Internal flanges on a simple box

tom_jelly

Trying to build a simple box with internal flanges on the short edges:
https://cad.onshape.com/documents/5f1c31d062bf63ebc9b618df/w/05d2c5137bef06dc4795322a/e/4fbd7d02cc119f2fad494830
but I'm not able to get that to work, and if I highlight the flat portion of the edge of one of the intersecting sides and move the face the face moved is the entire width of the joint so there doesn't seem to be a way to move that face and add the bend afterward.  Am I missing something or is this functionality just not available yet?

tom_jelly

yes, exactly, thanks.  What is the order of operations to get that outcome?

philip_thomas

@tom_jelly thank you for posting a link as that usually helps a lot. In this case however ,i am at a loss as to imagine what you are trying to create.
Do you have a picture you could add to the document or maybe model an approximation of what you are trying to achieve in sheet metal?
Thank you.

tom_jelly

'm just trying to put flanges on the 4 short joints of the box- in the example I provided they would are just butted, but I want a flange inside so they can be spot welded, for example

philip_thomas

@tom_jelly - Sorry, i am a sucky mind-reader (just ask my ex-wife) - is this what you're looking for (flanges on the four short edges for spot welding)?

Ben_Misegades

I'm playing around with it now to try to find a solution. I understand what you want to do, and I think the reason you're having issues is because when you create the sheetmetal box based off of the solid, it's automatically creating those tight corners, which don't seem to respond very well to editing.

I've figured one way out to do it, but it's way too much work, I'll update when if I find a simpler solution.

Ben_Misegades

So unfortunately, to me it looks like the answer to your question @tom_jelly is "no, not really" or at least, not with any method that I've tried.

The issue seems to lie with the "joints" that OS creates. It seems that OS does NOT like it when you break that seam with some sort of feature like a cutout or flange or anything like that, and it fails.

@philip_thomas have a look at my screenshot below. The edge selected is where @tom_jelly wants flanges created (if I'm understanding correctly) that would lie flat against the inner face of the long sides that could then be spot welded. 

NeilCooke

I'll have a look at this later if I have time, but if you take a look at my public Cardboard Box there is an internal flange in that. I think the trick is not to use Convert but build the flanges manually. 

Ben_Misegades

NeilCooke said:

I'll have a look at this later if I have time, but if you take a look at my public Cardboard Box there is an internal flange in that. I think the trick is not to use Convert but build the flanges manually. 

That's essentially what I had to do yesterday, but creating the tight corners manually, and then having to manually miter the top flanges etc. just took a lot of time, I was searching for a more elegant solution.

tom_jelly

So what I'm referring to is like what phillip_thomas drew above, but with single flanges rather than two and 90 degree bends in them (as pictured in the bes_misgades435 image above the side oriented up) rather than 45 degrees.  This is a method of construction used in just about every metal box I've ever seen that does not have seam welded edges, as constructed on a box and pan brake.  The tabbed sides of the box would have to be slightly shorter or longer so the tab can sit comfortably inside or outside the completed box as desired.  If it was possible to model on the flat view after converting from a solid it would be easy to model these tabs so they could be folded by the software without collision  I'm tied up so haven't tried to attempt that yet.  Sorry if this is not clear, here's what I mean:
http://www.nmia.com/~vrbass/pop-pop/pop.pop.pix/14.jpg

NeilCooke

You mean like this? It's all about the order and the flange position:

Ben_Misegades

@NeilCooke Yes, like that. Now run a series of miter flanges around the top edges

tom_jelly

yes, exactly, thanks.  What is the order of operations to get that outcome?

NeilCooke

tom_jelly said:

yes, exactly, thanks.  What is the order of operations to get that outcome?

The model is public, so please take a look.

https://cad.onshape.com/documents/85b12dcf80b1e9f2d16071a9/w/a619def0892ea584a8932404/e/cb77d2aaa7d805edea5bc0ff

brucebartlett

It's not neat but I managed to get the mitre flange around the top. 

https://cad.onshape.com/documents/58af342b7e286f105d19e136/w/bdccc8e04a86fd71f1e17092/e/df0833e443c280dc25edbf24

Ben_Misegades

@brucebartlett Congrats on having the patience to do all that

I'm hoping that with a future OS update, we'll have more freedom to work in the tight corner regions

brucebartlett

Slightly off subject of the original post but as I was playing with the box to get a nice clean flat pattern I changed the settings from obround to tear but still seem to be getting a .317 gap. I was expecting faces to touch here so there is no cut in on the flat pattern.

Is this what others would expect or is it just me. 

lana

Does this make sense ?
https://cad.onshape.com/documents/58adb941df48ba0f834cb1db/w/e88929a871f23c308e97d789/e/b47f29b3491dcfdb8c6e746a

lana

@brucebartlett
 That tear is there only if you turn on miter. Will be addressed.

tom_jelly

OK looks like I got it:
https://cad.onshape.com/documents/5acb5c0d86583b829af86242/w/3cb1656c25118fc7b0440c22/e/7e8efb5c3d46714c1602942e

Iam still unable, no matter how I try, to be able to even SELECT this loft surface to thicken it, or solid to convert it: (see three parts studio tabs)

https://cad.onshape.com/documents/dbdf83c59a653cf03abbb5cb/w/3219a463aef22f82069eca74/e/35f1dd239075c19f0d5727a4

Consists of two 40 sided inscribed polygons lofted as a surface.  In sheet metal, with thicken selected, when I draw a rectangle around the whole image it never changes color.  With convert selected it always fails.  lofted as a solid, I can exclude the top and bottom face and one or none of the facets but then it still fails so I am unable to select bends. As an experiment I created an identical surface loft with only 5 sides and thicken worked, thus it would appear that the issue is not with technique but with processing.  As there was no spinning wait sign this was not  immediately apparent.  The example provided to me by onshape staff earlier was many sided so it obviously worked at your end- is the processing issue my PC, the speed of my connection, or something else?  Next experiment I guess is to increase the number of facets to see where it fails....

tom_jelly

I increased the facets to 20 on the next tab and it worked, but more slowly so looks like number crunching is the issue. Works well if you give it time, Is there a time out built in?

lana

@tom_jelly
In solid funnel loft  the side faces are non-planar.

Sheet metal convert can not handle them. The polygons in loft profiles need to be carefully aligned (e.g. both placement points horizontal with center) in order to get planar faces in the loft

brucebartlett

lana said:

Does this make sense ?
https://cad.onshape.com/documents/58adb941df48ba0f834cb1db/w/e88929a871f23c308e97d789/e/b47f29b3491dcfdb8c6e746a

Yes, that makes sense and is the best workflow for this box, I was making it so hard in my example above. I had a play with your model here to try and close the corners up a bit more, also love how you can place a miter angle on the edges of the return flanges, I chose 60deg and changed the bend rad to .03in.

https://cad.onshape.com/documents/58b09b43c87b9810506ba1a2/w/ca9a7b0008b86a489381fcd9/e/e454041960945cb75a6fdc6d