How do I cut an extrusion from a surface

[darbycrouch]

Hi,

This is my first post. I hope someone can help me.
I have been given a file initially made in Solidworks that consists of the front end of a car made with surfaces. I have the Solidworks file as well as a IGES export and a STEP file version. The ultimate goal is to slice this model into 1-1/2 " slices so that it can be exported to BobCAD/CAM and milled.

I have tried creating a plane off to the side of the model and drawing a pair of rectangles then extruding a cut through the model. Inventor does not allow me to even select the cut feature (I think this is called 'subtract', sorry I am not in front of my Inventor PC at the moment.)

My question is, how can I take a 3D model made entirely of surfaces, and make a set of cuts so that I am left with only a slice of the model, which I can then export as an IGES or STEP file to be milled?

I am fairly well versed in Inventor, but only making solid parts, not working much with surfaces.

Thanks.

[JD Mather]

Sounds like you need to create workplanes, start a 2D sketch on workplane and Project Cut Edges.

Cut Edges.jpg

[darbycrouch]

JD,

Thanks for the speedy reply. I am not trying to project edges into a sketch. In the .jpg you posted, there is a set of planes that slice the model up. What I need is a way to take a slice of the model between two planes, and get rid of all of the surfaces on either side of them. I want to be left with surfaces, but only the ones between two of the planes. I will use these surfaces for milling purposes. The CAM program I am using (BobCAD) does not have any way that I know of to ignore parts of a model, so I have to modify the model before I import it to show only the slice of the whole model that I need.
Hope that makes it more clear.

Thanks

[Bishop]

Use the planes that JD laid out, then use either the SPLIT or TRIM tools.

[dshowalt]

To tag-on to Bishop. Create the work planes whatever distance appart you want then. After you split the solid into seperate solids. Use the Manage tab and the Make Part button to create individual parts for export to your CAM Program

[darbycrouch]

Thanks for all of the suggestions. I have had some success! I was able to slice up the part the way I wanted to. There are still two problems that I have to deal with now:

1. This part has 420 surfaces. In order to split it, I had to select each surface to be cut individually and split it. This is monotonous to say the least. Once I have split the everything, I have to delete the rest of the unneeded surfaces individually as well. This is tedious. However it is much better than where I was a week ago. I am wondering if there is a way that I can import the part as a single "thingy" and split it in one operation instead of several hundred? (I pretty sure that "thingy" is not the correct technical term, but I hope you know what I mean.)

2. The original part consisted of 420 surfaces, few of which are properly connected together. This thing is not even close to water tight. In order to mill this part out, I need to have a surface along the top as I only have a hollow shell to work with right now. I used the "Project cut edges" function onto a sketch. This looks good, but it does not create a closed loop. If you zoom in, there are gaps all over the place. I tried to manually bridge these gaps but some of them are so small that I can't zoom close enough to draw a line. If I use the "Close Loop" function, it will usually tell me something like "Can't do something or other with fixed geometry". Again, I am not at my Inventor PC to give you the exact error. I have considered just free-hand sketching a closed loop along the edge of the part which would probably work well enough considering the size of the bit I am using to mill with. Also, I tried to stitch surfaces together, which appeared to work, but when I projected cut edges, the edges still didn't line up, even though the surfaces under them looked like they did.
Does anyone have any ideas for how to draw this perimeter?

[JD Mather]

Probably I would try to do an automatic stitch or failing that - untrim the original surfaces and then retrim correctly.

http://home.pct.edu/~jmather/AU2008/...P%20Mather.pdf

[dshowalt]

Could you post a copy of the file so we could look at it? Roll the End Of Part marker up to the top of the tree save the file and Right mouse click on the file to send it to a zip folder and post here so we can look at it.