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rayhawk

Sweep on self intersecting path

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rayhawk

I can't seem to figure out how to do this. I basically have a profile that is defined 0.010" below the surface of the part, and is on a radius. I have created a cut section and work plane at this depth, sketched the path of the cutout, and extruded to the correct depth. With or without the extrusion, I cannot figure out how to apply the radius correctly. Fillet does work, but then I have no way to extend the fillet up to the top surface of the part. So I figured I need to sketch the fillet, and then sweep it around using my path. The problem is I get an error saying I can't use a self intersecting path or loop for this operation. I can do it on the intersecting path no problem but I need it to go all the way around and I don't want to sketch a bunch of profiles. I hope it is clear from the screenshot attached what I am talking about. Thanks.

 

portplate3.jpg

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JD Mather
I hope it is clear from the screenshot attached what I am talking about.

 

 

Can't you attach the file here? Simply roll up the EOP, Save and zip.

 

What kind of fillet are you trying? Face Fillet? Rule Fillet?

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rayhawk

Here it is, as for the fillet I attempted, I tried edge fillet.

PP3.zip

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JD Mather

How will that part be manufactured? Will the slot be cut on a milling machine or will it be a molded part? I ask because the solution will be dependent on the manufacturing process.

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rayhawk
How will that part be manufactured? Will the slot be cut on a milling machine or will it be a molded part? I ask because the solution will be dependent on the manufacturing process.

 

It is a machined part, and the cutout will be made with a ball nose endmill with a nominal radius of 0.094". The cutout is a 2d shape, but due to the shallow depth, it ends up having to be defined at the depth as shown so that I can check it on the CMM after manufacturing. There is no straight section to define the path at, as you see in the other deeper cutout. Actually, I am trying to use the model primarily for measuring the part against.

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JD Mather
...made with a ball nose endmill with a nominal radius of 0.094".

 

Not possible to get the tool in there without gouging adjacent faces - you have other fillets in the slot with smaller radii than that.

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rayhawk
Not possible to get the tool in there without gouging adjacent faces - you have other fillets in the slot with smaller radii than that.

 

The cutout has a nominal depth of 0.062", so with a 0.094" radius ball nose cutter, you are working part way up the radius on the end of the cutter, which goes from 0 at the end of the cutter up to 0.094" at 0.094" from the end. There are two radii you are looking at with a ball nose cutter. One based on the cutter diameter and one based on the ball nose diameter. On a standard ball nose endmill they are the same. So the radius at the depth shown can be less than the major cutter radius.

 

This is why I was trying to use the path as defined to make the cutout, since it is defined at a depth 0.010" below the surface, and has a radius of 0.094". I don't think fillet will work correctly here. The sweep would be the best simulation of a cutter that size moving around the profile, but I don't know how to get around that error message.

 

The final cutout will be similar to the other cutout on the part, only at a much shallower depth, but the same tool does both cutouts.

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JD Mather
...you are working part way up the radius on the end of the cutter,

 

I'll take another look when I get a chance. The solution will most likely involve the clever use of some surface modeling.

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rayhawk
I'll take another look when I get a chance. The solution will most likely involve the clever use of some surface modeling.

 

Any help is greatly appreciated, thanks for taking the time to look at it.

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rayhawk

I found an error in my sketch leading to the intersecting loops error, basically I had an untrimmed line segment causing this. Unfortunately I now get an error: "sweep profile intersects wire". Clicking on the error shows the sweep path and I believe where the path is very narrow is causing the error.

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rayhawk

This is a bit closer, I basically got the sweep to work only part way around, I keep getting the "sweep profile intersects wire" error. As you can see, I created two profiles to sweep, one to trim the edge, and one to join the surfaces and create the fillet. For some reason, the edge sweep works fine, but the other sweep to join the surfaces and create the fillet doesn't work? I faked it by using a combination of the sweep part way around and a fillet (where I could), but as you can see it is not correct.

Fillet.zip

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rayhawk

I have not been able to solve this fillet issue, and the same issue has showed up on several of the family of parts I am trying to model in Inventor. We will likely end up having to pay the manufacturer to make the models. I dont want to shortchange inventor as I am still new to it, but is this a weak area for the program? I keep hearing solidworks is a better program, would I have the same problem in solidworks? I would like some feedback as we are considering purchasing solidworks.

 

As far as I see it, if I can create a feature in Mastercam, i.e. it is easily machined, Inventor should be able to do it with relative ease. Instead, I have been trying for 2 weeks now to put in a constant fillet all the way around a path. I can't believe it is really that difficult.

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JD Mather
I can't believe it is really that difficult.

 

I don't like the looks of your geometry - so I didn't put any more effort into it.

 

Good luck with SWx unless you chage your method.

 

If you are doing it in a CAM package where is the centerline of the tool path? I didn't see you define that anywhere in the files you attached - you were trying to sweep from edge rather than centerline.

 

Knowing the centerline path the fillets will come out to whatever they are.

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rayhawk
I don't like the looks of your geometry - so I didn't put any more effort into it.

 

Good luck with SWx unless you chage your method.

 

If you are doing it in a CAM package where is the centerline of the tool path? I didn't see you define that anywhere in the files you attached - you were trying to sweep from edge rather than centerline.

 

Knowing the centerline path the fillets will come out to whatever they are.

 

In mastercam you work to the edge of the cutter, and it will figure out the path it needs to take based on the cutter size you give it. After all, I can't directly measure the path centerline, but I can measure the edge. I would be happy to change my method but the geometry is what it is, I didn't design the part, I just have to make it. I dont know enough about Inventor or Solidworks to know whether it can be modeled in either program, that is why I am looking for feedback.

 

I will attempt your method of defining a centerline path, hopefully that is the trick to getting it to work. Thanks for all your efforts.

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JD Mather

A second trick is to create the material removed as a solid body and the Combine-Subtract. Part of the problem is the partial fillet when the cutting tool is full radius. Solve that problem and all should fall into place.

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Ahmad Sharifi

i tried using .07" radi, and it worked, i don't know if that is what you're looking for?

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rayhawk
i tried using .07" radi, and it worked, i don't know if that is what you're looking for?

 

Thanks for trying, you are correct it will work with a smaller radius, but that is not the part I am trying to duplicate. It's ok, the cutter will put the correct shape in the part, even if Inventor doesn't like it!

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