Results 1 to 15 of 15

Thread: Problem with step file

  1. #1

    Problem with step file

    Looking to have a part milled, and the CNC outfit we sent it to had this to say "the part appears to be modeled as more than one component. In order to quote your part we will need the components combined into a single model." This was designed in F360 and exported as a .step file. Any ideas how to solve this? I know when I've had the same part 3D printed, the printers asked if this is supposed to be one piece, as there are several "shells" in the model. I said yes. I assume this same issue is what the CNC outfit is having. Can I turn the entire model into a single component in F360 and solve this?

  2. #2
    Join Date
    Oct 2007
    Location
    Dawson Creek, BC
    Posts
    1,033
    The 3D printer uses a .stl file. That is basically a 3D mesh surface that represents your part. A step file is a solid model and is much better to use for producing accurate dimensioned parts. If modeled as separate pieces you will need to mold them all into one or provide the shop separate parts. I am not a fusion user, but I know how to do that in solidworks.

  3. #3
    As far as I can tell, I did the design as one piece. So I'm not sure what the issue is, or how to correct it. Here it is:

    https://www.dropbox.com/s/7alkdrcukm...20SS.step?dl=0

  4. #4
    Join Date
    Oct 2007
    Location
    Dawson Creek, BC
    Posts
    1,033
    I see the problem. The file is coming up as four solid bodies. The CNC shop is wondering if you want them as separate parts. Looking at the parts I think you will need to have them milled as separate bodies. You have undercut profiles, and unless you are working with someone with a five axis machine I doubt they will be doing that in the shape you have. Even then, I doubt they could mill into the tight intersection point. I would break into two parts. The bottom part will have a top and bottom setup, and the top can be another. I would look at your geometry again. The bottom cone does not fit perfectly in the upper part. A shop with a big HAAS, will cut this out exactly as you show.

    SW_Help.jpg

    Here is a cross section of your model. I can see one part is overlapping the other.

    section.jpg
    Last edited by Brad Shipton; 04-08-2019 at 10:56 PM.

  5. #5
    Quote Originally Posted by Brad Shipton View Post
    The bottom cone does not fit perfectly in the upper part.
    Can you point to exactly where you mean?

    I'll have to modify for CNC-friendly milling, that's for sure. Still, how would one make this one body? I don't even know how it ended up as several bodies in teh first place or what design techniques to use in F360 to avoid it in the future. This must be done as one piece.

  6. #6
    Join Date
    Oct 2007
    Location
    Dawson Creek, BC
    Posts
    1,033
    I think you will need to find someone with a lathe if you want to mill as a single piece that looks exactly as the model. It is that fine undercut region where you will have the problem. Easy to make in a 3d printer. What is the material?

    I added a couple of red lines to highlight where one body is crossing the other.

    section.jpg

  7. #7
    Ok, that is where I thought you were referring to. This will be done in aluminum. I can extend that lower mount to the cone, so there will be no undercut. So is there no way to go from a surface model (who cares what is going on inside) and derive a step file from that?

  8. #8
    Join Date
    Oct 2007
    Location
    Dawson Creek, BC
    Posts
    1,033
    I am not sure how it is done in fusion, but in solidworks when you extrude a surface you click a button that tells the software the extrusion is to be added to the part as a solid body, and not create a separate body. There are other surface errors, so I cannot fix this in solidworks without re-creating the geometry from scratch. There only seems to be four basic extrusions, so I would take a look at your file. It should be easy to fix.

    Looking at this help file I think you have to go back to your extrusions and simply click off the "create new body" for each extrusion. That will join the extrusions together. I would edit the part to make it look like how the machinist can cut the part. That saves questions. Make sure to include tolerances in your holes if something is to fit a certain way. Hope this helps.

    help-file.jpg
    http://help.autodesk.com/view/fusion...A-948ECFC6A93F

  9. #9
    Join Date
    Feb 2013
    Location
    Tippecanoe County, IN
    Posts
    836
    Quote Originally Posted by Brandon Thill View Post
    Can I turn the entire model into a single component in F360 and solve this?
    Yes, I do exactly that for 3D printing. Select the bodies you want to fabricate and use Modify/Combine to put that combined body into a new component. Be sure that "Save Tools" and "New Component" boxes are checked. You can then export that component as a STEP file. That's easily done by right clicking on the new component's listing in the browser and choosing "Export" from the context menu.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  10. #10
    Brad> I can do that using Join instead of Create New Body, I'll try that

    David> Ah, thanks! That might work best.

  11. #11
    Join Date
    Mar 2014
    Location
    Iowa USA
    Posts
    4,441
    Quote Originally Posted by Brandon Thill View Post
    Ok, that is where I thought you were referring to. This will be done in aluminum. I can extend that lower mount to the cone, so there will be no undercut. So is there no way to go from a surface model (who cares what is going on inside) and derive a step file from that?
    I don't think I could do that in one piece even 3D printing. If you have ever ran a CNC router or milling machine you will see the problem right off. It needs to be done as two pieces the way you have it drawn.
    Last edited by Bill George; 04-09-2019 at 9:19 AM.
    Retired Guy- Central Iowa.HVAC/R , Cloudray Galvo Fiber , -Windows 10

  12. #12
    Join Date
    Mar 2003
    Location
    SE PA - Central Bucks County
    Posts
    65,685
    I agree with Bill based on the renderings that were displayed a few posts ago. It will need to be at least two components that you assemble after the fact unless the shop you use has really fancy/expensive 5-axis capability. If you do two components to join, be sure you build in alignment of the components into the design.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  13. #13
    Join Date
    Oct 2007
    Location
    Dawson Creek, BC
    Posts
    1,033
    Bill, it is pretty cool what you can do with 3D printing for parts like this. It is slow going, but I have watched ours print parts out into space. Printing flat is not a very good idea many times if you have a large volume of plastic at the base. Too much shrinkage/heat/cool problems. I think you could make it by rotating the part at an angle and making supports. I think he has already printed the part and that is why he was confused by the CNC guys questions. .stl models are not very useful for many machinist level CAM packages for a whole host of reasons.

    When modeling parts like this it is best to keep in mind how you are going to machine them. Mechanical CAD (MCAD) packages are insanely fussy about things and when you are building features on to other parts of a model it can get difficult to fix later since most of the time you end up with relationships between new and older features of the model. It took me quite a long time to get used to sketch based modeling. It is very different from other packages where you can cheat and make things look okay.

  14. #14
    Join Date
    Mar 2014
    Location
    Iowa USA
    Posts
    4,441
    The overhang between the top and bottom pieces would be difficult to print without support and the same would be difficult to mill or rout with CNC. I agree 100% when designing for production you need to be aware of the limitations of the machines.
    Retired Guy- Central Iowa.HVAC/R , Cloudray Galvo Fiber , -Windows 10

  15. #15
    I've printed a couple dozen of these, but they have been SLS Nylon, so no problems with that tech. Thanks everyone for the help! I should be able to use one of the solutions going forward.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •