43 Replies Latest reply on Feb 5, 2014 1:12 AM by John Burrill

    Where do I start? Part for school

    Chris McKinnon

      I am trying to model this part.  I believe what I want to do is sketch the shape shown by the section cut out and then do a revolve.  When I try to model that 40 degree angle it ends up not looking right at all, maybe I am missing some relations to keep it in place?  I am starting to figure this all out, but I still feel I need to work on design intent.  Can someone give me some pointers as to where I need to start to get this right?  Im guessing it wont take that long once I get it going. 

        • Re: Where do I start? Part for school
          J. Mather

          Attach what you have attempted so far. *.sldprt

          • Re: Where do I start? Part for school
            Glenn Schroeder

            Welcome to the forum.  You're right about needing to start with a revolve of the section cut.  If yours doesn't look right to you I'd suggest posting what you have so far. I'm sure someone will be glad to take a look at it (click on "Use advanced editor" at top right of the dialog box to post files).

              • Re: Where do I start? Part for school
                Chris McKinnon

                I dont think uploading what I got will get us there. Ha, I am playing with it.  This is frustrating because I can fly through certain things in class and understand it on my projects, but then I get to something that seems to be easy and I am lost.  Pretty much when I make the shape and start dimensioning it I get lost as to what Im relating to what, as I dimension the shape is changing (im guessing because I didnt make relations? maybe that would help?) and then I get lost and start all over.  I know I am not helping my case right now, but I really feel like I am stuck on square one with this. 

                  • Re: Where do I start? Part for school
                    Glenn Schroeder

                    Chris McKinnon wrote:

                     

                    as I dimension the shape is changing (im guessing because I didnt make relations? maybe that would help?) and then I get lost and start all over.

                     

                    It's often best to place one or two main sketch entities first and dimension them before proceeding.  That way when you place the other sketch entities you can get them closer to the correct scale right away and they won't fly all over the place when you dimension them.  SW2014 has fixed this issue, but the student edition, which I assume you're using, is always one year behind.

                • Re: Where do I start? Part for school
                  Tony Cantrell

                  Draw the profile in the right plane and revolve it 270 degrees. The 40 degree dim is for the slot.

                    • Re: Where do I start? Part for school
                      J. Mather

                      Tony Cantrell wrote:

                       

                      Draw the profile in the right plane and revolve it 270 degrees. The 40 degree dim is for the slot.

                      I think that is for illustrative purposes in the book.

                      I have my students Revolve 360° and then create section view in the slddrw file.

                       

                      It is a bit surprising to me that an assignment like this would be given without substantial prior instruction.  By the time this chapter is reached in the book - a student should know how to create the sketch for this part.

                        • Re: Where do I start? Part for school
                          Chris McKinnon

                          It would be nice if we used the book, we hardly will even open the book I hear.  This is for Jig and Fixture class.  We recieved a series of parts to model and make drawings for the first week of class, Ive modeled all of them and this is the only one I cant even get going on.  Because of the cold weather we had the class the following week was cancelled so I was not able to get in there to ask any questions.  You are right, they want us to revolve it 360.  We do not need to make  a drawing for this part so I wont have to worry about the section view. 

                            • Re: Where do I start? Part for school
                              J. Mather

                              Chris McKinnon wrote:

                               

                              It would be nice if we used the book,

                              Well, the book would not tell you how to use SolidWorks to  model parts - that would come from classroom instruction.

                                • Re: Where do I start? Part for school
                                  Chris McKinnon

                                  My teacher talked more about what he did in the industry than he taught us what was assigned in the first solidworks class.  I have modeled a lot of parts, but this is the first that starts as a sketch and a revolve.  I know its my design intent that is holding me back.  I can completley understand how to model it but when I try and do it, it doesnt work so much. 

                                    • Re: Where do I start? Part for school
                                      Anna Wood

                                      You might try YouTube....  There are a lot of SolidWorks how to videos posted there that I bet would help.  I think the visual of seeing features used on screen would help turn on some lightbulbs for you.

                                       

                                      Cheers,

                                       

                                      Anna

                                        • Re: Where do I start? Part for school
                                          J. Mather

                                          Anna Wood wrote:

                                           

                                          You might try YouTube.... 

                                          Since it was indicated this is a school assignment, shouldn't that be part of the classroom instruction?

                                            • Re: Where do I start? Part for school
                                              Anna Wood

                                              If he was getting the instruction he needed he wouldn't be posting here would he? 

                                               

                                              Since he can't change his instructor, just giving him some options to supplement his classroom learning, much like he is already doing by posting here.

                                               

                                              Cheers,

                                               

                                              Anna

                                                • Re: Where do I start? Part for school
                                                  Lenny Bucholz

                                                  Anna Wood wrote:

                                                   

                                                  If he was getting the instruction he needed he wouldn't be posting here would he? 

                                                   

                                                  Since he can't change his instructor I am giving him some options to supplement his classroom learning, much like he is already doing by posting here.

                                                   

                                                  Cheers,

                                                   

                                                  Anna

                                                  good thing I'm an instructor, HELL I show my students in lab so they get the gist of making sketches and how to aproach them, some insight is better than no sight

                                                   

                                                  Where I get them is on the Final Exam and quizzes, thats when you get to see if they have learned anything.

                                                  • Re: Where do I start? Part for school
                                                    J. Mather

                                                    Anna Wood wrote:

                                                     

                                                    If he was getting the instruction he needed he wouldn't be posting here would he? 

                                                     

                                                    I wonder how much the OP (or the taxpayers, in other words, me) is paying for this instruction.

                                                    As near as I can dertermine, the general quality of instruction on these professional tools is abysmal.

                                                    I estimate that only 10% of any users from any source really know how to use the tools.

                                                      • Re: Where do I start? Part for school
                                                        Lenny Bucholz

                                                        J. Mather wrote:

                                                         

                                                        Anna Wood wrote:

                                                         

                                                        If he was getting the instruction he needed he wouldn't be posting here would he? 

                                                         

                                                        I wonder how much the OP (or the taxpayers, in other words, me) is paying for this instruction.

                                                        As near as I can dertermine, the general quality of instruction on these professional tools is abysmal.

                                                        I estimate that only 10% of any users from any source really know how to use the tools.

                                                        It's called MENTORING!

                                                          • Re: Where do I start? Part for school
                                                            J. Mather

                                                            Lenny Bucholz wrote:

                                                             

                                                            It's called MENTORING!

                                                             

                                                            We are getting off track here into a much larger topic, but I don't understand?

                                                              • Re: Where do I start? Part for school
                                                                Chris McKinnon

                                                                I have used solidworks enough to where I understand its features.  I have made quite a few parts, a lot of assemblies and a few drawings. My biggest problem is design intent and trying to decide the most efficiant method to come to the finished part.  I believe my school does a good job of giving us useful information. I mentioned my teacher got off topic a lot.  That was for my first solidworks class.  He gave us a lot of information that seemed to not relate to the current work at all, but later in the class you would come across it and now in my second semester some of the stuff he would ramble on about is finally starting to click.  For the most part, solidworks was introduced to us and we were shown resources such as here and youtube to use outside of class as well as user group meetings.  I believe the class could have had better discussions relating to what the current assignments were.  But everyone in the class was able to work through it on our own to do the work.   I dont like having to go back to class to ask questions.  I play around with it at home all the time trying to get a stare at my computer scree to try and figure out what I am doing and other features I might not have known the use for.  Ive used the solidworks classroom built into the student version on my own time.  I also have some friends that work in the industry that I can ask questions to. Sorry my question raised such a fuss.  I really believe I get good info at school but it is very much on me to learn how to design and utalize the program.  The only way to do that is ask questions and work on my own.

                                                                  • Re: Where do I start? Part for school
                                                                    J. Mather

                                                                    Chris McKinnon wrote:

                                                                     

                                                                    Sorry my question raised such a fuss.

                                                                    You have nothing to apologize for.  I have been in this business since '87 of the last century and it just bothers me that most instructors are lost in using these tools.  SolidWorks isn't just an electronic drafting board - it is a full engineering tool.  SolidWorks is a professional program that deserves (requires?) a professional level of preparation.  But where is there a MS or PhD - SolidWorks College of Education at some university to prepair instructors to teach it as the engineering tool that it is.  A full curriculum for the 21st century could be taught in an interesting and engaging, modern, way that is transferable across any of the modern design tools.

                                            • Re: Where do I start? Part for school
                                              John Burrill

                                              Chris, you've got the right concept, modeling the section view and revolving it around an axis, so that means you're either having difficulty visualizing what the undercut looks like or your having difficulty getting the sketching tools and relations to produce the right result.

                                              In either case, I suggest modeling that undercut as a seperate feature.

                                              Sketches with lots of enttities and complex relationships tend to be harder to edit because, one, it's easy to indadvertantly add relationships and, two, it's hard to predict how a complex sketch will update as you add constraints.

                                                • Re: Where do I start? Part for school
                                                  Chris McKinnon

                                                  I am trying to do a sketch now without the cut.  Thanks for the tip, I think it might help. 

                                                  • Re: Where do I start? Part for school
                                                    Chris McKinnon

                                                    This is how I started, and before I Try and revolve.  Am I right here or do I need more?  It doesnt look right to me. 

                                                      • Re: Where do I start? Part for school
                                                        J. Mather

                                                        Well for starters, the dimensions on the original are in inches while your units are in mm.

                                                         

                                                        Delete all of those radial dimensions - use diametral dimensions as given in the original.

                                                        You do this by first creating the Construction lines to control your geometry.

                                                         

                                                        Revolve.PNG

                                                         

                                                        By using this technique it is easy to find your (my) mistakes.  Oops!

                                                         

                                                        Revolve Rev1.png

                                                        Revolve Rev2.PNG

                                                          • Re: Where do I start? Part for school
                                                            Chris McKinnon

                                                            Please forgive me for not knowing, but what is the purpose of the construction lines to control the drawing?  I am very green at this, only my second semester.  Also,  for that 3 inch dimension. It looks wrong I knew it looked funny, but what is it supposed to be?  Isnt that what the dimensions are calling for?

                                                              • Re: Where do I start? Part for school
                                                                J. Mather

                                                                The construction lines aren't technically needed, but they help aid in making sure your object lines are horizontal and vertical to the  origin datum.

                                                                Also, the construction line in the center allows you to do the diametral rather than radial dimensions and also gives you your axis of Revolution.

                                                                 

                                                                 

                                                                The 3" is correct, in my original sketch I had 3.5 which was wrong.

                                                                  • Re: Where do I start? Part for school
                                                                    Chris McKinnon

                                                                    Cool, Im getting somewhere now. I have never used the diametral dimensions either.  Learned something.  I really appreciate you taking the time to lay it out for me. 

                                                                      • Re: Where do I start? Part for school
                                                                        J. Mather

                                                                        I guess you figured out that you need to click on the opposite side of the center line to get the diamtral dimension.

                                                                         

                                                                        Once you finish the sketch - I recommend that you attach the file again for double checking.

                                                                         

                                                                        Tip - for the 40° I added a vertical construction line to the midpoint of the short horizontal line.  And then added a Symmetry relation between the 3 lines.

                                                                         

                                                                        Revolve Feature.PNG

                                                                          • Re: Where do I start? Part for school
                                                                            Chris McKinnon

                                                                            I started all over again, when I switched to inches I got all screwed up when I tried to scale it.  But its done, I think.

                                                                              • Re: Where do I start? Part for school
                                                                                J. Mather

                                                                                Your sketch is not fully constrained (check lower right corner of screen when editing Sketch1.

                                                                                You are missing construction lines that I suggested earlier.

                                                                                 

                                                                                Use construction lines.

                                                                                Use construction lines.

                                                                                Use construction lines.

                                                                                Did I mention, use construction lines?

                                                                                • Re: Where do I start? Part for school
                                                                                  John Burrill

                                                                                  Chris, you don't have to scale your geometry to switch from inches to millimeters and back.  Just go into Options:Document Properties tab:Units Panel and set your base units and precision.

                                                                                  You can also specify units in the dimension value dialog box by appending in or mm to your dimension value.

                                                                                  You asked about construction geometry and how much you needed so here's a quick overview.

                                                                                  construction geometry are sketch entities that SolidWorks ignores when you build a solid or surface feature out of a sketch.  Construction geometry is created the same way normal sketch entities are.  When create a line, arc, spline or ellipse, the property manager displays a checkbox that lets you toggle the entity between normal and construction geometry.

                                                                                  construction_lines1.png

                                                                                  construction_lines2.png

                                                                                  There is no limit to the number of construction entities you can have in a sketch.

                                                                                  construction_lines3.png

                                                                                  construction_lines4.png

                                                                                  construction_lines5.png

                                                                                  construction_lines6.png

                                                                                    • Re: Where do I start? Part for school
                                                                                      Chris McKinnon

                                                                                      Thank you for that little input. I have been playing around with construction lines this morning and went back to some of my old parts to see where I could have used them.  When I mentioned I tried to scale the drawings it was when I did not have the sketch even close to being defined, I was just going around it the wrong way.  So when I started changing dimensions after switching the units the sketch started going every which way. It was just a thought to try and use scale to change all the dimensions at once but I ultimately just re drew it quick. 

                                                                                        • Re: Where do I start? Part for school
                                                                                          John Burrill

                                                                                          That happens.

                                                                                          You want to get that first entity close to the size of your sketch footprint so that when you sketch in subsequent areas of the profile, they're roughly in proportion to the geometry.

                                                                                          You should also take advantage of your origin point for constraining your sketch geometry.  When drawing a revolved profile, start there.  Additionally, for revolved features, get a centerline for your axis of revolution in the sketch early and constrain it.  This makes fully definingyour sketch easier.

                                                                                          Keep your sketches simple.  Don't get bogged down trying to make a detailed profile.

                                                                                          I didn't want to make another 9-mile cartouche of screen grabs, so I put some tips together and added them to a PDF.  Hope it helps.

                                                                      • Re: Where do I start? Part for school
                                                                        Mike Agan

                                                                        40 degrees needs a 70 degree dim. off centerline or 20 degree dim. off a face

                                                                        • Re: Where do I start? Part for school
                                                                          Stephen Bittner

                                                                          I find it interesting that the 1/4" inside radius is problematic when trying to use the "Sketch Fillet" prior to revolving. However, adding it as a fillet after the revolve is not a problem.

                                                                           

                                                                          Likewise, the drawing calls for 1/8" rounds and fillets IIRC....but the drawing isn't very clear as to where they should be placed.  /shrug