law curve from equation 2

[o0omirkoo0o]

Hi everyone.

I'm trying to generate a law curve using an equation.
The purpose of this is for creating a worm gear.

I have this data that i added into expression section:

Axial_module = 3
Normal_pressure_angle = 20
No_of_teeth = 30
No_of_thread = 1
Reference_diameter1 = 45

then i added this formulas too, ( NX automatically set then as lenght in mm):

Addendum = Axial_module
Tip_diameter1 = Reference_diameter1+(2*addendum)
Base_diameter1 = reference_diameter1*cos(normal_pressure_angle)
Tooth_depth = 2.25*Axial_module
Root_diameter1 = Tip_diameter1-(2*Tooth_depth)
Axial_circular_pitch = pi()*Axial_module
Teeth_thickness = Axial_circular_pitch/2
Semitopping = 0.1*Axial_module
Worm_facewidth = pi()*Axial_module*(4.5+(0.02*no_of_teeth))

Now, i'm adding also these formulas for a law curve and here start to get errors.
Main issue start from the theta, that seems i can not add unless i set a value for the 't'. If i add t=0 then i can proceed till the Yc formula.

theta = 90*t
base_radius1 = base_diameter1/2
angle_ratio = theta/360 ( need to fix the theta before add this )
S = angle_ratio*pi()*base_diameter1
Xc = base_radius1*cos(theta)
Yc = base_radius1*sin(theta)

When i start to add X and Y formula,

X = Xc+(S*sin(theta))

i get this error

and i can not add Y.

Y = Yc-(S*cos(theta))
Z = 0

I saw to add in a different MCAD ( creo ) the 't' without any value..
Any idea?

Thanks to everyone

 

[cowski]

Start a new metric file and import the expressions (attached). They give an output without any error messages, but I think I made an error somewhere as the output is only 1/4 of a circle. However, I hope that this gives you something to start with.

www.nxjournaling.com

 

[mmauldin]

I usually change the dimensionality to "Unitless" when whenever I am using equations. This prevents mixing angles with lengths and length x length turning into areas.