Molded Corner Boss

[gregfox]

I have a box with a boss in one corner (some distance from the wall), and I’d like to add two ribs (tangent to the outside of the boss OD, and each perpendicular to the inner wall of the box. I extruded the box and boss with a 1 degree taper.

My question is how to draw the sketch for the ribs so that they mate with both the boss and the sidewalls. I tried using the edge of the top of the box and outer (smallest diameter due to draft) of the boss (Convert Entities)to serve as the boundary for the rib, but got a space when I extruded up too the top of the wall. I know I can simply have the lines go in more to both the wall of the box and boss, but for arguments sake, lets assume a draft angle is such that would cause those lines to extend outside the box.

Is there a best way to do this from the bottom of the box and have the ribs be extrude with a draft rather than rib profile sketches on the wall sides extruded to the boss?

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[Eltron]

Can you post an example?

Dan

http://www.eltronresearch.com

Dan's Blog

 

[applejack2]

try the "rib" feature.

 

[CorBlimeyLimey]

Have you tried using the Insert > Fastening Feature > Mounting Boss function?

 

[gregfox]

I will look at the tried using the Insert > Fastening Feature > Mounting Boss function. I'm using SW 2007.

I'll post a pic later, thanks

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[gregfox]

here are the sketch and extruded pics

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[Eltron]

You can just do a sketch on the face of each of the legs of your boss, convert entities, and extrude up to the walls.

Dan

http://www.eltronresearch.com

Dan's Blog

 

[MDGroup]

There are a lot of different ways; you need to find what works best for you.

You can put the sketch on the top face; extruding down into the part. This way the draft is positive and the ribs will get larger; rather than getting smaller and leaving a gap. Extrude 'up to next' or 'up to body' so it doesn't break thru any of the side walls.

You could create all of the features without draft, and then add draft to all surfaces afterwards.

You could create a skecth on the 'gap' surface between the rib and the outer wall. Extrude a feature to fill in the gap. (Make sure the direction of the extrusion is the top edge of the part, not just normal to the drafted part)

Check out 'Delete Face'. It is a very powerful tool. You should be able to just Insert->Face->Delete and select the rib surface where the gap is. SW will just fill it in up to the side wall of the part. (A slightly hack command, but very useful)

Good Luck.

 

[applejack2]

here is an example with the rib feature.

 

[gregfox]

Eltron,
Do you mean what MD suggests, w Insert->Face->Delete?

MDGroup

Basically, I don’t know why my method gave me the gaps.

Going down, you would have to calculate the required wall thickness, which can be a pain, if you are changing box depth dimensions. Though I suppose I could make a formula in the width dimension of the sketch. At that rate, I should just have things stick up and trim everything with a cut extrude like a fly cutter or your face trick. Either way, they are more work than should be necessary…

Of course my preference is to apply draft in the end, but sometimes like radii, it does not always behave with intersecting faces. That and when designing top up, you can get odd errors when features change (e.g. radius eliminating a referenced edge)

applejack2 Is that with a draft?

Just as I asked that question and thought how it might be different from my part, it hit me. I THINK the draft was my problem, I was assuming that just the wall width dim were being drafted, but since it is not just two lines, but a rectangle, the sides were drafted as well. What an idiot… That is the trouble working in a vacuum.

Probably the best way would be to just put a plane between the wall and boss, and extrude up to next on each, or the rib tool.


Fox Manufacturing Group (Machining and Molding)[

http://tjmain.com/foxmfggroup.com/Home.html

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[Eltron]

No. I'm assuming you want your boss to merge with the walls for the height of the boss, right? Just click on one of the end faces of the boss. Start a sketch on that face. Convert all of the edges of that face and extrude "Up to Next" or "Up to Surface" in the direction of the wall. You'll have to do it for both ends of your boss.

Dan

http://www.eltronresearch.com

Dan's Blog

 

[applejack2]

I think I forgot to draft the box walls. here is an updated model.

 

[gregfox]

I think the plane between the boss and walls is the best option if I don't want to draft the faces after the fact, then mirror the boss and ribs. I'll play with the rib tool too.

Thanks for all the advice!

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