Can this bend be done in MOI3D?

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 From:  slipstick (TAY)
7530.1 
Hello,

I have this bracket that I made in Solidworks, just barely. I'd like to make it in MOI3D since I know it better. How would I do it? The bend isn't perpendicular to the long axis.




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 From:  Michael Gibson
7530.2 In reply to 7530.1 
Hi Slipstick, I've attached a result made in MoI, it looks like this:




It's probably best not to try to actually bend the shape using a deformation, but rather to cut the piece, rotate the end part as needed, then construct some surfaces to bridge the gap. To get a good quality bridging surface it's also probably best to construct an initially extended surface and then cut it rather than trying to build a surface just between the edges directly.

The file shows the stages of how it was constructed, I'll post some more explanation of each step in a little bit.

- Michael

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 From:  Michael Gibson
7530.3 In reply to 7530.1 
So here's some explanation of each step.

To make the base shape I drew 2 circles and a rectangle between them and used Construct > Boolean > Union to combine them, then did the same for the oblong opening and then drew a circle at the other end, then selected them and ran Construct > Extrude to make the base part.

Then I drew in an angled line for the desired angled bend axis, I moved it to the top surface by dragging it in a side view.

I then selected the bend axis and ran Construct > Offset with the "Both sides" option enabled to make 2 cutting lines on either side of the bend axis. Then select the part and run Edit > Trim, and select the 2 offset lines as the cutting objects. Select the inside piece as the piece to discard and then right-click to finish Trim, now the piece is cut into 2 separate objects.

Select the piece you want to rotate and then rotate it by your desired angle around the pivot axis by running Transform > Rotate > Rotate axis, snap the rotation axis points onto the ends of the center pivot line.

Now to get a good quality connecting surface that does not buckle or warp too much is a little tricky. I think it's probably best to make a extruded shape that has its extrusion direction going in the pivot axis direction and then trim that down afterwards.

To make the profile to extrude I put in 2 lines and then used Construct > Blend to make a smooth blend curve connecting them. Then the blend curve is what you extrude.

To position the lines correctly I started by drawing in one line like this, first point snapped on to the midpoint, and second one along the "Perp" snap, looks like this:



Then the trick is to get the line on the other side positioned in the aligned spot. To do that start drawing a second line but before you place the first point you will drag out a construction line to make a snap point at the correct location.

The way that looks is, after you have started the line command, move your mouse over the start point of the line you just previously drew, here:



Now click and hold down the mouse button and while keeping it held down drag out a construction line, while still holding the mouse down move over to the other edge and find the "perp" snap over there, release the mouse button when you find it, looks like this:



Now that construction line has ended where you want to start the line at, there will be an "end" snap there now so click it for the start point of your line, and then place the second point at a "perp" straight snap spot same as the other line, looks like this:




Now select the 2 lines near their ends you want to connect and run Construct > Blend to build a blend curve which looks like this:




Repeat that on the underside as well. Then select the blend curves, run Construct > Extrude and check the "Both sides" option and build the extended bridging surfaces.

After that switch to the Top view and draw in some cutting lines between endpoints, and then select the extended extrusions and run Edit > Trim, and use the cutting lines to cut off the ends.

Then the remaining areas can be surfaced by selecting the 4 boundary edges and running Construct > Network. After that select all the pieces and use Edit > Join to glue them together into a finished solid.


Hope this helps!

- Michael

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 From:  Michael Gibson
7530.4 In reply to 7530.1 
Or another way to get the lines to blend between is to draw in a perpendicular line on the pivot axis on the initial flat part, then trim it into pieces using the same offsets used to cut the surface, and also select the line when you do the Rotate axis to rotate the end piece. That then doesn't involve any fancy snapping with construction lines like the way I described above uses.

- Michael
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Message 7530.5 deleted 10 Aug 2015 by MIKULAS

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 From:  Mik (MIKULAS)
7530.6 
Hi slipstick,

maybe this way will be useful for you as well.



Mik
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 From:  DannyT (DANTAS)
7530.7 
You guys do realise the bracket is bent at 90° to the bottom plane but skewed at an angle.


~Danny~
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 From:  Michael Gibson
7530.8 In reply to 7530.7 
Hi Danny, yeah I guess so - I didn't know what angle it was bent to just looking at the screenshot.

That's why it is usually better to get a 3D model file so that the actual geometry can be examined from many different angles and zoom levels rather than just observing a screenshot alone...

- Michael
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 From:  BurrMan
7530.9 In reply to 7530.7 
I saw what I perceive as errors in the model/part listed and thought I would comment...

I don't thing you can "bend" metal this way without ruining it structurally.. So the part would be a "welded part"....

Here's a video of how I would model it:



Taking note of the last part of the video and the fillet that took a couple attempts....

In the other models, it seems the bottom part is being "brought back" to meet with the vertical part... I think this is an error and is creating a structurally weak point in the part....

Doing it as in the video keeps the dimension of the bottom part in tact.... The 2 parts would then be welded together....

Hard to tell from your sceengrab Danny, but it looks like your model may have this part modeled as in the video also?
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 From:  Karsten (KMRQUS)
7530.10 In reply to 7530.1 
Hi slipstick,

here is another one. I started with the the midsurfaces of the geometry (normally you have to use also a correction factor) without Radius. then I filleted the unjoined faces - you get an fillet with overrun. I connected the resulting edges of the trimmed faces with blend and projected the result with curve->Project->closesest Points to the fillet. Trimmed it with the curves and joined all faces together. With Offset in both directions I give the whole a thickness. I closed the outer sides with planar faces an Network. I've projected the edges of the midsurface to a plane that's normal to the fillet direction. Reconstructed the curve with 100 Points and unwraped it by script. Extruded both curves separatly to the same length so you can get an unbended view of the part using flow command:-)

I hope it may help you!

Kind regards
Karsten

EDITED: 15 Jun by KMRQUS

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 From:  slipstick (TAY)
7530.11 
Thanks to one and all. I learned a lot here with this.

I finally went with Michael's approach.

I am replicating a bracket that broke off of an engine.

It will be sent to a shop after it is dimensioned and they will make it out of bar stock, I imagine.


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