Last time we created a yo-yo body and learned how to use rotational extrusions and mirrored sketches.  In this lesson we'll learn how sweeps work, start using assemblies, and learn about the SolidWorks assembly attachments called "mates". At the end we'll have a functional yo-yo...well, sort of! Let's get started!

1. Create a new document, and choose the Right plane to start your sketch.
   
   
   
   
   
   
2. Draw a horizontal straight line about 2” long (start at the origin)
3. Select the spline tool. Click on the end of your last line, and draw a loop.
1. You may need to play around with this a little since you don’t want your loop to overlap itself at all
2. We need smooth curvature, so be sure not to make any “sharp” bends
   
   
   
   
   
   
   
   
   
   
4. Now selecting the Front plane, start a new sketch. You will need to rotate the view manually either by clicking with the center mouse wheel and dragging across the window, or by using the standard view buttons.
5. Select the circle tool and sketch a small circle at the origin.
1. If you created the other lines properly, this should be centered on the straight line.
6. Dimension this circle with a 0.0625” (1/16”) diameter using the “smart dimensions” tool.
   
   
   
   
   
7. Now click the Sweep/Swept feature button on the Features Toolbar.
   
   
   
   
   
   
   
8. Your profile is the circle; your path is the line.
1. You might see how this could be useful for making complex paths
2. Feel free to play with this feature when you have some free time!
   
   
   
   
   
   
9. If you get an error message and SW doesn’t let you create the sweep, there might be something wrong with your model.
1. Make sure that the circle we are “sweeping” over the long profile is significantly smaller than the line. If the 3D solid will intersect itself because the loop is too small or the circle too large, SW will give you an error message
2. There may be a sharp angle between the straight line and the loop. To fix this, simply apply a large sketch fillet to the first sketch, say, ½ to 1” radius.
10. If you went through the yo-yo tutorial, you should now we have a yo-yo string and a body, but they’re in separate documents. We create a SolidWorks assembly document to put our pieces together.
    
    
    
    
    
    
11. Create a new Assembly document (File, New, Assembly).
12. Using the “Insert Components” dialog (replaces the property manager), select your yo-yo body or using the browse dialog locate and insert this.
1. The first part you insert into an assembly will be the “origin”. If you delete this origin part and insert parts later, the assembly will NOT be constrained in 3D space, a big problem for FEA or any physical simulations.
13. We will use the concept of mates—creating relationships between the parts using the geometry we have created.
1. For this step we will use a less-useful mate, the “tangent” mate to fix our string to the inner radius of the yoyo.
14. Not completely constrained, but it will work for this non-functional model (prop)
15. Your yo-yo is complete!

Labels: 3d modeling, CAD, CAD lesson, guide, Parametric Modeling, SolidWorks, yo yo

I'm starting a series of lessons on beginning CAD with SolidWorks, a great 3D package that I have grown to depend on and enjoy. SolidWorks has some great tutorials within the software you can use - I started writing these tutorials as part of  a one day course I taught for beginners. These are designed for use while using a copy of SolidWorks. So, without further ado, let your introduction to parametric modeling begin!

SolidWorks is a great tool, because you can sit down and learn how to do things yourself.  Some other modeling programs have such a complicated workflow that it is almost necessary to have either a teacher or manual.  SolidWorks is a powerful CAD package, but is presented in a format that is easy to process and understand. I encourage you to play around and learn your own workflow and explore features we may not cover here.

What to take away:
- A basic understanding of how 3D CAD works (terminology, etc) and how to leverage the tools provided to produce simple and functional models.
- “Best practices” or design methodologies to create models that are realistic in terms of constraints and manufacturing techniques
- Design intent – constraining your sketches & dimensions in ways that simplify future modification without losing the reasoning behind certain dimensions (1/2 of width d, etc)

Basic Features
Extrude Boss/Base
Extrude Cut
Sweeps
Rotational Solids
Rotational Cuts
Lofts
Sheet Metal
Fillets/Chamfers

How do we create parts? With sketches - using basic shapes – circles, rectangles, lines, curves – or complex geometry such as splines, repeating patterns, etc.

Solidworks allows rapid model creation by allowing the use of pre-existing geometry to constrain features & sketches.

Lesson 1.1: The Interface

The Solidworks interface is a large window where you create and modify your design, surrounded by toolbars that enhance your interaction with the 3d model.

When starting out, you can use large icons with text labels – as you get more advanced, you can turn the labels off, use small icons, even turn toolbars on and off.  When you feel really comfortable with the program, you can customize toolbars down to the order of icons and set the content for each toolbar.

Throughout the different versions of SolidWorks the icons for different operations have remained the same. The yellowish icons are for operations called "features" -- they modify or create 3D geometries. The blue icons are sketch related operations and create 2D layouts that are used to create 3D geometries through extrusions, cuts, and rotations. You can intuit this from the well-designed buttons that either show an enclosed volume or a line segment.

**Tools you will make use of** the zoom functions and standard views are your best friends! Learn to be comfortable with them, and understand the rotation of your models. I highly recommend that you add the standard views to your toolbar if they aren't already there. Just right click anywhere on the toolbar and select "Standard Views."

Labels: CAD, CAD lesson, Parametric Modeling, SolidWorks