Slot Patterning Within Boundary

[friedm4]

Hi all, I am attempting to pattern slots in Design mode across a rectangular face at a 45 deg angle within a rectangular boundary. The slot width and spacing are set with parameters, which we would like to not break the modeling when edited.

Since there is no way to pattern slots without patterning rectangles and filleting one by one (and Fusion can't trim/break "Slot" geometry while retaining the round ends), I followed the method shown in this link: Fusion 360 | Slots Within Boundary - YouTube.

The slot is initially made using thin extrude to create the slot and extending to object, then adding a fillet.

These two features (extrude+filllet) are then patterned using rectangular pattern and then mirrored. (You have to mirror because "extend to object" unfortunately is unable to extend in two directions to the same object, and splitting into two limiting objects still fails due to the reasons below...)

   

However, when I increase the number of pattern instances to a number where the slots start outside of the boundary the compute fails (Error: R-Pattern2 Compute Failed):

 

The end goal is cutting slots in Manufacture using Slot, which does not work with rectangles. We could perhaps re-draw and pattern center lines, and then use Trace, but we would like to see the model in Design as it will look.

Any ideas?

Model: https://a360.co/3NkU8yF 

[davebYYPCU]

You have no User Parameters, so I am not sure how Parametric to make it.

Sometimes we can be too clever.

Might help.......

[jhackney1972]

I think your answer is to create a second boundary surface which you can use to change your Thin Extrude to two sided and use the "To Object" selecting one boundary for one direction and the other for the opposite direction.  you can then place your fillet on each end and eliminate the Mirror.  Model is attached.

[Bunga777]

@jhackney1972 

I've had patterns fail in these cases and dealt with them in various ways, but the idea of having another surface was hard to come up with.

I would be glad if you could elaborate on the logic as to why you came up with the idea of setting a different surface as another boundary.

[jhackney1972]

I do not if there is a lot of logic to my solution.  I use a variety of duplicate bodies and components to get Fusion 360 to do what I want.  In this case I know that Fusion 360 refuses to use the same surface for a two side Thin Extrusion, so I just give it another one to use.  I often add components, on top of other ones, so I can get double motions in assemblies, then hide the extra component.  Here is an example of that.

[Bunga777]

@jhackney1972 

Thanks, I'll experiment and try some things.

[ericjforman]

@jhackney1972 I'm working with the OP on this. Thank you for your response.

We already tried the two separate boundaries, but it fails for two reasons:

1. One or more of the features is not modeled correctly. You can see this even in your screencast, look at the upper right slot.

2. If you attempt to edit anything, Fusion gives a "too many pattern instances" warning (since it must use Adjust and not Optimized), and then a Compute Failed error. You can see this if you attempt to change parameters for the slotWidth (in thin extrude) or spacing (in pattern). 

I've attached the model again with the two boundaries, the names cleaned up, and parameters named.

Model: https://a360.co/3NkU8yF 

 

 

[TrippyLighting]

If you create the fillet as a rule fillet after the pattern as shown in the video tutorial, the pattern will not return an error message.

I've tested a few things and I believe the "Adjust" option in the pattern tool is buggy.

@jeff_strater @Phil.E could you check this out please?

[ericjforman]

I'm not sure what video tutorial you're referring to (@jhackney1972 used a full round fillet, pre-pattern), but I think I know what you mean.

If I use a rule fillet after the pattern, I assume you mean select the pattern feature as the input for the rule fillet - it does do most of them, but not all, and I see weirdness like this:

What am I doing wrong? 

 

 

 

[Phil.E]

@TrippyLighting You may well be correct, but after reading this post, I don't know which model to look at or what the exact problem is. Lots of images, red circles, and workarounds here. Can you boil it down to a single model, and what I can do to use it to replicate an issue?

[ericjforman]

Phil, you can look at the model linked in posts above: https://a360.co/3NkU8yF

There are two attempts to pattern slots to boundary, seen as the last four operations on the timeline (with one or the other set suppressed): 

1. Thin Extrude, Fillet, then Pattern

2. Thin Extrude, Pattern, then Rule Fillet

#1 fails on the pattern (also resulting in inconsistent fillets missing)

#2 doesn't fail, but the pattern is also missing some features (and the resulting fillets are incomplete)

If you edit either of the Patterns, you will see that not all features are being patterned.

It seems it doesn't like going in two directions to two boundaries using Adjust to calc the results...

[Bunga777]

This setup seems to work.

However, there are a few strange places that come up.

I tried to make it possible to change various things with parameters.

The number of slots is automatically calculated from the length of the diagonal.

I have attached the data.

[jhackney1972]

Attached you will find my model.  It is not the one you supplied but it is the same geometry.  The parameters are the same, just the names are a bit different.  This is one touchy model.  If you want to vary the box size or slot margin parameters, you MUST decrease the Slot_Count parameter to a much smaller number.  After the box size updates open the parameter dialog box and increase the Slot_Count parameter (odd numbers only), let it update, until you get what you want.  If you exceed the number, that fit comfortably, it will fail.  Model is attached.

[davebYYPCU]

I didn't use To Object in my workflow, and presume you found no construction errors in my version?

[KristianLaholm]

I only want to add that you are using the wrong axis for the rectangular pattern in your file.
You should be using the diagonal of the rectangle.

[TrippyLighting]

@KristianLaholm Spot on!

This explains why some of the slots toward the corners aren't cut!

[laughingcreek]

well, everybody else was having fun, so I wanted to play too!

the problem with the slots not cutting all the way out can be avoided by just doing half, and starting the extrude offset out a bit (which also allows pattering on the 45deg instead of the diagonal.  using the diagonal is fine, but does require a bit of math to get the spacing. rather let fusion do that bit)

the problem with the slot fillet not working where the slot runs up in the corner can be addresses by putting a fillet on the extrude-too fence. (although that slot doesn't run all the way up into the corner when you do that, but seems to look alright.)  this variations seems to be fairly tolerant of parameter changes-

[ericjforman]

@laughingcreek Thank you, this is the final piece of the puzzle! We realized early that patterning from the non-45 diagonal would work, but we hadn't put together that the pattern itself could still be 45°and the negative offset would take care of the other errors.

And yes, the boundary fillet works well to take care of corner issues, another great tip. If anyone is interested, I found using slotWidth/2 for that fillet (i.e. tiny) keeps the slots exactly to the boundary and works with most parameter changes.

@friedm4 can you mark that post as the solution? And thank you to everyone who responded, it's always fun to have a supportive communities for these little challenges!