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- View Offline
- Navigating drawings with the View Cube and other navigation tools
- Sketching geometry
- Dimensioning parts
- Creating parameters
- Drawing circles, squares, and other shapes
- Creating extrusions
- Creating and managing constraints in assemblies
- Setting basic drawing dimensions
Skill Level Beginner
Now that we have a solid understanding of what Constraints are, how they work, and how to manage them, we can continue assembling parts. Before we get started, in the previous movie we heard an audio indicator, and we saw a preview when a constraint was applied. A lot of times people find the audio indication a little disruptive during the design process, so I am going to show you how to turn that off for this movie. If you go the Application menu and select Options you can make sure this Assembly tab is selected, and there's a check box that says Constrain audio notification we are going to unchecked that so that we can disable that notification.
We still get the preview so we can see the constraint, but the noise won't distract us during the process. Now we are ready to begin constraining parts. I am going to right-click and bring up my Constraint dialog box from the Marking menu, and I am going to constrain the Crankshaft to the Engine Block. I am going to that by selecting the center axes of the Crankshaft and a center axis that runs to the center of the Engine Block. I am going to select OK to apply that constraint and close the dialog box, and we can now see the Crankshaft slides through the center of the Engine Block, and it rotates, but it's always locked in position.
Next we are going to look at assembling the Crank Arm and the Crankshaft together. Again, from the Marking menu will select the Constraint option and here we will zoom in and select the inner axis for the end of the Crank Arm and pan over and select the Cylindrical Face on the Crankshaft. Now you can notice we get the preview, but no audio indicator, and we can continue on. I'm going to go ahead and apply this constraint, and we are ready to move to our next constraint. Before we do that, I'm going to go ahead and cancel this dialog box.
From time to time, it's always a good idea to get out of the Constraint dialog and just double check some of the motions. You can see here that my parts are starting to work right together, but they are not quite there. The next company to take is to constrain the two faces between these two parts. From the Marking menu, I'll select the Constraint option, and this time I am going to select the face of the Crankshaft and rotate around and zoom in a bit and select the face on the Crank Arm. The two faces are now touching each other. If I zoom in from the right, you can see that there is 0 Offset between the two.
Before I apply that constraint, because in the real world these parts are not going to be rubbing up against each other perfectly, I am going to add a very small gap between the two pieces. I am going to enter .005, and you can see it update on the screen, and that looks perfect. So we are going to a go ahead and hit OK to apply the constraint, and now we can now zoom out and begin assembling our next components. In this step we are going to go ahead and connect the Piston Pin to the Piston Head. So I'll right-click to bring up my Marking menu and select the Constraint option, this time I am going to select the Cylindrical Axis through pin, and I'm going to zoom in and select the Axis to hold that pin belongs in. You can see the preview, and that looks right.
I am going to go ahead and click Apply to accept that, and if you notice, the end of the pin is curved. This is because it's going to be pressed into the Piston head, and we need to make sure it's properly aligned. So we are going to select the axis on that curved edge and then the axis on the Piston Head, and the two Parts become connected. If I click OK, we can see the result. If I click and drag on the Piston Head, these two components move as one now because they are properly constrained together. If I were to click and drag the pin, the same action occurs.
Now we are ready to a symbol the Piston Head to the Crank Arm. Let's zoom back out and rotate into a view where it will give us our best ability to do the constraining. And I'm going to drag the part so that these two components are near each other, just to make the selection process easier. I am going to right-click to bring up my Marking menu and select Constrain again, and this time I'm going to select the center axis for the Crank Arm, and I am going to select the center axis of the pin. I'm going to hit OK to apply those two constraints and test motion again.
If I click and drag the piston head you can see that it rotates around the Crankshaft, which is what we want it to do. But it is able to float along the axis of the Crank Arm, and this is exactly what we want. The actual piston position is going to be defined by the center of the Piston Shaft. We can go ahead and apply that constraint now so you see what I mean. I am going to right-click and bring up my Marking menu and select the Constraint option, this time we will select the axis through the Piston Head and the axis to the Piston Shaft. You'll notice that the two are perfectly aligned now, but it's slid away from the Crank Arm, and that's okay at this point. Let me show you what I mean.
If I hit click OK to apply that constraint and close the dialog box I can left-click and drag on the Crankshaft, and as that component moves you can see the Piston moving up and down in the Piston Shaft. So we are almost there, but we still have a couple more constraints to finish. Now we are ready to add the Pulley Shaft to the Crank Arm. I am going to drag this component down so it's a little bit closer to where we need it to be, and we'll rotate around so that we can see from the other side. I like positioning the components a little bit closer just to make selections easier from time to time.
Now we have the components rotated in the proper position, and we can right-click to bring up our Marking menu and select the Constraint dialog. We can now pick the face of the Crank Arm, rotate around and get the Front Face of the pulley arm, and you can see them snap into place with each other. I am going to apply that constraint, and now I have got the faces touching, but I don't have the parts aligned properly. I am going to select the center axis of the Pulley Arm and the center axis of the Crankshaft to properly position the two components.
I can hit Apply and cancel this dialog box to double check my work. If we zoom in a bit, we notice there is one thing I forgot. I forgot to add the gap between the two faces. That's okay, though. I can always go back and edit that constraint. One of the nice features of the Assembly environment is the ability to right-click on a part and select Find in Browser. This isn't so important when you only have a few parts, but once you get 100 parts into a browser, it makes it very easy to find things very quickly.
Now that I found the part in the browser, I can expand it and look for the mate we just created, here it is Mate 11. I am going to right-click on it and select Edit, and we can now enter our Offset. From the preview, you can see that now we're matching on both sides, and this is appropriate, so I am going to hit OK and continue on. The last component we need to assemble is the Face Plate we created during the Part Modeling chapter. We'll go ahead and bring up our Constraint dialog box from the Marking menu, we'll select the top Face of the boss, and we can rotate around to select the backside of the Pulley Shaft.
In doing so, you can see the preview puts these two faces together, and that's the way it's supposed to be so we are good there. We're going to go ahead and click OK to accept that and close the dialog box. At this point, we are nearly complete with our Assembly. The last item we need to do is Align the Face Plate with the Engine Block, but we are going to do that with an Insert Constraint in the next movie.