Break and Regroup Holes

Introduction

This topic provides an example of how and why to use Break Hole Group and Regroup Holes for Mill drilling features. Click here to expand on the subject of Hole Groups.

This section explains Hole Groups and how to define their parameters in the Mill Wizards for all Mill Hole drilling features. This information applies to standard, multiaxis, and cross drilling (Mill Turn).

What is a Hole Group?

A Hole Group can be one or more holes that share three parameters: Diameter, Top of Feature, and Feature Depth. All holes that you select for a feature that share these parameters are automatically placed into a single Hole Group. Read the following section for further hole group requirements for each drilling type.

Standard Drilling

The following images show a standard drilling part with holes at three different levels on the model and two hole diameters. The hole groups for this part are shown with the same color.

Notice the holes that share the same diameter, top of feature, and feature depth have the same color. The software automatically creates the Hole Groups as shown after selecting all of the holes for a single drilling feature.

Multiaxis Drilling

In addition to the three shared parameters, multiaxis drilling groups must also share the same tool orientation (tool vector) in order to be grouped.

The following images show a multiaxis drilling part with two hole diameters and five different tool orientations. The hole groups for this part are shown with the same color.

Notice that even though the three larger holes on top have the same diameter, depth, and top of feature, these holes cannot be in a single hole group because they don't share the same tool orientation (tool vector). This is also true for the two sets of smaller holes on the opposing faces, except that they do create two hole groups (shown in blue and green), one for each tool vector.

Cross Drilling

Cross drilling hole groups require the same three shared parameters, but the exception here is that the tool orientation/rotation angle does not affect the grouping of holes as it does in multiaxis drilling.

The following images show a part with all cross drill style holes at various locations around the model. There are two hole diameters with holes that share the same top of feature and feature depth. The holes groups created from this part are shown with the same color.

Why Use Hole Groups?

Hole groups allow you to define more than one depth for drilling within a single feature. A single hole feature can have one or more hole groups so you can optimize the hole features that you create and eliminate the need for extra features. Hole groups also provide more clearance options, or Group Retracts, to handle the rapid movements between hole groups.

Modifying Hole Groups - Feature Settings

The following information explains the use of hole groups in the Feature page of all Mill Hole Wizards.

Using the Hole Groups Table

The Hole Groups section of the Feature settings provides a table for editing Hole Groups and their parameters. You can set the Top of Feature and Feature Depth by typing the values or selecting geometry. You can also break hole groups into separate groups and then regroup them as needed, for example, to modify the rapid movement between holes.

Important: All of the values that display in the Hole Groups table (except Number) can be editing by clicking that item in the table and typing the new value or name. The buttons next to the Hole Groups table are used with the Hole Groups that are selected in the table. When you click a Hole Group in the table, a preview of the holes displays inside the dialog box to help you visualize the parameters for that group.

Hole Groups

Number	Name	Top of Feature	Feature Depth
1	Group 1	-1.0000	1.0000
2	Group 2	-0.5000	1.5000
3	Group 3	0.0000	2.0000

Break Hole Group

Regroup Hole

Pick Top

Pick Bottom

Number

Each hole group is given a number as a reference to the group in the table. This number is automatically created and cannot be edited.

Name

Hole groups are automatically named in sequential order with the format of name and number (Group 1). Click the name of any hole group in the table to make it available for editing. Type the new name to create a custom name for the group.

Top of Feature

The Top of Feature is the top of the hole as an incremental value from the Machine Setup or machining origin location. Click the Top of Feature value in the table to make it available for editing. Type the new value to set the top of feature for the hole group. After selecting a group in the list, you can use the Pick Top button to set the value using geometry selection.

Important: For multiaxis drilling, the Top of Feature is in reference to the selected geometry, not the machining origin. For cross drilling, the Top of Feature is a radial distance from the center of the part (or the Z-axis of the machining origin for Mill Turn jobs).

Feature Depth

The Feature Depth is the depth of the hole as a positive incremental value from the Top of Feature. You can click the value in the table to make it available for editing. Type the new value to set the Feature Depth. You can also use the Pick Bottom button to set the value using geometry selection (after selecting a group in the list). Be sure to properly set the Top of Feature before selecting the Feature Depth.

Tip: For cross drilling (Mill Turn), the Top of Feature and Feature Depth values are calculated as a radial distance from the rotation axis/machining origin. Selecting cylindrical surfaces allows the software to properly calculate both of these values. When using any other geometry type, if the hole extends past the center of the part, you may need to manually type the appropriate Top of Feature and/or Feature Depth value instead of using Pick Top or Pick Bottom.

Counterbore Depth

The Counterbore Depth is the depth of the larger hole for counterbore holes. This is a positive incremental value from the Top of Feature. Click the Counterbore Depth value in the table to make it available for editing. After selecting a group in the list, you can use the Pick Counterbore Depth button to set the value using geometry selection.

Break Hole Group

The Break Hole Group button breaks the selected Hole Groups into separate single-hole groups. This can only be used when there is more than one hole in the group. Each resulting hole group contains a single hole and the naming follows that of the original group in the format: previous group name, period, new group number (Group 1.1, Group 1.2).

Regroup Holes

The Regroup Holes button takes all selected Hole Groups from the list and makes a single hole group. The naming of the new group follows that of the hole group with the lowest number.

Important: In order to regroup holes, the groups that you select must share the same Top of Feature and Feature Depth. Edit these values in the table to be the same for all holes that you want to regroup before clicking Regroup Holes. Note that for multiaxis drilling, holes must also share the same tool orientation or direction vector in order to be grouped.

Pick Top

The Pick Top button is used to set the Top of Feature value by selecting geometry such as a point, snap point, or surface edge. Select a Hole Group in the list before clicking Pick Top, or if you don't select a group, you can set the Top of Feature for all groups.

Pick Bottom

The Pick Bottom button is used to set the Feature Depth value by selecting geometry such as a point, snap point, or surface edge. Select a Hole Group in the list before clicking Pick Bottom, or if you don't select a group, you can set the Feature Depth for all groups.

Pick Counterbore Bottom

The Pick Counterbore Bottom button is used to set the Counterbore Depth value by selecting geometry such as a point, snap point, or surface edge. Select a Hole Group in the list before clicking Pick Counterbore Bottom, or if you don't select a group, you can set the Counterbore Depth for all groups.

Previewing the Hole Groups

To make it easier to visualize the parameters you are defining, when you click a group in the Hole Groups table, a preview displays inside the dialog box. The preview displays each hole, the machine setup (machining origin), the feature preview (top, bottom, and diameter), and the workpiece if you have selected one for the job.

View Controls

The Hole Groups preview uses the standard mouse controls for altering the viewing position of the preview.

You can Rotate the view by dragging with the left mouse button in the preview window. (You can also drag with the middle mouse button.)
You can Pan the view by holding down Ctrl (on the keyboard) and dragging with the middle mouse button.
You can Zoom in or out using the scroll wheel (rolling the middle mouse button forward or backward).

Viewing the Workpiece

The Hole Groups preview may or may not display the part, based on whether or not you have selected a workpiece for the job. Workpiece selection is the first step of using the Stock Wizard, or it can be assigned (or removed) using the Workpiece item in the CAM Tree.

Selecting Multiple Hole Groups

The Hole Groups table allows for multiple selections using standard controls as follows.

Important: You can click anywhere in the row of a group to select that group in the list. When you click any value other than the number, it becomes available for editing. When adding or removing selections using modifier keys (Ctrl or Shift), select a group by clicking its row under the Number column.

Click anywhere in the row of a group to select that group.
Hold down the Ctrl key and click any group to add it to or remove it from the selection.
After selecting one group, hold the Shift key and click another group to select all groups in between the first and second selections.
Tip - when you have multiple groups selected in the table, you can click any other group to select it and clear the other selections.

Hole Groups - Operation Settings

When you go to the Parameters page for any drilling operation in the Mill Hole Wizards, the Hole Groups section displays the name of each Hole Group in the feature. You then select the group name before setting the effective depth, overall depth, and cycle type settings, such as pecking, for each group.

Part Model

This example uses the following standard drilling part, but this information can be applied to all drilling types.

Toolpath

After creating a Mill Hole feature and selecting all of the holes in the model, two features are created with the following toolpath result.

Hole Groups

For reference, the following image shows all hole groups that the software automatically creates, using one color for each group. All holes in a single hole group must share the same diameter, top of feature, and feature depth.

Why We Use Break Hole Group

With hole groups, the rapid plane value determines the rapid movement within a hole group. The group retracts, however, determine the rapid movement between hole groups.

With the example part and toolpath shown, the rapid plane used within hole groups is not clearing the steps of the model when moving from one side of the part to the other. This is shown in the following images.

Although the rapid plane value could be increased, we want to make our toolpath as efficient as possible, and doing so would cause a lot of extra movement within hole groups. For this reason, we use Break Hole Group to separate the hole groups that contain holes on opposite sides of the part. The result is that group retracts are used between the new groups, thus clearing the steps of the model and creating a more efficient toolpath.

Using Break Hole Group and Regroup Holes

Now we edit the feature and modify our hole groups on the Feature page of the wizard.

First, we select a group in the Hole Groups list to show the preview of the group in the dialog box.

Note that you can click anywhere in a row to select a group, but if you click the Name, Top of Feature, or Feature Depth value, it becomes available for editing. (Either way, the group is selected when the row displays in dark blue.)

The Hole Groups preview displays directly inside the dialog box to make it easy to visualize the groups. The Group 1 preview is shown next.

Tip: Use the mouse directly inside the Hole Groups preview window to control the viewing orientation as follows:

• Click and drag to rotate the view (you can use the left or middle mouse button).
• Use the scroll wheel (middle mouse button) to zoom in or zoom out.
• Hold Ctrl and drag the middle mouse button to pan the view.

With Group 1 selected, we click the Break Hole Group button.

Group 1 is separated into four single-hole groups as shown next. Again, we select the group in the Hole Groups list to display the preview.

Notice the naming of the new groups: Group 1.1, Group 1.2, Group 1.3. This makes it easy to manage the newly created hole groups.

Group 1.1	Group 1.2

Group 1.3	Group 1.4

We can see that we want to regroup Group 1.1 and Group 1.4 as well as Group 1.2 and 1.3.

In the Hole Groups list, we click Group 1.1 to select it.

Next we press and hold the Ctrl key, and click Group 1.4 to select both groups.

Tip: You multi-select items in the Hole Groups list using the Shift and/or Ctrl keys. Hold Ctrl and click a group to add it to or remove it from the current selection. Hold Shift and click a group to select all groups between the first and second selections. (When removing selections using Ctrl, click the row of a group in the Number column.)

With both Group 1.1 and Group 1.4 selected, click the Regroup Holes button to create a new group from the selections.

Important: When using Regroup Holes, the Top of Feature and Feature Depth must be the same for all selected groups. For this example, the values are already correct for all groups, but you can edit the values directly in the Hole Groups table, if needed, before clicking Regroup Holes.

The software uses the name of the lowest numbered group, so our new group is named Group 1.1.

In the list, click Group 1.1 to show the preview and confirm the proper grouping.

Group 1.2 and Group 1.3 are regrouped next using the same process.

The exact same process is used to break Group 2 and then regroup the holes that are on the same side of the part.

Group 2

Breaking Group 2 results in the following groups.

Group 2.1	Group 2.2

Group 2.3	Group 2.4

Group 2.1 and Group 2.4 are regrouped to create a new Group 2.1.

Group 2.2 and Group 2.3 are regrouped to create a new Group 2.2.

Finally, we compute the toolpath to update the changes made to the hole groups.

(The hole groups in the second feature are regrouped to match what we did in the first feature.)

The second image shows that the toolpath now properly retracts between each hole group and clears the steps of the model resulting in a more efficient toolpath.

This concludes the example.