Standard Melt Flow Test Load Selection Criteria for Polyethylene Sourcing
Polyethylene sourcing requires specifying exact test loads, temperatures, and standards to isolate molecular structure and enforce contractual lot consistency.
Method B Volume Flow
Meaning
Automated sensors track the displacement of a piston to calculate the rate of resin flow. In method b volume flow testing, an optical encoder or mechanical probe measures the distance the piston travels over a set time. This approach eliminates the need for manual cutting and weighing of the plastic.
It is the preferred technique for materials with high flow rates or for high volume laboratories.
Piston Displacement
The equipment records the exact start and end positions of the plunger.
Software Calculation
Algorithms determine the flow rate by multiplying the displacement by the cross sectional area of the barrel. Because method b volume flow relies on electronic timing, it offers higher repeatability than manual methods. The system can take multiple readings during a single test to ensure consistency.
This data is then converted into a volume flow rate expressed in cubic centimetres per ten minutes.
Processors Utility
Injection speed settings on the machine depend on this information. Knowing the method b volume flow allows for a direct comparison between different resin batches without the influence of density changes. This value helps in predicting the fill time for complex moulds.
Reliable flow data reduces the time spent on trial and error during the startup of a new job.