20 Replies Latest reply on Oct 11, 2016 11:47 AM by Doug Seibel

    how do i dimension this?

    Zach Worman

      So this is the deck of a truck we will build this winter. My question is how do I get the guys on the floor all the dimension's they need without making the print unreadable? This is all one weldment.

       

      Truck deck.png

        • Re: how do i dimension this?
          Tony Cantrell

          Insert a weldment cutlist for the members size and length, then I would use ordinate dims for horizontal and vertical locations

          • Re: how do i dimension this?
            Deepak Gupta

            I would divide it into multiple configuration and bodies. Then I would dimension those as separate views and show a combined full view with connection dimensions.

            • Re: how do i dimension this?
              Anna Wood

              Ask your guys on the shop floor what they would like to see on your drawing?

              Break the views down into how your people will build up the frame.

              Will likely take multiple views to get the info communicated that your people need.

              • Re: how do i dimension this?
                Elmar Klammer

                Looks like you have two main rails with cross rails sitting on top. Each gusseted with added plate or members in various section.

                I would make a section view horizontal to dimension all the cross members and show gussets (no hidden lines shown and section all the way)

                Then I add vertical cross sections with the section depth limited to show only the relevant pieces. Add a few details view and the whole thing should fit on one or two pages that can be easily read. You want to indicate where the heel side of each crossing profile is so the shop knows where the web of each member is located. Dimension from the center line and give reference dimensions for checking. This is a weldment part so you will add body drawings for members that need more than cutting. I usually keep plate outside weldments by creating an assembly that has your weldment frame and add plates as parts. You can make two configurations if you want that can show a first and final stage of the frame structure. Create the configuration 1st stage and add a delete body feature and remove all members that are not initially welded.

                Make a page for stage 1 and a page for final frame. The cutlist will update if you do it right.

                 

                Remember, use hidden lines wisely and avoid them if you can. Try to limit section depth to show only relevant members. Add horizontal section where applicable. Use sections wisely and keep the number low. I usually add a 3d view that helps the shop guy visualize the whole thing. Try to show it in the orientation in which the frame will be fitted or welded.

                 

                oh yeah...I would not mix plate and structural members. Not time efficient if you need to include drawings. Multibody sheetmetal is too quirky....make an assemblies and keep them separated....much faster...

                 

                To maximize paper space, I would rotate the vertical sections 90 deg in a way that always shows top side in the same orientation. Looking at this frame, I would use two pages top. D-size paper with BOM and all weld symbols included.

                Note the red sketch lines was done quick, if I spend another ten minutes, I would probably be able to eliminate some of the sections. Depends if your little added pieces have a common reference.

                 

                 

                 

                • Re: how do i dimension this?
                  Glenn Schroeder

                  You've received a lot of good ideas, but I'm afraid I'm going to have to disagree with Elmar Klammer about creating an assembly to include plate.  See Using Plate in Weldments.

                   

                  # 15 (Showing single bodies of a multi-body part in a drawing view) at Frequently Asked Forum Questions might also be of some help to you.

                  • Re: how do i dimension this?
                    Ryan McVay

                    I've worked on similar large weldments in the past. I was also the first guy to give the mfg group a drawing pack that included several pages of part locations, dimensions and cross sections. Then I included a second set of sheets for welding. When dealing with traditional drawing it was always 2D. The problem here is that when you have large weldments like this you can't tell what 2D line is what edge. What part gets the bevel edge, which part gets the stitch weld, etc.

                     

                    To alleviate this issue all my weld details were actually 3D views showing the parts and where the welds went. The shop loved this. So, much so that they took me out for pizza one Friday.

                     

                    We all get tied up with the traditional 2D drawings that we forget that the 3D is there to help. Take advantage of this. Oh, and don't forget to allow your mfg guys the ability to view the model and rotate it around, take measurements, because we can't get them all!

                    As for individual piece parts our system required that each part have its own part number and drawing. So that takes care of piece part issues. The weldment then contained locations part locations, assembly level features like milling down mtg pads and then critical hole patterns machined at assy for precision location of other components.

                    • Re: how do i dimension this?
                      Zach Worman

                      Thank you all for you thoughts. Everyone has such great ideas and ways to do things, you all have given me so many options. In one of the post's someone talked about getting input from the guys that will be building this, well i'm not only the guy the does most of the modeling i'm also one of our lead fabricators/welders. So with that in mind I know from other builds that structural members are never straight. When we model or draw things in the perfect world of solidworks with out fancy cultists and our perfect prints how do we accommodate for the crappy hot rolled extruded members??

                        • Re: how do i dimension this?
                          Jim Steinmeyer

                          Tolerances?

                          • Re: how do i dimension this?
                            Ryan McVay

                            Zach Worman In the past, I used cross slots for position to make up for poor steel structural components- horizontal slot on one component and vertical slot on the matching component. You can also go the route of welding mtg plates and then coming back and machining them in a secondary operation after welding. Although this can be a huge challenge to find  machine shops to handle large weldments, it is quite effective.

                            • Re: how do i dimension this?
                              Elmar Klammer

                              Structural members have a tolerance in terms of twist, bow etc. You usually dimension to centerlines for symmetric members like beams. Channels and Angles are dimensioned to the heel of the profile. Truck frames are not precision machines and most often flex under load or in use. Straightness and twist take precedence in most cases.

                              Choose a system that works for your company. Most time we create sub assemblies to speed up production and overall management of large frames. Regarding multi-body sheet metal technique, well I have used both and found that using a mix of assembly and weldment technique to be most economic i.a.w. fastest when you include all aspects like BOM, drawing 3d & 2d, export formats, editing and managing of design.

                              • Re: how do i dimension this?
                                Doug Seibel

                                On the print...

                                By using dimensions and tolerances.

                                For instance, if I have a plate with a hole in it and it is critical that the hole be a certain distance from the edge of the plate...I will dimension the hole from the edge of the plate instead of from the center of the plate.

                                 

                                But for the most part, it is all on the builder.  A flat cement floor, a carpenter square, a level, a laser chalkline or two, a tape measure...simple tools coupled with the exceptional skills of the builder.  If you are going to be making several of the same thing, then jigs & fixtures are useful.