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PARAMETRIC SOLID MODELING AND DESIGN

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PARAMETRIC SOLID MODELING AND DESIGN

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    1. PARAMETRIC SOLID MODELING AND DESIGN ENDG 105 Class 8.1 Part 1: Modeling Complex Objects Part 2: Creation of Drawings

    2. Part Modeling Review - 3D Operations Sophisticated methods exist to create 3D objects from 2D sketches, but most are combinations of four basic techniques:

    4. Part Modeling Revolutions A revolved feature is created by rotating a sketch around an axis. Revolving a sketch requires the user to indicate the axis of revolution and the number of degrees that the sketch will revolve. The axis of revolution can be a separate line outside the sketch, or an edge that is part of the sketch to be revolved

    5. Part Modeling Revolutions

    6. Part Modeling Secondary Features Not every object can be created with a single sketch and a basic extrude, revolve, sweep, or loft operation. Multiple sketches and solids need to be combined to create more complex objects.

    7. Part Modeling Secondary Features The first step required to model a complex object is to recognize the basic form that best represents the overall shape of the object. This basic shape is called the base feature and it is created using a single extrude or revolve. Subsequent features are combined with the base feature to create the final object.

    8. Part Modeling Secondary Features

    9. Part Modeling Secondary Features Solids are combined using Boolean operations: Union ( ? ): addition of two overlapping solids. Difference ( - ): it removes the overlapping volume between two solids from the one listed first in the operation. Also known as cut. Intersection (n ): the intersection between two solid parts is a solid that keeps only the volume of overlap (counted once) between the two.

    10. Part Modeling Secondary Features Example (Shaft) Lets build the shaft shown on this slide. Building this shaft by extrusion, the initial feature will be a circle centered on the origin. Assume a diameter of 1.00 and a length of 1.00. Place your initial sketch on the XZ plane. Use view cube to go to top view Draw and fully define the sketch, then extrude it to create the Base Feature. Note that if you correctly placed the center of the circle on the origin, it will only require one dimension to fully define the circle.

    11. Part Modeling Secondary Features Example (Shaft) With a base feature defined, additional features can be added. To place a second sketch, you must define a plane on which to place the sketch. This can be either one of the standard planes or a planar surface of the part. In this case, you want to use the upper surface of the cylinder as your sketch plane. This will anchor the sketch to that surface, so that if the size of the initial cylinder is modified, this sketch will move accordingly. THAT IS PARAMETRIC MODELING..

    12. Part Modeling Secondary Features Example (Shaft) Left Click on the top surface and it will highlight. Right-click and select New Sketch. The grid appears on the top surface with a dot in the center of the top surface. This is the origin for this sketch. Draw a circle, centered at the origin, just smaller than the existing face. Dimension it to be diameter .75 Select finish sketch

    13. Part Modeling Secondary Features Example (Shaft) Extruding a secondary feature is basically identical to extruding the base feature. Select the Extrude icon. Select the profile (somewhere inside the .75 Diameter circle) The depth will default to the previous depth. Change the depth to 2.50

    14. Part Modeling Secondary Features Example (Shaft) To add the final feature the keyseat (the slot down the side) one more sketch needs to be added to the part. Select the very top of the shaft and start a new sketch. Dimension it as shown on the next slide. Note the .2813 should be the diameter of the shaft/2 - 3/32 Add a tangent relationship between the green side and the circle to fully define the sketch.

    15. Part Modeling Secondary Features Example (Shaft)

    16. Part Modeling Secondary Features - Example You used the Boolean operation Union when you added the second cylinder to the first. To create the slot you will use the Boolean operation subtract. Select the Extrude icon. Select the middle button to cut Adjust the distance to 2.5 Select the profile (the rectangle for keyseat)(slot)

    17. Part Modeling Secondary Features Example (Shaft) This completes the shaft as shown to the right. Save the shaft to your flash drive or user folder The next step is to draw the pulley which would go on the shaft.

    18. Part Modeling Secondary Features Example (Pulley) How would you create the pulley?

    19. Part Modeling Secondary Features Example (Pulley) The base feature for the guide wheel shown on the previous slide will be created by revolving a sketch of the shape of the wheel. (similar to a half section) Begin a new part and sketch the following base sketch. There are a few sort of tricky methods to get the sketch to be fully constrained.

    20. Part Modeling Secondary Features Example (Pulley)

    21. Using Centerlines and Construction lines In addition to the normal lines used to create a profile in sketch mode, there are two other types of lines that can be created for use in a sketch. Construction lines These are lines that is used in a sketch to reference a dimension or sketch entity to, but are not needed to create the closed sketch profile Construction lines can not be used to create a closed profile of you sketch Centerlines These are used to reference an axis off of the profiled sketch edge that the feature will be rotated around

    22. Using Centerlines and Construction lines As we discussed earlier, different line types can be drawn. To create a centerline Draw the given line Select the line Select the line-type from the format area of ribbon Select Centerline To create a construction line Follow the same steps as above Select Construction Note: Once the construction line type has been selected, all further lines drawn will be construction lines. To avoid this De-select the given construction line De-select button in the format area

    23. Dimensioning out a sketch Whenever a part is dimensioned, if a certain feature is dimensioned to a centerline, then it will be shown as a diameter dimension In addition, dimensions can be referenced to a whole line or arc feature or to the endpoints of a line feature

    24. Revolve the Sketch

    25. Part Modeling Secondary Features Example (Pulley) Add a matching keyway on the Guide Wheel to match the keyway in the shaft. The results should look like the figure shown to the right. Save this file.

    26. Drawing Creation Selection of the Template Now that we have created our solid, we need to create a drawing of it. Because we have already constrained and dimensioned the object, this step is considerably easier than in AutoCAD. Go to new and select quick launch Browse to 105 Library Raborn folder and select ASSEMTITLE.idw

    27. Orthographic Drawing In the .idw file, click on Base View and follow directions in box. First view you insert is always Base View.(Place Views Tab)

    28. Insert base view into new sheet

    29. Add views

    30. Project Other Views

    31. Projecting Isometric views

    32. Drawing Creation Creation of Views Create a layout of views similar to the one shown below.

    33. Edit View To show the isometric view as it would appear in an .ipt file (shaded), Right click on the view Select Edit View Check desired look. If your view doesnt have hidden lines, you can add here

    34. Centerlines (Annotate Tab) To add center marks use the Center Mark Command To add centerlines use one of the Centerline commands

    35. Centerlines To adjust centerlines you can grab grips and adjust Right-click and edit You can also right-click and edit the center mark style(this is a global edit)

    36. Drawing Creation Complete Drawing

    37. To add text to titleblock Use Text command (Annotate Tab) Pick text location text editor appears Type in text Move if necessary to line up with existing text

    38. Turn in pulley drawing for in-class assignment 8.1(save as to make it your drawing)

    39. Individual Homework Assignment 8.1 Make solid models of the Problem 2 on page 80, and Problem 4 page 81 of the textbook. Plot orthographic views of each.(use the ASSEMTITLE.idw template) No dimensions Due one week from today.

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