angle units within expressions

[Anonymous]

I am trying to use expression tan(tool_tipAngle).

The angle is 45 deg but the calculated value is 0.0637707.  As far as I know tan(45 deg) = 1.

Why??

Thanks

Marek

[Anonymous]

What is the diameter of your tool?

[Anonymous]

3/8" dia

[Steinwerks]

Is it using the .01" diameter? Are you using tool_diameter or tool_tipDiameter in your calculation?

[Anonymous]

Actually, I want to have formula to calculate distance from tool tip to full too diameter  ((tool_diameter-tool_tipDiameter)/2)/tan(tool_taperAngle) 

I am getting problem with tan(tool_taperAngle)    the returned value should be 1 for 45 deg.  I have no idea why I am getting 0.0637707 in

I am "cheating" and I use regular endmill to get helical ramp down as I want it. With chamfer tool I am not getting what I want to.

[peter.pretsch]

Hi Marek,

the angle is in radians. You can use the following formula to have the flute length match the tip diameter and tool_diameter.

((tool_diameter-tool_tipDiameter)/2)/Math.tan(tool_taperAngle*2*Math.PI/360)

Kind regards,

Peter

[daniel_lyall]

@Anonymous there's some usefull info here http://nicholscornercam.blogspot.co.nz/2017/06/tool-parameters-for-fusion-expressions.html?m=1

[Anonymous]

Peter,

Does it depends on what kind of field format is the expression used in?

I have tried to enter Math.tan(45.*Math.PI/180) just to verify calculated value.  I found, I do not know why, some inconsistency.

When I have entered  Math.tan(45.*Math.PI/180) into Axial Stock Leave field,  I have got 0.0393701 in.  (2D Contour)

When the same was entered into field Lead-IN Sweep Angle , the displayed value was 1 deg.

Can you please verify if you are getting the same results?

Thanks

Marek

[peter.pretsch · Accepted solution]

I can confirm that i am seeing the same and the reason is that the return value from the Math.tan is automatically treated as a value in millimeters that is then in turn converted to a value in inches.

So yes, you are right that there is different behavior for fields with different sets of units: spatial, angular, velocity etc.

You can circumvent this inconvenience by using this formula in inch documents:

((1 in)*Math.tan(45.*Math.PI/180) )

Kind regards,

Peter

[Anonymous]

Thanks

[Anonymous]

Peter,

On the other hand, Can this behavior be considered as a bug?

Since the unit is set to inch then all numbers should be displayed in the same unit.

If someone wants to use formula to use it in these fields and will not catch it, the result might be  a scrapped part.

Thanks

Marek 

[peter.pretsch]

Yes, this is a known bug that is tracked as CAM-1157.

Kind regards,

Peter