Figure 16 shows the effect of screw helix angle
on the screw characteristics.
It may be noted that similar results were obtained for different values of the helix angle
([Theta]) without adding similar figures in this paper.
In a screw rotating within a barrel, the velocity in the mixing channel is influenced by (i) the relative motion of the screw and the barrel, (ii) the helix angle
of the mixing head which make the drag flow induced by the barrel at an angle to the relative motion, thus producing a secondary flow transverse to the mixing channel, (iii) the adherence of fluid to mixing flights as well as channel walls and barrel which creates a velocity distribution between the flights.
It is therefore necessary to calculate the flow profile to find the shear and elongation rates, the axial (down-channel) pressure gradient, and the backflow and to see how these parameters vary with rotation speed, throughput, helix angle
, and viscosity.
b], the barrel velocity, at an angle of [Theta], the helix angle
, to the stationary screw channel.
The larger long wing helix angle
considerably increased the axial flow of material iN the mixer chamber (figure 4 and table 4).
Twist multipliers are also included to provide a measure of helix angle
and inherent fatigue resistance.
Larger helix angle
of long blade gives better mixing performance.
The ring-type cutter must be set at the appropriate thread helix angle
Comparing helix angle
([Beta]) and taper angle ([Alpha]) in design points 2, 4, 8, we find that as the helix angle
increases, the taper angle must be decreased to satisfy these design criteria.
The Super Profiler Helical Cutters (left in photo) feature all effective cutting flutes in a negative helix angle
for high feed and metal removal in contouring and profiling operations.
Depending upon the helix angle
of the rotors, this flux may be backward or forward.