Presenting The

Master Craftsmanship In

Barrier Feed Screw Technology In India

By Raj Engineering Works

At REW every month we makes more than 200 sets of Barrier type screw barrel, some of them are larger than 3000 mm up to 7000 mm in length. 

But before reading more about our Barrier Screw Barrel let's learn some information about Barrier Screw Barrels.

What is a Barrier Screw ?
In short, Barrier screws are a way to increase throughput of single-screw extruders and to improve melt quality. They keep unmelted solids in the primary screw channel by increasing the flight clearance on the downstream side, while letting the fluid melt escape over the barrier flight into the secondary channel. That way, the solids don't randomly disperse into the metering section. This allows for extrusion at higher pressures and higher rates without sacrificing melt quality.

APPLICATION AND ADVANTAGES OF BARRIER SCREW

Barrier screws have a number of advantages, but the most important is the ability of the designer to pinpoint the location where melting is to be completed. In conventional screws, the typical melting pattern occurs in the compression section. The channel depth is gradually reduced in this region, forcing unmelted polymer outward, where it is subjected to high shear forces that cause it to melt.

One of the advantages of barrier screws is that for the most part they eliminate the problems associated with solids-bed breakup that are typical in conventionally flighted screws. Many conventional screws have to rely on restrictive mixing sections to complete the melting process because solids conveyed into the metering section are difficult to melt. With barrier screws this is essentially eliminated, as solids are trapped in the solids channel until they pass over the barrier and/or a high-shear section at the end of the barrier section.

Barrier screws are a way to increase throughput of single-screw extruders and to improve melt quality. They keep unmelted solids in the primary screw channel by increasing the flight clearance on the downstream side, while letting the fluid melt escape over the barrier flight into the secondary channel. That way, the solids don't randomly disperse into the metering section. This allows for extrusion at higher pressures and higher rates without sacrificing melt quality.

Barrier screws are popular in applications like blown film that require low melt temperature and high output rate with consistent melt quality. Today many barrier designs also incorporate a mixing section to maximize extrusion quality. In injection molding, barrier screws reduce recovery times and improve melt quality.

Screw diameter 22 mm to 250 mm

Screw length up to 5000mm in one piece and 9000 mm in Two piece.

Barrel OD upto 350mm.

Materials:

EN41B Nitriding steel (Musco) (default), German Imported 41CrMoAl7 Equivalent, China's 38CrMoAlA also available on special request.

Hardfacing alloy Stellite and Colmonoy 

Hardfacing Superalloys- Inconel, Hastelloy.

Gas nitriding: Thickness from 0.5 to 0.7 mm, hardness ~ 60-75 HRC ~ 1000 HV.

Plasma Nitriding on special request also available.

Hardchrome plating as default process in all screw.

Bimetallic treatment with HSS M type or Tool steel D2.

Ultimate solution for abrasive and wear resistance WCNi Carbide Matrix composite with 88% Tungsten metal.

Production time: Within 2-4 weeks depending on the complexity of the part.

Call Now +91- 8128381431 (24x7 technical helpline), 9924225214, 7874581018, 9558327739

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