topic Re: difficulty creating unifrom thickness with .75" fillet on top edge in Inventor Forum

difficulty creating unifrom thickness with .75" fillet on top edge

Anonymous — Mon, 18 Apr 2016 21:37:06 GMT

I am having difficulty creating this part with uniform thickness and a .75" fillet on the top edge. All hard edges must be broken for the molding process. Any recommendations on how to proceed?

Re: difficulty creating unifrom thickness with .75" fillet on top edge

JDMather — Mon, 18 Apr 2016 21:55:26 GMT

There are a ton of errors in that file.

You should have stopped at the second Extrusion and asked questions.

Actually, you should have stopped at Sketch1 and asked questions.

I recommend that you start over from scratch and attach your new attempt here as soon as Sketch1 is completed.

Re: difficulty creating unifrom thickness with .75" fillet on top edge

Anonymous — Mon, 18 Apr 2016 22:04:05 GMT

Here is sketch 1 started over. Should i extrude out the lip on the outside and then shell the interior?

Re: difficulty creating unifrom thickness with .75" fillet on top edge

JDMather — Mon, 18 Apr 2016 22:14:14 GMT

@Anonymous wrote:

Here is sketch 1 started over. ...

You have already gone too far.

I do not see Tangent constraints in the sketch?

I do not see Vertical constraints in the sketch?

Inventor should be adding these constraints for you - automatically.

There are a lot of dimensions missing.

I expect that when I start adding the missing dimensions that the geometry sizes won't make logical sense for manufacturability.

Re: difficulty creating unifrom thickness with .75" fillet on top edge

JDMather — Mon, 18 Apr 2016 22:16:11 GMT

@Anonymous wrote:

Here is sketch 1 started over. ...

One of the dimensions is d657?

How can that be?

Did you really really start over?

Do you have a clean template?

Re: difficulty creating unifrom thickness with .75" fillet on top edge

CCarreiras — Mon, 18 Apr 2016 22:16:50 GMT

Hi!

first of all......... fully constrain your sketch.

It's missing 39 dimensions (or geometrical) constrains to keep the sketch fixed and stable, and i believe there are lot's of tangent constrains missing.

Re: difficulty creating unifrom thickness with .75" fillet on top edge

JDMather — Mon, 18 Apr 2016 22:19:26 GMT

This angle looks suspicious to me?

Shouldn't these lines be parallel?

Re: difficulty creating unifrom thickness with .75" fillet on top edge

JDMather — Mon, 18 Apr 2016 22:31:21 GMT

Simply adding some of the missing constraints (that Inventor would normally add for you - automatically) significantly reduces the number of dimensions needed to define the geometry for manufacture.

Re: difficulty creating unifrom thickness with .75" fillet on top edge

Anonymous — Mon, 18 Apr 2016 23:48:56 GMT

Here is the left shell with constraints. I have it down to 1 dimension needed, however, i can not figure out which is needed as it is a closed loop.

Re: difficulty creating unifrom thickness with .75" fillet on top edge

JDMather — Tue, 19 Apr 2016 01:07:12 GMT

Many of your dimensions look like they were just "thrown" on there and don't make logical sense from a manufacturing and inspection perspective. Also, the jump from d327 to d657 going on to d738. They should start from d0.

And given that the part is to be shelled - there is no reason that I can figure out that the offset loop is needed.

I think you can significantly simplify this design. It looks to me like you are reluctant to start over from scratch and it looks to me like you are doing too much work. All of this can be significantly simplfied.

Re: difficulty creating unifrom thickness with .75" fillet on top edge

Anonymous — Tue, 19 Apr 2016 01:49:00 GMT

The dimensions on sketch 1 were needed to constrain each individual line. I tried using as little dimensioning as possible, and went back to try clean up to the minimum quantity needed.

The offset was needed because the feature has a .5" offset on one side and shelled on the interior.

What i am unsure about is how to shell this feature with the topology that it now has, and secondly, how to include the .25" fillet to the perimeter of the top edge?