23 Replies Latest reply on May 19, 2017 5:34 PM by Chad Huleatt

    Skeleton Sketch Part Method for Large Assemblies

    Matt Peneguy

      First off, I have to thank John Stoltzfus for his help in getting us to our current position.  We see the value in the Skeleton Sketch Part Method because inevitably near the end of our projects we are having to make fundamental design changes.  So, we need a robust method of handling those changes to our assemblies.  I worked with John and tried to map out what I thought would be a good workflow. 

      Currently, we are struggling with how we are to set up our "zones" and we are hoping that someone that uses this method for something like ship building can give some additional guidance.  For instance, my current thinking is that machinery attached to the movable span should be part of the movable span (machinery subassembly with SSP should be in the movable span ASM).  My previous thinking was that all of my machinery should be in a "master machinery" assembly.  This is all so new to me that I am having trouble wrapping my head around all of it.  I reached out to our VAR and they offered a one on one 2 day web session.  I don't want to go that route because we have 5 people who will actively be using SolidWorks with this method.  I'll follow-up and see about on-site training for all 5 of us.  In the meantime, I was hoping there was someone out there who uses this SSP method for large assemblies that could assist us.

      Here's a little background:

      We design movable bridges with civil, mechanical, electrical and architectural.  Previously we would recreate the structure from the 2d structural drawings and add our machinery subassemblies (which is our part of the design).  We would end up with close to 10k parts in various subassemblies:

       

      The flow chart for the next bridge I am working on may be something like this (which is a different bridge type than pictured above):

      Notice the "M2 Clutch ASM" is part of the "Tower Machinery ASM" which is part of the "Towers ASM".  This is my current thought process in breaking this down.  This is instead of having the Clutch ASM reside in a "Master Machinery" assembly that would be in the Bridge ASM.

       

      As part of this process we plan to continue to document the procedure (see the attachment),  It already has a simple example for anyone interested in test driving the SSP method.

        • Re: Skeleton Sketch Part Method for Large Assemblies
          John Stoltzfus

          Matt Peneguy - looks like things are progressing right along...  The most difficult thing to wrap my head around is Design Intent and with an assembly and equipment of your caliber - it just takes more of a thought process.   Keep a close tab/record of all the challenges

           

          The only comment I want to add is when you make changes what moves? what do you want to move and what do you want to remain stable?

           

          Scott Casale added a Design Intent Thread, would be good to hear from you after you have the project completed and reviewed.....

           

          The Design Intent Thread

            • Re: Skeleton Sketch Part Method for Large Assemblies
              Matt Peneguy

              Thanks for posting the cross link, I'm currently reading the paper Dan Pihlaja posted.  I may be in some trouble:

              The process, however, is not easy. Selecting a specific strategy and making modeling decisions are

              activities that strongly depend on the user’s cognitive abilities and her experience and skills to understand and

              break down the design [9, 10]. To exacerbate the situation, most CAD trainings are aimed at learning how to use

              a specific software tool rather than how to create robust and reusable CAD models.

              Good thing I've got coworkers smarter than me to sort it out...

              • Re: Skeleton Sketch Part Method for Large Assemblies
                Matt Peneguy

                John Stoltzfus and anyone else using this method,

                I think we've made a little more progress on the flow chart above.  I have made some modifications based on zones and once I get the flow chart fixed I'll update the above chart.  It seems to be the only way to handle this.  It's probably second nature to you, but it is difficult to train this old horse a new trick...

                What I now need help with is what to do you for all of the fasteners?!!!  Our structural guys love bolts.  Try taking a look under an steel structure overpass sometime...Bolts, bolts, bolts everywhere.  Everywhere there are bolts I see mates, and for performance, I want to limit the mates.  We can show one of their connections with all of the bolts then just show the holes in all the other locations.  That is what our structural guys do now.  Though, there is some value in having all the bolts at all locations for accounting purposes.  What are your thoughts on that?

                Regardless how we handle the structural bolts, I'd like to know how something like a lot of bought hardware should be handled with the Skeleton Sketch Part method.  What are some ideas?

                  • Re: Skeleton Sketch Part Method for Large Assemblies
                    John Stoltzfus

                    The main purpose for a Skeleton Sketch or a Master Part is to control any parametric components that make the models more robust and easier to change then the Top Down  (edited) Bottom Up design process.  The issue with any process used, is the over usage of relations, is it sketches,  mates or patterns etc, so my suggestion is that the SSP can be used for hole locations which are populated to the solid model and are cut using those SSP coordinates.  You now have a choice to mate to the cut hole or the SSP hole sketch etc..

                     

                    The biggest benefit using the SSP process is changes downstream and again have coordinate components to make it easy to make changes and within that process I've learned to eliminate circular rebuilds by pushing information down the feature tree rather then having a sketch at the bottom of your feature tree and trying to pull the info up.. So really what the SSP does more then anything else is that it makes you "Think" about "Design Intent" right from the start and really in my mind is the most important aspect for any project.   Without that process we try to "Push" our way through to get this done and then that done and all of a sudden we're so far into the project and then the customer calls and says that they want a few changes, so you make those changes and now it affects more items then you realized, so do you start over or spend the next two days fixing, I can tell you that it is much easier planning for changes then to deal with stuff like that.

                     

                    So to answer your question, Fasteners, have nothing to do with the SSP directly, those are installed later, just like in real life.

                    • Re: Skeleton Sketch Part Method for Large Assemblies
                      Bernie Daraz

                      Matt, I am assuming that you use a lot of bolts and nuts and I'm also assuming the bolted connection is frequently the same in terms of assembly thickness. Why not save a set assembly of a bolt, washer and nut as a part with the distance mate set so it would match the assembly thickness. You could then place many assemblies very quickly. I would suppress the threads too but I wouldn't think you would show them.

                        • Re: Skeleton Sketch Part Method for Large Assemblies
                          Matt Peneguy

                          Thanks Bernie Daraz and John Stoltzfus,

                          I think I can combine both of your ideas and take my fasteners to the next level.  Previously I had bolts, nuts and washers all as separate parts.  I got the idea to combine the bolt with a washer and the nut with its washer to reduce the number of mates.  I put all of the information for the fastener group into the bolt with washer part and excluded the nut and washer part from the BOM.  I get accurate weights and all the proper information is pushed into the BOM.  But, I may be able to make a configured part that is all four components; bolt, nut and 2 washers.  I'll have to think about the repercussions of that though, because it may not "look" correct in the drawings because the washer for the nut won't be flush with the face of whatever parts I'm bolting together in all cases.

                          And John, I like the idea of adding a point to my bolt part and mating that coincident to the hole wizard sketch point. 1 mate per bolt! Correction, 2 mates per bolt.

                          We'll see where this goes.  I have attached my existing bolt with washer using the previous method for anyone interested in using it.

                            • Re: Skeleton Sketch Part Method for Large Assemblies
                              Bernie Daraz

                              Matt,

                               

                              I had a few minutes to kill so I opened the bolt up. First let me say I was shocked the bolt file size was so large, it must be a toolbox part. I'm one of those guys that does not use the Toolbox, I create or download and screw or bolt I need.

                               

                              I made a bolt assembly like I described previously and mated the top washer under the bolt head, then mated the nut to the washer but did not mate the distance. I mated the nut and washer to the underside of the plate. Now I can use Copy with Mates and repeat the assembly easily.

                               

                              Your bolt file was 3.4mb and the assembly I attached below is only 277kb. test assembly.JPG

                              • Re: Skeleton Sketch Part Method for Large Assemblies
                                Chad Huleatt

                                Do you use smart components? I've experimented with them recently, and found them to be really useful. In my case I just drop the brackets shown into the assembly, click "add smart features" and it adds bolts, nuts, washers (you can also make it drill holes but I don't like to do that as it creates more external references between files, and so stuff creeps in that isn't driven by skeleton sketch part)

                                 

                                  • Re: Skeleton Sketch Part Method for Large Assemblies
                                    Matt Peneguy

                                    I agree with John Stoltzfus that you are onto something that may warrant its own thread.  I have played around with smart features. And at one time when I was adding each individual component I had spent the time to make a smart bolt.  But as Bernie Daraz states above I discovered copy with mates and use that most times. 

                                    It all depends on your workflow, and how much time you spend doing repetitive tasks.  In your case it looks like you can save a lot of time and effort if you have a lot of those brackets.  My bolts always seem to vary a lot from connection to connection, spacing etc.  But having that first bolt auto select the diameter is of benefit and I may look back into it.

                                  • Re: Skeleton Sketch Part Method for Large Assemblies
                                    John Stoltzfus

                                    Matt Peneguy wrote:

                                    And John, I like the idea of adding a point to my bolt part and mating that coincident to the hole wizard sketch point. 1 mate per bolt!

                                    We'll see where this goes. I have attached my existing bolt with washer using the previous method for anyone interested in using it.

                                     

                                    If you want to use a one mate process then you need to draw the exact hole size and mate the under side of the bolt head (circle) coincident, now the bolt could still rotate and the "Lock Rotation" wouldn't work, otherwise it's two or more mates, also the circle would need to be drawn on the right side of the plates etc or the bolt would show sunk into the metal. A one mate process is my preference, but it takes a little more planing ahead of time, (Design Intent).

                                     

                                    Mating to the sketch point wouldn't align the bolt with any of the faces or the axis of the hole.. 

                                      • Re: Skeleton Sketch Part Method for Large Assemblies
                                        Matt Peneguy

                                        John,

                                        You are absolutely correct!  I need two mates.  I actually figured that out on the way home yesterday and thought about trying to log in last night and fix my post.  But I never got around to it.  How do I edit my post?  I don't see any options for that.

                                        And further to your point, and more to Chad Huleatt's point, there is a way to trick a smart component to do a concentric and coincident mate by setting the part up with a concentric face mate and then going into the mate and changing it to the circular edge of the face.  If you do that, then when you select where to place the smart component you only have to make one selection and you will get two mates concentric and coincident.  Before I discovered copy with mates, this was a real time saver.

                              • Re: Skeleton Sketch Part Method for Large Assemblies
                                Chad Huleatt

                                Very interesting - I've also appreciated John Stoltzfus help with this type of thing. Can't give much input on zones, because most of what we do is handled by one designer.

                                 

                                Unrelated question: how do you tackle FEA/ engineering? Do you use solidworks simulation or export to different software? I'm wondering because right now our company is looking at different options for engineering certification, and we're having a hard time finding any structural engineers who use solidworks.

                                  • Re: Skeleton Sketch Part Method for Large Assemblies
                                    John Stoltzfus

                                    Chad Huleatt wrote:

                                    Unrelated question: how do you tackle FEA/ engineering? Do you use solidworks simulation or export to different software? I'm wondering because right now our company is looking at different options for engineering certification, and we're having a hard time finding any structural engineers who use solidworks.

                                     

                                    That would be a great topic to start on another thread....

                                    • Re: Skeleton Sketch Part Method for Large Assemblies
                                      Matt Peneguy

                                      Chad Huleatt,

                                      John is correct, you have stumbled onto another great topic for another thread.  The short answer is that our structural guys use STAAD and MIDAS (they used to use LUSAS).  I haven't played with MIDAS, but LUSAS was awful.  In STAAD you enter your truss dimensions and assign profiles to your stick figure.  STAAD really doesn't apply to what mechanical engineers do most of the time.

                                      We haven't done a full bridge where all of our structural drawings are cut from SolidWorks.  That is my end goal and at that point, yes I think we will need to be using simulation tools for their trusses, at least to check.

                                      Currently we have a license of Premium and haven't had a greater FEA need than it provides.

                                      If you do create a new thread about this, it may be a good idea to notify Glenn Schroeder.  He apparently work for Texas's transportation research center.  I am sure he works with some civil engineers and he may have some good input on how they do their FEA.