8 Replies Latest reply on Dec 2, 2017 12:20 AM by Erik Bilello

    Barrel Cam with Lever follower not working as expected.

    Quenton Kilgore

      I am trying to use a barrel cam to move a lever. The cam follower portion will not follow the grove I put in the barrel. It actually follows the grove but not in the correct position on the cam. Almost like it is 180 degrees off.

       

      When I add the pins that it is supposed to actuate the whole assembly locks up. It will only move a small portion of a turn.

       

       

      Lower_Frame_Snip  is just the barrel, cam follower, and the lever.

       

      Lower_Frame_Snip-2 has the pins added.

        • Re: Barrel Cam with Lever follower not working as expected.
          J. Mather

          The cam does not appear to have been modeled correctly and I see a lot of unconstrained sketches?

          I cannot understand the logic of designing something of this complexity with underdefined geometry?

            • Re: Barrel Cam with Lever follower not working as expected.
              Quenton Kilgore

              No Logic involved. Lack of training and experience. I am not very familiar with solidworks. I know my way around and know how to design things to make them work. But I have never tried to draw something this complex before and It is showing me that there are some things I still need to learn about solidworks.

               

              What do you mean by unconstrained? The only thing I am finding on this subject is about fully defining my sketches. I found my error there and am fixing my underdefined sketches but the - mark is still showing up in my assembly.

               

              What is incorrect about the way I modeled the cam. I looked at several examples and tutorials and followed them. What did I miss.

                • Re: Barrel Cam with Lever follower not working as expected.
                  J. Mather

                  Quenton Kilgore wrote:

                  What is incorrect about the way I modeled the cam. I looked at several examples and tutorials and followed them. What did I miss.

                  Can you provide link to examples/tutorials that you referenced.

                   

                  The process to create a proper groove is complex and compounded by the issues:

                  - beginner level experience - having difficulty constraining sketches (this is usually covered in first class).

                  - you are using an older version, which would add to the difficulty of communicating/demonstrating correct technique.

                   

                  If you can provide the links to the references you are using that might save a lot of time in reproducing information.

                    • Re: Barrel Cam with Lever follower not working as expected.
                      Quenton Kilgore

                      I am using solidworks 2016.

                      I download several different Barrel Cam drawings from Grab Cad and looked at how they were built. . I cannot find the tutorials but they went like this.

                       

                      Draw your cylinder

                      Create a plane tangent to your cylinder.

                      Draw your pattern

                      Use wrap tool to wrap around your cylinder

                      use deboss to set your depth in the wrap tool.

                       

                      The cam follower and works as expected. Until I add the lever. Is this due to improper constraints?

                      Can you point me in a direction to learn more about constraints at the sketch level?

                      My experience with putting things into motion in solidworks is very limited. I am usually building tooling that does not move.

                        • Re: Barrel Cam with Lever follower not working as expected.
                          Matt Peneguy

                          Quenton,

                          Before proceeding, take J. Mather's advice and make sure all your sketches are fully constrained.  What he didn't mention is that if you presented a model with unconstrained sketches at a reputable school teaching SWX, I'm pretty sure you'd get a failing grade.  So, it is the very first step in sketching anything.

                          I usually don't refer people to Youtube because there is a lot of bad information on there and learning SWX from youtube is not a good idea, But, here's a video showing how relations work and how you can go about fully constraining your sketches:

                          How To Dimension, Constrain, and Add Relations To A Sketch In Solidworks - YouTube

                          I didn't watch the whole video, but the guy seems to do a good job in the first 3 minutes.  I recommend you watch it before proceeding, if you aren't going to seek out a better resource to learn SWX.

                            • Re: Barrel Cam with Lever follower not working as expected.
                              Quenton Kilgore

                              I went through that video. And it was well done.

                               

                              I would love to seek out a professional resource to learn Solidworks but it is not really an option for me. I could go into a lot of detail here but long story short. Cost too much for the training you get. They want over 1000 for 3 Days (18 Hours). I am showing co-workers that ponied up the dough how to do a lot of stuff that was not covered. None of them caught the issues with my drawings. ...

                               

                              I went through and fixed the Constraints and relations in my sketches and the assembly has same issues.

                               

                              Please look at this and see what I am missing.

                               

                              All of the help is very much appreciated.

                                • Re: Barrel Cam with Lever follower not working as expected.
                                  Erik Bilello

                                  Quenton,

                                   

                                  Depending on where in the world you are (literally) this may not be an option for you, but I would recommend looking for a community college (or whatever they call a 2 year associate degree sort of place where you are) that offers SWs courses.  It will probably cost less than you're quoting, from what I gather is from your VAR.  You'll need to find the time for a semester of classes, which I know can be tough when you've got a job too, but spreading it out over time will make it easier to really get the details down and resolve problems.  Even if the instructor isn't the most experienced (J. Mather can't be everywhere), you can learn a lot from your fellow students when you're not all too pressed for time to share your knowledge.

                                  Another good resource is a SolidWorks user group.  Again, depending on where you are, that might not be an option, but I'd look around for one if I were you.

                                  From what I've seen, I tend to agree with Matt about Youtube, you need to know a fair bit about SW (or whatever you're looking for) just to be able to decide if the video is any good.  Once you know what you're doing it can be a good resource, but be wary of it as a way to learn the basics.

                                   

                                  Good luck,

                                  Erik,

                      • Re: Barrel Cam with Lever follower not working as expected.
                        J. Mather

                        I wrote this eleven years ago - and today I would model in a more streamlined and robust way, but this should give you some ideas.

                        The geometry is actually a bit complex if trying to do it right.

                        And make sure to allow for clearance for the follower - make the diameter a bit smaller than the slot width.

                        There is one other additional trick, that is, well a bit tricky to get the motion.