REPEAT ALONG A SWEEP

[MB_3972011]

Dear all, 

I'm using CREO 10

i would know if could be possible to repeat a part along a sweep feature keeping a specific orientation compared to the assembly, for example i would:

-repeat the grey part along the sweep cut keeping the same reciprocal alignment

-merge all the bodies obtained in a single one

-subtract the body obtained from the white one

the result should be similar to this one

but the way that i obtained it, is not easy to use and to manipulate and the subtract command always fail.

Maybe there is another way that i haven't considered how to do this. 

Thanks  previously for the help

[tbraxton]

It is not clear to me exactly what you are asking. Look at this function as it may provide the resultant geometry you are seeking.

About Volume Helical Sweeps

[MB_3972011]

Hi,

From  what i have understood i can use this function only if the body is obtained from a revolution but the body that i'm considering is something with a particular shape like a shaped bottle. 

Thanks

[tbraxton]

I am still not clear on exactly what you need to do with the geometry. Can you explain the requirement of "-repeat the grey part along the sweep cut keeping the same reciprocal alignment" with some sketches or screen shots.

The picture in the first post of the desired result looks like a result of a helical sweep (helix trajectory) of a constant cross section with a variable pitch.

[MartinHanak]

Hi,

I think OP wants to simulate material removal using a special tool along a special path.

[MB_3972011]

Hi, 

imagine a situatuon like this one .

Feedscrew with orange ext diameter and light blue inner diameter. 

If i'll consider as diameter of the "housing" the yellow one the housing will be too small, if i'll consider the violet one'll be too large. 

So i can't consider a section only and i'ts not a revolution.

Consider also that this ll change also according to the pitch along the feedscrew. 

Another case is when u have shaped bottles so i can't consider it as a revoluted object, hope i was clear enought. 

Thanks

[tbraxton]

You are in need of a design that will be equivalent to this mechanism for a specific shape of bottle?

[MB_3972011]

Someting similar but in this case,m as the feedscrew is touching the bottle only on the "most big " dimension, there isn't the problem that i explained. 

From what i see these feedscrews are also tilting the bottle from longside leading to short side leading in this case but i don't need this up to now. 

Thanks

[tbraxton]

If the position of the bottle is constant relative to the feed screw cylinder, then a volume helical sweep will generate the volume needed to cut the screw. You would define the section in the volume helical sweep by using the bottle profile. Unless I am missing something it looks like this would work.

If one is to assume that the bottle position varies with respect to the axis of rotation of the feed screw, then it becomes more complicated.

[MB_3972011]

Hi, you are perfectly right in this case but unfortuantely i have to work also with bottles like these that aren't obtained by a revolution of a section. 

Image just for reference. 

Just to recap, problems arrives once i have both conditions verified :

-feedscrew placed at an height different from the "bigger section" position

-bottle/section not obtained by revolution. 

 

[tbraxton]

If the volumetric helical sweep is not suitable then you may have to develop a custom solution.

Summary of known limitations:
• Volume Helical Sweep only provides geometric operations to remove material. You cannot create or add material.
• The section that defines the cutting tool may only contain lines and arcs forming a convex shape.
• Geometric conditions leading to self-intersections of the calculated envelope inside the cutting area are not supported as described in the following cases:
• When trajectory radius is smaller than the tool radius
• For setup and geometry-dependent ranges of adjustment angles
• The helix trajectory is regenerated by this feature, cannot be referenced to (free) curve and is limited:
• The axis of rotation is straight
• The helix amplitude is a free sketch
• But the pitch is linear (or constant), however it can be adjusted to a set of multiple linear pitches in a row
• Use this to work around any non-constant pitch
• The success of the geometric operation may be dependent on part accuracy. It is recommended to use absolute accuracy with values ranging between o.oimm and o.ooimm.

Creating this type of geometry is not trivial and most CAD systems would have similar limitations. Inventor has an add on extension to design feed scrolls.

Feed Scroll Generator

[MB_3972011]

Up to now i've been able to generate a similar resut with a geometry obtained by a surface cut on multiple points. 

A quite complicate solution but seems a relly strong and robust result, Also the definition of the pitch etc is done in really helpful way. 

I still have to do tests with a non circular surface but it looks promising. 

Attached the video tutorial. 

https://www.youtube.com/watch?v=GpCUbKinj04