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Beginner’s Guide to SolidWorks 2011 – Level II Alejandro Reyes, MSME Certified

Beginner’s Guide to SolidWorks 2011 – Level II Alejandro Reyes, MSME Certified SolidWorks Professional NEW Level II with Advanced topics to prepare for the Certified SolidWorks Associate Exam: Sheet Metal, Molds, Surfacing, Weldments, Multi Bodies and more… SDC www.SDCpublications.com Schroff Development Corporation PUBLICATIONS Beginner's Guide to SolidWorks 2011 – Level II 5 Multi Body Parts As we stated earlier, multi body parts allow us to do certain operations that would be difficult to accomplish with a single body part. First, we’ll talk about how to make multi body parts, and after that how to use them. 1. – Multi body parts are made by adding material that is not connected to the current solid, that is purposely not merged to it, or by splitting an existing body. To show this, make a new part, and add a sketch to the Front plane as shown. We will not worry about dimensions here as we are just illustrating the concept of how multi bodies work. 2. – Select the “Boss Extrude” command. Notice that we are not given a warning about having two separate bodies; it just works. Extrude any size that looks similar to the following image (dimensions are not important at this time) and click OK to finish. (Making two or more extruded/revolved/swept/lofted features would work just the same.) The first thing we notice is a new folder in the FeatureManager called “Solid Bodies(2)”. This folder is automatically added when SolidWorks detects multiple disjointed bodies in a part and lists the number of bodies found in the part (in this case, 2). If we expand the folder, we can see the two bodies in our part listed under it. The important thing to know and remember is that multi body parts are not to be confused or used as an assembly; parts and assemblies have significant differences and each serves a different purpose. A multi body part is used mostly as a means to an end. Beginner's Guide to SolidWorks 2011 – Level II 6 3. – The next step is to add a new feature. When working in a multi body part we can make ‘local’ operations; for example, a shell feature affecting only one body. Select the “Shell” command from the Features toolbar, and shell the bottom body as indicated. 4. – Select the Fillet command and round two corners to the top body as shown. To help the reader understand the concept of local operations better, “local” means that we can add applied features (features that don't require a sketch like Shell, Fillet, Chamfer, Draft, etc.) to each body separately. Notice the name of a body changes to the last feature applied to it. Beginner's Guide to SolidWorks 2011 – Level II 7 5. – When working with multi body parts, adding more features automatically selects existing bodies to modify; this is the default behavior. Optionally, we can select which bodies to “merge” (or fuse with) to make a single body, or select which bodies to cut. Here we'll make a new boss and explore the option to merge two existing bodies. Select the front face of a body and make the following sketch. 6. – Extrude the sketch into the existing bodies. Notice the “Merge result” option in the Extrude command. It's always been there (except when there are no existing bodies), and by default is always checked. A new option at the bottom of the Extrude command is “Feature Scope”. This is where we can select which bodies to affect, either “All bodies” or “Selected bodies” and either is automatically or manually selected. By default Feature Scope is set to “Selected bodies” and “Auto-select”. These two options mean that by default the new feature will merge with any body it intersects. Uncheck “Merge result” and click OK to finish (when unchecked, “Feature Scope” is automatically removed.) Beginner's Guide to SolidWorks 2011 – Level II 8 7. – The result is three bodies in our part. See how the different bodies’ edges intersect each other. If we had left the “Merge result” option checked, we would not see these edges overlapping as they would have merged into a single body. Edit the definition of the last extrusion to explore the effect of different “Merge Result” and “Feature Scope” combinations. Combination: Result: Merge Result: Checked Feature Scope: Auto-Select Single body. By touching both existing bodies “Auto-select” merges them, fusing them into a single solid body. The “Solid Bodies” folder is no longer visible. Beginner's Guide to SolidWorks 2011 – Level II 9 Merge result: Checked Auto-select: Unchecked Add shell body to selection box Two bodies. We are telling the Boss-Extrude to merge only to the Shell body (or whichever we pick). Notice the edges of the upper body and the Boss-Extrude overlap, as they are different bodies. 8. –The “Merge result” option works the same way with any feature that adds material to the part, including revolved boss, sweep, loft, etc. Now we’ll see how it works when we remove material. Delete the Boss-Extrude feature and keep the sketch. Select the sketch and click in Cut-Extrude using the “Through All” option. In this case the only difference from a boss extrude is that we only have the “Feature Scope” option at the bottom with the same selection options: “All bodies” or “Selected Bodies,” and with the “Auto-select” or manually selected bodies. Leave the “Auto-select” option on and click OK to finish. Beginner's Guide to SolidWorks 2011 – Level II 10 9. – What we end up with is the same two bodies we had before, but now they have a cut through them. 10. – Edit the Cut-Extrude definition, turn off the “Auto-select” option in the “Feature Scope,” and select only the top body. Click OK to finish. Now we are only modifying the top solid, even if the Cut-Extrude overlaps the lower body. And just as with the features that add material, this technique works the same way with all the features that remove material including revolved cut, sweep cut, loft cut, etc. Beginner's Guide to SolidWorks 2011 – Level II 11 11. – Modeling with multi bodies is a powerful technique to model parts that would otherwise be difficult to complete. One frequently used technique is called “bridging”; this means to connect two or more bodies by adding material between them to merge into a single solid body. Reasons to use this technique may include a model where we know what opposite sides/ends of a part look like, but we may not know what the middle (the “bridge”) should be like. For our example we’ll assume that we need to design a car’s wheel. We know what the actual tire and hub dimensions should be, but we don’t know yet what the spokes will look like; we just know it has to look great . We’ll assume the dimensions for the wheel are as shown in the following sketches. The first part of the wheel will be the hub or mounting pad. Draw the following sketch in the Right plane and make a 360°Boss-Revolve. Tire dimensions are usually in millimeters. Since the sketch dimensions are given in millimeters, be sure to change your part’s dimensions accordingly (Tools, Options, Document Options, Units). Pay attention to the diameter dimensions (doubled about the horizontal centerline). 12. – Make a pattern of 5 holes to mount the wheel to the car. Beginner's Guide to SolidWorks 2011 – Level II 12 13. – Now we’ll make the wheel’s rim that matches the tire. Draw the following sketch also in the Right plane. (The 330 mm diameter dimension is doubled about the horizontal centerline as diameter.) TIP: Make the two short lines on the sides equal, and the two lines connected to the 12mm horizontal line also equal. 14. – After finishing the sketch, make a Revolved-Boss. Since this is an open sketch we will be warned about closing it if we don’t want a thin feature. Select NO when asked. Make a thin revolved feature 5mm thick going inside. Beginner's Guide to SolidWorks 2011 – Level II 13 After finishing the revolved feature, we can see that now we have two bodies. 15. – Now we need to make the spoke in the wheel; this is the part where we can get creative. We’ll assume our limitations are defined by the hub and the actual rim where the tire mounts. We’ll design the first spoke and will not merge it to any other body; we’ll have to make a couple of local operations on the spoke and show how to make a body pattern later on. Switch to a Right view and add a sketch in the Right plane. Change to “Hidden Lines Visible” mode for visibility. A shaded model is shown for sketch clarity. Make arcs tangent to both lines and each other, and with equal radii. The vertical lines are coincident to the first hole in the hub and the rim’s outside edge. This will be the path uploads/Geographie/ guide-to-solidworks.pdf