14 Replies Latest reply on Jan 19, 2018 1:39 PM by Kelvin Lamport

    Skeletons and bottom-up approach

    Ignacio Vital

      Hi all,

       

      This is my first topic here. I read the forums, but I never asked before.

       

      In my company, we work with solidworks since 2016. We design and manufacture refrigerated truck bodies and we are having some troubles about our assemblies.

       

      The assemblies are not difficult to create or mate, but we want to improve our use of Solidworks to achieve better assemblies. By the moment, we use a bottom-up approach, because 90% of our parts are cubes and the others are from our suppliers. We have our products and we customize each body for each client.

       

      We don't use a top-down approach, because when the measures change the lineal patterns are modified and we have to add or remove some parts. Then we are thinking about doing Skeletons for Bottom-up assemblies, to add mates between part and sketch or planes and not between part faces in the assemblies.

       

      When we start a new body, now we pack & go a body and modify it for the project, but if you have to modify a linear pattern you can have problems because you can break mates.

       

      For design purpose we could do our assemblies easily, but for our manufacturing process we cannot simplify the CAD Models to automatize them.

       

      Do you think a skeleton for this purpose could be a good idea?

       

      Do you think it is a better idea have a SSP or a skeleton built in the assembly?

       

      Thank you all.

        • Re: Skeletons and bottom-up approach
          Solid Air

          Yes we sucessfully use this method where I work.

          • Re: Skeletons and bottom-up approach
            Igor Fomenko

            In any case read about using of sldsetdocprop.exe utility it helps you a lot.

            In this case all your custom tollbox parts (CTP) look and behave like Toolbox parts. And this very convenient because:

            1. they can not be mirrored

            2. they can be excluded from Pack&Go by one click on checkbox

            3. they differ from nonstandard parts and assemblies in tree

            4. you can`t make them virtual by mistake (it is very good in case you deside to make assembly with CTP virtual)

            At any moment you can set this IsToolboxPart property back. I`ve used this strategy for a long time with success.

            One important note about mirror of assembly with these CTP:

            for example you have a big bolted frame assembly and want to mirror it

            in this case (with CTP) you don`t need to uncheck mirror flag of all these CTP, SW makes this authomatically (CTP saves a huge amount of your time in this case)

            these CTP looks different not only in tree but in BOM also, this helps you too

              • Re: Skeletons and bottom-up approach
                Ignacio Vital

                Hi Igor,

                 

                I haven't need to use the Toolbox in our assemblies by the moment, because we join most of the parts with glue.

                 

                Now, we want to detail more our models and we start to add the ribets, and screws we need at the end of our manufacturing process, and I am interested in what you tell me, but I don't know exactly what are you talking about.

                 

                Do you have some information which I can check to learn more?

                 

                Thanks for the reply,

                 

                Ignacio

              • Re: Skeletons and bottom-up approach
                John Stoltzfus

                Welcome to the Forum Ignacio Vital

                 

                Is one way better then the other? will always remain a question. 

                 

                I use the SSP with every project and have stable, easy to modify assemblies and I would have a hard time changing.  I feel that truly understanding your workflow and in house process dictates how you need to model.  The SSP can also be a solid model or a combination of Sketches and Solids, it doesn't just have to be Sketches, and the only time you add sketches in an SSP is when more than one component share the same element, such as a hole or cutout etc...  Otherwise what pertains to just a single part, that stays with the part and isn't needed in the SSP.

                 

                For an example - here I design furniture or rather take furniture designs that either a customer brings in or our sales/marketing team comes up with, these designs are given to me in one of the following medias...  1. A simple hand sketch  2.  A detailed drawing  3. A Picture - then I need to compare the notes and the media given and make the assemblies.  There is one given in any of the media given and that is there is a huge possibility of 4 to 6 changes, maybe the design element is what is shown but some details added or some details eliminated, so for me I need a workflow designed to make easy changes and that is the value of using the SSP process.  Understanding how SW rebuilds and keeping a detailed Feature Tree helps tremendously with my workflow, for me it's not how fast you can get the initial model put together, it's about ease of change, being able to change one or more dimensions and every move is parametric without a forest fire in the Feature Tree.  The ultimate test in any model/assembly is to delete a part and there are No Errors except missing mates.  If you do a bottom up process, try deleting the first part, you know what'll happen, all the parts after that part fail.

                 

                Again - for me the SSP is the only possible trouble free modeling

                 

                Make today great,

                 

                John

                  • Re: Skeletons and bottom-up approach
                    Ignacio Vital

                    Hi John,

                     

                    Thanks for the reply.

                     

                    I downloaded the presentation you did about SSP, and I am trying to understand better the method to use it.

                     

                    Yes, we need something that allow us to change easily our product to the specifications our clients want. And our problem is that we had, and have, a lot of work and the work of the day didn't allow us to think in what will be the next step to work efficiently and better. These days are being relaxed and we can think more in improvements for our design processes.

                     

                    Like you, we had our products, but we manufacture drawings, or ideas for some clients and we need to easily modify our models.

                     

                    These days I have to do a generic model for one of our products and I want to prepare it in a better way.

                     

                    Regards,

                     

                    Ignacio

                  • Re: Skeletons and bottom-up approach
                    Kelvin Lamport

                    Ignacio Vital The SSP approach can be used in both assemblies and parts. When inserting the SSP into a part, it can be located so that the part origin is at a logical location within the part itself, but when inserting the part into an assembly, the SSP origins of the part and assy can be used to automatically place the part. Best of both worlds and with minimal mates.

                      • Re: Skeletons and bottom-up approach
                        Ignacio Vital

                        Hi Kevin,

                         

                        Then, if I understand what you're trying to tell me, the way to do this will be generate part files copying my SSP and then, in this files, generate my parts in the position where they will be in the assy, so your mates always be origin SSP with origin part.

                         

                        Then, I understand too, if I have subassemblies in my main assy, the SSP for my subassemblies, and the parts in these subassemblies, always will be the SSP for the main assy, the other idea I have is to have different SSP, one for each sub assy, and one SSP in general assy which join the anothers SSP.

                         

                        Without trying any of this approaches previously, I think I will work with the first option, because my main assys do not usually have more than 100 parts and, this way, the part always is in the position after its generation.

                         

                        Thank you for your time.

                          • Re: Skeletons and bottom-up approach
                            John Stoltzfus

                            Just a word of caution with part in part modeling - do yourself a favor with any workflow, as you go along make some major changes to the assembly and see what happens, that will tell a lot..  I have tried an assembly using part in part modeling and had issues with the parts updating the way they should, however that would be my first choice if I could get it to rebuild properly.  If there are guy using a part in part workflow, it would be nice if they would upload a simple assembly with a written process.  I know it works well for an initial design, but like I said here I'm exposed to at least 4 changes with every assembly and if I make those changes I need to have everything rebuild parametric.

                            • Re: Skeletons and bottom-up approach
                              Kelvin Lamport

                              To clarify, generating part files from a SSP using the Copy and Save option is not the same as inserting a part into a part.

                              The Copy & Save method will create non-associated parts, whereas the Insert > Part method creates parts associated with the same SSP.

                                • Re: Skeletons and bottom-up approach
                                  Ignacio Vital

                                  Hi Kevin,

                                   

                                  What you are telling me is if I insert the SSP in the other parts I only have to modify it once and it changes for all my other parts, but if I do a save and copy I have to change the SSP in each part if I want to mantain my assembly stable.

                                   

                                  If this is correct, yes, I should work this way. I didn't know about this feature and I haven't imaginated I can do this. I have a lot to learn about SW...

                                   

                                  Thank you

                                    • Re: Skeletons and bottom-up approach
                                      Kelvin Lamport
                                      What you are telling me is if I insert the SSP in the other parts I only have to modify it once and it changes for all my other parts

                                      That is correct.

                                       

                                      ... if I do a save and copy I have to change the SSP in each part if I want to mantain my assembly stable.

                                      Yes but as John Stoltzfus stated..

                                      do yourself a favor with any workflow, as you go along make some major changes to the assembly and see what happens, that will tell a lot..  I have tried an assembly using part in part modeling and had issues with the parts updating the way they should, however that would be my first choice if I could get it to rebuild properly.

                                    • Re: Skeletons and bottom-up approach
                                      John Stoltzfus

                                      Kelvin Lamport -  Copy & Save went over my head, I thought you meant inserting a part into a part....

                                       

                                      I have a small assembly that I'll be trying it on sometime soon, still not sure how it will help keeping component parametric...