Chamfer Issue

[Anonymous]

I have a cylinder here with 2 holes through it. One of the holes I am
applying a chamfer to both ends. The problem is that the chamfer IV is
creating is not the same on both ends. Please see attached.

Maybe I am missing something very fundamental

Troy

IV10 sp2
win 2000

[hallstevenson]

I think you need to check the part back in before you post it. I can only look at things, not edit anything.

I did see that the chamfer preview only shows (2) preview lines vs 4-6 on the other side....

[Anonymous]

Looks like you found an interesting bug.

But I would be very careful about using a chamfer on that feature anyway - you do realize a chamfer will not give you the same geometry as a standard revolving cutting tool?
(see attached)

[Anonymous]

> think you need to check the part back in before you post it. I can only look at things, not edit anything.

You can edit it - but do a Save Copy As...

[Anonymous]

JDMATHER wrote:
> Looks like you found an interesting bug.
>
> But I would be very careful about using a chamfer on that feature anyway - you do realize a chamfer will not give you the same geometry as a standard revolving cutting tool?
> (see attached)

Yes I realize that. I was fooling around with a few things when I
stumbled upon this.

[Anonymous]

that is strange,

I tried removing the one chamfer feature and adding 2 separate chamfers, one
for each hole.,
I got the same result. one does appear to be bigger than the other

what I DIDN'T do was try to create a drawing of the part and do a cross
section to see if in fact the chamfer was different. Ahhh time constraints
in life..

Give it a try and see what you come up with.


"Troy Grose >" <"mount_mordor ATbITTmEsPAM Hotmail DOT com">
wrote in message news:5026004@discussion.autodesk.com...
JDMATHER wrote:
> Looks like you found an interesting bug.
>
> But I would be very careful about using a chamfer on that feature anyway -
you do realize a chamfer will not give you the same geometry as a standard
revolving cutting tool?
> (see attached)

Yes I realize that. I was fooling around with a few things when I
stumbled upon this.

[Anonymous]

There are different methods of solving a "chamfer" that will satisfy numeric
input (D x D, D x A, etc.) and give different results on a cylindrical surface.
I ~thought~ that ACIS only used a rolling ball solution, but that's apparently
not true (going from discussion, can't see part). Is there perhaps something to
be seen if you expand the dialog; some solution option choice?

[R.Corriveau]

"I ~thought~ that ACIS only used a rolling ball solution"

Wouldn't that apply to fillets and not chamfers?

[R.Corriveau]

"going from discussion, can't see part"

[Anonymous]

>(going from discussion, can't see part).

Here ya go. I added a hole with revolved cut "chamfers". The other hole has chamfers made as one feature (it doesn't matter if done with one feature or two - the results are the same, that is the chamfers solve differently).

[Anonymous]

Well it's a good thing I really don't have to make the chamfer like
that, but boy it's not good when IV can't seem to solve what I think is
a pretty simple part:~/

JDMATHER wrote:
>> (going from discussion, can't see part).
>
> Here ya go. I added a hole with revolved cut "chamfers". The other hole has chamfers made as one feature (it doesn't matter if done with one feature or two - the results are the same, that is the chamfers solve differently)=

[Anonymous]

> Wouldn't that apply to fillets and not chamfers?

Well, this is a stretch for me, so take it with a grain of salt:
Either one. I think the analogy is rolling a ball and tracing the tangent /
contact point. That trace describes the trim curve for the existing surfaces.
For the fillet / round the ball also provides the section. For the chamfer a
"ruled" surfaces is created. I think the term is actually used in reference to
both in the ACIS documentation.

> "going from discussion, can't see part"

That's interesting. Comparing it to the attached (shows two solution options);
it appears that the "shape" is the same on both ends of Troy's, just different
dimensions. Looking along the bore axis may be more telling in that regard?
I'm baffled. Maybe Autodesk will pick up on it and enlighten us.

[Anonymous]

> Here ya go.

Ah! Sorry, JD. Didn't intend to ignore you. DWF's don't show up on news
readers. OE, could see a 32 kb post with no attachment or ...?, so had a look
via the web interface.

I think there might be a clue there; looking at the internal "seam" edges on the
chamfer surfaces. If the reference is established in those locations it will
probably explain the difference in size, tho' think it's the reverse of what I'd
expect. Why one is at zero degrees (ref'd the cylinder axis) and the other is
rotated 90 is a mystery. I tried duplicating that in IV6 and couldn't get a
mismatched set of chamfers. Thought maybe where the "pick point" was
would make a difference, but not so.

[Anonymous]

Troy, if you needed to make such a thing, I found a couple of ways to do it.
Since the chamfer is applied differently between the "entry" edge and the
"exit" edge, you can create a hole from each side so you have two entry
edges, or extrude cut both ways from the center plane to get two exit edges.
Workaround, though- shouldn't be necessary.
--
Sam
Eli Lilly and Company, Indianapolis

"Troy Grose >" <"mount_mordor ATbITTmEsPAM Hotmail DOT com">
wrote in message news:5026275@discussion.autodesk.com...
Well it's a good thing I really don't have to make the chamfer like
that, but boy it's not good when IV can't seem to solve what I think is
a pretty simple part:~/

JDMATHER wrote:
>> (going from discussion, can't see part).
>
> Here ya go. I added a hole with revolved cut "chamfers". The other hole
has chamfers made as one feature (it doesn't matter if done with one feature
or two - the results are the same, that is the chamfers solve differently)=

[Anonymous]

Thanks, but I don't need a workaround.

Troy

Sam Bixler wrote:
> Troy, if you needed to make such a thing, I found a couple of ways to do it.
> Since the chamfer is applied differently between the "entry" edge and the
> "exit" edge, you can create a hole from each side so you have two entry
> edges, or extrude cut both ways from the center plane to get two exit edges.
> Workaround, though- shouldn't be necessary.

[Anonymous]

I assume you have discovered that creating the hole by subtracting a circle
(cylinder) from the center of your cylinder outward in both directions does
not create this problem.

kp




"Troy Grose >" <"mount_mordor ATbITTmEsPAM Hotmail DOT com">
wrote in message news:5026004@discussion.autodesk.com...
JDMATHER wrote:
> Looks like you found an interesting bug.
>
> But I would be very careful about using a chamfer on that feature anyway -
you do realize a chamfer will not give you the same geometry as a standard
revolving cutting tool?
> (see attached)

Yes I realize that. I was fooling around with a few things when I
stumbled upon this.