Screw And Barrels

THE SCREW FOR INJECTION MOULDING MACHINE

Application

The barrier design is solution to application where high-output is needed. The melting efficiency of barrier design is better than a conventional compression screw and we can design the screw depper for more throughput.


Advantage

• Highest throughput in the industry
• Low melt temperature
• Highest efficiency of any screw design
• Melt quality can be controlled by varying the barrier gap
• Less back pressure required

How does the Barrier Screw Works?
   
The feed section establishes solids convey in the same ways as a conventional screw. At the beginning of the transition (compression) zone, a second flight is started. This flight separates the solids channel from the melt channel. As material progress down the transition, melting continues as the solids are pressed and sheared against the barrel, forming a melt film, the barrier flight moves under the melt film and the melt is collected in the solid pellets and melted polymer are separated and different function are performed on each.

The melt channel is deep, giving low shear and reduction the possibility of overheating the melted pellets against the barrel for efficient frictional melting, breakup of solids bed does not occur to stop this frictional melting. The solids bed continues to get shall over and finally disappears into the back side of the primary flight.


PLASMA NITRIDED

Long life
Very good abrasive



BARRELS

Hikon supplies a complete range of injection barrels selected to much customer requirements. The barrel construction ranges from the ultimate wear resistance by doing plasma nitride process compare to economical nitride Barrels.

Product Description

• Extruder barrel screw specifications:
• Diameter: φ15-φ300
• Length-diameter ratio: L/D=15-46
• Injection molding machine melt glue tubing (barrel) screw specifications:
• Mould clamp force: 250t-3200t
• Injection amount: 30g-2500g
• Technology index:
• Nitriding layer: 0.5-0.8mm
• Nitriding hardness: ï¼?950HV
• Nitriding brittleness: ＜level 2
• Linearity: 0.015mm/m
• Surface roughness: Rao0.4/m

Vented or two-stage screws are applied when volatiles must be removed in order to make a satisfactory product.    


How does a vented screw function?

First, it reduces the melt pressure to atmospheric, so there is no tendency for the polymer to be pumped out the vent opening. That is accomplished by increasing the channel volume so that the output of the extruder only partially fills the flights under the vent.

A vented or two-stage screw is essentially two screws on the same shaft. The first works as a conventional screw by feeding, melting, and conveying the polymer forward. The second screw does the same, except it is melt-fed by the first screw.


The first screw operates with no head pressure, while the second has to overcome any head pressure from the die and other downstream components. In order to keep the vent section of the screw from filling and developing vent flow, the second screw must have more output capacity than the first screw.

Proper venting with no leakage or vent flow does not depend solely on the design of the screw. The barrel vent opening has to be fitted with a contoured plug called a diverter. The diverter deflects polymer away from the opening or else it will quickly become filled with melt. Its design is more of an art than a science but there are many variations that work, all using the same principles.

Design of the vent section of the screw can be optimized for removing volatiles in applications such as devolatilizing printed films and resins that are highly hygroscopic. Another approach is to make a three-stage screw with two vent sections, thereby doubling the devolatilizing area. Also, vacuum pumps can be applied to the vent to remove residual volatiles with low vapor pressure.
 

Hikon provides all designs of mixing zones for proper mixing of the polymer during extrusion.Mixing designs depends on polymer properties and other parameters.

We offer a superior quality of products, which is made using optimum quality raw materials. Our products can be customized as per requirements of our clients as well as several industries. Fabricated in various styles, makes our products suitable for pipes and sheets.