Pro/ENGINEER Tutorial 3 - Working with Datum Planes

In this tutorial, we will be discussing more advancedways datum planes and axes can be used to create features. In many cases,the default trio of datum planes or existing surfaces of the part do notprovide an appropriate sketch plane for the creation of a feature profile.The creation of datum planes and axes follow the rules of geometry. Thatis, only certain combinations of existing points, axes, planes, and scalarvalues can be used to unequivically define new axes (lines) and planes.These combinations of existing geometric elements are used in conjuctionwith datum creation commands. Options include:

Offset - a scalar distance in a defined direction from ageometric element (a vector).
Angled - a scalar angle from a plane or edge/axis.
Tangent to a Circle - the new axis/plane is tangent to acircular element.
Normal to a Plane or Surface - the new axis/plane is normal(perpendicular) to a circular element.
Through - the new axis/plane passes through an existing axis/edgeor plane.
Parallel - the new axis/plane is parallel to an existingaxis/edge or plane.
Two Planes - the new axis is the intersection of two planes.

In some cases more than one of these options must be used to definitelylocate a new datum. For example, an angled datum might be creating by firstdefining the rotational aixs the plane passes through, then definingthe angle the plane makes with an existing plane.

A good example of when new datum planes are needed, is when you createfeatures on the curved surfaces of a part. We will create such a part inthis tutorial.

Start is you have in the past two tutorials by creating a newpart called con_ring.

Next, create the default datum planes.

Then, create the initial protrusion:

create>protrusion>extrude | solid | done>both sides

DTM2 will be your sketch plane, and DTM3 will be chosenas a Bottom reference plane.

The protruded disk will have an outer diameter of 2.5 and aninner diameter of 1.0 (see Note below). The thickness willbe 0.375.As seen in Figure 1. Remember to align the circlecenters to the datums.

NOTE: To place a diameter dimension, double click on thecircle with the left button, then place the dimension with the middle button.

Figure 1

Next a through hole will be placed, bisected by DTM3 (see Figure2).

Create the hole using the following commands.

create>solid>hole>straight | done | linear | done

DTM1 is your placement (sketch) plane and be aligned to DTM2and DTM3, your two reference planes.

The hole will have a diameter of 0.16.

The next operation will be to create a new offset datum plane.This plane will be used to create a cut. An existing datum, DTM1will be the parent plane to the new (child) datum.

create>datum>plane>offset

Click on DTM1 as the reference plane.

NOTE: Ensure the green arrow off of DTM1 is pointing tothe right.

Next choose Enter Value on the menu and enter 1.10

Click on done.

DTM4 will be created as seen in Figure 2.

Figure 2

Use the new datum, DTM4, as your sketch plane and DTM2 asthe reference plane to make a Thru all cut in the part. After choosingDTM4as the sketch plane, ensure the arrow is pointing away from thecenter of the disc.

The cut, which will be referred to as a notch, will be 0.375wide, centered on the horizontal reference plane of the disc, with a heightthe same as the thickness of the disc. The sketch only requires two elements:a center line aligned to DTM3 and a centered rectangle aligned to the topand bottom of the disk.

The final cut should look like Figure 3.

Figure 3

For the next operation, we will create an angled datum plane. Firstyou need to define the axis the plane will go through:

create>datum>plane>through

click on the axis perpendicular and through the center of the disc

Next, define the angle of the plane:

angle>(click on DTM3)>done>enter value>

NOTE: If arrow is pointing in the clockwise direction,enter -30.

If arrow is pointing in the counter-clockwise direction,

Enter 30.

See Figure 4 to see the location of the new plane, DTM5.

Now will we create a plane parallel to DTM5 and tangentto the outer surface of the ring.

create>datum>plane>parallel

click on the newly created angled datum plane, DTM5 Now indicatethat the plane will be tangent to the ring:

tangent

Using Query Select, click on the outer curved surfaceof the disk, above the angled datum plane. Make sure you select the curvedperimeter surface of the cylinder, not the flat top. Now select:

done.

See Figure 4 to see the location of the new datum, DTM6.Look at the figure to see the new hole and notch being cut. First createthe hole.

Create a One-sided hole with a diameter 0.19. You canuseDTM5 as the placement plane and align to the center axis ofthe ring and DTM2 for the references.

NOTE: If you sent the hole going the wrong direction or did atwo-sided hole, you can use redefine to correct it. See the changingfeatures instructional sheet for more information.

Now use the newest datum, DTM6, to create anothernotch.

Create a blind notch will the same dimensions as the first notch(0.375 wide, centered about the centerline). Since the datum ison the outer surface of the cylinder, we will be cutting towards thecenter with a blind cut. The depth of the cut will be 0.15.

The part should now look like Figure 4.

Figure 4

Now we will create another angled datum plane and then an offset datumplane for another notch.

create>datum>plane>through

Click on the axis going through the center of the disc.

angle >(click on the first angled plane, DTM5)>done>EnterValue

You will now be prompted for an angle. Enter 60, if showing clockwisedirection. Enter 120, if showing counter-clockwise direction.

Using the angled datum plane, offset another datum plane fromit. Refer to Figure 5.

create>datum>plane>offset>(pick the datum you just created,DTM7)>Enter Value

When prompted for an offset value, the arrow will be pointingup and to the right. You want the plane to go down and to the left.To accomplish this enter the value, as a negative, -1.10.

Use the newest datum plane, DTM8, as a sketch plane and DTM2as a reference plane.

Since this datum is offset so that it is inside the cylinder,you will be making a Thru all cut away from the center ofthe cylinder.

Make a notch in the disc with the same dimensions as the original notch(0.375 wide, centered about the centerline).

The final part will look like Figures 5a and 5b.

Figure 5a

Figure 5b

NOTE: The datum planes can be turned off from the environmentmenu.

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