Surface Modeling for Mechanical Design?

[jeff4136]

View attachment 1902


2006-03-02_164324_double_helix_var_pitch.prt.zip (WF2)

This is actually in response to a similar discussion on another forum but thought it might be of interest to some here as well and, maybe, prompt other contributions.

Anyone want to model the entire screw?

http://home.pct.edu/~jmather/IMAGES/EX-SCREW.jpg
Edited by: jeff4136

 

[solidworm]

 

[design-engine]

thats an impressive screw... I am sorry i missed it. Why does it need to look like that?I have learned from Jeff's trajpar posts too. Thanks.
Edited by: design-engine

 

[dgs]

Is this a screw from an injection molding machine barrel?

 

[mcgowanp]

Hey lads, anyone know why I have no active sketch tools when in the helical sweep graph??


Paddy

 

[jeff4136]

I don't know anything about the design criteria for that or the specific
application. I ran across someone trying to figure out how to model it,
was just getting my Pro/E feet wet and ... there it is.


As for the modeling techniques and function creation details; I had to
relearn what I'd done there. Helical sweeps aren't something I use
frequently.


Unlike a regular Graph feature, the Pitch Graph is just an indicator.
No sketch entities are created in it. The function allows you define
intermediate pitch definition points (sketcher points in the Swp Profile)
that define position and enter pitch values in the Pitch definition.


The curves shown in the Pitch Graph are system created monotone segments
between points. (Monontone = constant sign slope, e.g. not inflected.
Someone with a better head for geometry than I will have to explain the
details, but as I see it what you're defining with a pitch value is the
tangent vector slope at that point.)


In the attached:
. Edit Definition (Surface id 40).
. Select Swp Profile and Define, Modify, Done, Sketch.
.. Note the Sketch Point on helical axis (I think it can be acually
be anywhere; the Y axis displacement is what's important.) Ok
or Cancel out.
. Select Pitch and Define.
.. Arrange / resize the graph window so the Sweep Profile can be seen.
.. Select Add Point on the Menu Manager and pick the Sketcher Point.
.. Note the Pitch value (it corresponds to existing curve) and change
to suit.
. To add another Pitch definition point; modify the Swp Profile, add
another Sketcher Point, Modify Pitch, Add Point, etc.
. To Change Value; pick the point in the main graphics window (showing
the Swp Profile) rather than the value in the Pitch Graph window.
(WF2 attachment) 2008-10-11_213228_var_pitch_var_rad.prt.zip

 

[kdem]

Hey lads, anyone know why I have no active sketch tools when in the helical sweep graph??


Paddy

When you are in the sketcher environment check Tools>Customize Screen to see if the Sketcher Tools option is checked.

 

[jeff4136]

The Helical Sweep Pitch Graph (which I think is what's intended) is not a sketch environment.

 

[kdem]

Ah, My misunderstanding.

 

[mcgowanp]

Yeah mine too, shows how much I have used the pitch by graph option!! So did anyone actually model the whole screw??