George and Shana Blog, 5 Dec. 2012
Unit 2 Lesson 3, Modifying Material Properties
Sustainability Xpress and Simulation Xpress features that are “great”
This tutorial uses a part that we haven’t drawn yet. We decided to just use the bracket we drew in Lesson 2 (hopefully you saved yours).
Tools > Sustainability Xpress, then selected the materials as the narrator says.
Set first choice as backdrop, then use solidworks to find similar materials based on things like strength and density. Sustainability Xpress now allows you to compare environmental impacts of comparable materials in the form of a series of pie charts.
Simulation Xpress allows you to see how a part will respond when different loads are applied.
For this we followed the narrator’s instructions and drew a plate from scratch. He talks really fast in describing how to draw the plate, but if you watch the video closely you’ll see that he grabs the rectangle tool to draw the initial rectangle. Following his directions to set the dimensions and use the extrusion tool was straightforward.
Next you go to Evaluate Tab > SimulationXpress Analysis Wizard (before you do this, you need to click the check mark on the left in the extrude tool, at which point the part turns grey).
As instructed we added fixtures both ends of the board (you have to navigate around it to make the ends visible to do this). We set the force to 100N applied to the top of the board, set the material to alloy steel, then clicked “Run Simulation” to see how the board would bend when the force was applied. It wiggled! Cool movie in the next post!
Next we went off the script and changed the material to ABS plastic. It looked basically the same. Then we changed it to Cast Carbon Steel, which also looked the same.
Guess what, they look the same because the animation automatically scales the level of deflection. But if you look at the numbers, you will see the differences. If you click Results > Displacement in the left tool bar you will see a picture of the displacements with the size of displacement indicated by color. When you do this for carbon steel, you get a max displacement of about 6e-4 mm, and if you do it with ABS the max displacement is about 6e-2 mm, so steel is in fact stiffer than plastic! Here is a picture of the deflected bar colored by the magnitude of the deflection:
Now we move onto Unit 3
Lesson 1: Assembly project
Create a new assembly project.
Guess what – there is supposed to be a Solidworks education directory that has some robot parts in it, but we don’t have one on the GoS Computer. (This explains why we had to use our own part in Unit2, Lesson 3). We’ll have to work on this in the future, but for now we decided to make an assembly using our own parts. We used the bracket that we made earlier, then we made a pin with a diameter of 0.5” to fit in large hole on the bracket.
Next we opened a new assembly, then brought them in by going to “begin assembly” then browsing to find the bracket and pin parts that we had drawn earlier. Using these two parts we tried the various modes of the Mate tool. Here is a photo that results from performing two mating operations: concentric mating of the axes of the rod and the hole; and coincident mating of the hole and the circle at one end of the rod. It makes sense if you think about it a bit:
That’s it for today. This took about an hour, a big chunk of which was used doing non-tutorial things like searching for the supposed library and drawing extra parts so we could mate assemblies.
We only made it about halfway though the tutorial, we’ll try to get the educational library so we can do it all next time.
Hello Everyone! Welcome back for the second installment of our semi-exciting CAD adventure! Today we really dug into Solidworks by finishing the last tutorial in Unit 1 and continuing on to 2 more tutorials in Unit 2. Though not fascinating, these tutorials were much more rewarding. The last two even left us with shiny end-products – manifestations of what we had learned. Below is a breakdown of the specific skill-sets taught in each tutorial:
Unit 1: Intro to Solidworks
–> Lesson 3: Starting a New Project
- Navigate folders
- Open and save projects
- Orient yourself with the Solidworks interface: the various viewing
Unit 2: Building a Part
–> Lesson 1: Pre-CAD prep
Learn to make a C-Frame:
- Use the line tool
- Draw shapes
- Change measurements
- Use the relations tool
- Use the offset relations tool
- Use the extrude tool
- Use the fillet tool
–> Lesson 2: Creating a bracket
- Learn to make an L-Shaped Bracket:
- Review skills 1 learned in lesson 1
- Use the hole wizard
- Draw on the face of a part
- Use the extruded cut tool
Again, all of this took us about 50 minutes. We encourage you to try it out. Leave any questions in the ask box and we will try to answer to the best of our abilities.
Join us next Wednesday as we continue our tutorials and hopefully learn how to integrate parts into assemblies!
Hi Everyone, and welcome to our new Girls of Steel Solidworks blog. Each week, Shana and George will spend about an hour teaching themselves Solidworks and blogging about it here. Our hope is that this will result in a roadmap that you can use to learn along with us.
First, lets answer a few basic questions:
What is Solidworks? Solidworks is a computer aided design (CAD) program. It allows us to draw things (like robot parts) in 3D and then combine those parts into some larger assembly (like a robot).
Why should you learn Solidworks? Everyone on the Girls of Steel should learn Solidworks. It is the main tool that we will use to design and communicate about the robot. It doesn’t matter what your technical interests are, Solidworks will be useful to you and help you understand all of the different parts involved in building our robot.
Where can I get Solidworks? The team has licenses for Solidworks so that you can install it on your own Windows computer (see Tammy about getting the installation discs). We go over how to install it next week, but for now we will just use the Girls of Steel Solidworks computer, which is in George’s Agricultural Robotic Systems Lab just off of the highbay. You are welcome to use this computer. The username to use is cad, the password is solidworks. Here are some pictures to help you find the computer:
We will start this blog by working our way through a series of tutorials provided by Solidworks that are geared toward FIRST robotics. You can find them here: http://www.solidworks.com/sw/education/9931_ENU_HTML.htm
So, without further ado, let’s dig in!
Lesson 1: What is Solidworks? – This is actually a pretty boring movie, but it is short (less than 2 mintues) so watch it anyway, you might learn something.
Lesson 2: The Solidworks Interface – in this lesson, you will open up Solidworks, load a part that someone else created, and look at it. I know it doesn’t sound very exciting, but it is a first step toward bigger and better things. The tutorial uses a slightly older version than we have, but it is pretty straightforward to follow along.
The main thing you will do here is learn how to access a library of pre-made parts (there are thousands of them available!). We weren’t registered on the 3D Content Central website so on our first try we were unable to download the “center bolt wheel” part. We then created an account for the Girls of Steel (you are welcome to use this account if you don’t want to create your own, username: girlsofsteelrobotics, password: riveter). Then we logged in to that account, then searched for the wheel again. This time, success! Well, almost.
According to the tutorial, you are supposed to be able to drag the link 13_Center_Bolt_Wheel directly into Solidworks, but we were unable to do that. We had to download the part to a local directory (make sure you download the 2012 version of the part), then unzip it, then drag the resulting solidworks assembly document “User Library-13_Center_Bolt_Wheel” into the Solidworks window.
The result is in a nice shiny picture of the wheel. You can move the wheel around by holding down the center mouse button (scroll wheel) and moving the mouse around, or you can zoom in and out by scrolling the scroll wheel. If you are using the Girls of Steel Solidworks computer, you can also (in theory) move around with the fancy 3D joystick (see pic), but we sadly weren’t able to get this to work.
So that’s it for our first week. All of this took us about 50 minutes complete. Give it a try, and let us know how it goes! And tune in next week when we will tackle Lesson 3.