate are closely related. Higher injection pressures increase flow rate which increases molecular orientation. It also decreases viscosity, making cavity filling easier. As with the other three plastic processing variables, maintaining a consistent injection pressure will help produce parts with consistent properties.
Topics covered include:
- An explanation of the plastic pressure in the molding process
- How plastic pressure variations affect part properties
- How to interpret injection pressure data to optimize the molding cycle
- How to use the minimum injection pressure setting that will make good parts
Topics reviewed include:
- Understanding how the different machine controls affect the four plastic variables
- Where a machine control affects two or more of the four variables, which is the dominant effect and why
- How to use plastic behavior to your advantage when optimizing the molding process
- How to problem solve from the plastics point of view
Listen in on this FREE webinar to learn and apply molding techniques that will dramatically change the way you process.
