Helix Angle

3-D Screw.jpg

The helix angle is the angle of a screw flight relative to a plan perpendicular to the screw plane. Although the helix angle is not commonly altered from the standard square pitch, such a change can have a significant impact on processing.

The standard helix angle for most injection and extrusion screws is 17.6568º and is calculated as follows (a square pitch screw):

Helix Angle = arctangent of Lead/∏ x Diameter

A change to a smaller helix angle, hence more flight turns per diameter:

  • reduces the axial melting length;
  • conveys stiffer materials with greater ease (and less torque);
  • reduces the rate at which material is conveyed.

Changes in the helix angle are more common in two stage screws and special mixing screws than in metering screws.

Contact us for more information!

Get a FREE Quote

Industry Applications - Resins

See what Reiloy Westland Corporation screws can make!