Helical Cut Creation

[jmh]

I'm trying to create a helical cut along a part. I'd like the cut to extend along the y axis and turn about the same axis. Furthermore, I'd like the section of the cut to be constant when viewed along the y axis. Is this possible? I've tried creating helical sweep cuts but the section of the cut doesn't create in the direction I want it to.



Thanks!

 

[ProFishent]

Under Attributes make sure you specify thru axis, this will make it normal to the y axis. Also you can specify right or left handed.

 

[jmh]

Thru Axis creates a cut, extruded along the y axis, that is a constant section when viewing the xy plane. I want my cut to be a constant section when viewed perpendicular to the xz plane. Sorry if this wasn't clear earlier.

 

[mmead0ws]

I've seen a helical sweep created that mimicked what you want, but the geometry wasn't accurate to the sketch. Basically the sketch was at an angle to the y-axis.



I created a twist like this using a blend feature. However depending on the section, even the blend feature created some irregular cross sections. (never did figure that one out)



The third option I tried was a style feature. Creating the wireframe of the feature was time consuming and some companies don't own ISDX; but it made my geometry, constant / accurate sections and all.



I would suggest using the blend feature. It should have the best chance of working. It is a little more difficult to determine the pitch with a blend feature.



To get the geometry, create enough sections that the minimum rotation between any two sections is 45 degrees. If this is a tight pitch (creates several twists in the cut), don't create more than 1 pitch length (1 revolution) in the blend feature.



Copy the surfaces of the finished blended cut. Transform the surface copy along the y-axis one pitch length. The open ends of the surface transform should touch the bottom edges of the blended cut. Create a cut using the surface transform.



Finally, group and pattern the surface transform and the cut for as many revolutions as you need.



This is a lengthy workaround, but if you try to place all the sections in one blend feature, it will bring Pro/ENGINEER to its knees.



If anyone has a better method, I'd like to learn it.

 

[ProFishent]

Create a datum curve thru the axis of revolution

Create a coordinate system at the base of the curve

Create a datum curve from equation, use a cartesian csys

xor=5

yor=5

x=xor*cos(t*360*50)

y=yor*sin(t*360*50)

z=t*50

Create a Variable Section Sweep. Select Normal to Origin Traj. Use the first curve as the origin trajectory, use the helical curve as the x-trajectory. Sketch your section, and Viola!

 

[ProFishent]

Forgot to explain the equation



xor=x=radius

yor=y-radius

x=xor*cos(t*360*number of revolutions)

y=yor*sin(t*360*number of revolutions)

z=t*length along z



I use this equation because you can make an oval by varying xor and yor.

 

[ProFishent]

If you have a hard time with this shoot me an e-mail and I'll reply with an example part you can use. I do this all the time, my company makes a lot of drill bits. We are on version 2001.



rouleauc@synthes.com

 

[jmh]

ProFishent, that worked quite nicely. Thanks!

 

[ProFishent]

Glad to help!

 

[mmead0ws]

I gotta try this! It looks so simple. Thanks ProFishent!

 

[js4817]

ProFishent, can you send me the file of how to create the helical cut. I just want to learn more, if possible ca you please tell me the sequence??? Your help is appreciated!!

 

[donseib]

For creating a thread, should I make the curves (and length in formula) extend beyond the start and end surfaces? Also, how can the formula be changed to reflect a tapered (NPT) thread?