37 Replies Latest reply on Dec 22, 2012 1:32 PM by Paul Salvador

    best way to make these cuts

    Jesse Katz

      Ran into a couple things that have got me scratching my head.

       

      1) Need to make a series of cuts that essentially revolve around a cylinder, while following a guide path, while maintaining the correct orientation relative to the cylinder. Only way I've been able to acheive anything close to what I need so far was to do a sweep-cut, but I don't think that's actually 'right'. Need the cut line to remain perpendicular to the cylinder as it revolves around the cylinder and follows the guid path, and am not 100% sure that's what it's doing. Have also tried using lofted cut and that seems like it would be the correct tool, but am struggling with it and not getting the desired results - as shown in the 1st screen-capture. The two blue highlighted boxes represent the profiles, and have tried using all different kinds of guide paths. The cut path should extend all the way in to the cylinder, instead of making that gradual transition away from the cylinder as shown.

       

      2) Is there a way to make a similar feature (cut) from something like the end-face down to the depth of a guide-line? Sort of like what's showm in the 2nd screen capture, but would follow the curved line instead of stopping at the depth of the vertex.

       

      The 3rd screen capture shos what I'm actually trying to model. It's a series of fins that radiate out from a cylinder, but if you were to look at it from one of the end-faces, they're not all the same length. So when I make a revolve-cut around the cylinder, it creates that wavy profile. Need to be able to machine-out those pockets in order to create the fins, and the end-mill has to remain permendicular to the cylinder. Is this making any sense?

        • Re: best way to make these cuts
          Robert Stupplebeen

          Unfortunately, I can not open your part so hopefully this is not completely off.

           

          I think your part might be easier to make if you make the fins first then create the center region. Basically a multibody approach then merge together at the end.

           

          Your part's outside appears to be a series of arcs. If so instead of a swept cut you could do revolved cuts using the axes of center points of the arcs.

           

          I hope this helps.

          Rob Stupplebeen

            • Re: best way to make these cuts
              Jesse Katz

              Am using SW13, but you can't open the IGS file either?

               

              I have spent a lot of time re-ordering the features, but the features I'm trying to figure out how to create are dependent on the geometry of that curved line that cuts through the fins as it revolves around the cylinder (it's not a series of arcs, it's one continuous cut line).

                • Re: best way to make these cuts
                  Robert Stupplebeen

                  I can open the IGS it just really limits the flow working with a dumb solid. Because of this I needed to add an additional cut to pattern around.

                  1. Create an axis

                  2. Revolve your cut but overbuild the sketch to work for any orientation

                  3. Revolve cut

                  4. Pattern

                  I hope this helps.

                  Rob Stupplebeen

                  Cuts-RStupplebeen.jpg

                    • Re: best way to make these cuts
                      Jesse Katz

                      Ah, yeah, I knew that the IGS file wouldn't be as helpful without the feature tree, but didn't have any other option.

                       

                      So imagine that you're machining-out those pockets from the end-face, but you want to cut each pocket to the depth of that countoured line, while maintaining the same orientation.

                        • Re: best way to make these cuts
                          Robert Stupplebeen

                          Cut-Extrude up to surface I believe is what you need.

                          The pringle shape that is made on the right view needs to be extruded into a surface to catch the extrude.

                          I then did a radial pattern of a sketch that cuts the part. Please see the attached part.

                          I hope this helps.

                          Rob Stupplebeen

                           

                          PS Cool web page in your profile.

                          RadialFins-RStupplebeen.jpg

                            • Re: best way to make these cuts
                              Jesse Katz

                              Thanks for trying to help me work through this problem Rob, but I don't think that solution is going to work. Had thought about doing something like you are suggesting, but the problem is that if I make a cut or extrude a surface through the model from any one side, it won't give me the geometry I need. Not quite sure how to communicate this, but the endmill needs to remain perpendicular to the cylinder. Talking about where the beginning/end of each fin (where the fin meets the protective ring). Each one of those cuts needs to be perpendicular to the cylinder, which I can't accomplish by cutting through the model from any one side. The cut needs to radiate, if that's possible. Am sure there's a way to do this, but I can't figure out how.

                    • Re: best way to make these cuts
                      Jay Johnson

                      I can't open it either. It says future version. I am running SW 2012. Is 2013 out already?

                      • Re: best way to make these cuts
                        Chris Michalski

                        in your actual geometry (03.jpg) can you create a surface body from that complex OD edge and then extrude the cut offset from that surface?

                          • Re: best way to make these cuts
                            Jesse Katz

                            Am not sure I understand what you're suggesting. Could you please elaborate? The cut would need to radiate, as everything is concentric to the cylinder. I know the wavy line is a little bit misleading, but that's an illusion created by the length of the fins being inconsistent. The large chamfers on the end-faces of the cylinders, out towards the fins could actually be turned on a lathe though.

                          • Re: best way to make these cuts
                            Jesse Katz

                            Maybe it would help to explain in a little bit more detail what I'm actually trying to accomplish.

                             

                            This is a housing for an LED light and those are protective rings around the cooling fins. This part is going to be CNC machined on a 4th axis mill with three setups: one from each end-face, and then the middle section of each fin will be carved-out as the part rotates. In the 3rd screen capture, you can see that the diameter of the cylinder in the middle is not consistent. What I need to be able to do is cut the larger parts of the cylinder away, down to the depth of the smaller part of the cylinder. But I can only remove material out to the protective rings, keeping the endmill perpendicular to the cylinder. So I just want the cut-paths to follow the contour of those wavy lines around the protective rings. But I'll be damned if I can figure out how to do that. Have just never run into something like this before.

                              • Re: best way to make these cuts
                                Chris Michalski

                                sorry Jesse, I'm old school (2007) but here is a model to look at.

                                 

                                1) eliminate that cut so you have a 2 half loops on that edge

                                2) create a boundary surface using those 2 edges

                                3) create a body of your cut, deeper than the limiting surface (don't merge results)

                                4) cut the body with the surface

                                5) combine (subtract) this trimmed body from the main body

                                 

                                there is likely an easier way, but I'm not very experienced in surfaces so this is the first one I found.

                                 

                                hope it helps.

                                  • Re: best way to make these cuts
                                    Jesse Katz

                                    Thanks Chris. Do not have much experience with surfaces either. This is all new to me, and am just figuring out how to use a lot of these tools. Your model isn't going to work for me, but I don't know if your methods might. Take a look at this screen capture of you model. Specifically, the two blue highlighted lines. Those need to be perpendicular to the cylinder, and radiate from the centerline of the cylinder.

                                      • Re: best way to make these cuts
                                        Chris Michalski

                                        ok...

                                         

                                        #1) this is likely about the most difficult way to do this known to man, but it's the only way known to THIS man :-D

                                         

                                        If you make a body that is the straight cut from the axial end (don't merge)

                                        using the straight faces of this make 2 sketches with convert entitites for a loft

                                        make 3D sketches at the vertices to control the loft (unfortunately the swoopy one you can't easily define)

                                        but through several surface manipulations you can extend and trim to get a surface that you can use as the end surface to extrude a part up to and combine/subtract

                                          (you can likely also do this with a simple extrude cut up to surface instead)

                                         

                                        edit: mind you, if you try to add the filets to look like an end mill cut it everything falls to pieces because the surfaces are no longer realistic.

                                  • Re: best way to make these cuts
                                    Ash Combe

                                    Hey Jesse,

                                     

                                    Is this kinda what you are looking for? It’s basically the same approach as Chris but a whole lot less complicated.

                                     

                                    Make a composite curve from the edge that you want the cutout to go up to then make a boundary surface from it. Not sure why but it only works by selecting half the edge, not the full way around the part. Then put a sketch on the top face exactly like you did but choose “Up To Surface” and select the new boundary surface. Everything is linked so any changes to geometry higher up the feature tree will update the curve and surface.

                                      • Re: best way to make these cuts
                                        Jesse Katz

                                        No, not exactly. Those cut lines at the inside corners are not perpendicular to the centerline of the cylinder. Take another look at Chris' file.

                                          • Re: best way to make these cuts
                                            Ash Combe

                                            Well that's very simple to fix, I just made my sketch collinear with your existing feature, it's a simple change to the sketch. The point of the model is to show how to do a cut “Up To Surface” to achieve the same results as Chris’ model in a lot less steps.

                                              • Re: best way to make these cuts
                                                Jesse Katz

                                                OK, thanks. Will take another look at how you did that tomorrow. Really appreciate all the help with this.

                                                  • Re: best way to make these cuts
                                                    Jesse Katz

                                                    Spent some time trying to figure out how to that boundary surface worth the way I want/need it to Ash, but am having a hard time figuring it out. Still pretty new to all these surfacing tools and techniques. Most of the projects I've worked on in the past were more traditional welments and sheetmetal and machined parts. Spent about half the day watching tutorials and reading about surfacing. Starting to understand how it all works (at least in theory), but am still puzzeld about how to get the geometry right in this application. Created a 3D sketch with some lines that radiate out from, are perpendicular to, the centerline. Was that the right approach to take? What now?

                                                      • Re: best way to make these cuts
                                                        Ash Combe

                                                        Surf Colours.PNG

                                                         

                                                        My apologies Jesse. I was running on the thought that you wanted the RED faces the be perpendicular to the GREEN face, but I’ve finally realized that it’s the line interfacing the RED and BLUE faces that you want perpendicular as well. Sorry for driving you on a bum steer!

                                                         

                                                        What you want is a little more tricky! Chris’s path while being a little complicated is a good way to go. I’ll keep working on it, it’s got me intrigued on what’s the simplest way to do this.

                                                         

                                                        Again, sorry if I’ve confused you!

                                                          • Re: best way to make these cuts
                                                            Jesse Katz

                                                            Are you kidding? You don't need to apologize for trying to help! Has been difficult to explain exactly what I'm trying to do, but think you are understanding my intentions correctly now. It really all comes down to manufacturability and it's not going to be very difficult to make these parts, but designing them has been challenging. Motivating me to get more familiar with the surfacing tools for sure, but am finding it difficult to follow the logic behind the solution that Chris proposed. Mostly because I'm not very well-aquainted with these tools and techniques I'm sure, but this area of SW is not exactly intuitive. Can anyone help me to better understand how the steps in Chris' model actually work? Thanks again.

                                                • Re: best way to make these cuts
                                                  Ash Combe

                                                  Is this more like what you’re after? If you’re having difficulty visualizing the curved face (like I was) turn on Zebra Stripes and Curvature.

                                                    • Re: best way to make these cuts
                                                      Jesse Katz

                                                      Unfortunately, no. Please take a look at the lines that I've added to your model. The blue surface needs to follow those lines, which radiate from the centerline of the cylinder, and they are all perpendicular to that centerline as well.

                                                       

                                                      Chris has sent me some helpful emails with a few more tips and will post-back as soon as I've had some time to take a look at what he's done.

                                                        • Re: best way to make these cuts
                                                          Scott Pinnow

                                                          Here's my atempt at it. I don't have much knowledge of surfacing so I went with a lofted cut with guide curves.

                                                          • Re: best way to make these cuts
                                                            Chris Michalski

                                                            Jesse asked me to post these to see if anyone more adept at surfaces could figure out a way to fix the transitions.

                                                             

                                                            The most accurate way I know to start is to actual create several cylindrical bodies to represent the endmill cutter.  Then you can use the curve at the surface as a guide.  The problem comes in when you go to make a surface or use an edge driven curve because there is no easy way to transfer that edge curve to its mate at the finish diameter surface.

                                                             

                                                            Hence my use of a bunch of copies in the curve driven body and then a combine (subtract) to remove them (followed by some manual cleaning up).

                                                             

                                                            It would be good enough for sending to a 3D printer, but that surface is far from ideal.

                                                             

                                                            Take a crack at it and see what you can do.  Even though it's not my project I'd be interested in knowing what someone can think of (in part because I've spent about 10 hours trying to make it work because it seems like it should be so simple).

                                                             

                                                            p.s. does SW 2012 (or anything newer than 2009) let you make a cylindrical cam?  basically the mill bit is following that edge like a cam on a rotating shaft, if they've added more cam features that might eliminate all the hoops to jump through.

                                                              • Re: best way to make these cuts
                                                                Jesse Katz

                                                                That's not why I asked you to post here Chris. I was just saying that I really appreciated all your help and thought other people might also find it helpful if/when they run into similar problems. That's all.

                                                                  • Re: best way to make these cuts
                                                                    Jesse Katz

                                                                    Am sure you have all been holding your breath, so wanted to post an update to let everyone know how this turned out. Finished the project. Never really figured out the 'right' way to do this, but here's the workaround I used:

                                                                     

                                                                    Lots of construction geometry. Used these lines that radiated outward from a centerline that ran through the center of the cylinder. Each of those line runs through the middle of a spoke, and is offset from the wavy path by a certain distance, and is perpendicular to the centerline that all the other lines radiate out from.

                                                                    Screen Shot 2012-11-19 at 7.17.56 PM.png

                                                                     

                                                                    Then I created a path that swept through all those points using a few splines. That's how I created the cut paths.

                                                                    Screen Shot 2012-11-19 at 7.18.22 PM.png

                                                                     

                                                                    But I was having a LOT of trouble with the models breaking any time I made changes to the geometry or tried to rebuild the model after adding a new feature. Probably burned a solid day or two just trying to figure out what combination of features would work. There seemed to be some kind of ghost in the machine, because I couldn't account for the way SW was behaving. Probably a lack of understanding on my part (that's usually the case), but it was terribly frustrating.

                                                                    Screen Shot 2012-11-04 at 12.33.01 PM.png

                                                                     

                                                                    All worked out in the end though. Here are a couple screenshots of the light when it was almost finished so you can see how they'll have to be machined. Think there still might be a few small issues where the geometry is not quite right, but to such a small degree that we can just resolve those issues when these parts are getting transferred into the CAM side of things.

                                                                    Screen Shot 2012-11-27 at 6.02.26 PM.pngScreen Shot 2012-11-27 at 6.01.46 PM.png

                                                                    Screen Shot 2012-11-27 at 5.57.49 PM.pngScreen Shot 2012-12-11 at 1.49.43 PM.png

                                                                    Screen Shot 2012-11-27 at 6.00.14 PM.png

                                                            • Re: best way to make these cuts
                                                              Paul Salvador

                                                              know this is old but,...maybe a simple "Ruled Surface" perpendicular to the axis is what you're looking?

                                                              ruled-surf.png