Bending Features & Considerations

Video Transcript:

Let’s review some advanced features of our bend processing systems. Now I’ve got 2 example parts in my cart already uploaded and configured in bending. These are exactly the same but one of them has extra cutouts pretty close to where the bends take place and one of them does not. So let’s look at the one that doesn’t have any issues.

Of course, here’s the flat pattern that we’ve unfolded and here’s the 3D model. Now this is a pretty simple part. We can watch it form on our press brake as we’ve gone over in other videos. It gives you an idea what it takes to make the part. Now, if I pull up the other part, notice that it has a warning and it says there’s reduced flange support. Well, what does that mean? Well, these bends close to these cut outs so in these yellow highlighted regions, the die actually makes contact with those cutouts or those cutouts are inside the die keep out region. So just to give you an idea, this dotted line is roughly where the die is going to make contact with the part and this is where the punch is going to make contact, and then this dark gray region is where the bend is going to take place from the flat pattern. So what does that look like? Well if we look at the bend simulation, in this case, here’s the die on the bottom, punch on the top and notice that these holes are inside where the die makes contact. So what this can cause to happen is the metal wants to form where it’s easiest to form. So if you have cutouts inside this die keep out region, it effectively will make this part wider in this direction and shorter in this direction because it pulls the effective punch line toward that spot and that can cause problems.

Now, there’s 2 ways that you can solve this or 3 really.  One is that you can take these cutouts and move them further away from the line so that they don’t get close but another thing you can do is quite a bit simpler. Go to the flat pattern in our system and select one of the bend lines. If you scroll down on the left here, there’s an inner bend radius setting which is automatic. This will try to match your model as closely as possible. However, you have the option to select a manual bend radius, and you can go in here and say, well I want a 1.1 millimeter radius. Well what difference does that make? What it effectively does, when you have a tighter radius, it uses a smaller die, and you can see that here. Now in this case there’s still some region at the beginning of that bend, let’s back up here, where that hole is slightly in contact with the die keep out region but, if you go through to the end, it actually loses contact part way through. So there’s a really great chance that this smaller die will produce a part that doesn’t get deformed.  Now the nice thing is, that while we did change this radius, it doesn’t change the size of the part. I can toggle back and forth between my original uploaded model, and the one that OSH Cut’s system edited. And notice that while it does make that bend tighter, it does not change the size of the part. So this is one way that you can avoid that kind of deformation which is really nice.

Another way though, is that you can back out and look. Notice that there’s a drop down here. Now this won’t be true of all parts, but it works out that this part could be made out of tube as well. So If I go in and select tube and then I choose material that matches the size, those warnings are gone. And the reason for that is we are taking a pre-existing tube which is actually a square profile. You can see the profile right here in this view. And it’s just saying, hey I want the bottom half of that tube roughly, with these holes cut out. The nice thing about that is that it’s already a square profile and we’re just cutting this piece out. So it actually doesn’t matter if there’s cutouts close to the bend line because we’re not forming it on a press brake.

Now, tube can be a little bit more expensive. In this case it is actually a fair amount more expensive than sheet metal, so the best solution is going to be to do a tighter bend radius on these lines, just to minimize the likelihood that there will be distortion.