Blend in NX

[cubalibre000]

Hi,
I've imported a plastic part made with other CAD.
I need to make some modifications via ST and some blends must be removed.
Now I need to recreate these blends.
As you can see in the 'blend' image, the radius in the hole on inclined surface is 'constant'.
All blends on this part are like this.
I'm trying to create blend, but as you can see in the 'blend nx' image, the behavior is different.
There is an option in the blend command to obtain this result ?

Thank you...

Using NX 8 and TC9.1

 

[moog2]

use the face blend command, and pick "tangency constraint" , If you create a plane at an offset from your outside surface, then create an intersection curve with it, and the hole surface, use that curve as the tangency curve, then you can easily vary the radius with the plane offset.
If you want to use the blend feature, you could use the "variable radius points" but it won't be as good as the face blend , as it'll be more of a free-hand type of adjustment. (unless someone else can suggest a cunning way of setting it up ??)

 

[JohnRBaker]

Attached is one approach, showing a side-by-side comparison with a conventional edge blend.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[cubalibre000]

Hi John,
your example doesn't match to what I need.
The blend has constant cord.
Maybe can be done with Aesthetic Face Blend, but I've Mach 1 license, and Aesthetic Face Blend need Mach 3.
I attach an image of what Catia do.

Thank you...

Using NX 8 and TC9.1

 

[JohnRBaker]

If Catia does this and is there's a consensus that this is truly a useful capability, based on our recent success with moving several major customers from Catia to NX, I would expect that this may be addressed sooner rather than later (no guarantee, just a suspicion).

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[Toost]

Here's a slightly simpler method using the tangency string mentioned by Moog. ( NX8)
The offset in face has a few different algorithms which might give different results.

But, a little remark on the "result", - If we do this , the radius will be constantly changing since the cord is locked and depending on the manufacturing method of the part it might need extra manufacturing time / cost. - Instead of a single full size cutter all around.
- The part is saved in face analysis display mode showing the varying radius.

Regards,
Tomas

 

[cubalibre000]

Toost,
the Moog solution doesn't produce the correct result.
In mechanical design, maybe this blend is not important, but in consumer product is used very often.

Thank you...

Using NX 8 and TC9.1

 

[Toost]

i somehow missed the attachment...
Have a look.

Regards,
Tomas

 

[cubalibre000]

Hi Toost,
this workaround is excessive if you have lots of this situations.
Aesthetic Face Blend does without wa, but you need Mach 3 license, while Catia and Solidworks do in the basic license.

Thank you...

Using NX 8 and TC9.1

 

[Toost]

Agreed that it is a extra workaround, since the offset in face curve and the extra selection of that curve in the face blend, but i realized after sending the example that it could have been made slightly simpler, one can select the edge(s) to blend instead of the faces, which saves a few clisks. - The Face Blend will still highlight/select the faces in face chain 1 and 2.



Regards,
Tomas

 

[Xwheelguy]

So put an ER in if you feel the workaround is excessive. It's just phone call or online form away. Given it may be a little more work, at least you can achieve the result and not just stop in your tracks, right?

There are about 3-5 different ways to achieve the same result, but few will involve using Edge Blend. Have you tried using a Variable Radius Edge Blend, inputting different values along the sharp edge? Not as pretty, but it MIGHT work. Given that you've not shown concern about continuity, I don't really see how a chordal blend is going to be that much visually different than a Face Blend on a physical part, but I do understand that the point is to make the task easy as well as matching any data you already have.

Another method that would work is similar to what Toost suggested using Offset Curve in Face. Start by using the sharp edge and an offset value that's half of the chord distance on each side of the sharp edge and then using a Soft Blend. Same principle as the Face Blend but allowing you to control BOTH tangent edges. This type of Face Blend will give you additional control of the cross sectional shape of the blend (depth/skew) as well as adding G2 continuity as an option, something CATIA doesn't offer with their basic blend (for which you're probably paying more money, if I recall correctly). Speaking of which, I believe the cost of adding a full suite of Shape Studio with NX's Advanced Designer bundle is still cheaper than a P2 seat of CATIA. I could very well be wrong, as it's been a few years since I've had to deal with pricing either software. If you're doing any sort of mid-range to advanced styling, then you'd be wise to invest the extra money in getting the higher-end NX Mach license at some point in time.

I put an ER in for conic/elliptical Edge Blends as well as chordal length blends either just before or very early into the NX series of what used to be UG and it wasn't until NX8 that the conic Edge Blend appeared (ironically AFTER I changed jobs and no longer had a need for it) - so you aren't the only person out there going through frustrations like this. Sometimes software developers are slow to listen to the users, just seems to be the nature of the beast at times. Siemens at least listens to their users outside of the country that holds their headquarters (something I cannot say for CATIA, given my short experiences with them). How many Dassault employees do you see answering questions in the CATIA forum? While today you may be frustrated, at least you KNOW there's an ear belonging to Siemens that is listening and I'm quite sure that "the ear" doesn't just let things sit if there is any substance to it.

Hope you get your problem resolved.

Tim Flater
NX Designer
NX 7.5.4.4 MP2
WinXP Pro x64 SP2
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB

 

[Xwheelguy]

Didn't see it until later, but I didn't intentionally omit moog2's suggestion as being along the same lines as the workflow of creating a Soft Blend. I had just skimmed through the thread without making note of who posted what and overlooked moog2 - sorry for that, moog2.

Tim Flater
NX Designer
NX 7.5.4.4 MP8
WinXP Pro x64 SP2
Intel Xeon 2.53 GHz 6GB RAM
NVIDIA Quadro 4000 2GB