# SolidWorks 2010- P9

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## SolidWorks 2010- P9

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SolidWorks 2010- P9: Whether you are a new user of SolidWorks or a professional who wants to improve your skills, this book was written for you. Learning any software can be difficult at times. You launch the software for the first time, and you feel overwhelmed, not knowing how to even start a new document. In 3D CAD programs, it can be especially difficult. Many times a whole new vocabulary and a whole new creative environment are introduced.

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## Nội dung Text: SolidWorks 2010- P9

1. Dimension Sketches with Centerlines 209 Dimension Sketches with Centerlines By now you have surely become comfortable with adding dimensions to fully define sketches. Now it is time to introduce another cool dimensioning trick with sketches. As you know, clicking two points or sketch segments will define the distance between the two entities. But since your sketch has a centerline that represents the axis of revolution for the part, you can use that centerline to define the diameter of the part even though only half is shown in the sketch. This is a great way to control the design intent of the part since you are probably more apt to require the diameter controlled rather than the radius. Specifying the diameter of a sketch feature is extremely easy if you already know how to add a dimension, as you will see in the following steps: 1. Select Smart Dimension in the shortcut bar. 2. Select the vertical centerline, and then select the short vertical seg- ment at the bottom of the sketch. 3. The dimension placement is important for how you want to define the sketch. On one side of the centerline, the dimension will be the distance from the centerline to the sketch segment or the radius of the shaft (see Figure 5.9). F I g u R e 5 . 9 Defining the radius of a part 4. Move the mouse pointer to the other side of the centerline, and the dimension changes to show the diameter of the shaft. With the
2. 210 Chapter 5 • Creating a Revolved Part dimension showing the diameter, click and release the left mouse button to place the dimension (see Figure 5.10). F I g u R e 5 . 1 0 Defining the diameter of a part 5. In the Modify window, make the diameter 1.000, and click the green check mark. 6. Making a dimension a diameter also works with points on the sketch. With the Dimension tool still active, select the centerline again, and select the undefined endpoint of the small arc, as shown in Figure 5.11. F I g u R e 5 . 1 1 Defining the diameter from a point on the sketch 7. Move the mouse pointer to the opposite side of the centerline again to make the dimension a diameter dimension, and accept its location. 8. In the Modify window, add the value .900 for the diameter of the shaft at the end of the arc. 9. In addition to lines and points, you can also specify the diameter for an arc at the tangency. Select the centerline again, but this time press and hold the Shift button on your keyboard while selecting the large arc (see Figure 5.12).
3. Mirror a Sketch 211 F I g u R e 5 . 1 2 Defining the diameter for an arc at the tangent point 10. Move the mouse pointer to the other side of the centerline, and accept the dimension once it changes to a diameter dimension. In the Modify window, specify the value 1.100, and click the green check mark. Rather than specifying the radius of the arc, this approach specifies the diam- eter of the shaft at the largest part of the arc, allowing the radius and length of the arc to float depending on the other dimensions in the sketch. Mirror a Sketch O A centerline rep- Mirroring a sketch or part of a sketch is a great time-saver when areas of the resenting the axis sketch are symmetric. Using a centerline as the mirror point, items that you of revolution for a select can be mirrored so they take on the relations and dimensions specified in part can be used to the original section. If you haven’t used another CAD package that has a mirror define the diameter function, the length of the mirror line does not matter; instead, the actual angle of the part. used is important. This should become clear as you use the Mirror tool in the next few steps. 1. Before mirroring the sketch, you need to finish dimensioning some items. Select the small vertical segment that makes up the 1.00 diam- eter, and place the dimension to the side. In the Modify window, add the value .250.
4. 212 Chapter 5 • Creating a Revolved Part 2. Next, select the horizontal line at the bottom of the sketch. Then select the under-defined point at the end of the short arc, and place the dimension so that it is shown as a vertical dimension. In the Modify window, make the value .350. 3. Press Esc on the keyboard to exit the dimension mode. 4. Double-click the scroll wheel or press F on your keyboard to fit the entire sketch into the graphics area. 5. Select the Sketch tab on the CommandManager, and click the Mirror Entities button. 6. Select all the sketch entities that are not centerlines. The easiest way to do this is to window over the sketch selecting all the items. Then while holding the Ctrl key on the keyboard, deselect the centerlines. 7. Ensure that Copy is selected in the Mirror PropertyManager. 8. Next click the Mirror About field in the Mirror PropertyManager. 9. In the graphics area, select the horizontal centerline. A yellow pre- view will show what the mirrored entities will look like in the graph- ics area (see Figure 5.13). 10. Click the green check mark in the PropertyManager to accept the mirror sketch entities. The sketch now contains the mirror image of the lower half of the shaft above the mirror line with the same size and relations defined in the original section (see Figure 5.14).
5. Mirror a Sketch 213 F I g u R e 5 . 1 3 Preview of mirrored entities F I g u R e 5 . 1 4 Part of a sketch created through mirroring
6. 214 Chapter 5 • Creating a Revolved Part Trim Sketch entities Even the most perfectly planned sketch will require segments to be trimmed. As you build your sketch by adding sketch entities, you will often be required to trim a segment using an existing sketch entity as the trimming plane. Even the small- est line that is not properly terminated will cause issues when you attempt to cre- ate a feature. In your sketch, you will be adding one last sketch entity that will be used to complete the profile, and you will need to trim all the segments to create one continuous profile. But first you need to add the last entity. Here’s how: 1. Select the Circle command in the shortcut bar. 2. Move the mouse pointer to the middle of the sketch, onto the point where the two large arcs merge, and click the left mouse button. 3. Move the mouse pointer away from the point selected until the radius of the circle is about .150, as shown next to the mouse pointer in Figure 5.15. Click and release the left mouse button to create the circle. F I g u R e 5 . 1 5 Using the Circle command 4. Open the shortcut bar, and select Trim Entities. In the Trim PropertyManager, you will notice there are five different ways to use the Trim tool. Each has its strengths and weaknesses, and rather than show you how to use each of them at this point, we’ll just briefly touch on each of them. Power Trim The Power Trim option allows you to trim multiple sketch enti- ties by dragging the mouse pointer across the segments to be trimmed. This is
7. Tr i m S k e t c h E n t i t i e s 215 extremely helpful when you have many items that would be too tedious to indi- vidually select. Corner Trim The Corner Trim tool trims or extends line segments to create a corner. If a selected segment is too short to meet where the obvious corner should be created, the segment will extend. Trim Away Inside The Trim Away Inside tool allows you to select two sketch entities and then trim away nonclosed sketch entities that intersect with both of the selected entities or none of them. An example of a closed sketch entity would be a circle. That means even if a circle crosses both of the selected items, it could not be trimmed with the Trim Away Inside option. Trim Away Outside The Trim Away Outside tool acts the same as the Trim Away Inside option except sketch entities that fall outside the two entities selected can be trimmed. Trim To Closest The Trim To Closest option is my most frequently used trimming option. We find that this option is the most useful since it trims anything to the nearest sketch entity without the need to preselect a trimming entity. In fact, in this particular sketch, it will be the option that will be used to clean up the profile. To perform the trim, do the following: 1. Select Trim To Closest in the Trim PropertyManager. 2. Select the two arc segments that fall inside the circle to trim off the segment. 3. Then, select the two segments of the circle that fall inside the sketch profile to remove them, making one continuous profile.
8. 216 Chapter 5 • Creating a Revolved Part 4. Click the green check mark in the PropertyManager to exit Trim. 5. Since the ends of the large arcs were trimmed back, the relationship to the original endpoint was lost. You need to ensure that the arcs are still connected to the endpoint of the horizontal centerline to maintain the integrity of the sketch. While holding the Ctrl key on your keyboard, select one of the large arcs and the endpoint of the horizontal centerline. 6. Release the Ctrl key, and select the coincident relation in the context toolbar. 7. Add the coincident relation to the second large arc as well. 8. Select Smart Dimension in the shortcut bar, and click the remaining section of the circle at the middle of the sketch. 9. Place the radius dimension, and enter the radius value of .100 in the Modify window. 10. Now, select the vertical centerline of the sketch, and hold the Shift button on the keyboard while selecting the middle arc segment. 11. Place the dimension, and set the value to 1.250 in the Modify window, as in Figure 5.16. 12. The sketch should be fully defined, as you will be able to tell by all the sketch segments shown in black and the words Fully Defined in the status bar. If the sketch is not fully defined, recheck your sketch for all relationship and dimensions.
9. Revolve the Sketch 217 F I g u R e 5 . 1 6 A trimmed sketch segment Revolve the Sketch Now that you have fully defined the sketch that makes up the profile for the lamp shaft, you can create the revolved part. All that is required in the sketch is that a centerline be present to use as an axis of revolution and that all the sketch entities be on one side of the centerline only. The profile that will be used must also be a closed profile, but since you created the sketch with an obvious divid- ing line, SolidWorks will be able to place a line along the centerline to close the sketch. To revolve the part, do the following: 1. Select the Features tab on the CommandManager, and click the Revolved Boss/Base button. 2. A SolidWorks message box will prompt you stating that the sketch needs to be closed and asking whether you would like to automati- cally close the sketch. Since you do need it to be closed, click Yes. N O t e Depending on how the sketch was created, SolidWorks will not always be able to properly determine how to close the sketch. This sketch is fairly simple, and it will have no problem, but if there is any doubt, it would not be a bad idea to close the sketch manually with a line connected to the two open ends of the sketch. 3. Since there is more than one centerline in the sketch, the Revolve tool doesn’t know which one will be used to revolve the sketch. This can be seen by the lack of a selected axis of revolution in the Revolve PropertyManager. This means that you must select the vertical center- line that makes up the axis of the sketch manually (see Figure 5.17).
10. 218 Chapter 5 • Creating a Revolved Part F I g u R e 5 . 1 7 Selecting a centerline around which to rotate the sketch The preview in the graphics area will show what the revolved part will look like when created. 4. In the Revolve PropertyManager, the only options that you need to be concerned with are Revolve Type and Angle Of The Revolution. The Revolve Type setting should already be set to One-Direction, and the angle should be set to 360°. If that is the case, click the green check mark to create the revolved part. The base feature for the lamp shaft has been created! See Figure 5.18. F I g u R e 5 . 1 8 Preview of a revolved part