Posi-Melt^™ MB Barrier Screws

Why Posi-Melt^™ MB Barrier Screws?

The Posi-Melt^™ patented feed screw is a core change to the geometry of the antiquated general purpose “GP” screw technology developed in 1950s. The Posi-Melt's^™ unique flight design alters the flight pitch and root of the screw through the melting section making them un-tangential with each other disrupting laminar flow. The geometry increases plastic exposure to the barrel wall by up to 60% delivering a uniform homogenized melt. The Posi-Melt^™ is the most versatile screw technology available in the industry today for delivering a high-quality melt at a low manufacturing cost. The design has succeeded processing resins from LCP to PC and Rigid PVC with diameters from 14mm through 240mm.

The MB-XLA™ is a barrier mixer screw using the Posi-Melt™ and MB-XLA™ geometries. The screw utilizes a unique barrier section with the barrier starting on the trailing edge of the primary flight and catching up to the same flight downstream on the leading edge. The MB barrier forces the polymer between the barrier flight and the barrel ID for added extensional strain to complete melting.

To compete with the best parallel barrier designs in the world for output, we designed our own High Output Posi-Melt screw that utilizes a unique barrier section that is similar to the Mallifer concept only that our barrier starts on the trailing edge of the primary flight and catches up to the same flight downstream on the leading edge. Forcing the polymer over a barrier land increases the likeli-hood that each pellet will be thoroughly melted. The MB-XLA™ design is used in applications where there is a need for High Output, the residence time is < 90 seconds and or the swept volume is > two diameters or where there is a need for exact color matching.

Our proprietary “MB” barrier forces the polymer between the barrier flight and the barrel ID for added extensional strain to assure complete melting. We can couple the “XLA” mixer to the Barrier for processing a variety of resin groups including PP, HDPE, LDPE, PS, PET, ABS, and other groups delivering the highest outputs and homogenization available. All Posi-Melt screws are designed to have an adequate feed depth to promote solids conveying to build pressure for moving the polymer through the transition and metering zones. Additional care is taken to design-in the proper leading and trailing edge radii to avoid low velocity sections in the channel and to maximize the pressure. The benefits of our design are color and material change over times are reduced compared to our competition because these is no need for two separate channels to achieve thorough melting and good dispersion the channel is 100% pressurized throughout for positive solids conveying, melting, and pumping.