Alternatively, the solid section can be made with open line sketch and adding thickness by Thicken Sketch.

Transcription

1 Sketcher All feature creation begins with two-dimensional drawing in the sketcher and then adding the third dimension in some way. The sketcher has many menus to help create various types of sketches. The section of solid models must be closed without any loose open ends and any overlapping with other curves. If there are more than one outline, they must not intersect and all of them must be closed. Alternatively, the solid section can be made with open line sketch and adding thickness by Thicken Sketch. The section of surfaces (i.e., quilts) can be any way, open and intersect.

2 Sketch Window

3 The Initial Orientation of Sketch Plane (SP) In Creo, the initial orientation of the sketch plane and its reference planes is in 3D. You can use Sketch View command in Graphics Toolbar to get the sketch view rather than 3D.

4 Weak and Strong Dimensions When a geometry is sketched, the default dimensions (so called, weak dimensions) are given. The dimension can be changed by double clicking it and entering a new value > CR.

5 Use Sketch View and then sketch with Line and Circle similar to below. This shows default dimensions. Also, the sketch is shaded because the sketch is closed (i.e., successful).

6 1. Click and hold a dimension and move to a new position. 2. Double click a dimension and edit it and end it with CR. Repeat this for all dimensions as shown below.

7 To Create Dimensions Click Dimension > select the entity or entities with the left mouse button > place the dimension at the desired position using the middle mouse button.

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12 Relations Tools > Relation > enter the relation as shown below > Ok

13 To Control the Dimensions Turn on/off the display in Graphics Toolbar.

14 To Modify the Number of Decimal Places in Dimensions, click Parameters tab and change it (see below).

15 To Replace a Dimension Replacing an existing sketcher dimension with an equivalent one that retains the symbolic dimension (sd#) of the original is useful to preserve additional data associated with the original dimension (for example, geometric tolerance symbol or extra text added in drawing mode). Click a dimension > MRB > Replace > create a new equivalent dimension.

16 In this example, the bottom horizontal dimension is to be replaced by another new horizontal dimension.

17 Negative Dimensions For linear dimensions, you can enter a negative dimension value. This causes the geometry to reverse direction. In Sketcher, the negative sign always appears next to the dimension. In Part mode, dimension values always appear as positive.

18 Creating Geometry in Sketcher

19 Tangent to Three Entities Spline Use Edge / Edge Offset Coordinate System Axis Point

20 Text

21 Manipulating Sketcher Geometry Dragging Dynamic Trim of Section Entities Trim Entities to Each Other (Other Entities) Divide Entities Intersect Entities Mirror Geometry Dynamic Trimming and Possible Problems

22 Dragging Any geometry can be dragged to change the shape.

23 To move a line, click select the line and then drag.

24 Dynamic Trim of Section Entities Edit > Trim > Delete Segment > click any segment to remove. When the mouse is over a segment, it is highlighted ready to be selected.

25 Trim Entities to Each Other (Other Entites) Edit > Trim > Corner > click two entities (they do not have to intersect) on the portion of the entity to keep

26 Trim Entities by an Increment Sketch > click Intent Manager (to turn off) > Geom Tools > Trim > Increm > Enter the incremental length. A positive value lengthens an entity, and a negative value shortens it. Note to use Untrim Last if needed

27 Trim Entities to a Specific Length Sketch > click Intent Manager (to turn off) > Geom Tools > Trim > Increm > Enter the incremental length. A positive value lengthens an entity, and a negative value shortens it. Note to use Untrim Last if needed

28 Divide Edit > Trim > Divide > Click the entity at the locations where you want to divide.

29 Intersect Entities Sketch > click Intent Manager (to turn off) > Geom Tools > Intersect > pick the first and second entities near the intersection point > Yes (to delete dimensions). The entities are split at the intersection point

30 Trim Entities to a Bounding Entity

31 Mirror Geometry Mirror Sketcher geometry about a sketched centerline. Select an entity or multiple entities to mirror > click or Edit > Mirror > select a center line

32 Dynamic Trimming and Possible Problems First use [Extrude > Sketch > pick the top datum plane for sketch plane > click Sketch button]. Now, in the sketcher, sketch the rough half section and a horizontal line as shown. Don t worry about the dimensions right now. Note that a straight horizontal line is used to trim the arcs.

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37 Example 1 Create the following model by using various sketcher menus and constraints.

38 Tangent and Trim Extrude > in the sketch mode draw circles and lines Constraint > Tangent Pick on one outer circle and then the line (make the line tangent to circle) Repeat this for all tangent lines Constraint > Trim select entities to trim (i.e., delete) Hole and Copy (see the website, Edit Feature > Copy, for details):

39 Hole Dialog Window ABOUT THREADS For second linear reference, pick on the axis of the big hole and then HP to specify the distance from the axis along HP.

40 Example 2 Create the following model using the half sections in the sketcher.

41 Sketch/Mirror and Tangent Extrude > Sketch the cylinder on HDP. For key hole, draw half the section in sketch mode and use Mirror menu Create center line Draw lines Change dimensions as needed Select lines to mirror [shift key down and selecting lines] Click Mirror menu Pick on center line for mirroring For protruded part to the right, draw half the section in sketch mode and use Mirror menu Create center line Draw lines Use constraint Tangent to make the line tangent to circle Override default dimensions and change dimensions as needed Select lines to mirror [shift key down and selecting lines] Click Mirror menu Pick on center line for mirroring

42 Dimension Note that the angle dimension appearing in protruded part is not active dimension, but reference dimension and must not be used to define the shape.

43 Example 3 Create the extended part that uses part of the outline of the existing part on the right.

44 Project Create the object on the right-side with a spline and lines Create two datum planes. First one at 30 o angle to the front face of the right-side object thru the vertical edge at front*. The second one is created by offset from the previous at 60 distance Create > Solid > Protrusion > Extrude > One Side Select the second datum plane as sketch plane [do not flip arrow direction ** ] and top datum as top plane Sketch > Project > Loop > select the front face of the object which is defined by the loop (you may rotate the object for viewing. Now you see projected sketch on the sketch plane) Draw a vertical line and Trim Sketch Done > Depth > Till Surface > select the front face of the original object * Thru > Select Edge > Angle > Select Plane > Done > enter value ** keep default direction because we use UpTo Surface.

45 Hint: if you make a mistake in sketching and want to redo some parts, then use quit > cancel and then click the item in dialog you want to redo.

46 Dimension

47 Example 4 Create the part below by using Offset Edge.

48 Offset Edge Extrude > > construct the bottom block with a round. Extrude > One Side > select the top surface as SP > select the front face as bottom RP > close refs window Sketch > Edge Offset > Chain > select the first line and the last line to offset clockwise (Arc can offset up to its radius). Type in the value (can be negative) for offset OK

49 Dimension

50 Working with Sections To Retrieve an Existing Section or Drawing To Copy Imported Drawings into Sketcher Edit > Copy Edit > Scale and Rotate To Exit Sketcher with an Incomplete Section

51 Edit > Copy

52 Edit > Scale and Rotate